luna - sqlite/sqlite3.h

    1/*
    2** 2001-09-15
    3**
    4** The author disclaims copyright to this source code.  In place of
    5** a legal notice, here is a blessing:
    6**
    7**    May you do good and not evil.
    8**    May you find forgiveness for yourself and forgive others.
    9**    May you share freely, never taking more than you give.
   10**
   11*************************************************************************
   12** This header file defines the interface that the SQLite library
   13** presents to client programs.  If a C-function, structure, datatype,
   14** or constant definition does not appear in this file, then it is
   15** not a published API of SQLite, is subject to change without
   16** notice, and should not be referenced by programs that use SQLite.
   17**
   18** Some of the definitions that are in this file are marked as
   19** "experimental".  Experimental interfaces are normally new
   20** features recently added to SQLite.  We do not anticipate changes
   21** to experimental interfaces but reserve the right to make minor changes
   22** if experience from use "in the wild" suggest such changes are prudent.
   23**
   24** The official C-language API documentation for SQLite is derived
   25** from comments in this file.  This file is the authoritative source
   26** on how SQLite interfaces are supposed to operate.
   27**
   28** The name of this file under configuration management is "sqlite.h.in".
   29** The makefile makes some minor changes to this file (such as inserting
   30** the version number) and changes its name to "sqlite3.h" as
   31** part of the build process.
   32*/
   33#ifndef SQLITE3_H
   34#define SQLITE3_H
   35#include <stdarg.h>     /* Needed for the definition of va_list */
   36
   37/*
   38** Make sure we can call this stuff from C++.
   39*/
   40#ifdef __cplusplus
   41extern "C" {
   42#endif
   43
   44
   45/*
   46** Facilitate override of interface linkage and calling conventions.
   47** Be aware that these macros may not be used within this particular
   48** translation of the amalgamation and its associated header file.
   49**
   50** The SQLITE_EXTERN and SQLITE_API macros are used to instruct the
   51** compiler that the target identifier should have external linkage.
   52**
   53** The SQLITE_CDECL macro is used to set the calling convention for
   54** public functions that accept a variable number of arguments.
   55**
   56** The SQLITE_APICALL macro is used to set the calling convention for
   57** public functions that accept a fixed number of arguments.
   58**
   59** The SQLITE_STDCALL macro is no longer used and is now deprecated.
   60**
   61** The SQLITE_CALLBACK macro is used to set the calling convention for
   62** function pointers.
   63**
   64** The SQLITE_SYSAPI macro is used to set the calling convention for
   65** functions provided by the operating system.
   66**
   67** Currently, the SQLITE_CDECL, SQLITE_APICALL, SQLITE_CALLBACK, and
   68** SQLITE_SYSAPI macros are used only when building for environments
   69** that require non-default calling conventions.
   70*/
   71#ifndef SQLITE_EXTERN
   72# define SQLITE_EXTERN extern
   73#endif
   74#ifndef SQLITE_API
   75# define SQLITE_API
   76#endif
   77#ifndef SQLITE_CDECL
   78# define SQLITE_CDECL
   79#endif
   80#ifndef SQLITE_APICALL
   81# define SQLITE_APICALL
   82#endif
   83#ifndef SQLITE_STDCALL
   84# define SQLITE_STDCALL SQLITE_APICALL
   85#endif
   86#ifndef SQLITE_CALLBACK
   87# define SQLITE_CALLBACK
   88#endif
   89#ifndef SQLITE_SYSAPI
   90# define SQLITE_SYSAPI
   91#endif
   92
   93/*
   94** These no-op macros are used in front of interfaces to mark those
   95** interfaces as either deprecated or experimental.  New applications
   96** should not use deprecated interfaces - they are supported for backwards
   97** compatibility only.  Application writers should be aware that
   98** experimental interfaces are subject to change in point releases.
   99**
  100** These macros used to resolve to various kinds of compiler magic that
  101** would generate warning messages when they were used.  But that
  102** compiler magic ended up generating such a flurry of bug reports
  103** that we have taken it all out and gone back to using simple
  104** noop macros.
  105*/
  106#define SQLITE_DEPRECATED
  107#define SQLITE_EXPERIMENTAL
  108
  109/*
  110** Ensure these symbols were not defined by some previous header file.
  111*/
  112#ifdef SQLITE_VERSION
  113# undef SQLITE_VERSION
  114#endif
  115#ifdef SQLITE_VERSION_NUMBER
  116# undef SQLITE_VERSION_NUMBER
  117#endif
  118
  119/*
  120** CAPI3REF: Compile-Time Library Version Numbers
  121**
  122** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
  123** evaluates to a string literal that is the SQLite version in the
  124** format "X.Y.Z" where X is the major version number (always 3 for
  125** SQLite3) and Y is the minor version number and Z is the release number.)^
  126** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
  127** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
  128** numbers used in [SQLITE_VERSION].)^
  129** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
  130** be larger than the release from which it is derived.  Either Y will
  131** be held constant and Z will be incremented or else Y will be incremented
  132** and Z will be reset to zero.
  133**
  134** Since [version 3.6.18] ([dateof:3.6.18]),
  135** SQLite source code has been stored in the
  136** <a href="http://fossil-scm.org/">Fossil configuration management
  137** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
  138** a string which identifies a particular check-in of SQLite
  139** within its configuration management system.  ^The SQLITE_SOURCE_ID
  140** string contains the date and time of the check-in (UTC) and a SHA1
  141** or SHA3-256 hash of the entire source tree.  If the source code has
  142** been edited in any way since it was last checked in, then the last
  143** four hexadecimal digits of the hash may be modified.
  144**
  145** See also: [sqlite3_libversion()],
  146** [sqlite3_libversion_number()], [sqlite3_sourceid()],
  147** [sqlite_version()] and [sqlite_source_id()].
  148*/
  149#define SQLITE_VERSION        "3.53.1"
  150#define SQLITE_VERSION_NUMBER 3053001
  151#define SQLITE_SOURCE_ID      "2026-05-05 10:34:17 c88b22011a54b4f6fbd149e9f8e4de77658ce58143a1af0e3785e4e6475127e9"
  152#define SQLITE_SCM_BRANCH     "branch-3.53"
  153#define SQLITE_SCM_TAGS       "release version-3.53.1"
  154#define SQLITE_SCM_DATETIME   "2026-05-05T10:34:17.344Z"
  155
  156/*
  157** CAPI3REF: Run-Time Library Version Numbers
  158** KEYWORDS: sqlite3_version sqlite3_sourceid
  159**
  160** These interfaces provide the same information as the [SQLITE_VERSION],
  161** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
  162** but are associated with the library instead of the header file.  ^(Cautious
  163** programmers might include assert() statements in their application to
  164** verify that values returned by these interfaces match the macros in
  165** the header, and thus ensure that the application is
  166** compiled with matching library and header files.
  167**
  168** <blockquote><pre>
  169** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
  170** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 );
  171** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
  172** </pre></blockquote>)^
  173**
  174** ^The sqlite3_version[] string constant contains the text of the
  175** [SQLITE_VERSION] macro.  ^The sqlite3_libversion() function returns a
  176** pointer to the sqlite3_version[] string constant.  The sqlite3_libversion()
  177** function is provided for use in DLLs since DLL users usually do not have
  178** direct access to string constants within the DLL.  ^The
  179** sqlite3_libversion_number() function returns an integer equal to
  180** [SQLITE_VERSION_NUMBER].  ^(The sqlite3_sourceid() function returns
  181** a pointer to a string constant whose value is the same as the
  182** [SQLITE_SOURCE_ID] C preprocessor macro.  Except if SQLite is built
  183** using an edited copy of [the amalgamation], then the last four characters
  184** of the hash might be different from [SQLITE_SOURCE_ID].)^
  185**
  186** See also: [sqlite_version()] and [sqlite_source_id()].
  187*/
  188SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
  189SQLITE_API const char *sqlite3_libversion(void);
  190SQLITE_API const char *sqlite3_sourceid(void);
  191SQLITE_API int sqlite3_libversion_number(void);
  192
  193/*
  194** CAPI3REF: Run-Time Library Compilation Options Diagnostics
  195**
  196** ^The sqlite3_compileoption_used() function returns 0 or 1
  197** indicating whether the specified option was defined at
  198** compile time.  ^The SQLITE_ prefix may be omitted from the
  199** option name passed to sqlite3_compileoption_used().
  200**
  201** ^The sqlite3_compileoption_get() function allows iterating
  202** over the list of options that were defined at compile time by
  203** returning the N-th compile time option string.  ^If N is out of range,
  204** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_
  205** prefix is omitted from any strings returned by
  206** sqlite3_compileoption_get().
  207**
  208** ^Support for the diagnostic functions sqlite3_compileoption_used()
  209** and sqlite3_compileoption_get() may be omitted by specifying the
  210** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
  211**
  212** See also: SQL functions [sqlite_compileoption_used()] and
  213** [sqlite_compileoption_get()] and the [compile_options pragma].
  214*/
  215#ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
  216SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
  217SQLITE_API const char *sqlite3_compileoption_get(int N);
  218#else
  219# define sqlite3_compileoption_used(X) 0
  220# define sqlite3_compileoption_get(X)  ((void*)0)
  221#endif
  222
  223/*
  224** CAPI3REF: Test To See If The Library Is Threadsafe
  225**
  226** ^The sqlite3_threadsafe() function returns zero if and only if
  227** SQLite was compiled with mutexing code omitted due to the
  228** [SQLITE_THREADSAFE] compile-time option being set to 0.
  229**
  230** SQLite can be compiled with or without mutexes.  When
  231** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
  232** are enabled and SQLite is threadsafe.  When the
  233** [SQLITE_THREADSAFE] macro is 0,
  234** the mutexes are omitted.  Without the mutexes, it is not safe
  235** to use SQLite concurrently from more than one thread.
  236**
  237** Enabling mutexes incurs a measurable performance penalty.
  238** So if speed is of utmost importance, it makes sense to disable
  239** the mutexes.  But for maximum safety, mutexes should be enabled.
  240** ^The default behavior is for mutexes to be enabled.
  241**
  242** This interface can be used by an application to make sure that the
  243** version of SQLite that it is linking against was compiled with
  244** the desired setting of the [SQLITE_THREADSAFE] macro.
  245**
  246** This interface only reports on the compile-time mutex setting
  247** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
  248** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
  249** can be fully or partially disabled using a call to [sqlite3_config()]
  250** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
  251** or [SQLITE_CONFIG_SERIALIZED].  ^(The return value of the
  252** sqlite3_threadsafe() function shows only the compile-time setting of
  253** thread safety, not any run-time changes to that setting made by
  254** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
  255** is unchanged by calls to sqlite3_config().)^
  256**
  257** See the [threading mode] documentation for additional information.
  258*/
  259SQLITE_API int sqlite3_threadsafe(void);
  260
  261/*
  262** CAPI3REF: Database Connection Handle
  263** KEYWORDS: {database connection} {database connections}
  264**
  265** Each open SQLite database is represented by a pointer to an instance of
  266** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
  267** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
  268** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
  269** and [sqlite3_close_v2()] are its destructors.  There are many other
  270** interfaces (such as
  271** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
  272** [sqlite3_busy_timeout()] to name but three) that are methods on an
  273** sqlite3 object.
  274*/
  275typedef struct sqlite3 sqlite3;
  276
  277/*
  278** CAPI3REF: 64-Bit Integer Types
  279** KEYWORDS: sqlite_int64 sqlite_uint64
  280**
  281** Because there is no cross-platform way to specify 64-bit integer types
  282** SQLite includes typedefs for 64-bit signed and unsigned integers.
  283**
  284** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
  285** The sqlite_int64 and sqlite_uint64 types are supported for backwards
  286** compatibility only.
  287**
  288** ^The sqlite3_int64 and sqlite_int64 types can store integer values
  289** between -9223372036854775808 and +9223372036854775807 inclusive.  ^The
  290** sqlite3_uint64 and sqlite_uint64 types can store integer values
  291** between 0 and +18446744073709551615 inclusive.
  292*/
  293#ifdef SQLITE_INT64_TYPE
  294  typedef SQLITE_INT64_TYPE sqlite_int64;
  295# ifdef SQLITE_UINT64_TYPE
  296    typedef SQLITE_UINT64_TYPE sqlite_uint64;
  297# else
  298    typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
  299# endif
  300#elif defined(_MSC_VER) || defined(__BORLANDC__)
  301  typedef __int64 sqlite_int64;
  302  typedef unsigned __int64 sqlite_uint64;
  303#else
  304  typedef long long int sqlite_int64;
  305  typedef unsigned long long int sqlite_uint64;
  306#endif
  307typedef sqlite_int64 sqlite3_int64;
  308typedef sqlite_uint64 sqlite3_uint64;
  309
  310/*
  311** If compiling for a processor that lacks floating point support,
  312** substitute integer for floating-point.
  313*/
  314#ifdef SQLITE_OMIT_FLOATING_POINT
  315# define double sqlite3_int64
  316#endif
  317
  318/*
  319** CAPI3REF: Closing A Database Connection
  320** DESTRUCTOR: sqlite3
  321**
  322** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
  323** for the [sqlite3] object.
  324** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
  325** the [sqlite3] object is successfully destroyed and all associated
  326** resources are deallocated.
  327**
  328** Ideally, applications should [sqlite3_finalize | finalize] all
  329** [prepared statements], [sqlite3_blob_close | close] all [BLOB handles], and
  330** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
  331** with the [sqlite3] object prior to attempting to close the object.
  332** ^If the database connection is associated with unfinalized prepared
  333** statements, BLOB handlers, and/or unfinished sqlite3_backup objects then
  334** sqlite3_close() will leave the database connection open and return
  335** [SQLITE_BUSY]. ^If sqlite3_close_v2() is called with unfinalized prepared
  336** statements, unclosed BLOB handlers, and/or unfinished sqlite3_backups,
  337** it returns [SQLITE_OK] regardless, but instead of deallocating the database
  338** connection immediately, it marks the database connection as an unusable
  339** "zombie" and makes arrangements to automatically deallocate the database
  340** connection after all prepared statements are finalized, all BLOB handles
  341** are closed, and all backups have finished. The sqlite3_close_v2() interface
  342** is intended for use with host languages that are garbage collected, and
  343** where the order in which destructors are called is arbitrary.
  344**
  345** ^If an [sqlite3] object is destroyed while a transaction is open,
  346** the transaction is automatically rolled back.
  347**
  348** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
  349** must be either a NULL
  350** pointer or an [sqlite3] object pointer obtained
  351** from [sqlite3_open()], [sqlite3_open16()], or
  352** [sqlite3_open_v2()], and not previously closed.
  353** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
  354** argument is a harmless no-op.
  355*/
  356SQLITE_API int sqlite3_close(sqlite3*);
  357SQLITE_API int sqlite3_close_v2(sqlite3*);
  358
  359/*
  360** The type for a callback function.
  361** This is legacy and deprecated.  It is included for historical
  362** compatibility and is not documented.
  363*/
  364typedef int (*sqlite3_callback)(void*,int,char**, char**);
  365
  366/*
  367** CAPI3REF: One-Step Query Execution Interface
  368** METHOD: sqlite3
  369**
  370** The sqlite3_exec() interface is a convenience wrapper around
  371** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
  372** that allows an application to run multiple statements of SQL
  373** without having to use a lot of C code.
  374**
  375** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
  376** semicolon-separated SQL statements passed into its 2nd argument,
  377** in the context of the [database connection] passed in as its 1st
  378** argument.  ^If the callback function of the 3rd argument to
  379** sqlite3_exec() is not NULL, then it is invoked for each result row
  380** coming out of the evaluated SQL statements.  ^The 4th argument to
  381** sqlite3_exec() is relayed through to the 1st argument of each
  382** callback invocation.  ^If the callback pointer to sqlite3_exec()
  383** is NULL, then no callback is ever invoked and result rows are
  384** ignored.
  385**
  386** ^If an error occurs while evaluating the SQL statements passed into
  387** sqlite3_exec(), then execution of the current statement stops and
  388** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
  389** is not NULL then any error message is written into memory obtained
  390** from [sqlite3_malloc()] and passed back through the 5th parameter.
  391** To avoid memory leaks, the application should invoke [sqlite3_free()]
  392** on error message strings returned through the 5th parameter of
  393** sqlite3_exec() after the error message string is no longer needed.
  394** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
  395** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
  396** NULL before returning.
  397**
  398** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
  399** routine returns SQLITE_ABORT without invoking the callback again and
  400** without running any subsequent SQL statements.
  401**
  402** ^The 2nd argument to the sqlite3_exec() callback function is the
  403** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
  404** callback is an array of pointers to strings obtained as if from
  405** [sqlite3_column_text()], one for each column.  ^If an element of a
  406** result row is NULL then the corresponding string pointer for the
  407** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
  408** sqlite3_exec() callback is an array of pointers to strings where each
  409** entry represents the name of a corresponding result column as obtained
  410** from [sqlite3_column_name()].
  411**
  412** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
  413** to an empty string, or a pointer that contains only whitespace and/or
  414** SQL comments, then no SQL statements are evaluated and the database
  415** is not changed.
  416**
  417** Restrictions:
  418**
  419** <ul>
  420** <li> The application must ensure that the 1st parameter to sqlite3_exec()
  421**      is a valid and open [database connection].
  422** <li> The application must not close the [database connection] specified by
  423**      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
  424** <li> The application must not modify the SQL statement text passed into
  425**      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
  426** <li> The application must not dereference the arrays or string pointers
  427**       passed as the 3rd and 4th callback parameters after it returns.
  428** </ul>
  429*/
  430SQLITE_API int sqlite3_exec(
  431  sqlite3*,                                  /* An open database */
  432  const char *sql,                           /* SQL to be evaluated */
  433  int (*callback)(void*,int,char**,char**),  /* Callback function */
  434  void *,                                    /* 1st argument to callback */
  435  char **errmsg                              /* Error msg written here */
  436);
  437
  438/*
  439** CAPI3REF: Result Codes
  440** KEYWORDS: {result code definitions}
  441**
  442** Many SQLite functions return an integer result code from the set shown
  443** here in order to indicate success or failure.
  444**
  445** New error codes may be added in future versions of SQLite.
  446**
  447** See also: [extended result code definitions]
  448*/
  449#define SQLITE_OK           0   /* Successful result */
  450/* beginning-of-error-codes */
  451#define SQLITE_ERROR        1   /* Generic error */
  452#define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
  453#define SQLITE_PERM         3   /* Access permission denied */
  454#define SQLITE_ABORT        4   /* Callback routine requested an abort */
  455#define SQLITE_BUSY         5   /* The database file is locked */
  456#define SQLITE_LOCKED       6   /* A table in the database is locked */
  457#define SQLITE_NOMEM        7   /* A malloc() failed */
  458#define SQLITE_READONLY     8   /* Attempt to write a readonly database */
  459#define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
  460#define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
  461#define SQLITE_CORRUPT     11   /* The database disk image is malformed */
  462#define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
  463#define SQLITE_FULL        13   /* Insertion failed because database is full */
  464#define SQLITE_CANTOPEN    14   /* Unable to open the database file */
  465#define SQLITE_PROTOCOL    15   /* Database lock protocol error */
  466#define SQLITE_EMPTY       16   /* Internal use only */
  467#define SQLITE_SCHEMA      17   /* The database schema changed */
  468#define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
  469#define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
  470#define SQLITE_MISMATCH    20   /* Data type mismatch */
  471#define SQLITE_MISUSE      21   /* Library used incorrectly */
  472#define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
  473#define SQLITE_AUTH        23   /* Authorization denied */
  474#define SQLITE_FORMAT      24   /* Not used */
  475#define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
  476#define SQLITE_NOTADB      26   /* File opened that is not a database file */
  477#define SQLITE_NOTICE      27   /* Notifications from sqlite3_log() */
  478#define SQLITE_WARNING     28   /* Warnings from sqlite3_log() */
  479#define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
  480#define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
  481/* end-of-error-codes */
  482
  483/*
  484** CAPI3REF: Extended Result Codes
  485** KEYWORDS: {extended result code definitions}
  486**
  487** In its default configuration, SQLite API routines return one of 30 integer
  488** [result codes].  However, experience has shown that many of
  489** these result codes are too coarse-grained.  They do not provide as
  490** much information about problems as programmers might like.  In an effort to
  491** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8]
  492** and later) include
  493** support for additional result codes that provide more detailed information
  494** about errors. These [extended result codes] are enabled or disabled
  495** on a per database connection basis using the
  496** [sqlite3_extended_result_codes()] API.  Or, the extended code for
  497** the most recent error can be obtained using
  498** [sqlite3_extended_errcode()].
  499*/
  500#define SQLITE_ERROR_MISSING_COLLSEQ   (SQLITE_ERROR | (1<<8))
  501#define SQLITE_ERROR_RETRY             (SQLITE_ERROR | (2<<8))
  502#define SQLITE_ERROR_SNAPSHOT          (SQLITE_ERROR | (3<<8))
  503#define SQLITE_ERROR_RESERVESIZE       (SQLITE_ERROR | (4<<8))
  504#define SQLITE_ERROR_KEY               (SQLITE_ERROR | (5<<8))
  505#define SQLITE_ERROR_UNABLE            (SQLITE_ERROR | (6<<8))
  506#define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
  507#define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
  508#define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
  509#define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
  510#define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
  511#define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
  512#define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
  513#define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
  514#define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
  515#define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
  516#define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
  517#define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
  518#define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
  519#define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
  520#define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
  521#define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
  522#define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
  523#define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
  524#define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
  525#define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
  526#define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
  527#define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
  528#define SQLITE_IOERR_DELETE_NOENT      (SQLITE_IOERR | (23<<8))
  529#define SQLITE_IOERR_MMAP              (SQLITE_IOERR | (24<<8))
  530#define SQLITE_IOERR_GETTEMPPATH       (SQLITE_IOERR | (25<<8))
  531#define SQLITE_IOERR_CONVPATH          (SQLITE_IOERR | (26<<8))
  532#define SQLITE_IOERR_VNODE             (SQLITE_IOERR | (27<<8))
  533#define SQLITE_IOERR_AUTH              (SQLITE_IOERR | (28<<8))
  534#define SQLITE_IOERR_BEGIN_ATOMIC      (SQLITE_IOERR | (29<<8))
  535#define SQLITE_IOERR_COMMIT_ATOMIC     (SQLITE_IOERR | (30<<8))
  536#define SQLITE_IOERR_ROLLBACK_ATOMIC   (SQLITE_IOERR | (31<<8))
  537#define SQLITE_IOERR_DATA              (SQLITE_IOERR | (32<<8))
  538#define SQLITE_IOERR_CORRUPTFS         (SQLITE_IOERR | (33<<8))
  539#define SQLITE_IOERR_IN_PAGE           (SQLITE_IOERR | (34<<8))
  540#define SQLITE_IOERR_BADKEY            (SQLITE_IOERR | (35<<8))
  541#define SQLITE_IOERR_CODEC             (SQLITE_IOERR | (36<<8))
  542#define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
  543#define SQLITE_LOCKED_VTAB             (SQLITE_LOCKED |  (2<<8))
  544#define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
  545#define SQLITE_BUSY_SNAPSHOT           (SQLITE_BUSY   |  (2<<8))
  546#define SQLITE_BUSY_TIMEOUT            (SQLITE_BUSY   |  (3<<8))
  547#define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
  548#define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))
  549#define SQLITE_CANTOPEN_FULLPATH       (SQLITE_CANTOPEN | (3<<8))
  550#define SQLITE_CANTOPEN_CONVPATH       (SQLITE_CANTOPEN | (4<<8))
  551#define SQLITE_CANTOPEN_DIRTYWAL       (SQLITE_CANTOPEN | (5<<8)) /* Not Used */
  552#define SQLITE_CANTOPEN_SYMLINK        (SQLITE_CANTOPEN | (6<<8))
  553#define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
  554#define SQLITE_CORRUPT_SEQUENCE        (SQLITE_CORRUPT | (2<<8))
  555#define SQLITE_CORRUPT_INDEX           (SQLITE_CORRUPT | (3<<8))
  556#define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
  557#define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))
  558#define SQLITE_READONLY_ROLLBACK       (SQLITE_READONLY | (3<<8))
  559#define SQLITE_READONLY_DBMOVED        (SQLITE_READONLY | (4<<8))
  560#define SQLITE_READONLY_CANTINIT       (SQLITE_READONLY | (5<<8))
  561#define SQLITE_READONLY_DIRECTORY      (SQLITE_READONLY | (6<<8))
  562#define SQLITE_ABORT_ROLLBACK          (SQLITE_ABORT | (2<<8))
  563#define SQLITE_CONSTRAINT_CHECK        (SQLITE_CONSTRAINT | (1<<8))
  564#define SQLITE_CONSTRAINT_COMMITHOOK   (SQLITE_CONSTRAINT | (2<<8))
  565#define SQLITE_CONSTRAINT_FOREIGNKEY   (SQLITE_CONSTRAINT | (3<<8))
  566#define SQLITE_CONSTRAINT_FUNCTION     (SQLITE_CONSTRAINT | (4<<8))
  567#define SQLITE_CONSTRAINT_NOTNULL      (SQLITE_CONSTRAINT | (5<<8))
  568#define SQLITE_CONSTRAINT_PRIMARYKEY   (SQLITE_CONSTRAINT | (6<<8))
  569#define SQLITE_CONSTRAINT_TRIGGER      (SQLITE_CONSTRAINT | (7<<8))
  570#define SQLITE_CONSTRAINT_UNIQUE       (SQLITE_CONSTRAINT | (8<<8))
  571#define SQLITE_CONSTRAINT_VTAB         (SQLITE_CONSTRAINT | (9<<8))
  572#define SQLITE_CONSTRAINT_ROWID        (SQLITE_CONSTRAINT |(10<<8))
  573#define SQLITE_CONSTRAINT_PINNED       (SQLITE_CONSTRAINT |(11<<8))
  574#define SQLITE_CONSTRAINT_DATATYPE     (SQLITE_CONSTRAINT |(12<<8))
  575#define SQLITE_NOTICE_RECOVER_WAL      (SQLITE_NOTICE | (1<<8))
  576#define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
  577#define SQLITE_NOTICE_RBU              (SQLITE_NOTICE | (3<<8))
  578#define SQLITE_WARNING_AUTOINDEX       (SQLITE_WARNING | (1<<8))
  579#define SQLITE_AUTH_USER               (SQLITE_AUTH | (1<<8))
  580#define SQLITE_OK_LOAD_PERMANENTLY     (SQLITE_OK | (1<<8))
  581#define SQLITE_OK_SYMLINK              (SQLITE_OK | (2<<8)) /* internal only */
  582
  583/*
  584** CAPI3REF: Flags For File Open Operations
  585**
  586** These bit values are intended for use in the
  587** 3rd parameter to the [sqlite3_open_v2()] interface and
  588** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
  589**
  590** Only those flags marked as "Ok for sqlite3_open_v2()" may be
  591** used as the third argument to the [sqlite3_open_v2()] interface.
  592** The other flags have historically been ignored by sqlite3_open_v2(),
  593** though future versions of SQLite might change so that an error is
  594** raised if any of the disallowed bits are passed into sqlite3_open_v2().
  595** Applications should not depend on the historical behavior.
  596**
  597** Note in particular that passing the SQLITE_OPEN_EXCLUSIVE flag into
  598** [sqlite3_open_v2()] does *not* cause the underlying database file
  599** to be opened using O_EXCL.  Passing SQLITE_OPEN_EXCLUSIVE into
  600** [sqlite3_open_v2()] has historically been a no-op and might become an
  601** error in future versions of SQLite.
  602*/
  603#define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
  604#define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
  605#define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
  606#define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
  607#define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
  608#define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
  609#define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
  610#define SQLITE_OPEN_MEMORY           0x00000080  /* Ok for sqlite3_open_v2() */
  611#define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
  612#define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
  613#define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
  614#define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
  615#define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
  616#define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
  617#define SQLITE_OPEN_SUPER_JOURNAL    0x00004000  /* VFS only */
  618#define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
  619#define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
  620#define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
  621#define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
  622#define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
  623#define SQLITE_OPEN_NOFOLLOW         0x01000000  /* Ok for sqlite3_open_v2() */
  624#define SQLITE_OPEN_EXRESCODE        0x02000000  /* Extended result codes */
  625
  626/* Reserved:                         0x00F00000 */
  627/* Legacy compatibility: */
  628#define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
  629
  630
  631/*
  632** CAPI3REF: Device Characteristics
  633**
  634** The xDeviceCharacteristics method of the [sqlite3_io_methods]
  635** object returns an integer which is a vector of these
  636** bit values expressing I/O characteristics of the mass storage
  637** device that holds the file that the [sqlite3_io_methods]
  638** refers to.
  639**
  640** The SQLITE_IOCAP_ATOMIC property means that all writes of
  641** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
  642** mean that writes of blocks that are nnn bytes in size and
  643** are aligned to an address which is an integer multiple of
  644** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
  645** that when data is appended to a file, the data is appended
  646** first then the size of the file is extended, never the other
  647** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
  648** information is written to disk in the same order as calls
  649** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
  650** after reboot following a crash or power loss, the only bytes in a
  651** file that were written at the application level might have changed
  652** and that adjacent bytes, even bytes within the same sector are
  653** guaranteed to be unchanged.  The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
  654** flag indicates that a file cannot be deleted when open.  The
  655** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
  656** read-only media and cannot be changed even by processes with
  657** elevated privileges.
  658**
  659** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
  660** filesystem supports doing multiple write operations atomically when those
  661** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and
  662** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].
  663**
  664** The SQLITE_IOCAP_SUBPAGE_READ property means that it is ok to read
  665** from the database file in amounts that are not a multiple of the
  666** page size and that do not begin at a page boundary.  Without this
  667** property, SQLite is careful to only do full-page reads and write
  668** on aligned pages, with the one exception that it will do a sub-page
  669** read of the first page to access the database header.
  670*/
  671#define SQLITE_IOCAP_ATOMIC                 0x00000001
  672#define SQLITE_IOCAP_ATOMIC512              0x00000002
  673#define SQLITE_IOCAP_ATOMIC1K               0x00000004
  674#define SQLITE_IOCAP_ATOMIC2K               0x00000008
  675#define SQLITE_IOCAP_ATOMIC4K               0x00000010
  676#define SQLITE_IOCAP_ATOMIC8K               0x00000020
  677#define SQLITE_IOCAP_ATOMIC16K              0x00000040
  678#define SQLITE_IOCAP_ATOMIC32K              0x00000080
  679#define SQLITE_IOCAP_ATOMIC64K              0x00000100
  680#define SQLITE_IOCAP_SAFE_APPEND            0x00000200
  681#define SQLITE_IOCAP_SEQUENTIAL             0x00000400
  682#define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
  683#define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000
  684#define SQLITE_IOCAP_IMMUTABLE              0x00002000
  685#define SQLITE_IOCAP_BATCH_ATOMIC           0x00004000
  686#define SQLITE_IOCAP_SUBPAGE_READ           0x00008000
  687
  688/*
  689** CAPI3REF: File Locking Levels
  690**
  691** SQLite uses one of these integer values as the second
  692** argument to calls it makes to the xLock() and xUnlock() methods
  693** of an [sqlite3_io_methods] object.  These values are ordered from
  694** least restrictive to most restrictive.
  695**
  696** The argument to xLock() is always SHARED or higher.  The argument to
  697** xUnlock is either SHARED or NONE.
  698*/
  699#define SQLITE_LOCK_NONE          0       /* xUnlock() only */
  700#define SQLITE_LOCK_SHARED        1       /* xLock() or xUnlock() */
  701#define SQLITE_LOCK_RESERVED      2       /* xLock() only */
  702#define SQLITE_LOCK_PENDING       3       /* xLock() only */
  703#define SQLITE_LOCK_EXCLUSIVE     4       /* xLock() only */
  704
  705/*
  706** CAPI3REF: Synchronization Type Flags
  707**
  708** When SQLite invokes the xSync() method of an
  709** [sqlite3_io_methods] object it uses a combination of
  710** these integer values as the second argument.
  711**
  712** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
  713** sync operation only needs to flush data to mass storage.  Inode
  714** information need not be flushed. If the lower four bits of the flag
  715** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
  716** If the lower four bits equal SQLITE_SYNC_FULL, that means
  717** to use Mac OS X style fullsync instead of fsync().
  718**
  719** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
  720** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
  721** settings.  The [synchronous pragma] determines when calls to the
  722** xSync VFS method occur and applies uniformly across all platforms.
  723** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
  724** energetic or rigorous or forceful the sync operations are and
  725** only make a difference on Mac OSX for the default SQLite code.
  726** (Third-party VFS implementations might also make the distinction
  727** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
  728** operating systems natively supported by SQLite, only Mac OSX
  729** cares about the difference.)
  730*/
  731#define SQLITE_SYNC_NORMAL        0x00002
  732#define SQLITE_SYNC_FULL          0x00003
  733#define SQLITE_SYNC_DATAONLY      0x00010
  734
  735/*
  736** CAPI3REF: OS Interface Open File Handle
  737**
  738** An [sqlite3_file] object represents an open file in the
  739** [sqlite3_vfs | OS interface layer].  Individual OS interface
  740** implementations will
  741** want to subclass this object by appending additional fields
  742** for their own use.  The pMethods entry is a pointer to an
  743** [sqlite3_io_methods] object that defines methods for performing
  744** I/O operations on the open file.
  745*/
  746typedef struct sqlite3_file sqlite3_file;
  747struct sqlite3_file {
  748  const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
  749};
  750
  751/*
  752** CAPI3REF: OS Interface File Virtual Methods Object
  753**
  754** Every file opened by the [sqlite3_vfs.xOpen] method populates an
  755** [sqlite3_file] object (or, more commonly, a subclass of the
  756** [sqlite3_file] object) with a pointer to an instance of this object.
  757** This object defines the methods used to perform various operations
  758** against the open file represented by the [sqlite3_file] object.
  759**
  760** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element
  761** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
  762** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
  763** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
  764** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
  765** to NULL.
  766**
  767** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
  768** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
  769** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
  770** flag may be ORed in to indicate that only the data of the file
  771** and not its inode needs to be synced.
  772**
  773** The integer values to xLock() and xUnlock() are one of
  774** <ul>
  775** <li> [SQLITE_LOCK_NONE],
  776** <li> [SQLITE_LOCK_SHARED],
  777** <li> [SQLITE_LOCK_RESERVED],
  778** <li> [SQLITE_LOCK_PENDING], or
  779** <li> [SQLITE_LOCK_EXCLUSIVE].
  780** </ul>
  781** xLock() upgrades the database file lock.  In other words, xLock() moves the
  782** database file lock in the direction NONE toward EXCLUSIVE. The argument to
  783** xLock() is always one of SHARED, RESERVED, PENDING, or EXCLUSIVE, never
  784** SQLITE_LOCK_NONE.  If the database file lock is already at or above the
  785** requested lock, then the call to xLock() is a no-op.
  786** xUnlock() downgrades the database file lock to either SHARED or NONE.
  787** If the lock is already at or below the requested lock state, then the call
  788** to xUnlock() is a no-op.
  789** The xCheckReservedLock() method checks whether any database connection,
  790** either in this process or in some other process, is holding a RESERVED,
  791** PENDING, or EXCLUSIVE lock on the file.  It returns, via its output
  792** pointer parameter, true if such a lock exists and false otherwise.
  793**
  794** The xFileControl() method is a generic interface that allows custom
  795** VFS implementations to directly control an open file using the
  796** [sqlite3_file_control()] interface.  The second "op" argument is an
  797** integer opcode.  The third argument is a generic pointer intended to
  798** point to a structure that may contain arguments or space in which to
  799** write return values.  Potential uses for xFileControl() might be
  800** functions to enable blocking locks with timeouts, to change the
  801** locking strategy (for example to use dot-file locks), to inquire
  802** about the status of a lock, or to break stale locks.  The SQLite
  803** core reserves all opcodes less than 100 for its own use.
  804** A [file control opcodes | list of opcodes] less than 100 is available.
  805** Applications that define a custom xFileControl method should use opcodes
  806** greater than 100 to avoid conflicts.  VFS implementations should
  807** return [SQLITE_NOTFOUND] for file control opcodes that they do not
  808** recognize.
  809**
  810** The xSectorSize() method returns the sector size of the
  811** device that underlies the file.  The sector size is the
  812** minimum write that can be performed without disturbing
  813** other bytes in the file.  The xDeviceCharacteristics()
  814** method returns a bit vector describing behaviors of the
  815** underlying device:
  816**
  817** <ul>
  818** <li> [SQLITE_IOCAP_ATOMIC]
  819** <li> [SQLITE_IOCAP_ATOMIC512]
  820** <li> [SQLITE_IOCAP_ATOMIC1K]
  821** <li> [SQLITE_IOCAP_ATOMIC2K]
  822** <li> [SQLITE_IOCAP_ATOMIC4K]
  823** <li> [SQLITE_IOCAP_ATOMIC8K]
  824** <li> [SQLITE_IOCAP_ATOMIC16K]
  825** <li> [SQLITE_IOCAP_ATOMIC32K]
  826** <li> [SQLITE_IOCAP_ATOMIC64K]
  827** <li> [SQLITE_IOCAP_SAFE_APPEND]
  828** <li> [SQLITE_IOCAP_SEQUENTIAL]
  829** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN]
  830** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE]
  831** <li> [SQLITE_IOCAP_IMMUTABLE]
  832** <li> [SQLITE_IOCAP_BATCH_ATOMIC]
  833** <li> [SQLITE_IOCAP_SUBPAGE_READ]
  834** </ul>
  835**
  836** The SQLITE_IOCAP_ATOMIC property means that all writes of
  837** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
  838** mean that writes of blocks that are nnn bytes in size and
  839** are aligned to an address which is an integer multiple of
  840** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
  841** that when data is appended to a file, the data is appended
  842** first then the size of the file is extended, never the other
  843** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
  844** information is written to disk in the same order as calls
  845** to xWrite().
  846**
  847** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
  848** in the unread portions of the buffer with zeros.  A VFS that
  849** fails to zero-fill short reads might seem to work.  However,
  850** failure to zero-fill short reads will eventually lead to
  851** database corruption.
  852*/
  853typedef struct sqlite3_io_methods sqlite3_io_methods;
  854struct sqlite3_io_methods {
  855  int iVersion;
  856  int (*xClose)(sqlite3_file*);
  857  int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
  858  int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
  859  int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
  860  int (*xSync)(sqlite3_file*, int flags);
  861  int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
  862  int (*xLock)(sqlite3_file*, int);
  863  int (*xUnlock)(sqlite3_file*, int);
  864  int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
  865  int (*xFileControl)(sqlite3_file*, int op, void *pArg);
  866  int (*xSectorSize)(sqlite3_file*);
  867  int (*xDeviceCharacteristics)(sqlite3_file*);
  868  /* Methods above are valid for version 1 */
  869  int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
  870  int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
  871  void (*xShmBarrier)(sqlite3_file*);
  872  int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
  873  /* Methods above are valid for version 2 */
  874  int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
  875  int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
  876  /* Methods above are valid for version 3 */
  877  /* Additional methods may be added in future releases */
  878};
  879
  880/*
  881** CAPI3REF: Standard File Control Opcodes
  882** KEYWORDS: {file control opcodes} {file control opcode}
  883**
  884** These integer constants are opcodes for the xFileControl method
  885** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
  886** interface.
  887**
  888** <ul>
  889** <li>[[SQLITE_FCNTL_LOCKSTATE]]
  890** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
  891** opcode causes the xFileControl method to write the current state of
  892** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
  893** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
  894** into an integer that the pArg argument points to.
  895** This capability is only available if SQLite is compiled with [SQLITE_DEBUG].
  896**
  897** <li>[[SQLITE_FCNTL_SIZE_HINT]]
  898** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
  899** layer a hint of how large the database file will grow to be during the
  900** current transaction.  This hint is not guaranteed to be accurate but it
  901** is often close.  The underlying VFS might choose to preallocate database
  902** file space based on this hint in order to help writes to the database
  903** file run faster.
  904**
  905** <li>[[SQLITE_FCNTL_SIZE_LIMIT]]
  906** The [SQLITE_FCNTL_SIZE_LIMIT] opcode is used by in-memory VFS that
  907** implements [sqlite3_deserialize()] to set an upper bound on the size
  908** of the in-memory database.  The argument is a pointer to a [sqlite3_int64].
  909** If the integer pointed to is negative, then it is filled in with the
  910** current limit.  Otherwise the limit is set to the larger of the value
  911** of the integer pointed to and the current database size.  The integer
  912** pointed to is set to the new limit.
  913**
  914** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
  915** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
  916** extends and truncates the database file in chunks of a size specified
  917** by the user. The fourth argument to [sqlite3_file_control()] should
  918** point to an integer (type int) containing the new chunk-size to use
  919** for the nominated database. Allocating database file space in large
  920** chunks (say 1MB at a time), may reduce file-system fragmentation and
  921** improve performance on some systems.
  922**
  923** <li>[[SQLITE_FCNTL_FILE_POINTER]]
  924** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
  925** to the [sqlite3_file] object associated with a particular database
  926** connection.  See also [SQLITE_FCNTL_JOURNAL_POINTER].
  927**
  928** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]]
  929** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer
  930** to the [sqlite3_file] object associated with the journal file (either
  931** the [rollback journal] or the [write-ahead log]) for a particular database
  932** connection.  See also [SQLITE_FCNTL_FILE_POINTER].
  933**
  934** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
  935** The SQLITE_FCNTL_SYNC_OMITTED file-control is no longer used.
  936**
  937** <li>[[SQLITE_FCNTL_SYNC]]
  938** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
  939** sent to the VFS immediately before the xSync method is invoked on a
  940** database file descriptor. Or, if the xSync method is not invoked
  941** because the user has configured SQLite with
  942** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place
  943** of the xSync method. In most cases, the pointer argument passed with
  944** this file-control is NULL. However, if the database file is being synced
  945** as part of a multi-database commit, the argument points to a nul-terminated
  946** string containing the transactions super-journal file name. VFSes that
  947** do not need this signal should silently ignore this opcode. Applications
  948** should not call [sqlite3_file_control()] with this opcode as doing so may
  949** disrupt the operation of the specialized VFSes that do require it.
  950**
  951** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
  952** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
  953** and sent to the VFS after a transaction has been committed immediately
  954** but before the database is unlocked. VFSes that do not need this signal
  955** should silently ignore this opcode. Applications should not call
  956** [sqlite3_file_control()] with this opcode as doing so may disrupt the
  957** operation of the specialized VFSes that do require it.
  958**
  959** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
  960** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
  961** retry counts and intervals for certain disk I/O operations for the
  962** windows [VFS] in order to provide robustness in the presence of
  963** anti-virus programs.  By default, the windows VFS will retry file read,
  964** file write, and file delete operations up to 10 times, with a delay
  965** of 25 milliseconds before the first retry and with the delay increasing
  966** by an additional 25 milliseconds with each subsequent retry.  This
  967** opcode allows these two values (10 retries and 25 milliseconds of delay)
  968** to be adjusted.  The values are changed for all database connections
  969** within the same process.  The argument is a pointer to an array of two
  970** integers where the first integer is the new retry count and the second
  971** integer is the delay.  If either integer is negative, then the setting
  972** is not changed but instead the prior value of that setting is written
  973** into the array entry, allowing the current retry settings to be
  974** interrogated.  The zDbName parameter is ignored.
  975**
  976** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
  977** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
  978** persistent [WAL | Write Ahead Log] setting.  By default, the auxiliary
  979** write ahead log ([WAL file]) and shared memory
  980** files used for transaction control
  981** are automatically deleted when the latest connection to the database
  982** closes.  Setting persistent WAL mode causes those files to persist after
  983** close.  Persisting the files is useful when other processes that do not
  984** have write permission on the directory containing the database file want
  985** to read the database file, as the WAL and shared memory files must exist
  986** in order for the database to be readable.  The fourth parameter to
  987** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
  988** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
  989** WAL mode.  If the integer is -1, then it is overwritten with the current
  990** WAL persistence setting.
  991**
  992** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
  993** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
  994** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
  995** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
  996** xDeviceCharacteristics methods. The fourth parameter to
  997** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
  998** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
  999** mode.  If the integer is -1, then it is overwritten with the current
 1000** zero-damage mode setting.
 1001**
 1002** <li>[[SQLITE_FCNTL_OVERWRITE]]
 1003** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
 1004** a write transaction to indicate that, unless it is rolled back for some
 1005** reason, the entire database file will be overwritten by the current
 1006** transaction. This is used by VACUUM operations.
 1007**
 1008** <li>[[SQLITE_FCNTL_VFSNAME]]
 1009** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
 1010** all [VFSes] in the VFS stack.  The names of all VFS shims and the
 1011** final bottom-level VFS are written into memory obtained from
 1012** [sqlite3_malloc()] and the result is stored in the char* variable
 1013** that the fourth parameter of [sqlite3_file_control()] points to.
 1014** The caller is responsible for freeing the memory when done.  As with
 1015** all file-control actions, there is no guarantee that this will actually
 1016** do anything.  Callers should initialize the char* variable to a NULL
 1017** pointer in case this file-control is not implemented.  This file-control
 1018** is intended for diagnostic use only.
 1019**
 1020** <li>[[SQLITE_FCNTL_VFS_POINTER]]
 1021** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
 1022** [VFSes] currently in use.  ^(The argument X in
 1023** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
 1024** of type "[sqlite3_vfs] **".  This opcode will set *X
 1025** to a pointer to the top-level VFS.)^
 1026** ^When there are multiple VFS shims in the stack, this opcode finds the
 1027** upper-most shim only.
 1028**
 1029** <li>[[SQLITE_FCNTL_PRAGMA]]
 1030** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA]
 1031** file control is sent to the open [sqlite3_file] object corresponding
 1032** to the database file to which the pragma statement refers. ^The argument
 1033** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
 1034** pointers to strings (char**) in which the second element of the array
 1035** is the name of the pragma and the third element is the argument to the
 1036** pragma or NULL if the pragma has no argument.  ^The handler for an
 1037** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
 1038** of the char** argument point to a string obtained from [sqlite3_mprintf()]
 1039** or the equivalent and that string will become the result of the pragma or
 1040** the error message if the pragma fails. ^If the
 1041** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal
 1042** [PRAGMA] processing continues.  ^If the [SQLITE_FCNTL_PRAGMA]
 1043** file control returns [SQLITE_OK], then the parser assumes that the
 1044** VFS has handled the PRAGMA itself and the parser generates a no-op
 1045** prepared statement if result string is NULL, or that returns a copy
 1046** of the result string if the string is non-NULL.
 1047** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
 1048** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
 1049** that the VFS encountered an error while handling the [PRAGMA] and the
 1050** compilation of the PRAGMA fails with an error.  ^The [SQLITE_FCNTL_PRAGMA]
 1051** file control occurs at the beginning of pragma statement analysis and so
 1052** it is able to override built-in [PRAGMA] statements.
 1053**
 1054** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
 1055** ^The [SQLITE_FCNTL_BUSYHANDLER]
 1056** file-control may be invoked by SQLite on the database file handle
 1057** shortly after it is opened in order to provide a custom VFS with access
 1058** to the connection's busy-handler callback. The argument is of type (void**)
 1059** - an array of two (void *) values. The first (void *) actually points
 1060** to a function of type (int (*)(void *)). In order to invoke the connection's
 1061** busy-handler, this function should be invoked with the second (void *) in
 1062** the array as the only argument. If it returns non-zero, then the operation
 1063** should be retried. If it returns zero, the custom VFS should abandon the
 1064** current operation.
 1065**
 1066** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
 1067** ^Applications can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
 1068** to have SQLite generate a
 1069** temporary filename using the same algorithm that is followed to generate
 1070** temporary filenames for TEMP tables and other internal uses.  The
 1071** argument should be a char** which will be filled with the filename
 1072** written into memory obtained from [sqlite3_malloc()].  The caller should
 1073** invoke [sqlite3_free()] on the result to avoid a memory leak.
 1074**
 1075** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
 1076** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
 1077** maximum number of bytes that will be used for memory-mapped I/O.
 1078** The argument is a pointer to a value of type sqlite3_int64 that
 1079** is an advisory maximum number of bytes in the file to memory map.  The
 1080** pointer is overwritten with the old value.  The limit is not changed if
 1081** the value originally pointed to is negative, and so the current limit
 1082** can be queried by passing in a pointer to a negative number.  This
 1083** file-control is used internally to implement [PRAGMA mmap_size].
 1084**
 1085** <li>[[SQLITE_FCNTL_TRACE]]
 1086** The [SQLITE_FCNTL_TRACE] file control provides advisory information
 1087** to the VFS about what the higher layers of the SQLite stack are doing.
 1088** This file control is used by some VFS activity tracing [shims].
 1089** The argument is a zero-terminated string.  Higher layers in the
 1090** SQLite stack may generate instances of this file control if
 1091** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
 1092**
 1093** <li>[[SQLITE_FCNTL_HAS_MOVED]]
 1094** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
 1095** pointer to an integer and it writes a boolean into that integer depending
 1096** on whether or not the file has been renamed, moved, or deleted since it
 1097** was first opened.
 1098**
 1099** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]]
 1100** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the
 1101** underlying native file handle associated with a file handle.  This file
 1102** control interprets its argument as a pointer to a native file handle and
 1103** writes the resulting value there.
 1104**
 1105** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
 1106** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging.  This
 1107** opcode causes the xFileControl method to swap the file handle with the one
 1108** pointed to by the pArg argument.  This capability is used during testing
 1109** and only needs to be supported when SQLITE_TEST is defined.
 1110**
 1111** <li>[[SQLITE_FCNTL_NULL_IO]]
 1112** The [SQLITE_FCNTL_NULL_IO] opcode sets the low-level file descriptor
 1113** or file handle for the [sqlite3_file] object such that it will no longer
 1114** read or write to the database file.
 1115**
 1116** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
 1117** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
 1118** be advantageous to block on the next WAL lock if the lock is not immediately
 1119** available.  The WAL subsystem issues this signal during rare
 1120** circumstances in order to fix a problem with priority inversion.
 1121** Applications should <em>not</em> use this file-control.
 1122**
 1123** <li>[[SQLITE_FCNTL_ZIPVFS]]
 1124** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
 1125** VFS should return SQLITE_NOTFOUND for this opcode.
 1126**
 1127** <li>[[SQLITE_FCNTL_RBU]]
 1128** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
 1129** the RBU extension only.  All other VFS should return SQLITE_NOTFOUND for
 1130** this opcode.
 1131**
 1132** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]]
 1133** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then
 1134** the file descriptor is placed in "batch write mode", which
 1135** means all subsequent write operations will be deferred and done
 1136** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].  Systems
 1137** that do not support batch atomic writes will return SQLITE_NOTFOUND.
 1138** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
 1139** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or
 1140** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make
 1141** no VFS interface calls on the same [sqlite3_file] file descriptor
 1142** except for calls to the xWrite method and the xFileControl method
 1143** with [SQLITE_FCNTL_SIZE_HINT].
 1144**
 1145** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]]
 1146** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write
 1147** operations since the previous successful call to
 1148** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically.
 1149** This file control returns [SQLITE_OK] if and only if the writes were
 1150** all performed successfully and have been committed to persistent storage.
 1151** ^Regardless of whether or not it is successful, this file control takes
 1152** the file descriptor out of batch write mode so that all subsequent
 1153** write operations are independent.
 1154** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
 1155** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
 1156**
 1157** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]]
 1158** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write
 1159** operations since the previous successful call to
 1160** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back.
 1161** ^This file control takes the file descriptor out of batch write mode
 1162** so that all subsequent write operations are independent.
 1163** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
 1164** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
 1165**
 1166** <li>[[SQLITE_FCNTL_LOCK_TIMEOUT]]
 1167** The [SQLITE_FCNTL_LOCK_TIMEOUT] opcode is used to configure a VFS
 1168** to block for up to M milliseconds before failing when attempting to
 1169** obtain a file lock using the xLock or xShmLock methods of the VFS.
 1170** The parameter is a pointer to a 32-bit signed integer that contains
 1171** the value that M is to be set to. Before returning, the 32-bit signed
 1172** integer is overwritten with the previous value of M.
 1173**
 1174** <li>[[SQLITE_FCNTL_BLOCK_ON_CONNECT]]
 1175** The [SQLITE_FCNTL_BLOCK_ON_CONNECT] opcode is used to configure the
 1176** VFS to block when taking a SHARED lock to connect to a wal mode database.
 1177** This is used to implement the functionality associated with
 1178** SQLITE_SETLK_BLOCK_ON_CONNECT.
 1179**
 1180** <li>[[SQLITE_FCNTL_DATA_VERSION]]
 1181** The [SQLITE_FCNTL_DATA_VERSION] opcode is used to detect changes to
 1182** a database file.  The argument is a pointer to a 32-bit unsigned integer.
 1183** The "data version" for the pager is written into the pointer.  The
 1184** "data version" changes whenever any change occurs to the corresponding
 1185** database file, either through SQL statements on the same database
 1186** connection or through transactions committed by separate database
 1187** connections possibly in other processes. The [sqlite3_total_changes()]
 1188** interface can be used to find if any database on the connection has changed,
 1189** but that interface responds to changes on TEMP as well as MAIN and does
 1190** not provide a mechanism to detect changes to MAIN only.  Also, the
 1191** [sqlite3_total_changes()] interface responds to internal changes only and
 1192** omits changes made by other database connections.  The
 1193** [PRAGMA data_version] command provides a mechanism to detect changes to
 1194** a single attached database that occur due to other database connections,
 1195** but omits changes implemented by the database connection on which it is
 1196** called.  This file control is the only mechanism to detect changes that
 1197** happen either internally or externally and that are associated with
 1198** a particular attached database.
 1199**
 1200** <li>[[SQLITE_FCNTL_CKPT_START]]
 1201** The [SQLITE_FCNTL_CKPT_START] opcode is invoked from within a checkpoint
 1202** in wal mode before the client starts to copy pages from the wal
 1203** file to the database file.
 1204**
 1205** <li>[[SQLITE_FCNTL_CKPT_DONE]]
 1206** The [SQLITE_FCNTL_CKPT_DONE] opcode is invoked from within a checkpoint
 1207** in wal mode after the client has finished copying pages from the wal
 1208** file to the database file, but before the *-shm file is updated to
 1209** record the fact that the pages have been checkpointed.
 1210**
 1211** <li>[[SQLITE_FCNTL_EXTERNAL_READER]]
 1212** The EXPERIMENTAL [SQLITE_FCNTL_EXTERNAL_READER] opcode is used to detect
 1213** whether or not there is a database client in another process with a wal-mode
 1214** transaction open on the database or not. It is only available on unix. The
 1215** (void*) argument passed with this file-control should be a pointer to a
 1216** value of type (int). The integer value is set to 1 if the database is a wal
 1217** mode database and there exists at least one client in another process that
 1218** currently has an SQL transaction open on the database. It is set to 0 if
 1219** the database is not a wal-mode db, or if there is no such connection in any
 1220** other process. This opcode cannot be used to detect transactions opened
 1221** by clients within the current process, only within other processes.
 1222**
 1223** <li>[[SQLITE_FCNTL_CKSM_FILE]]
 1224** The [SQLITE_FCNTL_CKSM_FILE] opcode is for use internally by the
 1225** [checksum VFS shim] only.
 1226**
 1227** <li>[[SQLITE_FCNTL_RESET_CACHE]]
 1228** If there is currently no transaction open on the database, and the
 1229** database is not a temp db, then the [SQLITE_FCNTL_RESET_CACHE] file-control
 1230** purges the contents of the in-memory page cache. If there is an open
 1231** transaction, or if the db is a temp-db, this opcode is a no-op, not an error.
 1232**
 1233** <li>[[SQLITE_FCNTL_FILESTAT]]
 1234** The [SQLITE_FCNTL_FILESTAT] opcode returns low-level diagnostic information
 1235** about the [sqlite3_file] objects used access the database and journal files
 1236** for the given schema.  The fourth parameter to [sqlite3_file_control()]
 1237** should be an initialized [sqlite3_str] pointer.  JSON text describing
 1238** various aspects of the sqlite3_file object is appended to the sqlite3_str.
 1239** The SQLITE_FCNTL_FILESTAT opcode is usually a no-op, unless compile-time
 1240** options are used to enable it.
 1241** </ul>
 1242*/
 1243#define SQLITE_FCNTL_LOCKSTATE               1
 1244#define SQLITE_FCNTL_GET_LOCKPROXYFILE       2
 1245#define SQLITE_FCNTL_SET_LOCKPROXYFILE       3
 1246#define SQLITE_FCNTL_LAST_ERRNO              4
 1247#define SQLITE_FCNTL_SIZE_HINT               5
 1248#define SQLITE_FCNTL_CHUNK_SIZE              6
 1249#define SQLITE_FCNTL_FILE_POINTER            7
 1250#define SQLITE_FCNTL_SYNC_OMITTED            8
 1251#define SQLITE_FCNTL_WIN32_AV_RETRY          9
 1252#define SQLITE_FCNTL_PERSIST_WAL            10
 1253#define SQLITE_FCNTL_OVERWRITE              11
 1254#define SQLITE_FCNTL_VFSNAME                12
 1255#define SQLITE_FCNTL_POWERSAFE_OVERWRITE    13
 1256#define SQLITE_FCNTL_PRAGMA                 14
 1257#define SQLITE_FCNTL_BUSYHANDLER            15
 1258#define SQLITE_FCNTL_TEMPFILENAME           16
 1259#define SQLITE_FCNTL_MMAP_SIZE              18
 1260#define SQLITE_FCNTL_TRACE                  19
 1261#define SQLITE_FCNTL_HAS_MOVED              20
 1262#define SQLITE_FCNTL_SYNC                   21
 1263#define SQLITE_FCNTL_COMMIT_PHASETWO        22
 1264#define SQLITE_FCNTL_WIN32_SET_HANDLE       23
 1265#define SQLITE_FCNTL_WAL_BLOCK              24
 1266#define SQLITE_FCNTL_ZIPVFS                 25
 1267#define SQLITE_FCNTL_RBU                    26
 1268#define SQLITE_FCNTL_VFS_POINTER            27
 1269#define SQLITE_FCNTL_JOURNAL_POINTER        28
 1270#define SQLITE_FCNTL_WIN32_GET_HANDLE       29
 1271#define SQLITE_FCNTL_PDB                    30
 1272#define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE     31
 1273#define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE    32
 1274#define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE  33
 1275#define SQLITE_FCNTL_LOCK_TIMEOUT           34
 1276#define SQLITE_FCNTL_DATA_VERSION           35
 1277#define SQLITE_FCNTL_SIZE_LIMIT             36
 1278#define SQLITE_FCNTL_CKPT_DONE              37
 1279#define SQLITE_FCNTL_RESERVE_BYTES          38
 1280#define SQLITE_FCNTL_CKPT_START             39
 1281#define SQLITE_FCNTL_EXTERNAL_READER        40
 1282#define SQLITE_FCNTL_CKSM_FILE              41
 1283#define SQLITE_FCNTL_RESET_CACHE            42
 1284#define SQLITE_FCNTL_NULL_IO                43
 1285#define SQLITE_FCNTL_BLOCK_ON_CONNECT       44
 1286#define SQLITE_FCNTL_FILESTAT               45
 1287
 1288/* deprecated names */
 1289#define SQLITE_GET_LOCKPROXYFILE      SQLITE_FCNTL_GET_LOCKPROXYFILE
 1290#define SQLITE_SET_LOCKPROXYFILE      SQLITE_FCNTL_SET_LOCKPROXYFILE
 1291#define SQLITE_LAST_ERRNO             SQLITE_FCNTL_LAST_ERRNO
 1292
 1293/* reserved file-control numbers:
 1294**                                         101
 1295**                                         102
 1296**                                         103
 1297*/
 1298
 1299
 1300/*
 1301** CAPI3REF: Mutex Handle
 1302**
 1303** The mutex module within SQLite defines [sqlite3_mutex] to be an
 1304** abstract type for a mutex object.  The SQLite core never looks
 1305** at the internal representation of an [sqlite3_mutex].  It only
 1306** deals with pointers to the [sqlite3_mutex] object.
 1307**
 1308** Mutexes are created using [sqlite3_mutex_alloc()].
 1309*/
 1310typedef struct sqlite3_mutex sqlite3_mutex;
 1311
 1312/*
 1313** CAPI3REF: Loadable Extension Thunk
 1314**
 1315** A pointer to the opaque sqlite3_api_routines structure is passed as
 1316** the third parameter to entry points of [loadable extensions].  This
 1317** structure must be typedefed in order to work around compiler warnings
 1318** on some platforms.
 1319*/
 1320typedef struct sqlite3_api_routines sqlite3_api_routines;
 1321
 1322/*
 1323** CAPI3REF: File Name
 1324**
 1325** Type [sqlite3_filename] is used by SQLite to pass filenames to the
 1326** xOpen method of a [VFS]. It may be cast to (const char*) and treated
 1327** as a normal, nul-terminated, UTF-8 buffer containing the filename, but
 1328** may also be passed to special APIs such as:
 1329**
 1330** <ul>
 1331** <li>  sqlite3_filename_database()
 1332** <li>  sqlite3_filename_journal()
 1333** <li>  sqlite3_filename_wal()
 1334** <li>  sqlite3_uri_parameter()
 1335** <li>  sqlite3_uri_boolean()
 1336** <li>  sqlite3_uri_int64()
 1337** <li>  sqlite3_uri_key()
 1338** </ul>
 1339*/
 1340typedef const char *sqlite3_filename;
 1341
 1342/*
 1343** CAPI3REF: OS Interface Object
 1344**
 1345** An instance of the sqlite3_vfs object defines the interface between
 1346** the SQLite core and the underlying operating system.  The "vfs"
 1347** in the name of the object stands for "virtual file system".  See
 1348** the [VFS | VFS documentation] for further information.
 1349**
 1350** The VFS interface is sometimes extended by adding new methods onto
 1351** the end.  Each time such an extension occurs, the iVersion field
 1352** is incremented.  The iVersion value started out as 1 in
 1353** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2
 1354** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased
 1355** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6].  Additional fields
 1356** may be appended to the sqlite3_vfs object and the iVersion value
 1357** may increase again in future versions of SQLite.
 1358** Note that due to an oversight, the structure
 1359** of the sqlite3_vfs object changed in the transition from
 1360** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0]
 1361** and yet the iVersion field was not increased.
 1362**
 1363** The szOsFile field is the size of the subclassed [sqlite3_file]
 1364** structure used by this VFS.  mxPathname is the maximum length of
 1365** a pathname in this VFS.
 1366**
 1367** Registered sqlite3_vfs objects are kept on a linked list formed by
 1368** the pNext pointer.  The [sqlite3_vfs_register()]
 1369** and [sqlite3_vfs_unregister()] interfaces manage this list
 1370** in a thread-safe way.  The [sqlite3_vfs_find()] interface
 1371** searches the list.  Neither the application code nor the VFS
 1372** implementation should use the pNext pointer.
 1373**
 1374** The pNext field is the only field in the sqlite3_vfs
 1375** structure that SQLite will ever modify.  SQLite will only access
 1376** or modify this field while holding a particular static mutex.
 1377** The application should never modify anything within the sqlite3_vfs
 1378** object once the object has been registered.
 1379**
 1380** The zName field holds the name of the VFS module.  The name must
 1381** be unique across all VFS modules.
 1382**
 1383** [[sqlite3_vfs.xOpen]]
 1384** ^SQLite guarantees that the zFilename parameter to xOpen
 1385** is either a NULL pointer or string obtained
 1386** from xFullPathname() with an optional suffix added.
 1387** ^If a suffix is added to the zFilename parameter, it will
 1388** consist of a single "-" character followed by no more than
 1389** 11 alphanumeric and/or "-" characters.
 1390** ^SQLite further guarantees that
 1391** the string will be valid and unchanged until xClose() is
 1392** called. Because of the previous sentence,
 1393** the [sqlite3_file] can safely store a pointer to the
 1394** filename if it needs to remember the filename for some reason.
 1395** If the zFilename parameter to xOpen is a NULL pointer then xOpen
 1396** must invent its own temporary name for the file.  ^Whenever the
 1397** xFilename parameter is NULL it will also be the case that the
 1398** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
 1399**
 1400** The flags argument to xOpen() includes all bits set in
 1401** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
 1402** or [sqlite3_open16()] is used, then flags includes at least
 1403** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE].
 1404** If xOpen() opens a file read-only then it sets *pOutFlags to
 1405** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
 1406**
 1407** ^(SQLite will also add one of the following flags to the xOpen()
 1408** call, depending on the object being opened:
 1409**
 1410** <ul>
 1411** <li>  [SQLITE_OPEN_MAIN_DB]
 1412** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
 1413** <li>  [SQLITE_OPEN_TEMP_DB]
 1414** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
 1415** <li>  [SQLITE_OPEN_TRANSIENT_DB]
 1416** <li>  [SQLITE_OPEN_SUBJOURNAL]
 1417** <li>  [SQLITE_OPEN_SUPER_JOURNAL]
 1418** <li>  [SQLITE_OPEN_WAL]
 1419** </ul>)^
 1420**
 1421** The file I/O implementation can use the object type flags to
 1422** change the way it deals with files.  For example, an application
 1423** that does not care about crash recovery or rollback might make
 1424** the open of a journal file a no-op.  Writes to this journal would
 1425** also be no-ops, and any attempt to read the journal would return
 1426** SQLITE_IOERR.  Or the implementation might recognize that a database
 1427** file will be doing page-aligned sector reads and writes in a random
 1428** order and set up its I/O subsystem accordingly.
 1429**
 1430** SQLite might also add one of the following flags to the xOpen method:
 1431**
 1432** <ul>
 1433** <li> [SQLITE_OPEN_DELETEONCLOSE]
 1434** <li> [SQLITE_OPEN_EXCLUSIVE]
 1435** </ul>
 1436**
 1437** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
 1438** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
 1439** will be set for TEMP databases and their journals, transient
 1440** databases, and subjournals.
 1441**
 1442** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
 1443** with the [SQLITE_OPEN_CREATE] flag, which are both directly
 1444** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
 1445** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the
 1446** SQLITE_OPEN_CREATE, is used to indicate that file should always
 1447** be created, and that it is an error if it already exists.
 1448** It is <i>not</i> used to indicate the file should be opened
 1449** for exclusive access.
 1450**
 1451** ^At least szOsFile bytes of memory are allocated by SQLite
 1452** to hold the [sqlite3_file] structure passed as the third
 1453** argument to xOpen.  The xOpen method does not have to
 1454** allocate the structure; it should just fill it in.  Note that
 1455** the xOpen method must set the sqlite3_file.pMethods to either
 1456** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
 1457** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
 1458** element will be valid after xOpen returns regardless of the success
 1459** or failure of the xOpen call.
 1460**
 1461** [[sqlite3_vfs.xAccess]]
 1462** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
 1463** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
 1464** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
 1465** to test whether a file is at least readable.  The SQLITE_ACCESS_READ
 1466** flag is never actually used and is not implemented in the built-in
 1467** VFSes of SQLite.  The file is named by the second argument and can be a
 1468** directory. The xAccess method returns [SQLITE_OK] on success or some
 1469** non-zero error code if there is an I/O error or if the name of
 1470** the file given in the second argument is illegal.  If SQLITE_OK
 1471** is returned, then non-zero or zero is written into *pResOut to indicate
 1472** whether or not the file is accessible.
 1473**
 1474** ^SQLite will always allocate at least mxPathname+1 bytes for the
 1475** output buffer xFullPathname.  The exact size of the output buffer
 1476** is also passed as a parameter to both  methods. If the output buffer
 1477** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
 1478** handled as a fatal error by SQLite, vfs implementations should endeavor
 1479** to prevent this by setting mxPathname to a sufficiently large value.
 1480**
 1481** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
 1482** interfaces are not strictly a part of the filesystem, but they are
 1483** included in the VFS structure for completeness.
 1484** The xRandomness() function attempts to return nBytes bytes
 1485** of good-quality randomness into zOut.  The return value is
 1486** the actual number of bytes of randomness obtained.
 1487** The xSleep() method causes the calling thread to sleep for at
 1488** least the number of microseconds given.  ^The xCurrentTime()
 1489** method returns a Julian Day Number for the current date and time as
 1490** a floating point value.
 1491** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
 1492** Day Number multiplied by 86400000 (the number of milliseconds in
 1493** a 24-hour day).
 1494** ^SQLite will use the xCurrentTimeInt64() method to get the current
 1495** date and time if that method is available (if iVersion is 2 or
 1496** greater and the function pointer is not NULL) and will fall back
 1497** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
 1498**
 1499** ^The xSetSystemCall(), xGetSystemCall(), and xNextSystemCall() interfaces
 1500** are not used by the SQLite core.  These optional interfaces are provided
 1501** by some VFSes to facilitate testing of the VFS code. By overriding
 1502** system calls with functions under its control, a test program can
 1503** simulate faults and error conditions that would otherwise be difficult
 1504** or impossible to induce.  The set of system calls that can be overridden
 1505** varies from one VFS to another, and from one version of the same VFS to the
 1506** next.  Applications that use these interfaces must be prepared for any
 1507** or all of these interfaces to be NULL or for their behavior to change
 1508** from one release to the next.  Applications must not attempt to access
 1509** any of these methods if the iVersion of the VFS is less than 3.
 1510*/
 1511typedef struct sqlite3_vfs sqlite3_vfs;
 1512typedef void (*sqlite3_syscall_ptr)(void);
 1513struct sqlite3_vfs {
 1514  int iVersion;            /* Structure version number (currently 3) */
 1515  int szOsFile;            /* Size of subclassed sqlite3_file */
 1516  int mxPathname;          /* Maximum file pathname length */
 1517  sqlite3_vfs *pNext;      /* Next registered VFS */
 1518  const char *zName;       /* Name of this virtual file system */
 1519  void *pAppData;          /* Pointer to application-specific data */
 1520  int (*xOpen)(sqlite3_vfs*, sqlite3_filename zName, sqlite3_file*,
 1521               int flags, int *pOutFlags);
 1522  int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
 1523  int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
 1524  int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
 1525  void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
 1526  void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
 1527  void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
 1528  void (*xDlClose)(sqlite3_vfs*, void*);
 1529  int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
 1530  int (*xSleep)(sqlite3_vfs*, int microseconds);
 1531  int (*xCurrentTime)(sqlite3_vfs*, double*);
 1532  int (*xGetLastError)(sqlite3_vfs*, int, char *);
 1533  /*
 1534  ** The methods above are in version 1 of the sqlite_vfs object
 1535  ** definition.  Those that follow are added in version 2 or later
 1536  */
 1537  int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
 1538  /*
 1539  ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
 1540  ** Those below are for version 3 and greater.
 1541  */
 1542  int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
 1543  sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
 1544  const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
 1545  /*
 1546  ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
 1547  ** New fields may be appended in future versions.  The iVersion
 1548  ** value will increment whenever this happens.
 1549  */
 1550};
 1551
 1552/*
 1553** CAPI3REF: Flags for the xAccess VFS method
 1554**
 1555** These integer constants can be used as the third parameter to
 1556** the xAccess method of an [sqlite3_vfs] object.  They determine
 1557** what kind of permissions the xAccess method is looking for.
 1558** With SQLITE_ACCESS_EXISTS, the xAccess method
 1559** simply checks whether the file exists.
 1560** With SQLITE_ACCESS_READWRITE, the xAccess method
 1561** checks whether the named directory is both readable and writable
 1562** (in other words, if files can be added, removed, and renamed within
 1563** the directory).
 1564** The SQLITE_ACCESS_READWRITE constant is currently used only by the
 1565** [temp_store_directory pragma], though this could change in a future
 1566** release of SQLite.
 1567** With SQLITE_ACCESS_READ, the xAccess method
 1568** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
 1569** currently unused, though it might be used in a future release of
 1570** SQLite.
 1571*/
 1572#define SQLITE_ACCESS_EXISTS    0
 1573#define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
 1574#define SQLITE_ACCESS_READ      2   /* Unused */
 1575
 1576/*
 1577** CAPI3REF: Flags for the xShmLock VFS method
 1578**
 1579** These integer constants define the various locking operations
 1580** allowed by the xShmLock method of [sqlite3_io_methods].  The
 1581** following are the only legal combinations of flags to the
 1582** xShmLock method:
 1583**
 1584** <ul>
 1585** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
 1586** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
 1587** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
 1588** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
 1589** </ul>
 1590**
 1591** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
 1592** was given on the corresponding lock.
 1593**
 1594** The xShmLock method can transition between unlocked and SHARED or
 1595** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
 1596** and EXCLUSIVE.
 1597*/
 1598#define SQLITE_SHM_UNLOCK       1
 1599#define SQLITE_SHM_LOCK         2
 1600#define SQLITE_SHM_SHARED       4
 1601#define SQLITE_SHM_EXCLUSIVE    8
 1602
 1603/*
 1604** CAPI3REF: Maximum xShmLock index
 1605**
 1606** The xShmLock method on [sqlite3_io_methods] may use values
 1607** between 0 and this upper bound as its "offset" argument.
 1608** The SQLite core will never attempt to acquire or release a
 1609** lock outside of this range
 1610*/
 1611#define SQLITE_SHM_NLOCK        8
 1612
 1613
 1614/*
 1615** CAPI3REF: Initialize The SQLite Library
 1616**
 1617** ^The sqlite3_initialize() routine initializes the
 1618** SQLite library.  ^The sqlite3_shutdown() routine
 1619** deallocates any resources that were allocated by sqlite3_initialize().
 1620** These routines are designed to aid in process initialization and
 1621** shutdown on embedded systems.  Workstation applications using
 1622** SQLite normally do not need to invoke either of these routines.
 1623**
 1624** A call to sqlite3_initialize() is an "effective" call if it is
 1625** the first time sqlite3_initialize() is invoked during the lifetime of
 1626** the process, or if it is the first time sqlite3_initialize() is invoked
 1627** following a call to sqlite3_shutdown().  ^(Only an effective call
 1628** of sqlite3_initialize() does any initialization.  All other calls
 1629** are harmless no-ops.)^
 1630**
 1631** A call to sqlite3_shutdown() is an "effective" call if it is the first
 1632** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
 1633** an effective call to sqlite3_shutdown() does any deinitialization.
 1634** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
 1635**
 1636** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
 1637** is not.  The sqlite3_shutdown() interface must only be called from a
 1638** single thread.  All open [database connections] must be closed and all
 1639** other SQLite resources must be deallocated prior to invoking
 1640** sqlite3_shutdown().
 1641**
 1642** Among other things, ^sqlite3_initialize() will invoke
 1643** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
 1644** will invoke sqlite3_os_end().
 1645**
 1646** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
 1647** ^If for some reason, sqlite3_initialize() is unable to initialize
 1648** the library (perhaps it is unable to allocate a needed resource such
 1649** as a mutex) it returns an [error code] other than [SQLITE_OK].
 1650**
 1651** ^The sqlite3_initialize() routine is called internally by many other
 1652** SQLite interfaces so that an application usually does not need to
 1653** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
 1654** calls sqlite3_initialize() so the SQLite library will be automatically
 1655** initialized when [sqlite3_open()] is called if it has not been initialized
 1656** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
 1657** compile-time option, then the automatic calls to sqlite3_initialize()
 1658** are omitted and the application must call sqlite3_initialize() directly
 1659** prior to using any other SQLite interface.  For maximum portability,
 1660** it is recommended that applications always invoke sqlite3_initialize()
 1661** directly prior to using any other SQLite interface.  Future releases
 1662** of SQLite may require this.  In other words, the behavior exhibited
 1663** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
 1664** default behavior in some future release of SQLite.
 1665**
 1666** The sqlite3_os_init() routine does operating-system specific
 1667** initialization of the SQLite library.  The sqlite3_os_end()
 1668** routine undoes the effect of sqlite3_os_init().  Typical tasks
 1669** performed by these routines include allocation or deallocation
 1670** of static resources, initialization of global variables,
 1671** setting up a default [sqlite3_vfs] module, or setting up
 1672** a default configuration using [sqlite3_config()].
 1673**
 1674** The application should never invoke either sqlite3_os_init()
 1675** or sqlite3_os_end() directly.  The application should only invoke
 1676** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
 1677** interface is called automatically by sqlite3_initialize() and
 1678** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
 1679** implementations for sqlite3_os_init() and sqlite3_os_end()
 1680** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
 1681** When [custom builds | built for other platforms]
 1682** (using the [SQLITE_OS_OTHER=1] compile-time
 1683** option) the application must supply a suitable implementation for
 1684** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
 1685** implementation of sqlite3_os_init() or sqlite3_os_end()
 1686** must return [SQLITE_OK] on success and some other [error code] upon
 1687** failure.
 1688*/
 1689SQLITE_API int sqlite3_initialize(void);
 1690SQLITE_API int sqlite3_shutdown(void);
 1691SQLITE_API int sqlite3_os_init(void);
 1692SQLITE_API int sqlite3_os_end(void);
 1693
 1694/*
 1695** CAPI3REF: Configuring The SQLite Library
 1696**
 1697** The sqlite3_config() interface is used to make global configuration
 1698** changes to SQLite in order to tune SQLite to the specific needs of
 1699** the application.  The default configuration is recommended for most
 1700** applications and so this routine is usually not necessary.  It is
 1701** provided to support rare applications with unusual needs.
 1702**
 1703** <b>The sqlite3_config() interface is not threadsafe. The application
 1704** must ensure that no other SQLite interfaces are invoked by other
 1705** threads while sqlite3_config() is running.</b>
 1706**
 1707** The first argument to sqlite3_config() is an integer
 1708** [configuration option] that determines
 1709** what property of SQLite is to be configured.  Subsequent arguments
 1710** vary depending on the [configuration option]
 1711** in the first argument.
 1712**
 1713** For most configuration options, the sqlite3_config() interface
 1714** may only be invoked prior to library initialization using
 1715** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
 1716** The exceptional configuration options that may be invoked at any time
 1717** are called "anytime configuration options".
 1718** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
 1719** [sqlite3_shutdown()] with a first argument that is not an anytime
 1720** configuration option, then the sqlite3_config() call will
 1721** return SQLITE_MISUSE.
 1722** Note, however, that ^sqlite3_config() can be called as part of the
 1723** implementation of an application-defined [sqlite3_os_init()].
 1724**
 1725** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
 1726** ^If the option is unknown or SQLite is unable to set the option
 1727** then this routine returns a non-zero [error code].
 1728*/
 1729SQLITE_API int sqlite3_config(int, ...);
 1730
 1731/*
 1732** CAPI3REF: Configure database connections
 1733** METHOD: sqlite3
 1734**
 1735** The sqlite3_db_config() interface is used to make configuration
 1736** changes to a [database connection].  The interface is similar to
 1737** [sqlite3_config()] except that the changes apply to a single
 1738** [database connection] (specified in the first argument).
 1739**
 1740** The second argument to sqlite3_db_config(D,V,...)  is the
 1741** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code
 1742** that indicates what aspect of the [database connection] is being configured.
 1743** Subsequent arguments vary depending on the configuration verb.
 1744**
 1745** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
 1746** the call is considered successful.
 1747*/
 1748SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
 1749
 1750/*
 1751** CAPI3REF: Memory Allocation Routines
 1752**
 1753** An instance of this object defines the interface between SQLite
 1754** and low-level memory allocation routines.
 1755**
 1756** This object is used in only one place in the SQLite interface.
 1757** A pointer to an instance of this object is the argument to
 1758** [sqlite3_config()] when the configuration option is
 1759** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].
 1760** By creating an instance of this object
 1761** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
 1762** during configuration, an application can specify an alternative
 1763** memory allocation subsystem for SQLite to use for all of its
 1764** dynamic memory needs.
 1765**
 1766** Note that SQLite comes with several [built-in memory allocators]
 1767** that are perfectly adequate for the overwhelming majority of applications
 1768** and that this object is only useful to a tiny minority of applications
 1769** with specialized memory allocation requirements.  This object is
 1770** also used during testing of SQLite in order to specify an alternative
 1771** memory allocator that simulates memory out-of-memory conditions in
 1772** order to verify that SQLite recovers gracefully from such
 1773** conditions.
 1774**
 1775** The xMalloc, xRealloc, and xFree methods must work like the
 1776** malloc(), realloc() and free() functions from the standard C library.
 1777** ^SQLite guarantees that the second argument to
 1778** xRealloc is always a value returned by a prior call to xRoundup.
 1779**
 1780** xSize should return the allocated size of a memory allocation
 1781** previously obtained from xMalloc or xRealloc.  The allocated size
 1782** is always at least as big as the requested size but may be larger.
 1783**
 1784** The xRoundup method returns what would be the allocated size of
 1785** a memory allocation given a particular requested size.  Most memory
 1786** allocators round up memory allocations at least to the next multiple
 1787** of 8.  Some allocators round up to a larger multiple or to a power of 2.
 1788** Every memory allocation request coming in through [sqlite3_malloc()]
 1789** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0,
 1790** that causes the corresponding memory allocation to fail.
 1791**
 1792** The xInit method initializes the memory allocator.  For example,
 1793** it might allocate any required mutexes or initialize internal data
 1794** structures.  The xShutdown method is invoked (indirectly) by
 1795** [sqlite3_shutdown()] and should deallocate any resources acquired
 1796** by xInit.  The pAppData pointer is used as the only parameter to
 1797** xInit and xShutdown.
 1798**
 1799** SQLite holds the [SQLITE_MUTEX_STATIC_MAIN] mutex when it invokes
 1800** the xInit method, so the xInit method need not be threadsafe.  The
 1801** xShutdown method is only called from [sqlite3_shutdown()] so it does
 1802** not need to be threadsafe either.  For all other methods, SQLite
 1803** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
 1804** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
 1805** it is by default) and so the methods are automatically serialized.
 1806** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
 1807** methods must be threadsafe or else make their own arrangements for
 1808** serialization.
 1809**
 1810** SQLite will never invoke xInit() more than once without an intervening
 1811** call to xShutdown().
 1812*/
 1813typedef struct sqlite3_mem_methods sqlite3_mem_methods;
 1814struct sqlite3_mem_methods {
 1815  void *(*xMalloc)(int);         /* Memory allocation function */
 1816  void (*xFree)(void*);          /* Free a prior allocation */
 1817  void *(*xRealloc)(void*,int);  /* Resize an allocation */
 1818  int (*xSize)(void*);           /* Return the size of an allocation */
 1819  int (*xRoundup)(int);          /* Round up request size to allocation size */
 1820  int (*xInit)(void*);           /* Initialize the memory allocator */
 1821  void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
 1822  void *pAppData;                /* Argument to xInit() and xShutdown() */
 1823};
 1824
 1825/*
 1826** CAPI3REF: Configuration Options
 1827** KEYWORDS: {configuration option}
 1828**
 1829** These constants are the available integer configuration options that
 1830** can be passed as the first argument to the [sqlite3_config()] interface.
 1831**
 1832** Most of the configuration options for sqlite3_config()
 1833** will only work if invoked prior to [sqlite3_initialize()] or after
 1834** [sqlite3_shutdown()].  The few exceptions to this rule are called
 1835** "anytime configuration options".
 1836** ^Calling [sqlite3_config()] with a first argument that is not an
 1837** anytime configuration option in between calls to [sqlite3_initialize()] and
 1838** [sqlite3_shutdown()] is a no-op that returns SQLITE_MISUSE.
 1839**
 1840** The set of anytime configuration options can change (by insertions
 1841** and/or deletions) from one release of SQLite to the next.
 1842** As of SQLite version 3.42.0, the complete set of anytime configuration
 1843** options is:
 1844** <ul>
 1845** <li> SQLITE_CONFIG_LOG
 1846** <li> SQLITE_CONFIG_PCACHE_HDRSZ
 1847** </ul>
 1848**
 1849** New configuration options may be added in future releases of SQLite.
 1850** Existing configuration options might be discontinued.  Applications
 1851** should check the return code from [sqlite3_config()] to make sure that
 1852** the call worked.  The [sqlite3_config()] interface will return a
 1853** non-zero [error code] if a discontinued or unsupported configuration option
 1854** is invoked.
 1855**
 1856** <dl>
 1857** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
 1858** <dd>There are no arguments to this option.  ^This option sets the
 1859** [threading mode] to Single-thread.  In other words, it disables
 1860** all mutexing and puts SQLite into a mode where it can only be used
 1861** by a single thread.   ^If SQLite is compiled with
 1862** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
 1863** it is not possible to change the [threading mode] from its default
 1864** value of Single-thread and so [sqlite3_config()] will return
 1865** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
 1866** configuration option.</dd>
 1867**
 1868** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
 1869** <dd>There are no arguments to this option.  ^This option sets the
 1870** [threading mode] to Multi-thread.  In other words, it disables
 1871** mutexing on [database connection] and [prepared statement] objects.
 1872** The application is responsible for serializing access to
 1873** [database connections] and [prepared statements].  But other mutexes
 1874** are enabled so that SQLite will be safe to use in a multi-threaded
 1875** environment as long as no two threads attempt to use the same
 1876** [database connection] at the same time.  ^If SQLite is compiled with
 1877** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
 1878** it is not possible to set the Multi-thread [threading mode] and
 1879** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
 1880** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
 1881**
 1882** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
 1883** <dd>There are no arguments to this option.  ^This option sets the
 1884** [threading mode] to Serialized. In other words, this option enables
 1885** all mutexes including the recursive
 1886** mutexes on [database connection] and [prepared statement] objects.
 1887** In this mode (which is the default when SQLite is compiled with
 1888** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
 1889** to [database connections] and [prepared statements] so that the
 1890** application is free to use the same [database connection] or the
 1891** same [prepared statement] in different threads at the same time.
 1892** ^If SQLite is compiled with
 1893** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
 1894** it is not possible to set the Serialized [threading mode] and
 1895** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
 1896** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
 1897**
 1898** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
 1899** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is
 1900** a pointer to an instance of the [sqlite3_mem_methods] structure.
 1901** The argument specifies
 1902** alternative low-level memory allocation routines to be used in place of
 1903** the memory allocation routines built into SQLite.)^ ^SQLite makes
 1904** its own private copy of the content of the [sqlite3_mem_methods] structure
 1905** before the [sqlite3_config()] call returns.</dd>
 1906**
 1907** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
 1908** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
 1909** is a pointer to an instance of the [sqlite3_mem_methods] structure.
 1910** The [sqlite3_mem_methods]
 1911** structure is filled with the currently defined memory allocation routines.)^
 1912** This option can be used to overload the default memory allocation
 1913** routines with a wrapper that simulates memory allocation failure or
 1914** tracks memory usage, for example. </dd>
 1915**
 1916** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt>
 1917** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes a single argument of
 1918** type int, interpreted as a boolean, which if true provides a hint to
 1919** SQLite that it should avoid large memory allocations if possible.
 1920** SQLite will run faster if it is free to make large memory allocations,
 1921** but some applications might prefer to run slower in exchange for
 1922** guarantees about memory fragmentation that are possible if large
 1923** allocations are avoided.  This hint is normally off.
 1924** </dd>
 1925**
 1926** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
 1927** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes a single argument of type int,
 1928** interpreted as a boolean, which enables or disables the collection of
 1929** memory allocation statistics. ^(When memory allocation statistics are
 1930** disabled, the following SQLite interfaces become non-operational:
 1931**   <ul>
 1932**   <li> [sqlite3_hard_heap_limit64()]
 1933**   <li> [sqlite3_memory_used()]
 1934**   <li> [sqlite3_memory_highwater()]
 1935**   <li> [sqlite3_soft_heap_limit64()]
 1936**   <li> [sqlite3_status64()]
 1937**   </ul>)^
 1938** ^Memory allocation statistics are enabled by default unless SQLite is
 1939** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
 1940** allocation statistics are disabled by default.
 1941** </dd>
 1942**
 1943** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
 1944** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
 1945** </dd>
 1946**
 1947** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
 1948** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
 1949** that SQLite can use for the database page cache with the default page
 1950** cache implementation.
 1951** This configuration option is a no-op if an application-defined page
 1952** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2].
 1953** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
 1954** 8-byte aligned memory (pMem), the size of each page cache line (sz),
 1955** and the number of cache lines (N).
 1956** The sz argument should be the size of the largest database page
 1957** (a power of two between 512 and 65536) plus some extra bytes for each
 1958** page header.  ^The number of extra bytes needed by the page header
 1959** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ].
 1960** ^It is harmless, apart from the wasted memory,
 1961** for the sz parameter to be larger than necessary.  The pMem
 1962** argument must be either a NULL pointer or a pointer to an 8-byte
 1963** aligned block of memory of at least sz*N bytes, otherwise
 1964** subsequent behavior is undefined.
 1965** ^When pMem is not NULL, SQLite will strive to use the memory provided
 1966** to satisfy page cache needs, falling back to [sqlite3_malloc()] if
 1967** a page cache line is larger than sz bytes or if all of the pMem buffer
 1968** is exhausted.
 1969** ^If pMem is NULL and N is non-zero, then each database connection
 1970** does an initial bulk allocation for page cache memory
 1971** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or
 1972** of -1024*N bytes if N is negative. ^If additional
 1973** page cache memory is needed beyond what is provided by the initial
 1974** allocation, then SQLite goes to [sqlite3_malloc()] separately for each
 1975** additional cache line. </dd>
 1976**
 1977** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
 1978** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer
 1979** that SQLite will use for all of its dynamic memory allocation needs
 1980** beyond those provided for by [SQLITE_CONFIG_PAGECACHE].
 1981** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
 1982** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
 1983** [SQLITE_ERROR] if invoked otherwise.
 1984** ^There are three arguments to SQLITE_CONFIG_HEAP:
 1985** An 8-byte aligned pointer to the memory,
 1986** the number of bytes in the memory buffer, and the minimum allocation size.
 1987** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
 1988** to using its default memory allocator (the system malloc() implementation),
 1989** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
 1990** memory pointer is not NULL then the alternative memory
 1991** allocator is engaged to handle all of SQLites memory allocation needs.
 1992** The first pointer (the memory pointer) must be aligned to an 8-byte
 1993** boundary or subsequent behavior of SQLite will be undefined.
 1994** The minimum allocation size is capped at 2**12. Reasonable values
 1995** for the minimum allocation size are 2**5 through 2**8.</dd>
 1996**
 1997** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
 1998** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
 1999** pointer to an instance of the [sqlite3_mutex_methods] structure.
 2000** The argument specifies alternative low-level mutex routines to be used
 2001** in place of the mutex routines built into SQLite.)^  ^SQLite makes a copy of
 2002** the content of the [sqlite3_mutex_methods] structure before the call to
 2003** [sqlite3_config()] returns. ^If SQLite is compiled with
 2004** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
 2005** the entire mutexing subsystem is omitted from the build and hence calls to
 2006** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
 2007** return [SQLITE_ERROR].</dd>
 2008**
 2009** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
 2010** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
 2011** is a pointer to an instance of the [sqlite3_mutex_methods] structure.  The
 2012** [sqlite3_mutex_methods]
 2013** structure is filled with the currently defined mutex routines.)^
 2014** This option can be used to overload the default mutex allocation
 2015** routines with a wrapper used to track mutex usage for performance
 2016** profiling or testing, for example.   ^If SQLite is compiled with
 2017** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
 2018** the entire mutexing subsystem is omitted from the build and hence calls to
 2019** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
 2020** return [SQLITE_ERROR].</dd>
 2021**
 2022** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
 2023** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
 2024** the default size of [lookaside memory] on each [database connection].
 2025** The first argument is the
 2026** size of each lookaside buffer slot ("sz") and the second is the number of
 2027** slots allocated to each database connection ("cnt").)^
 2028** ^(SQLITE_CONFIG_LOOKASIDE sets the <i>default</i> lookaside size.
 2029** The [SQLITE_DBCONFIG_LOOKASIDE] option to [sqlite3_db_config()] can
 2030** be used to change the lookaside configuration on individual connections.)^
 2031** The [-DSQLITE_DEFAULT_LOOKASIDE] option can be used to change the
 2032** default lookaside configuration at compile-time.
 2033** </dd>
 2034**
 2035** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
 2036** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is
 2037** a pointer to an [sqlite3_pcache_methods2] object.  This object specifies
 2038** the interface to a custom page cache implementation.)^
 2039** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
 2040**
 2041** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
 2042** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
 2043** is a pointer to an [sqlite3_pcache_methods2] object.  SQLite copies off
 2044** the current page cache implementation into that object.)^ </dd>
 2045**
 2046** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
 2047** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
 2048** global [error log].
 2049** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
 2050** function with a call signature of void(*)(void*,int,const char*),
 2051** and a pointer to void. ^If the function pointer is not NULL, it is
 2052** invoked by [sqlite3_log()] to process each logging event.  ^If the
 2053** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
 2054** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
 2055** passed through as the first parameter to the application-defined logger
 2056** function whenever that function is invoked.  ^The second parameter to
 2057** the logger function is a copy of the first parameter to the corresponding
 2058** [sqlite3_log()] call and is intended to be a [result code] or an
 2059** [extended result code].  ^The third parameter passed to the logger is
 2060** a log message after formatting via [sqlite3_snprintf()].
 2061** The SQLite logging interface is not reentrant; the logger function
 2062** supplied by the application must not invoke any SQLite interface.
 2063** In a multi-threaded application, the application-defined logger
 2064** function must be threadsafe. </dd>
 2065**
 2066** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
 2067** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
 2068** If non-zero, then URI handling is globally enabled. If the parameter is zero,
 2069** then URI handling is globally disabled.)^ ^If URI handling is globally
 2070** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
 2071** [sqlite3_open16()] or
 2072** specified as part of [ATTACH] commands are interpreted as URIs, regardless
 2073** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
 2074** connection is opened. ^If it is globally disabled, filenames are
 2075** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
 2076** database connection is opened. ^(By default, URI handling is globally
 2077** disabled. The default value may be changed by compiling with the
 2078** [SQLITE_USE_URI] symbol defined.)^
 2079**
 2080** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
 2081** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
 2082** argument which is interpreted as a boolean in order to enable or disable
 2083** the use of covering indices for full table scans in the query optimizer.
 2084** ^The default setting is determined
 2085** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
 2086** if that compile-time option is omitted.
 2087** The ability to disable the use of covering indices for full table scans
 2088** is because some incorrectly coded legacy applications might malfunction
 2089** when the optimization is enabled.  Providing the ability to
 2090** disable the optimization allows the older, buggy application code to work
 2091** without change even with newer versions of SQLite.
 2092**
 2093** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
 2094** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
 2095** <dd> These options are obsolete and should not be used by new code.
 2096** They are retained for backwards compatibility but are now no-ops.
 2097** </dd>
 2098**
 2099** [[SQLITE_CONFIG_SQLLOG]]
 2100** <dt>SQLITE_CONFIG_SQLLOG
 2101** <dd>This option is only available if sqlite is compiled with the
 2102** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
 2103** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
 2104** The second should be of type (void*). The callback is invoked by the library
 2105** in three separate circumstances, identified by the value passed as the
 2106** fourth parameter. If the fourth parameter is 0, then the database connection
 2107** passed as the second argument has just been opened. The third argument
 2108** points to a buffer containing the name of the main database file. If the
 2109** fourth parameter is 1, then the SQL statement that the third parameter
 2110** points to has just been executed. Or, if the fourth parameter is 2, then
 2111** the connection being passed as the second parameter is being closed. The
 2112** third parameter is passed NULL In this case.  An example of using this
 2113** configuration option can be seen in the "test_sqllog.c" source file in
 2114** the canonical SQLite source tree.</dd>
 2115**
 2116** [[SQLITE_CONFIG_MMAP_SIZE]]
 2117** <dt>SQLITE_CONFIG_MMAP_SIZE
 2118** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
 2119** that are the default mmap size limit (the default setting for
 2120** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
 2121** ^The default setting can be overridden by each database connection using
 2122** either the [PRAGMA mmap_size] command, or by using the
 2123** [SQLITE_FCNTL_MMAP_SIZE] file control.  ^(The maximum allowed mmap size
 2124** will be silently truncated if necessary so that it does not exceed the
 2125** compile-time maximum mmap size set by the
 2126** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
 2127** ^If either argument to this option is negative, then that argument is
 2128** changed to its compile-time default.
 2129**
 2130** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
 2131** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
 2132** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
 2133** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
 2134** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
 2135** that specifies the maximum size of the created heap.
 2136**
 2137** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
 2138** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
 2139** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
 2140** is a pointer to an integer and writes into that integer the number of extra
 2141** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
 2142** The amount of extra space required can change depending on the compiler,
 2143** target platform, and SQLite version.
 2144**
 2145** [[SQLITE_CONFIG_PMASZ]]
 2146** <dt>SQLITE_CONFIG_PMASZ
 2147** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
 2148** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
 2149** sorter to that integer.  The default minimum PMA Size is set by the
 2150** [SQLITE_SORTER_PMASZ] compile-time option.  New threads are launched
 2151** to help with sort operations when multithreaded sorting
 2152** is enabled (using the [PRAGMA threads] command) and the amount of content
 2153** to be sorted exceeds the page size times the minimum of the
 2154** [PRAGMA cache_size] setting and this value.
 2155**
 2156** [[SQLITE_CONFIG_STMTJRNL_SPILL]]
 2157** <dt>SQLITE_CONFIG_STMTJRNL_SPILL
 2158** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
 2159** becomes the [statement journal] spill-to-disk threshold.
 2160** [Statement journals] are held in memory until their size (in bytes)
 2161** exceeds this threshold, at which point they are written to disk.
 2162** Or if the threshold is -1, statement journals are always held
 2163** exclusively in memory.
 2164** Since many statement journals never become large, setting the spill
 2165** threshold to a value such as 64KiB can greatly reduce the amount of
 2166** I/O required to support statement rollback.
 2167** The default value for this setting is controlled by the
 2168** [SQLITE_STMTJRNL_SPILL] compile-time option.
 2169**
 2170** [[SQLITE_CONFIG_SORTERREF_SIZE]]
 2171** <dt>SQLITE_CONFIG_SORTERREF_SIZE
 2172** <dd>The SQLITE_CONFIG_SORTERREF_SIZE option accepts a single parameter
 2173** of type (int) - the new value of the sorter-reference size threshold.
 2174** Usually, when SQLite uses an external sort to order records according
 2175** to an ORDER BY clause, all fields required by the caller are present in the
 2176** sorted records. However, if SQLite determines based on the declared type
 2177** of a table column that its values are likely to be very large - larger
 2178** than the configured sorter-reference size threshold - then a reference
 2179** is stored in each sorted record and the required column values loaded
 2180** from the database as records are returned in sorted order. The default
 2181** value for this option is to never use this optimization. Specifying a
 2182** negative value for this option restores the default behavior.
 2183** This option is only available if SQLite is compiled with the
 2184** [SQLITE_ENABLE_SORTER_REFERENCES] compile-time option.
 2185**
 2186** [[SQLITE_CONFIG_MEMDB_MAXSIZE]]
 2187** <dt>SQLITE_CONFIG_MEMDB_MAXSIZE
 2188** <dd>The SQLITE_CONFIG_MEMDB_MAXSIZE option accepts a single parameter
 2189** [sqlite3_int64] parameter which is the default maximum size for an in-memory
 2190** database created using [sqlite3_deserialize()].  This default maximum
 2191** size can be adjusted up or down for individual databases using the
 2192** [SQLITE_FCNTL_SIZE_LIMIT] [sqlite3_file_control|file-control].  If this
 2193** configuration setting is never used, then the default maximum is determined
 2194** by the [SQLITE_MEMDB_DEFAULT_MAXSIZE] compile-time option.  If that
 2195** compile-time option is not set, then the default maximum is 1073741824.
 2196**
 2197** [[SQLITE_CONFIG_ROWID_IN_VIEW]]
 2198** <dt>SQLITE_CONFIG_ROWID_IN_VIEW
 2199** <dd>The SQLITE_CONFIG_ROWID_IN_VIEW option enables or disables the ability
 2200** for VIEWs to have a ROWID.  The capability can only be enabled if SQLite is
 2201** compiled with -DSQLITE_ALLOW_ROWID_IN_VIEW, in which case the capability
 2202** defaults to on.  This configuration option queries the current setting or
 2203** changes the setting to off or on.  The argument is a pointer to an integer.
 2204** If that integer initially holds a value of 1, then the ability for VIEWs to
 2205** have ROWIDs is activated.  If the integer initially holds zero, then the
 2206** ability is deactivated.  Any other initial value for the integer leaves the
 2207** setting unchanged.  After changes, if any, the integer is written with
 2208** a 1 or 0, if the ability for VIEWs to have ROWIDs is on or off.  If SQLite
 2209** is compiled without -DSQLITE_ALLOW_ROWID_IN_VIEW (which is the usual and
 2210** recommended case) then the integer is always filled with zero, regardless
 2211** if its initial value.
 2212** </dl>
 2213*/
 2214#define SQLITE_CONFIG_SINGLETHREAD         1  /* nil */
 2215#define SQLITE_CONFIG_MULTITHREAD          2  /* nil */
 2216#define SQLITE_CONFIG_SERIALIZED           3  /* nil */
 2217#define SQLITE_CONFIG_MALLOC               4  /* sqlite3_mem_methods* */
 2218#define SQLITE_CONFIG_GETMALLOC            5  /* sqlite3_mem_methods* */
 2219#define SQLITE_CONFIG_SCRATCH              6  /* No longer used */
 2220#define SQLITE_CONFIG_PAGECACHE            7  /* void*, int sz, int N */
 2221#define SQLITE_CONFIG_HEAP                 8  /* void*, int nByte, int min */
 2222#define SQLITE_CONFIG_MEMSTATUS            9  /* boolean */
 2223#define SQLITE_CONFIG_MUTEX               10  /* sqlite3_mutex_methods* */
 2224#define SQLITE_CONFIG_GETMUTEX            11  /* sqlite3_mutex_methods* */
 2225/* previously SQLITE_CONFIG_CHUNKALLOC    12 which is now unused. */
 2226#define SQLITE_CONFIG_LOOKASIDE           13  /* int int */
 2227#define SQLITE_CONFIG_PCACHE              14  /* no-op */
 2228#define SQLITE_CONFIG_GETPCACHE           15  /* no-op */
 2229#define SQLITE_CONFIG_LOG                 16  /* xFunc, void* */
 2230#define SQLITE_CONFIG_URI                 17  /* int */
 2231#define SQLITE_CONFIG_PCACHE2             18  /* sqlite3_pcache_methods2* */
 2232#define SQLITE_CONFIG_GETPCACHE2          19  /* sqlite3_pcache_methods2* */
 2233#define SQLITE_CONFIG_COVERING_INDEX_SCAN 20  /* int */
 2234#define SQLITE_CONFIG_SQLLOG              21  /* xSqllog, void* */
 2235#define SQLITE_CONFIG_MMAP_SIZE           22  /* sqlite3_int64, sqlite3_int64 */
 2236#define SQLITE_CONFIG_WIN32_HEAPSIZE      23  /* int nByte */
 2237#define SQLITE_CONFIG_PCACHE_HDRSZ        24  /* int *psz */
 2238#define SQLITE_CONFIG_PMASZ               25  /* unsigned int szPma */
 2239#define SQLITE_CONFIG_STMTJRNL_SPILL      26  /* int nByte */
 2240#define SQLITE_CONFIG_SMALL_MALLOC        27  /* boolean */
 2241#define SQLITE_CONFIG_SORTERREF_SIZE      28  /* int nByte */
 2242#define SQLITE_CONFIG_MEMDB_MAXSIZE       29  /* sqlite3_int64 */
 2243#define SQLITE_CONFIG_ROWID_IN_VIEW       30  /* int* */
 2244
 2245/*
 2246** CAPI3REF: Database Connection Configuration Options
 2247**
 2248** These constants are the available integer configuration options that
 2249** can be passed as the second parameter to the [sqlite3_db_config()] interface.
 2250**
 2251** The [sqlite3_db_config()] interface is a var-args function.  It takes a
 2252** variable number of parameters, though always at least two.  The number of
 2253** parameters passed into sqlite3_db_config() depends on which of these
 2254** constants is given as the second parameter.  This documentation page
 2255** refers to parameters beyond the second as "arguments".  Thus, when this
 2256** page says "the N-th argument" it means "the N-th parameter past the
 2257** configuration option" or "the (N+2)-th parameter to sqlite3_db_config()".
 2258**
 2259** New configuration options may be added in future releases of SQLite.
 2260** Existing configuration options might be discontinued.  Applications
 2261** should check the return code from [sqlite3_db_config()] to make sure that
 2262** the call worked.  ^The [sqlite3_db_config()] interface will return a
 2263** non-zero [error code] if a discontinued or unsupported configuration option
 2264** is invoked.
 2265**
 2266** <dl>
 2267** [[SQLITE_DBCONFIG_LOOKASIDE]]
 2268** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
 2269** <dd> The SQLITE_DBCONFIG_LOOKASIDE option is used to adjust the
 2270** configuration of the [lookaside memory allocator] within a database
 2271** connection.
 2272** The arguments to the SQLITE_DBCONFIG_LOOKASIDE option are <i>not</i>
 2273** in the [DBCONFIG arguments|usual format].
 2274** The SQLITE_DBCONFIG_LOOKASIDE option takes three arguments, not two,
 2275** so that a call to [sqlite3_db_config()] that uses SQLITE_DBCONFIG_LOOKASIDE
 2276** should have a total of five parameters.
 2277** <ol>
 2278** <li><p>The first argument ("buf") is a
 2279** pointer to a memory buffer to use for lookaside memory.
 2280** The first argument may be NULL in which case SQLite will allocate the
 2281** lookaside buffer itself using [sqlite3_malloc()].
 2282** <li><P>The second argument ("sz") is the
 2283** size of each lookaside buffer slot.  Lookaside is disabled if "sz"
 2284** is less than 8.  The "sz" argument should be a multiple of 8 less than
 2285** 65536.  If "sz" does not meet this constraint, it is reduced in size until
 2286** it does.
 2287** <li><p>The third argument ("cnt") is the number of slots.
 2288** Lookaside is disabled if "cnt"is less than 1.
 2289*  The "cnt" value will be reduced, if necessary, so
 2290** that the product of "sz" and "cnt" does not exceed 2,147,418,112. The "cnt"
 2291** parameter is usually chosen so that the product of "sz" and "cnt" is less
 2292** than 1,000,000.
 2293** </ol>
 2294** <p>If the "buf" argument is not NULL, then it must
 2295** point to a memory buffer with a size that is greater than
 2296** or equal to the product of "sz" and "cnt".
 2297** The buffer must be aligned to an 8-byte boundary.
 2298** The lookaside memory
 2299** configuration for a database connection can only be changed when that
 2300** connection is not currently using lookaside memory, or in other words
 2301** when the value returned by [SQLITE_DBSTATUS_LOOKASIDE_USED] is zero.
 2302** Any attempt to change the lookaside memory configuration when lookaside
 2303** memory is in use leaves the configuration unchanged and returns
 2304** [SQLITE_BUSY].
 2305** If the "buf" argument is NULL and an attempt
 2306** to allocate memory based on "sz" and "cnt" fails, then
 2307** lookaside is silently disabled.
 2308** <p>
 2309** The [SQLITE_CONFIG_LOOKASIDE] configuration option can be used to set the
 2310** default lookaside configuration at initialization.  The
 2311** [-DSQLITE_DEFAULT_LOOKASIDE] option can be used to set the default lookaside
 2312** configuration at compile-time.  Typical values for lookaside are 1200 for
 2313** "sz" and 40 to 100 for "cnt".
 2314** </dd>
 2315**
 2316** [[SQLITE_DBCONFIG_ENABLE_FKEY]]
 2317** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
 2318** <dd> ^This option is used to enable or disable the enforcement of
 2319** [foreign key constraints].  This is the same setting that is
 2320** enabled or disabled by the [PRAGMA foreign_keys] statement.
 2321** The first argument is an integer which is 0 to disable FK enforcement,
 2322** positive to enable FK enforcement or negative to leave FK enforcement
 2323** unchanged.  The second parameter is a pointer to an integer into which
 2324** is written 0 or 1 to indicate whether FK enforcement is off or on
 2325** following this call.  The second parameter may be a NULL pointer, in
 2326** which case the FK enforcement setting is not reported back. </dd>
 2327**
 2328** [[SQLITE_DBCONFIG_ENABLE_TRIGGER]]
 2329** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
 2330** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
 2331** There should be two additional arguments.
 2332** The first argument is an integer which is 0 to disable triggers,
 2333** positive to enable triggers or negative to leave the setting unchanged.
 2334** The second parameter is a pointer to an integer into which
 2335** is written 0 or 1 to indicate whether triggers are disabled or enabled
 2336** following this call.  The second parameter may be a NULL pointer, in
 2337** which case the trigger setting is not reported back.
 2338**
 2339** <p>Originally this option disabled all triggers.  ^(However, since
 2340** SQLite version 3.35.0, TEMP triggers are still allowed even if
 2341** this option is off.  So, in other words, this option now only disables
 2342** triggers in the main database schema or in the schemas of [ATTACH]-ed
 2343** databases.)^ </dd>
 2344**
 2345** [[SQLITE_DBCONFIG_ENABLE_VIEW]]
 2346** <dt>SQLITE_DBCONFIG_ENABLE_VIEW</dt>
 2347** <dd> ^This option is used to enable or disable [CREATE VIEW | views].
 2348** There must be two additional arguments.
 2349** The first argument is an integer which is 0 to disable views,
 2350** positive to enable views or negative to leave the setting unchanged.
 2351** The second parameter is a pointer to an integer into which
 2352** is written 0 or 1 to indicate whether views are disabled or enabled
 2353** following this call.  The second parameter may be a NULL pointer, in
 2354** which case the view setting is not reported back.
 2355**
 2356** <p>Originally this option disabled all views.  ^(However, since
 2357** SQLite version 3.35.0, TEMP views are still allowed even if
 2358** this option is off.  So, in other words, this option now only disables
 2359** views in the main database schema or in the schemas of ATTACH-ed
 2360** databases.)^ </dd>
 2361**
 2362** [[SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER]]
 2363** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
 2364** <dd> ^This option is used to enable or disable using the
 2365** [fts3_tokenizer()] function - part of the [FTS3] full-text search engine
 2366** extension - without using bound parameters as the parameters. Doing so
 2367** is disabled by default. There must be two additional arguments. The first
 2368** argument is an integer. If it is passed 0, then using fts3_tokenizer()
 2369** without bound parameters is disabled. If it is passed a positive value,
 2370** then calling fts3_tokenizer without bound parameters is enabled. If it
 2371** is passed a negative value, this setting is not modified - this can be
 2372** used to query for the current setting. The second parameter is a pointer
 2373** to an integer into which is written 0 or 1 to indicate the current value
 2374** of this setting (after it is modified, if applicable).  The second
 2375** parameter may be a NULL pointer, in which case the value of the setting
 2376** is not reported back. Refer to [FTS3] documentation for further details.
 2377** </dd>
 2378**
 2379** [[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION]]
 2380** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
 2381** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
 2382** interface independently of the [load_extension()] SQL function.
 2383** The [sqlite3_enable_load_extension()] API enables or disables both the
 2384** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].
 2385** There must be two additional arguments.
 2386** When the first argument to this interface is 1, then only the C-API is
 2387** enabled and the SQL function remains disabled.  If the first argument to
 2388** this interface is 0, then both the C-API and the SQL function are disabled.
 2389** If the first argument is -1, then no changes are made to the state of either
 2390** the C-API or the SQL function.
 2391** The second parameter is a pointer to an integer into which
 2392** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface
 2393** is disabled or enabled following this call.  The second parameter may
 2394** be a NULL pointer, in which case the new setting is not reported back.
 2395** </dd>
 2396**
 2397** [[SQLITE_DBCONFIG_MAINDBNAME]] <dt>SQLITE_DBCONFIG_MAINDBNAME</dt>
 2398** <dd> ^This option is used to change the name of the "main" database
 2399** schema.  This option does not follow the
 2400** [DBCONFIG arguments|usual SQLITE_DBCONFIG argument format].
 2401** This option takes exactly one additional argument so that the
 2402** [sqlite3_db_config()] call has a total of three parameters.  The
 2403** extra argument must be a pointer to a constant UTF8 string which
 2404** will become the new schema name in place of "main".  ^SQLite does
 2405** not make a copy of the new main schema name string, so the application
 2406** must ensure that the argument passed into SQLITE_DBCONFIG MAINDBNAME
 2407** is unchanged until after the database connection closes.
 2408** </dd>
 2409**
 2410** [[SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE]]
 2411** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
 2412** <dd> Usually, when a database in [WAL mode] is closed or detached from a
 2413** database handle, SQLite checks if if there are other connections to the
 2414** same database, and if there are no other database connection (if the
 2415** connection being closed is the last open connection to the database),
 2416** then SQLite performs a [checkpoint] before closing the connection and
 2417** deletes the WAL file.  The SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE option can
 2418** be used to override that behavior. The first argument passed to this
 2419** operation (the third parameter to [sqlite3_db_config()]) is an integer
 2420** which is positive to disable checkpoints-on-close, or zero (the default)
 2421** to enable them, and negative to leave the setting unchanged.
 2422** The second argument (the fourth parameter) is a pointer to an integer
 2423** into which is written 0 or 1 to indicate whether checkpoints-on-close
 2424** have been disabled - 0 if they are not disabled, 1 if they are.
 2425** </dd>
 2426**
 2427** [[SQLITE_DBCONFIG_ENABLE_QPSG]] <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
 2428** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
 2429** the [query planner stability guarantee] (QPSG).  When the QPSG is active,
 2430** a single SQL query statement will always use the same algorithm regardless
 2431** of values of [bound parameters].)^ The QPSG disables some query optimizations
 2432** that look at the values of bound parameters, which can make some queries
 2433** slower.  But the QPSG has the advantage of more predictable behavior.  With
 2434** the QPSG active, SQLite will always use the same query plan in the field as
 2435** was used during testing in the lab.
 2436** The first argument to this setting is an integer which is 0 to disable
 2437** the QPSG, positive to enable QPSG, or negative to leave the setting
 2438** unchanged. The second parameter is a pointer to an integer into which
 2439** is written 0 or 1 to indicate whether the QPSG is disabled or enabled
 2440** following this call.
 2441** </dd>
 2442**
 2443** [[SQLITE_DBCONFIG_TRIGGER_EQP]] <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt>
 2444** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not
 2445** include output for any operations performed by trigger programs. This
 2446** option is used to set or clear (the default) a flag that governs this
 2447** behavior. The first parameter passed to this operation is an integer -
 2448** positive to enable output for trigger programs, or zero to disable it,
 2449** or negative to leave the setting unchanged.
 2450** The second parameter is a pointer to an integer into which is written
 2451** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if
 2452** it is not disabled, 1 if it is.
 2453** </dd>
 2454**
 2455** [[SQLITE_DBCONFIG_RESET_DATABASE]] <dt>SQLITE_DBCONFIG_RESET_DATABASE</dt>
 2456** <dd> Set the SQLITE_DBCONFIG_RESET_DATABASE flag and then run
 2457** [VACUUM] in order to reset a database back to an empty database
 2458** with no schema and no content. The following process works even for
 2459** a badly corrupted database file:
 2460** <ol>
 2461** <li> If the database connection is newly opened, make sure it has read the
 2462**      database schema by preparing then discarding some query against the
 2463**      database, or calling sqlite3_table_column_metadata(), ignoring any
 2464**      errors.  This step is only necessary if the application desires to keep
 2465**      the database in WAL mode after the reset if it was in WAL mode before
 2466**      the reset.
 2467** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 1, 0);
 2468** <li> [sqlite3_exec](db, "[VACUUM]", 0, 0, 0);
 2469** <li> sqlite3_db_config(db, SQLITE_DBCONFIG_RESET_DATABASE, 0, 0);
 2470** </ol>
 2471** Because resetting a database is destructive and irreversible, the
 2472** process requires the use of this obscure API and multiple steps to
 2473** help ensure that it does not happen by accident. Because this
 2474** feature must be capable of resetting corrupt databases, and
 2475** shutting down virtual tables may require access to that corrupt
 2476** storage, the library must abandon any installed virtual tables
 2477** without calling their xDestroy() methods.
 2478**
 2479** [[SQLITE_DBCONFIG_DEFENSIVE]] <dt>SQLITE_DBCONFIG_DEFENSIVE</dt>
 2480** <dd>The SQLITE_DBCONFIG_DEFENSIVE option activates or deactivates the
 2481** "defensive" flag for a database connection.  When the defensive
 2482** flag is enabled, language features that allow ordinary SQL to
 2483** deliberately corrupt the database file are disabled.  The disabled
 2484** features include but are not limited to the following:
 2485** <ul>
 2486** <li> The [PRAGMA writable_schema=ON] statement.
 2487** <li> The [PRAGMA journal_mode=OFF] statement.
 2488** <li> The [PRAGMA schema_version=N] statement.
 2489** <li> Writes to the [sqlite_dbpage] virtual table.
 2490** <li> Direct writes to [shadow tables].
 2491** </ul>
 2492** </dd>
 2493**
 2494** [[SQLITE_DBCONFIG_WRITABLE_SCHEMA]] <dt>SQLITE_DBCONFIG_WRITABLE_SCHEMA</dt>
 2495** <dd>The SQLITE_DBCONFIG_WRITABLE_SCHEMA option activates or deactivates the
 2496** "writable_schema" flag. This has the same effect and is logically equivalent
 2497** to setting [PRAGMA writable_schema=ON] or [PRAGMA writable_schema=OFF].
 2498** The first argument to this setting is an integer which is 0 to disable
 2499** the writable_schema, positive to enable writable_schema, or negative to
 2500** leave the setting unchanged. The second parameter is a pointer to an
 2501** integer into which is written 0 or 1 to indicate whether the writable_schema
 2502** is enabled or disabled following this call.
 2503** </dd>
 2504**
 2505** [[SQLITE_DBCONFIG_LEGACY_ALTER_TABLE]]
 2506** <dt>SQLITE_DBCONFIG_LEGACY_ALTER_TABLE</dt>
 2507** <dd>The SQLITE_DBCONFIG_LEGACY_ALTER_TABLE option activates or deactivates
 2508** the legacy behavior of the [ALTER TABLE RENAME] command such that it
 2509** behaves as it did prior to [version 3.24.0] (2018-06-04).  See the
 2510** "Compatibility Notice" on the [ALTER TABLE RENAME documentation] for
 2511** additional information. This feature can also be turned on and off
 2512** using the [PRAGMA legacy_alter_table] statement.
 2513** </dd>
 2514**
 2515** [[SQLITE_DBCONFIG_DQS_DML]]
 2516** <dt>SQLITE_DBCONFIG_DQS_DML</dt>
 2517** <dd>The SQLITE_DBCONFIG_DQS_DML option activates or deactivates
 2518** the legacy [double-quoted string literal] misfeature for DML statements
 2519** only, that is DELETE, INSERT, SELECT, and UPDATE statements. The
 2520** default value of this setting is determined by the [-DSQLITE_DQS]
 2521** compile-time option.
 2522** </dd>
 2523**
 2524** [[SQLITE_DBCONFIG_DQS_DDL]]
 2525** <dt>SQLITE_DBCONFIG_DQS_DDL</dt>
 2526** <dd>The SQLITE_DBCONFIG_DQS option activates or deactivates
 2527** the legacy [double-quoted string literal] misfeature for DDL statements,
 2528** such as CREATE TABLE and CREATE INDEX. The
 2529** default value of this setting is determined by the [-DSQLITE_DQS]
 2530** compile-time option.
 2531** </dd>
 2532**
 2533** [[SQLITE_DBCONFIG_TRUSTED_SCHEMA]]
 2534** <dt>SQLITE_DBCONFIG_TRUSTED_SCHEMA</dt>
 2535** <dd>The SQLITE_DBCONFIG_TRUSTED_SCHEMA option tells SQLite to
 2536** assume that database schemas are untainted by malicious content.
 2537** When the SQLITE_DBCONFIG_TRUSTED_SCHEMA option is disabled, SQLite
 2538** takes additional defensive steps to protect the application from harm
 2539** including:
 2540** <ul>
 2541** <li> Prohibit the use of SQL functions inside triggers, views,
 2542** CHECK constraints, DEFAULT clauses, expression indexes,
 2543** partial indexes, or generated columns
 2544** unless those functions are tagged with [SQLITE_INNOCUOUS].
 2545** <li> Prohibit the use of virtual tables inside of triggers or views
 2546** unless those virtual tables are tagged with [SQLITE_VTAB_INNOCUOUS].
 2547** </ul>
 2548** This setting defaults to "on" for legacy compatibility, however
 2549** all applications are advised to turn it off if possible. This setting
 2550** can also be controlled using the [PRAGMA trusted_schema] statement.
 2551** </dd>
 2552**
 2553** [[SQLITE_DBCONFIG_LEGACY_FILE_FORMAT]]
 2554** <dt>SQLITE_DBCONFIG_LEGACY_FILE_FORMAT</dt>
 2555** <dd>The SQLITE_DBCONFIG_LEGACY_FILE_FORMAT option activates or deactivates
 2556** the legacy file format flag.  When activated, this flag causes all newly
 2557** created database files to have a schema format version number (the 4-byte
 2558** integer found at offset 44 into the database header) of 1.  This in turn
 2559** means that the resulting database file will be readable and writable by
 2560** any SQLite version back to 3.0.0 ([dateof:3.0.0]).  Without this setting,
 2561** newly created databases are generally not understandable by SQLite versions
 2562** prior to 3.3.0 ([dateof:3.3.0]).  As these words are written, there
 2563** is now scarcely any need to generate database files that are compatible
 2564** all the way back to version 3.0.0, and so this setting is of little
 2565** practical use, but is provided so that SQLite can continue to claim the
 2566** ability to generate new database files that are compatible with  version
 2567** 3.0.0.
 2568** <p>Note that when the SQLITE_DBCONFIG_LEGACY_FILE_FORMAT setting is on,
 2569** the [VACUUM] command will fail with an obscure error when attempting to
 2570** process a table with generated columns and a descending index.  This is
 2571** not considered a bug since SQLite versions 3.3.0 and earlier do not support
 2572** either generated columns or descending indexes.
 2573** </dd>
 2574**
 2575** [[SQLITE_DBCONFIG_STMT_SCANSTATUS]]
 2576** <dt>SQLITE_DBCONFIG_STMT_SCANSTATUS</dt>
 2577** <dd>The SQLITE_DBCONFIG_STMT_SCANSTATUS option is only useful in
 2578** [SQLITE_ENABLE_STMT_SCANSTATUS] builds. In this case, it sets or clears
 2579** a flag that enables collection of run-time performance statistics
 2580** used by [sqlite3_stmt_scanstatus_v2()] and the [nexec and ncycle]
 2581** columns of the [bytecode virtual table].
 2582** For statistics to be collected, the flag must be set on
 2583** the database handle both when the SQL statement is
 2584** [sqlite3_prepare|prepared] and when it is [sqlite3_step|stepped].
 2585** The flag is set (collection of statistics is enabled) by default.
 2586** <p>This option takes two arguments: an integer and a pointer to
 2587** an integer.  The first argument is 1, 0, or -1 to enable, disable, or
 2588** leave unchanged the statement scanstatus option.  If the second argument
 2589** is not NULL, then the value of the statement scanstatus setting after
 2590** processing the first argument is written into the integer that the second
 2591** argument points to.
 2592** </dd>
 2593**
 2594** [[SQLITE_DBCONFIG_REVERSE_SCANORDER]]
 2595** <dt>SQLITE_DBCONFIG_REVERSE_SCANORDER</dt>
 2596** <dd>The SQLITE_DBCONFIG_REVERSE_SCANORDER option changes the default order
 2597** in which tables and indexes are scanned so that the scans start at the end
 2598** and work toward the beginning rather than starting at the beginning and
 2599** working toward the end. Setting SQLITE_DBCONFIG_REVERSE_SCANORDER is the
 2600** same as setting [PRAGMA reverse_unordered_selects]. <p>This option takes
 2601** two arguments which are an integer and a pointer to an integer.  The first
 2602** argument is 1, 0, or -1 to enable, disable, or leave unchanged the
 2603** reverse scan order flag, respectively.  If the second argument is not NULL,
 2604** then 0 or 1 is written into the integer that the second argument points to
 2605** depending on if the reverse scan order flag is set after processing the
 2606** first argument.
 2607** </dd>
 2608**
 2609** [[SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE]]
 2610** <dt>SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE</dt>
 2611** <dd>The SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE option enables or disables
 2612** the ability of the [ATTACH DATABASE] SQL command to create a new database
 2613** file if the database filed named in the ATTACH command does not already
 2614** exist.  This ability of ATTACH to create a new database is enabled by
 2615** default.  Applications can disable or reenable the ability for ATTACH to
 2616** create new database files using this DBCONFIG option.<p>
 2617** This option takes two arguments which are an integer and a pointer
 2618** to an integer.  The first argument is 1, 0, or -1 to enable, disable, or
 2619** leave unchanged the attach-create flag, respectively.  If the second
 2620** argument is not NULL, then 0 or 1 is written into the integer that the
 2621** second argument points to depending on if the attach-create flag is set
 2622** after processing the first argument.
 2623** </dd>
 2624**
 2625** [[SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE]]
 2626** <dt>SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE</dt>
 2627** <dd>The SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE option enables or disables the
 2628** ability of the [ATTACH DATABASE] SQL command to open a database for writing.
 2629** This capability is enabled by default.  Applications can disable or
 2630** reenable this capability using the current DBCONFIG option.  If
 2631** this capability is disabled, the [ATTACH] command will still work,
 2632** but the database will be opened read-only.  If this option is disabled,
 2633** then the ability to create a new database using [ATTACH] is also disabled,
 2634** regardless of the value of the [SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE]
 2635** option.<p>
 2636** This option takes two arguments which are an integer and a pointer
 2637** to an integer.  The first argument is 1, 0, or -1 to enable, disable, or
 2638** leave unchanged the ability to ATTACH another database for writing,
 2639** respectively.  If the second argument is not NULL, then 0 or 1 is written
 2640** into the integer to which the second argument points, depending on whether
 2641** the ability to ATTACH a read/write database is enabled or disabled
 2642** after processing the first argument.
 2643** </dd>
 2644**
 2645** [[SQLITE_DBCONFIG_ENABLE_COMMENTS]]
 2646** <dt>SQLITE_DBCONFIG_ENABLE_COMMENTS</dt>
 2647** <dd>The SQLITE_DBCONFIG_ENABLE_COMMENTS option enables or disables the
 2648** ability to include comments in SQL text.  Comments are enabled by default.
 2649** An application can disable or reenable comments in SQL text using this
 2650** DBCONFIG option.<p>
 2651** This option takes two arguments which are an integer and a pointer
 2652** to an integer.  The first argument is 1, 0, or -1 to enable, disable, or
 2653** leave unchanged the ability to use comments in SQL text,
 2654** respectively.  If the second argument is not NULL, then 0 or 1 is written
 2655** into the integer that the second argument points to depending on if
 2656** comments are allowed in SQL text after processing the first argument.
 2657** </dd>
 2658**
 2659** [[SQLITE_DBCONFIG_FP_DIGITS]]
 2660** <dt>SQLITE_DBCONFIG_FP_DIGITS</dt>
 2661** <dd>The SQLITE_DBCONFIG_FP_DIGITS setting is a small integer that determines
 2662** the number of significant digits that SQLite will attempt to preserve when
 2663** converting floating point numbers (IEEE 754 "doubles") into text.  The
 2664** default value 17, as of SQLite version 3.52.0.  The value was 15 in all
 2665** prior versions.<p>
 2666** This option takes two arguments which are an integer and a pointer
 2667** to an integer.  The first argument is a small integer, between 3 and 23, or
 2668** zero.  The FP_DIGITS setting is changed to that small integer, or left
 2669** unaltered if the first argument is zero or out of range. The second argument
 2670** is a pointer to an integer.  If the pointer is not NULL, then the value of
 2671** the FP_DIGITS setting, after possibly being modified by the first
 2672** arguments, is written into the integer to which the second argument points.
 2673** </dd>
 2674**
 2675** </dl>
 2676**
 2677** [[DBCONFIG arguments]] <h3>Arguments To SQLITE_DBCONFIG Options</h3>
 2678**
 2679** <p>Most of the SQLITE_DBCONFIG options take two arguments, so that the
 2680** overall call to [sqlite3_db_config()] has a total of four parameters.
 2681** The first argument (the third parameter to sqlite3_db_config()) is
 2682** an integer.
 2683** The second argument is a pointer to an integer. If the first argument is 1,
 2684** then the option becomes enabled.  If the first integer argument is 0,
 2685** then the option is disabled.
 2686** If the first argument is -1, then the option setting
 2687** is unchanged.  The second argument, the pointer to an integer, may be NULL.
 2688** If the second argument is not NULL, then a value of 0 or 1 is written into
 2689** the integer to which the second argument points, depending on whether the
 2690** setting is disabled or enabled after applying any changes specified by
 2691** the first argument.
 2692**
 2693** <p>While most SQLITE_DBCONFIG options use the argument format
 2694** described in the previous paragraph, the [SQLITE_DBCONFIG_MAINDBNAME],
 2695** [SQLITE_DBCONFIG_LOOKASIDE], and [SQLITE_DBCONFIG_FP_DIGITS] options
 2696** are different.  See the documentation of those exceptional options for
 2697** details.
 2698*/
 2699#define SQLITE_DBCONFIG_MAINDBNAME            1000 /* const char* */
 2700#define SQLITE_DBCONFIG_LOOKASIDE             1001 /* void* int int */
 2701#define SQLITE_DBCONFIG_ENABLE_FKEY           1002 /* int int* */
 2702#define SQLITE_DBCONFIG_ENABLE_TRIGGER        1003 /* int int* */
 2703#define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
 2704#define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
 2705#define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE      1006 /* int int* */
 2706#define SQLITE_DBCONFIG_ENABLE_QPSG           1007 /* int int* */
 2707#define SQLITE_DBCONFIG_TRIGGER_EQP           1008 /* int int* */
 2708#define SQLITE_DBCONFIG_RESET_DATABASE        1009 /* int int* */
 2709#define SQLITE_DBCONFIG_DEFENSIVE             1010 /* int int* */
 2710#define SQLITE_DBCONFIG_WRITABLE_SCHEMA       1011 /* int int* */
 2711#define SQLITE_DBCONFIG_LEGACY_ALTER_TABLE    1012 /* int int* */
 2712#define SQLITE_DBCONFIG_DQS_DML               1013 /* int int* */
 2713#define SQLITE_DBCONFIG_DQS_DDL               1014 /* int int* */
 2714#define SQLITE_DBCONFIG_ENABLE_VIEW           1015 /* int int* */
 2715#define SQLITE_DBCONFIG_LEGACY_FILE_FORMAT    1016 /* int int* */
 2716#define SQLITE_DBCONFIG_TRUSTED_SCHEMA        1017 /* int int* */
 2717#define SQLITE_DBCONFIG_STMT_SCANSTATUS       1018 /* int int* */
 2718#define SQLITE_DBCONFIG_REVERSE_SCANORDER     1019 /* int int* */
 2719#define SQLITE_DBCONFIG_ENABLE_ATTACH_CREATE  1020 /* int int* */
 2720#define SQLITE_DBCONFIG_ENABLE_ATTACH_WRITE   1021 /* int int* */
 2721#define SQLITE_DBCONFIG_ENABLE_COMMENTS       1022 /* int int* */
 2722#define SQLITE_DBCONFIG_FP_DIGITS             1023 /* int int* */
 2723#define SQLITE_DBCONFIG_MAX                   1023 /* Largest DBCONFIG */
 2724
 2725/*
 2726** CAPI3REF: Enable Or Disable Extended Result Codes
 2727** METHOD: sqlite3
 2728**
 2729** ^The sqlite3_extended_result_codes() routine enables or disables the
 2730** [extended result codes] feature of SQLite. ^The extended result
 2731** codes are disabled by default for historical compatibility.
 2732*/
 2733SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
 2734
 2735/*
 2736** CAPI3REF: Last Insert Rowid
 2737** METHOD: sqlite3
 2738**
 2739** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
 2740** has a unique 64-bit signed
 2741** integer key called the [ROWID | "rowid"]. ^The rowid is always available
 2742** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
 2743** names are not also used by explicitly declared columns. ^If
 2744** the table has a column of type [INTEGER PRIMARY KEY] then that column
 2745** is another alias for the rowid.
 2746**
 2747** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of
 2748** the most recent successful [INSERT] into a rowid table or [virtual table]
 2749** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not
 2750** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred
 2751** on the database connection D, then sqlite3_last_insert_rowid(D) returns
 2752** zero.
 2753**
 2754** As well as being set automatically as rows are inserted into database
 2755** tables, the value returned by this function may be set explicitly by
 2756** [sqlite3_set_last_insert_rowid()]
 2757**
 2758** Some virtual table implementations may INSERT rows into rowid tables as
 2759** part of committing a transaction (e.g. to flush data accumulated in memory
 2760** to disk). In this case subsequent calls to this function return the rowid
 2761** associated with these internal INSERT operations, which leads to
 2762** unintuitive results. Virtual table implementations that do write to rowid
 2763** tables in this way can avoid this problem by restoring the original
 2764** rowid value using [sqlite3_set_last_insert_rowid()] before returning
 2765** control to the user.
 2766**
 2767** ^(If an [INSERT] occurs within a trigger then this routine will
 2768** return the [rowid] of the inserted row as long as the trigger is
 2769** running. Once the trigger program ends, the value returned
 2770** by this routine reverts to what it was before the trigger was fired.)^
 2771**
 2772** ^An [INSERT] that fails due to a constraint violation is not a
 2773** successful [INSERT] and does not change the value returned by this
 2774** routine.  ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
 2775** and INSERT OR ABORT make no changes to the return value of this
 2776** routine when their insertion fails.  ^(When INSERT OR REPLACE
 2777** encounters a constraint violation, it does not fail.  The
 2778** INSERT continues to completion after deleting rows that caused
 2779** the constraint problem so INSERT OR REPLACE will always change
 2780** the return value of this interface.)^
 2781**
 2782** ^For the purposes of this routine, an [INSERT] is considered to
 2783** be successful even if it is subsequently rolled back.
 2784**
 2785** This function is accessible to SQL statements via the
 2786** [last_insert_rowid() SQL function].
 2787**
 2788** If a separate thread performs a new [INSERT] on the same
 2789** database connection while the [sqlite3_last_insert_rowid()]
 2790** function is running and thus changes the last insert [rowid],
 2791** then the value returned by [sqlite3_last_insert_rowid()] is
 2792** unpredictable and might not equal either the old or the new
 2793** last insert [rowid].
 2794*/
 2795SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
 2796
 2797/*
 2798** CAPI3REF: Set the Last Insert Rowid value.
 2799** METHOD: sqlite3
 2800**
 2801** The sqlite3_set_last_insert_rowid(D, R) method allows the application to
 2802** set the value returned by calling sqlite3_last_insert_rowid(D) to R
 2803** without inserting a row into the database.
 2804*/
 2805SQLITE_API void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64);
 2806
 2807/*
 2808** CAPI3REF: Count The Number Of Rows Modified
 2809** METHOD: sqlite3
 2810**
 2811** ^These functions return the number of rows modified, inserted or
 2812** deleted by the most recently completed INSERT, UPDATE or DELETE
 2813** statement on the database connection specified by the only parameter.
 2814** The two functions are identical except for the type of the return value
 2815** and that if the number of rows modified by the most recent INSERT, UPDATE,
 2816** or DELETE is greater than the maximum value supported by type "int", then
 2817** the return value of sqlite3_changes() is undefined. ^Executing any other
 2818** type of SQL statement does not modify the value returned by these functions.
 2819** For the purposes of this interface, a CREATE TABLE AS SELECT statement
 2820** does not count as an INSERT, UPDATE or DELETE statement and hence the rows
 2821** added to the new table by the CREATE TABLE AS SELECT statement are not
 2822** counted.
 2823**
 2824** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
 2825** considered - auxiliary changes caused by [CREATE TRIGGER | triggers],
 2826** [foreign key actions] or [REPLACE] constraint resolution are not counted.
 2827**
 2828** Changes to a view that are intercepted by
 2829** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value
 2830** returned by sqlite3_changes() immediately after an INSERT, UPDATE or
 2831** DELETE statement run on a view is always zero. Only changes made to real
 2832** tables are counted.
 2833**
 2834** Things are more complicated if the sqlite3_changes() function is
 2835** executed while a trigger program is running. This may happen if the
 2836** program uses the [changes() SQL function], or if some other callback
 2837** function invokes sqlite3_changes() directly. Essentially:
 2838**
 2839** <ul>
 2840**   <li> ^(Before entering a trigger program the value returned by
 2841**        sqlite3_changes() function is saved. After the trigger program
 2842**        has finished, the original value is restored.)^
 2843**
 2844**   <li> ^(Within a trigger program each INSERT, UPDATE and DELETE
 2845**        statement sets the value returned by sqlite3_changes()
 2846**        upon completion as normal. Of course, this value will not include
 2847**        any changes performed by sub-triggers, as the sqlite3_changes()
 2848**        value will be saved and restored after each sub-trigger has run.)^
 2849** </ul>
 2850**
 2851** ^This means that if the changes() SQL function (or similar) is used
 2852** by the first INSERT, UPDATE or DELETE statement within a trigger, it
 2853** returns the value as set when the calling statement began executing.
 2854** ^If it is used by the second or subsequent such statement within a trigger
 2855** program, the value returned reflects the number of rows modified by the
 2856** previous INSERT, UPDATE or DELETE statement within the same trigger.
 2857**
 2858** If a separate thread makes changes on the same database connection
 2859** while [sqlite3_changes()] is running then the value returned
 2860** is unpredictable and not meaningful.
 2861**
 2862** See also:
 2863** <ul>
 2864** <li> the [sqlite3_total_changes()] interface
 2865** <li> the [count_changes pragma]
 2866** <li> the [changes() SQL function]
 2867** <li> the [data_version pragma]
 2868** </ul>
 2869*/
 2870SQLITE_API int sqlite3_changes(sqlite3*);
 2871SQLITE_API sqlite3_int64 sqlite3_changes64(sqlite3*);
 2872
 2873/*
 2874** CAPI3REF: Total Number Of Rows Modified
 2875** METHOD: sqlite3
 2876**
 2877** ^These functions return the total number of rows inserted, modified or
 2878** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
 2879** since the database connection was opened, including those executed as
 2880** part of trigger programs. The two functions are identical except for the
 2881** type of the return value and that if the number of rows modified by the
 2882** connection exceeds the maximum value supported by type "int", then
 2883** the return value of sqlite3_total_changes() is undefined. ^Executing
 2884** any other type of SQL statement does not affect the value returned by
 2885** sqlite3_total_changes().
 2886**
 2887** ^Changes made as part of [foreign key actions] are included in the
 2888** count, but those made as part of REPLACE constraint resolution are
 2889** not. ^Changes to a view that are intercepted by INSTEAD OF triggers
 2890** are not counted.
 2891**
 2892** The [sqlite3_total_changes(D)] interface only reports the number
 2893** of rows that changed due to SQL statement run against database
 2894** connection D.  Any changes by other database connections are ignored.
 2895** To detect changes against a database file from other database
 2896** connections use the [PRAGMA data_version] command or the
 2897** [SQLITE_FCNTL_DATA_VERSION] [file control].
 2898**
 2899** If a separate thread makes changes on the same database connection
 2900** while [sqlite3_total_changes()] is running then the value
 2901** returned is unpredictable and not meaningful.
 2902**
 2903** See also:
 2904** <ul>
 2905** <li> the [sqlite3_changes()] interface
 2906** <li> the [count_changes pragma]
 2907** <li> the [changes() SQL function]
 2908** <li> the [data_version pragma]
 2909** <li> the [SQLITE_FCNTL_DATA_VERSION] [file control]
 2910** </ul>
 2911*/
 2912SQLITE_API int sqlite3_total_changes(sqlite3*);
 2913SQLITE_API sqlite3_int64 sqlite3_total_changes64(sqlite3*);
 2914
 2915/*
 2916** CAPI3REF: Interrupt A Long-Running Query
 2917** METHOD: sqlite3
 2918**
 2919** ^This function causes any pending database operation to abort and
 2920** return at its earliest opportunity. This routine is typically
 2921** called in response to a user action such as pressing "Cancel"
 2922** or Ctrl-C where the user wants a long query operation to halt
 2923** immediately.
 2924**
 2925** ^It is safe to call this routine from a thread different from the
 2926** thread that is currently running the database operation.  But it
 2927** is not safe to call this routine with a [database connection] that
 2928** is closed or might close before sqlite3_interrupt() returns.
 2929**
 2930** ^If an SQL operation is very nearly finished at the time when
 2931** sqlite3_interrupt() is called, then it might not have an opportunity
 2932** to be interrupted and might continue to completion.
 2933**
 2934** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
 2935** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
 2936** that is inside an explicit transaction, then the entire transaction
 2937** will be rolled back automatically.
 2938**
 2939** ^The sqlite3_interrupt(D) call is in effect until all currently running
 2940** SQL statements on [database connection] D complete.  ^Any new SQL statements
 2941** that are started after the sqlite3_interrupt() call and before the
 2942** running statement count reaches zero are interrupted as if they had been
 2943** running prior to the sqlite3_interrupt() call.  ^New SQL statements
 2944** that are started after the running statement count reaches zero are
 2945** not effected by the sqlite3_interrupt().
 2946** ^A call to sqlite3_interrupt(D) that occurs when there are no running
 2947** SQL statements is a no-op and has no effect on SQL statements
 2948** that are started after the sqlite3_interrupt() call returns.
 2949**
 2950** ^The [sqlite3_is_interrupted(D)] interface can be used to determine whether
 2951** or not an interrupt is currently in effect for [database connection] D.
 2952** It returns 1 if an interrupt is currently in effect, or 0 otherwise.
 2953*/
 2954SQLITE_API void sqlite3_interrupt(sqlite3*);
 2955SQLITE_API int sqlite3_is_interrupted(sqlite3*);
 2956
 2957/*
 2958** CAPI3REF: Determine If An SQL Statement Is Complete
 2959**
 2960** These routines are useful during command-line input to determine if the
 2961** currently entered text seems to form a complete SQL statement or
 2962** if additional input is needed before sending the text into
 2963** SQLite for parsing.  ^These routines return 1 if the input string
 2964** appears to be a complete SQL statement.  ^A statement is judged to be
 2965** complete if it ends with a semicolon token and is not a prefix of a
 2966** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
 2967** string literals or quoted identifier names or comments are not
 2968** independent tokens (they are part of the token in which they are
 2969** embedded) and thus do not count as a statement terminator.  ^Whitespace
 2970** and comments that follow the final semicolon are ignored.
 2971**
 2972** ^These routines return 0 if the statement is incomplete.  ^If a
 2973** memory allocation fails, then SQLITE_NOMEM is returned.
 2974**
 2975** ^These routines do not parse the SQL statements and thus
 2976** will not detect syntactically incorrect SQL.
 2977**
 2978** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior
 2979** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
 2980** automatically by sqlite3_complete16().  If that initialization fails,
 2981** then the return value from sqlite3_complete16() will be non-zero
 2982** regardless of whether or not the input SQL is complete.)^
 2983**
 2984** The input to [sqlite3_complete()] must be a zero-terminated
 2985** UTF-8 string.
 2986**
 2987** The input to [sqlite3_complete16()] must be a zero-terminated
 2988** UTF-16 string in native byte order.
 2989*/
 2990SQLITE_API int sqlite3_complete(const char *sql);
 2991SQLITE_API int sqlite3_complete16(const void *sql);
 2992
 2993/*
 2994** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
 2995** KEYWORDS: {busy-handler callback} {busy handler}
 2996** METHOD: sqlite3
 2997**
 2998** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
 2999** that might be invoked with argument P whenever
 3000** an attempt is made to access a database table associated with
 3001** [database connection] D when another thread
 3002** or process has the table locked.
 3003** The sqlite3_busy_handler() interface is used to implement
 3004** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
 3005**
 3006** ^If the busy callback is NULL, then [SQLITE_BUSY]
 3007** is returned immediately upon encountering the lock.  ^If the busy callback
 3008** is not NULL, then the callback might be invoked with two arguments.
 3009**
 3010** ^The first argument to the busy handler is a copy of the void* pointer which
 3011** is the third argument to sqlite3_busy_handler().  ^The second argument to
 3012** the busy handler callback is the number of times that the busy handler has
 3013** been invoked previously for the same locking event.  ^If the
 3014** busy callback returns 0, then no additional attempts are made to
 3015** access the database and [SQLITE_BUSY] is returned
 3016** to the application.
 3017** ^If the callback returns non-zero, then another attempt
 3018** is made to access the database and the cycle repeats.
 3019**
 3020** The presence of a busy handler does not guarantee that it will be invoked
 3021** when there is lock contention. ^If SQLite determines that invoking the busy
 3022** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
 3023** to the application instead of invoking the
 3024** busy handler.
 3025** Consider a scenario where one process is holding a read lock that
 3026** it is trying to promote to a reserved lock and
 3027** a second process is holding a reserved lock that it is trying
 3028** to promote to an exclusive lock.  The first process cannot proceed
 3029** because it is blocked by the second and the second process cannot
 3030** proceed because it is blocked by the first.  If both processes
 3031** invoke the busy handlers, neither will make any progress.  Therefore,
 3032** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
 3033** will induce the first process to release its read lock and allow
 3034** the second process to proceed.
 3035**
 3036** ^The default busy callback is NULL.
 3037**
 3038** ^(There can only be a single busy handler defined for each
 3039** [database connection].  Setting a new busy handler clears any
 3040** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
 3041** or evaluating [PRAGMA busy_timeout=N] will change the
 3042** busy handler and thus clear any previously set busy handler.
 3043**
 3044** The busy callback should not take any actions which modify the
 3045** database connection that invoked the busy handler.  In other words,
 3046** the busy handler is not reentrant.  Any such actions
 3047** result in undefined behavior.
 3048**
 3049** A busy handler must not close the database connection
 3050** or [prepared statement] that invoked the busy handler.
 3051*/
 3052SQLITE_API int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
 3053
 3054/*
 3055** CAPI3REF: Set A Busy Timeout
 3056** METHOD: sqlite3
 3057**
 3058** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
 3059** for a specified amount of time when a table is locked.  ^The handler
 3060** will sleep multiple times until at least "ms" milliseconds of sleeping
 3061** have accumulated.  ^After at least "ms" milliseconds of sleeping,
 3062** the handler returns 0 which causes [sqlite3_step()] to return
 3063** [SQLITE_BUSY].
 3064**
 3065** ^Calling this routine with an argument less than or equal to zero
 3066** turns off all busy handlers.
 3067**
 3068** ^(There can only be a single busy handler for a particular
 3069** [database connection] at any given moment.  If another busy handler
 3070** was defined  (using [sqlite3_busy_handler()]) prior to calling
 3071** this routine, that other busy handler is cleared.)^
 3072**
 3073** See also:  [PRAGMA busy_timeout]
 3074*/
 3075SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
 3076
 3077/*
 3078** CAPI3REF: Set the Setlk Timeout
 3079** METHOD: sqlite3
 3080**
 3081** This routine is only useful in SQLITE_ENABLE_SETLK_TIMEOUT builds. If
 3082** the VFS supports blocking locks, it sets the timeout in ms used by
 3083** eligible locks taken on wal mode databases by the specified database
 3084** handle. In non-SQLITE_ENABLE_SETLK_TIMEOUT builds, or if the VFS does
 3085** not support blocking locks, this function is a no-op.
 3086**
 3087** Passing 0 to this function disables blocking locks altogether. Passing
 3088** -1 to this function requests that the VFS blocks for a long time -
 3089** indefinitely if possible. The results of passing any other negative value
 3090** are undefined.
 3091**
 3092** Internally, each SQLite database handle stores two timeout values - the
 3093** busy-timeout (used for rollback mode databases, or if the VFS does not
 3094** support blocking locks) and the setlk-timeout (used for blocking locks
 3095** on wal-mode databases). The sqlite3_busy_timeout() method sets both
 3096** values, this function sets only the setlk-timeout value. Therefore,
 3097** to configure separate busy-timeout and setlk-timeout values for a single
 3098** database handle, call sqlite3_busy_timeout() followed by this function.
 3099**
 3100** Whenever the number of connections to a wal mode database falls from
 3101** 1 to 0, the last connection takes an exclusive lock on the database,
 3102** then checkpoints and deletes the wal file. While it is doing this, any
 3103** new connection that tries to read from the database fails with an
 3104** SQLITE_BUSY error. Or, if the SQLITE_SETLK_BLOCK_ON_CONNECT flag is
 3105** passed to this API, the new connection blocks until the exclusive lock
 3106** has been released.
 3107*/
 3108SQLITE_API int sqlite3_setlk_timeout(sqlite3*, int ms, int flags);
 3109
 3110/*
 3111** CAPI3REF: Flags for sqlite3_setlk_timeout()
 3112*/
 3113#define SQLITE_SETLK_BLOCK_ON_CONNECT 0x01
 3114
 3115/*
 3116** CAPI3REF: Convenience Routines For Running Queries
 3117** METHOD: sqlite3
 3118**
 3119** This is a legacy interface that is preserved for backwards compatibility.
 3120** Use of this interface is not recommended.
 3121**
 3122** Definition: A <b>result table</b> is a memory data structure created by the
 3123** [sqlite3_get_table()] interface.  A result table records the
 3124** complete query results from one or more queries.
 3125**
 3126** The table conceptually has a number of rows and columns.  But
 3127** these numbers are not part of the result table itself.  These
 3128** numbers are obtained separately.  Let N be the number of rows
 3129** and M be the number of columns.
 3130**
 3131** A result table is an array of pointers to zero-terminated UTF-8 strings.
 3132** There are (N+1)*M elements in the array.  The first M pointers point
 3133** to zero-terminated strings that  contain the names of the columns.
 3134** The remaining entries all point to query results.  NULL values result
 3135** in NULL pointers.  All other values are in their UTF-8 zero-terminated
 3136** string representation as returned by [sqlite3_column_text()].
 3137**
 3138** A result table might consist of one or more memory allocations.
 3139** It is not safe to pass a result table directly to [sqlite3_free()].
 3140** A result table should be deallocated using [sqlite3_free_table()].
 3141**
 3142** ^(As an example of the result table format, suppose a query result
 3143** is as follows:
 3144**
 3145** <blockquote><pre>
 3146**        Name        | Age
 3147**        -----------------------
 3148**        Alice       | 43
 3149**        Bob         | 28
 3150**        Cindy       | 21
 3151** </pre></blockquote>
 3152**
 3153** There are two columns (M==2) and three rows (N==3).  Thus the
 3154** result table has 8 entries.  Suppose the result table is stored
 3155** in an array named azResult.  Then azResult holds this content:
 3156**
 3157** <blockquote><pre>
 3158**        azResult&#91;0] = "Name";
 3159**        azResult&#91;1] = "Age";
 3160**        azResult&#91;2] = "Alice";
 3161**        azResult&#91;3] = "43";
 3162**        azResult&#91;4] = "Bob";
 3163**        azResult&#91;5] = "28";
 3164**        azResult&#91;6] = "Cindy";
 3165**        azResult&#91;7] = "21";
 3166** </pre></blockquote>)^
 3167**
 3168** ^The sqlite3_get_table() function evaluates one or more
 3169** semicolon-separated SQL statements in the zero-terminated UTF-8
 3170** string of its 2nd parameter and returns a result table to the
 3171** pointer given in its 3rd parameter.
 3172**
 3173** After the application has finished with the result from sqlite3_get_table(),
 3174** it must pass the result table pointer to sqlite3_free_table() in order to
 3175** release the memory that was malloced.  Because of the way the
 3176** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
 3177** function must not try to call [sqlite3_free()] directly.  Only
 3178** [sqlite3_free_table()] is able to release the memory properly and safely.
 3179**
 3180** The sqlite3_get_table() interface is implemented as a wrapper around
 3181** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
 3182** to any internal data structures of SQLite.  It uses only the public
 3183** interface defined here.  As a consequence, errors that occur in the
 3184** wrapper layer outside of the internal [sqlite3_exec()] call are not
 3185** reflected in subsequent calls to [sqlite3_errcode()] or
 3186** [sqlite3_errmsg()].
 3187*/
 3188SQLITE_API int sqlite3_get_table(
 3189  sqlite3 *db,          /* An open database */
 3190  const char *zSql,     /* SQL to be evaluated */
 3191  char ***pazResult,    /* Results of the query */
 3192  int *pnRow,           /* Number of result rows written here */
 3193  int *pnColumn,        /* Number of result columns written here */
 3194  char **pzErrmsg       /* Error msg written here */
 3195);
 3196SQLITE_API void sqlite3_free_table(char **result);
 3197
 3198/*
 3199** CAPI3REF: Formatted String Printing Functions
 3200**
 3201** These routines are work-alikes of the "printf()" family of functions
 3202** from the standard C library.
 3203** These routines understand most of the common formatting options from
 3204** the standard library printf()
 3205** plus some additional non-standard formats ([%q], [%Q], [%w], and [%z]).
 3206** See the [built-in printf()] documentation for details.
 3207**
 3208** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
 3209** results into memory obtained from [sqlite3_malloc64()].
 3210** The strings returned by these two routines should be
 3211** released by [sqlite3_free()].  ^Both routines return a
 3212** NULL pointer if [sqlite3_malloc64()] is unable to allocate enough
 3213** memory to hold the resulting string.
 3214**
 3215** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
 3216** the standard C library.  The result is written into the
 3217** buffer supplied as the second parameter whose size is given by
 3218** the first parameter. Note that the order of the
 3219** first two parameters is reversed from snprintf().)^  This is an
 3220** historical accident that cannot be fixed without breaking
 3221** backwards compatibility.  ^(Note also that sqlite3_snprintf()
 3222** returns a pointer to its buffer instead of the number of
 3223** characters actually written into the buffer.)^  We admit that
 3224** the number of characters written would be a more useful return
 3225** value but we cannot change the implementation of sqlite3_snprintf()
 3226** now without breaking compatibility.
 3227**
 3228** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
 3229** guarantees that the buffer is always zero-terminated.  ^The first
 3230** parameter "n" is the total size of the buffer, including space for
 3231** the zero terminator.  So the longest string that can be completely
 3232** written will be n-1 characters.
 3233**
 3234** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
 3235**
 3236** See also:  [built-in printf()], [printf() SQL function]
 3237*/
 3238SQLITE_API char *sqlite3_mprintf(const char*,...);
 3239SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
 3240SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
 3241SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
 3242
 3243/*
 3244** CAPI3REF: Memory Allocation Subsystem
 3245**
 3246** The SQLite core uses these three routines for all of its own
 3247** internal memory allocation needs. "Core" in the previous sentence
 3248** does not include operating-system specific [VFS] implementation.  The
 3249** Windows VFS uses native malloc() and free() for some operations.
 3250**
 3251** ^The sqlite3_malloc() routine returns a pointer to a block
 3252** of memory at least N bytes in length, where N is the parameter.
 3253** ^If sqlite3_malloc() is unable to obtain sufficient free
 3254** memory, it returns a NULL pointer.  ^If the parameter N to
 3255** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
 3256** a NULL pointer.
 3257**
 3258** ^The sqlite3_malloc64(N) routine works just like
 3259** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
 3260** of a signed 32-bit integer.
 3261**
 3262** ^Calling sqlite3_free() with a pointer previously returned
 3263** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
 3264** that it might be reused.  ^The sqlite3_free() routine is
 3265** a no-op if it is called with a NULL pointer.  Passing a NULL pointer
 3266** to sqlite3_free() is harmless.  After being freed, memory
 3267** should neither be read nor written.  Even reading previously freed
 3268** memory might result in a segmentation fault or other severe error.
 3269** Memory corruption, a segmentation fault, or other severe error
 3270** might result if sqlite3_free() is called with a non-NULL pointer that
 3271** was not obtained from sqlite3_malloc() or sqlite3_realloc().
 3272**
 3273** ^The sqlite3_realloc(X,N) interface attempts to resize a
 3274** prior memory allocation X to be at least N bytes.
 3275** ^If the X parameter to sqlite3_realloc(X,N)
 3276** is a NULL pointer then its behavior is identical to calling
 3277** sqlite3_malloc(N).
 3278** ^If the N parameter to sqlite3_realloc(X,N) is zero or
 3279** negative then the behavior is exactly the same as calling
 3280** sqlite3_free(X).
 3281** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
 3282** of at least N bytes in size or NULL if insufficient memory is available.
 3283** ^If M is the size of the prior allocation, then min(N,M) bytes of the
 3284** prior allocation are copied into the beginning of the buffer returned
 3285** by sqlite3_realloc(X,N) and the prior allocation is freed.
 3286** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
 3287** prior allocation is not freed.
 3288**
 3289** ^The sqlite3_realloc64(X,N) interface works the same as
 3290** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
 3291** of a 32-bit signed integer.
 3292**
 3293** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
 3294** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
 3295** sqlite3_msize(X) returns the size of that memory allocation in bytes.
 3296** ^The value returned by sqlite3_msize(X) might be larger than the number
 3297** of bytes requested when X was allocated.  ^If X is a NULL pointer then
 3298** sqlite3_msize(X) returns zero.  If X points to something that is not
 3299** the beginning of memory allocation, or if it points to a formerly
 3300** valid memory allocation that has now been freed, then the behavior
 3301** of sqlite3_msize(X) is undefined and possibly harmful.
 3302**
 3303** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
 3304** sqlite3_malloc64(), and sqlite3_realloc64()
 3305** is always aligned to at least an 8 byte boundary, or to a
 3306** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
 3307** option is used.
 3308**
 3309** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
 3310** must be either NULL or else pointers obtained from a prior
 3311** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
 3312** not yet been released.
 3313**
 3314** The application must not read or write any part of
 3315** a block of memory after it has been released using
 3316** [sqlite3_free()] or [sqlite3_realloc()].
 3317*/
 3318SQLITE_API void *sqlite3_malloc(int);
 3319SQLITE_API void *sqlite3_malloc64(sqlite3_uint64);
 3320SQLITE_API void *sqlite3_realloc(void*, int);
 3321SQLITE_API void *sqlite3_realloc64(void*, sqlite3_uint64);
 3322SQLITE_API void sqlite3_free(void*);
 3323SQLITE_API sqlite3_uint64 sqlite3_msize(void*);
 3324
 3325/*
 3326** CAPI3REF: Memory Allocator Statistics
 3327**
 3328** SQLite provides these two interfaces for reporting on the status
 3329** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
 3330** routines, which form the built-in memory allocation subsystem.
 3331**
 3332** ^The [sqlite3_memory_used()] routine returns the number of bytes
 3333** of memory currently outstanding (malloced but not freed).
 3334** ^The [sqlite3_memory_highwater()] routine returns the maximum
 3335** value of [sqlite3_memory_used()] since the high-water mark
 3336** was last reset.  ^The values returned by [sqlite3_memory_used()] and
 3337** [sqlite3_memory_highwater()] include any overhead
 3338** added by SQLite in its implementation of [sqlite3_malloc()],
 3339** but not overhead added by any underlying system library
 3340** routines that [sqlite3_malloc()] may call.
 3341**
 3342** ^The memory high-water mark is reset to the current value of
 3343** [sqlite3_memory_used()] if and only if the parameter to
 3344** [sqlite3_memory_highwater()] is true.  ^The value returned
 3345** by [sqlite3_memory_highwater(1)] is the high-water mark
 3346** prior to the reset.
 3347*/
 3348SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
 3349SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
 3350
 3351/*
 3352** CAPI3REF: Pseudo-Random Number Generator
 3353**
 3354** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
 3355** select random [ROWID | ROWIDs] when inserting new records into a table that
 3356** already uses the largest possible [ROWID].  The PRNG is also used for
 3357** the built-in random() and randomblob() SQL functions.  This interface allows
 3358** applications to access the same PRNG for other purposes.
 3359**
 3360** ^A call to this routine stores N bytes of randomness into buffer P.
 3361** ^The P parameter can be a NULL pointer.
 3362**
 3363** ^If this routine has not been previously called or if the previous
 3364** call had N less than one or a NULL pointer for P, then the PRNG is
 3365** seeded using randomness obtained from the xRandomness method of
 3366** the default [sqlite3_vfs] object.
 3367** ^If the previous call to this routine had an N of 1 or more and a
 3368** non-NULL P then the pseudo-randomness is generated
 3369** internally and without recourse to the [sqlite3_vfs] xRandomness
 3370** method.
 3371*/
 3372SQLITE_API void sqlite3_randomness(int N, void *P);
 3373
 3374/*
 3375** CAPI3REF: Compile-Time Authorization Callbacks
 3376** METHOD: sqlite3
 3377** KEYWORDS: {authorizer callback}
 3378**
 3379** ^This routine registers an authorizer callback with a particular
 3380** [database connection], supplied in the first argument.
 3381** ^The authorizer callback is invoked as SQL statements are being compiled
 3382** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
 3383** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()],
 3384** and [sqlite3_prepare16_v3()].  ^At various
 3385** points during the compilation process, as logic is being created
 3386** to perform various actions, the authorizer callback is invoked to
 3387** see if those actions are allowed.  ^The authorizer callback should
 3388** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
 3389** specific action but allow the SQL statement to continue to be
 3390** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
 3391** rejected with an error.  ^If the authorizer callback returns
 3392** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
 3393** then the [sqlite3_prepare_v2()] or equivalent call that triggered
 3394** the authorizer will fail with an error message.
 3395**
 3396** When the callback returns [SQLITE_OK], that means the operation
 3397** requested is ok.  ^When the callback returns [SQLITE_DENY], the
 3398** [sqlite3_prepare_v2()] or equivalent call that triggered the
 3399** authorizer will fail with an error message explaining that
 3400** access is denied.
 3401**
 3402** ^The first parameter to the authorizer callback is a copy of the third
 3403** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
 3404** to the callback is an integer [SQLITE_COPY | action code] that specifies
 3405** the particular action to be authorized. ^The third through sixth parameters
 3406** to the callback are either NULL pointers or zero-terminated strings
 3407** that contain additional details about the action to be authorized.
 3408** Applications must always be prepared to encounter a NULL pointer in any
 3409** of the third through the sixth parameters of the authorization callback.
 3410**
 3411** ^If the action code is [SQLITE_READ]
 3412** and the callback returns [SQLITE_IGNORE] then the
 3413** [prepared statement] statement is constructed to substitute
 3414** a NULL value in place of the table column that would have
 3415** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
 3416** return can be used to deny an untrusted user access to individual
 3417** columns of a table.
 3418** ^When a table is referenced by a [SELECT] but no column values are
 3419** extracted from that table (for example in a query like
 3420** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback
 3421** is invoked once for that table with a column name that is an empty string.
 3422** ^If the action code is [SQLITE_DELETE] and the callback returns
 3423** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
 3424** [truncate optimization] is disabled and all rows are deleted individually.
 3425**
 3426** An authorizer is used when [sqlite3_prepare | preparing]
 3427** SQL statements from an untrusted source, to ensure that the SQL statements
 3428** do not try to access data they are not allowed to see, or that they do not
 3429** try to execute malicious statements that damage the database.  For
 3430** example, an application may allow a user to enter arbitrary
 3431** SQL queries for evaluation by a database.  But the application does
 3432** not want the user to be able to make arbitrary changes to the
 3433** database.  An authorizer could then be put in place while the
 3434** user-entered SQL is being [sqlite3_prepare | prepared] that
 3435** disallows everything except [SELECT] statements.
 3436**
 3437** Applications that need to process SQL from untrusted sources
 3438** might also consider lowering resource limits using [sqlite3_limit()]
 3439** and limiting database size using the [max_page_count] [PRAGMA]
 3440** in addition to using an authorizer.
 3441**
 3442** ^(Only a single authorizer can be in place on a database connection
 3443** at a time.  Each call to sqlite3_set_authorizer overrides the
 3444** previous call.)^  ^Disable the authorizer by installing a NULL callback.
 3445** The authorizer is disabled by default.
 3446**
 3447** The authorizer callback must not do anything that will modify
 3448** the database connection that invoked the authorizer callback.
 3449** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
 3450** database connections for the meaning of "modify" in this paragraph.
 3451**
 3452** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
 3453** statement might be re-prepared during [sqlite3_step()] due to a
 3454** schema change.  Hence, the application should ensure that the
 3455** correct authorizer callback remains in place during the [sqlite3_step()].
 3456**
 3457** ^Note that the authorizer callback is invoked only during
 3458** [sqlite3_prepare()] or its variants.  Authorization is not
 3459** performed during statement evaluation in [sqlite3_step()], unless
 3460** as stated in the previous paragraph, sqlite3_step() invokes
 3461** sqlite3_prepare_v2() to reprepare a statement after a schema change.
 3462*/
 3463SQLITE_API int sqlite3_set_authorizer(
 3464  sqlite3*,
 3465  int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
 3466  void *pUserData
 3467);
 3468
 3469/*
 3470** CAPI3REF: Authorizer Return Codes
 3471**
 3472** The [sqlite3_set_authorizer | authorizer callback function] must
 3473** return either [SQLITE_OK] or one of these two constants in order
 3474** to signal SQLite whether or not the action is permitted.  See the
 3475** [sqlite3_set_authorizer | authorizer documentation] for additional
 3476** information.
 3477**
 3478** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
 3479** returned from the [sqlite3_vtab_on_conflict()] interface.
 3480*/
 3481#define SQLITE_DENY   1   /* Abort the SQL statement with an error */
 3482#define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
 3483
 3484/*
 3485** CAPI3REF: Authorizer Action Codes
 3486**
 3487** The [sqlite3_set_authorizer()] interface registers a callback function
 3488** that is invoked to authorize certain SQL statement actions.  The
 3489** second parameter to the callback is an integer code that specifies
 3490** what action is being authorized.  These are the integer action codes that
 3491** the authorizer callback may be passed.
 3492**
 3493** These action code values signify what kind of operation is to be
 3494** authorized.  The 3rd and 4th parameters to the authorization
 3495** callback function will be parameters or NULL depending on which of these
 3496** codes is used as the second parameter.  ^(The 5th parameter to the
 3497** authorizer callback is the name of the database ("main", "temp",
 3498** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
 3499** is the name of the inner-most trigger or view that is responsible for
 3500** the access attempt or NULL if this access attempt is directly from
 3501** top-level SQL code.
 3502*/
 3503/******************************************* 3rd ************ 4th ***********/
 3504#define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
 3505#define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
 3506#define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
 3507#define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
 3508#define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
 3509#define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
 3510#define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
 3511#define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
 3512#define SQLITE_DELETE                9   /* Table Name      NULL            */
 3513#define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
 3514#define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
 3515#define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
 3516#define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
 3517#define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
 3518#define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
 3519#define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
 3520#define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
 3521#define SQLITE_INSERT               18   /* Table Name      NULL            */
 3522#define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
 3523#define SQLITE_READ                 20   /* Table Name      Column Name     */
 3524#define SQLITE_SELECT               21   /* NULL            NULL            */
 3525#define SQLITE_TRANSACTION          22   /* Operation       NULL            */
 3526#define SQLITE_UPDATE               23   /* Table Name      Column Name     */
 3527#define SQLITE_ATTACH               24   /* Filename        NULL            */
 3528#define SQLITE_DETACH               25   /* Database Name   NULL            */
 3529#define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
 3530#define SQLITE_REINDEX              27   /* Index Name      NULL            */
 3531#define SQLITE_ANALYZE              28   /* Table Name      NULL            */
 3532#define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
 3533#define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
 3534#define SQLITE_FUNCTION             31   /* NULL            Function Name   */
 3535#define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
 3536#define SQLITE_COPY                  0   /* No longer used */
 3537#define SQLITE_RECURSIVE            33   /* NULL            NULL            */
 3538
 3539/*
 3540** CAPI3REF: Deprecated Tracing And Profiling Functions
 3541** DEPRECATED
 3542**
 3543** These routines are deprecated. Use the [sqlite3_trace_v2()] interface
 3544** instead of the routines described here.
 3545**
 3546** These routines register callback functions that can be used for
 3547** tracing and profiling the execution of SQL statements.
 3548**
 3549** ^The callback function registered by sqlite3_trace() is invoked at
 3550** various times when an SQL statement is being run by [sqlite3_step()].
 3551** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
 3552** SQL statement text as the statement first begins executing.
 3553** ^(Additional sqlite3_trace() callbacks might occur
 3554** as each triggered subprogram is entered.  The callbacks for triggers
 3555** contain a UTF-8 SQL comment that identifies the trigger.)^
 3556**
 3557** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
 3558** the length of [bound parameter] expansion in the output of sqlite3_trace().
 3559**
 3560** ^The callback function registered by sqlite3_profile() is invoked
 3561** as each SQL statement finishes.  ^The profile callback contains
 3562** the original statement text and an estimate of wall-clock time
 3563** of how long that statement took to run.  ^The profile callback
 3564** time is in units of nanoseconds, however the current implementation
 3565** is only capable of millisecond resolution so the six least significant
 3566** digits in the time are meaningless.  Future versions of SQLite
 3567** might provide greater resolution on the profiler callback.  Invoking
 3568** either [sqlite3_trace()] or [sqlite3_trace_v2()] will cancel the
 3569** profile callback.
 3570*/
 3571SQLITE_API SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*,
 3572   void(*xTrace)(void*,const char*), void*);
 3573SQLITE_API SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*,
 3574   void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
 3575
 3576/*
 3577** CAPI3REF: SQL Trace Event Codes
 3578** KEYWORDS: SQLITE_TRACE
 3579**
 3580** These constants identify classes of events that can be monitored
 3581** using the [sqlite3_trace_v2()] tracing logic.  The M argument
 3582** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of
 3583** the following constants.  ^The first argument to the trace callback
 3584** is one of the following constants.
 3585**
 3586** New tracing constants may be added in future releases.
 3587**
 3588** ^A trace callback has four arguments: xCallback(T,C,P,X).
 3589** ^The T argument is one of the integer type codes above.
 3590** ^The C argument is a copy of the context pointer passed in as the
 3591** fourth argument to [sqlite3_trace_v2()].
 3592** The P and X arguments are pointers whose meanings depend on T.
 3593**
 3594** <dl>
 3595** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt>
 3596** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement
 3597** first begins running and possibly at other times during the
 3598** execution of the prepared statement, such as at the start of each
 3599** trigger subprogram. ^The P argument is a pointer to the
 3600** [prepared statement]. ^The X argument is a pointer to a string which
 3601** is the unexpanded SQL text of the prepared statement or an SQL comment
 3602** that indicates the invocation of a trigger.  ^The callback can compute
 3603** the same text that would have been returned by the legacy [sqlite3_trace()]
 3604** interface by using the X argument when X begins with "--" and invoking
 3605** [sqlite3_expanded_sql(P)] otherwise.
 3606**
 3607** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt>
 3608** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same
 3609** information as is provided by the [sqlite3_profile()] callback.
 3610** ^The P argument is a pointer to the [prepared statement] and the
 3611** X argument points to a 64-bit integer which is approximately
 3612** the number of nanoseconds that the prepared statement took to run.
 3613** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.
 3614**
 3615** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt>
 3616** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared
 3617** statement generates a single row of result.
 3618** ^The P argument is a pointer to the [prepared statement] and the
 3619** X argument is unused.
 3620**
 3621** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt>
 3622** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database
 3623** connection closes.
 3624** ^The P argument is a pointer to the [database connection] object
 3625** and the X argument is unused.
 3626** </dl>
 3627*/
 3628#define SQLITE_TRACE_STMT       0x01
 3629#define SQLITE_TRACE_PROFILE    0x02
 3630#define SQLITE_TRACE_ROW        0x04
 3631#define SQLITE_TRACE_CLOSE      0x08
 3632
 3633/*
 3634** CAPI3REF: SQL Trace Hook
 3635** METHOD: sqlite3
 3636**
 3637** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
 3638** function X against [database connection] D, using property mask M
 3639** and context pointer P.  ^If the X callback is
 3640** NULL or if the M mask is zero, then tracing is disabled.  The
 3641** M argument should be the bitwise OR-ed combination of
 3642** zero or more [SQLITE_TRACE] constants.
 3643**
 3644** ^Each call to either sqlite3_trace(D,X,P) or sqlite3_trace_v2(D,M,X,P)
 3645** overrides (cancels) all prior calls to sqlite3_trace(D,X,P) or
 3646** sqlite3_trace_v2(D,M,X,P) for the [database connection] D.  Each
 3647** database connection may have at most one trace callback.
 3648**
 3649** ^The X callback is invoked whenever any of the events identified by
 3650** mask M occur.  ^The integer return value from the callback is currently
 3651** ignored, though this may change in future releases.  Callback
 3652** implementations should return zero to ensure future compatibility.
 3653**
 3654** ^A trace callback is invoked with four arguments: callback(T,C,P,X).
 3655** ^The T argument is one of the [SQLITE_TRACE]
 3656** constants to indicate why the callback was invoked.
 3657** ^The C argument is a copy of the context pointer.
 3658** The P and X arguments are pointers whose meanings depend on T.
 3659**
 3660** The sqlite3_trace_v2() interface is intended to replace the legacy
 3661** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which
 3662** are deprecated.
 3663*/
 3664SQLITE_API int sqlite3_trace_v2(
 3665  sqlite3*,
 3666  unsigned uMask,
 3667  int(*xCallback)(unsigned,void*,void*,void*),
 3668  void *pCtx
 3669);
 3670
 3671/*
 3672** CAPI3REF: Query Progress Callbacks
 3673** METHOD: sqlite3
 3674**
 3675** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
 3676** function X to be invoked periodically during long running calls to
 3677** [sqlite3_step()] and [sqlite3_prepare()] and similar for
 3678** database connection D.  An example use for this
 3679** interface is to keep a GUI updated during a large query.
 3680**
 3681** ^The parameter P is passed through as the only parameter to the
 3682** callback function X.  ^The parameter N is the approximate number of
 3683** [virtual machine instructions] that are evaluated between successive
 3684** invocations of the callback X.  ^If N is less than one then the progress
 3685** handler is disabled.
 3686**
 3687** ^Only a single progress handler may be defined at one time per
 3688** [database connection]; setting a new progress handler cancels the
 3689** old one.  ^Setting parameter X to NULL disables the progress handler.
 3690** ^The progress handler is also disabled by setting N to a value less
 3691** than 1.
 3692**
 3693** ^If the progress callback returns non-zero, the operation is
 3694** interrupted.  This feature can be used to implement a
 3695** "Cancel" button on a GUI progress dialog box.
 3696**
 3697** The progress handler callback must not do anything that will modify
 3698** the database connection that invoked the progress handler.
 3699** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
 3700** database connections for the meaning of "modify" in this paragraph.
 3701**
 3702** The progress handler callback would originally only be invoked from the
 3703** bytecode engine.  It still might be invoked during [sqlite3_prepare()]
 3704** and similar because those routines might force a reparse of the schema
 3705** which involves running the bytecode engine.  However, beginning with
 3706** SQLite version 3.41.0, the progress handler callback might also be
 3707** invoked directly from [sqlite3_prepare()] while analyzing and generating
 3708** code for complex queries.
 3709*/
 3710SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
 3711
 3712/*
 3713** CAPI3REF: Opening A New Database Connection
 3714** CONSTRUCTOR: sqlite3
 3715**
 3716** ^These routines open an SQLite database file as specified by the
 3717** filename argument. ^The filename argument is interpreted as UTF-8 for
 3718** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
 3719** order for sqlite3_open16(). ^(A [database connection] handle is usually
 3720** returned in *ppDb, even if an error occurs.  The only exception is that
 3721** if SQLite is unable to allocate memory to hold the [sqlite3] object,
 3722** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
 3723** object.)^ ^(If the database is opened (and/or created) successfully, then
 3724** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
 3725** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
 3726** an English language description of the error following a failure of any
 3727** of the sqlite3_open() routines.
 3728**
 3729** ^The default encoding will be UTF-8 for databases created using
 3730** sqlite3_open() or sqlite3_open_v2().  ^The default encoding for databases
 3731** created using sqlite3_open16() will be UTF-16 in the native byte order.
 3732**
 3733** Whether or not an error occurs when it is opened, resources
 3734** associated with the [database connection] handle should be released by
 3735** passing it to [sqlite3_close()] when it is no longer required.
 3736**
 3737** The sqlite3_open_v2() interface works like sqlite3_open()
 3738** except that it accepts two additional parameters for additional control
 3739** over the new database connection.  ^(The flags parameter to
 3740** sqlite3_open_v2() must include, at a minimum, one of the following
 3741** three flag combinations:)^
 3742**
 3743** <dl>
 3744** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
 3745** <dd>The database is opened in read-only mode.  If the database does
 3746** not already exist, an error is returned.</dd>)^
 3747**
 3748** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
 3749** <dd>The database is opened for reading and writing if possible, or
 3750** reading only if the file is write protected by the operating
 3751** system.  In either case the database must already exist, otherwise
 3752** an error is returned.  For historical reasons, if opening in
 3753** read-write mode fails due to OS-level permissions, an attempt is
 3754** made to open it in read-only mode. [sqlite3_db_readonly()] can be
 3755** used to determine whether the database is actually
 3756** read-write.</dd>)^
 3757**
 3758** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
 3759** <dd>The database is opened for reading and writing, and is created if
 3760** it does not already exist. This is the behavior that is always used for
 3761** sqlite3_open() and sqlite3_open16().</dd>)^
 3762** </dl>
 3763**
 3764** In addition to the required flags, the following optional flags are
 3765** also supported:
 3766**
 3767** <dl>
 3768** ^(<dt>[SQLITE_OPEN_URI]</dt>
 3769** <dd>The filename can be interpreted as a URI if this flag is set.</dd>)^
 3770**
 3771** ^(<dt>[SQLITE_OPEN_MEMORY]</dt>
 3772** <dd>The database will be opened as an in-memory database.  The database
 3773** is named by the "filename" argument for the purposes of cache-sharing,
 3774** if shared cache mode is enabled, but the "filename" is otherwise ignored.
 3775** </dd>)^
 3776**
 3777** ^(<dt>[SQLITE_OPEN_NOMUTEX]</dt>
 3778** <dd>The new database connection will use the "multi-thread"
 3779** [threading mode].)^  This means that separate threads are allowed
 3780** to use SQLite at the same time, as long as each thread is using
 3781** a different [database connection].
 3782**
 3783** ^(<dt>[SQLITE_OPEN_FULLMUTEX]</dt>
 3784** <dd>The new database connection will use the "serialized"
 3785** [threading mode].)^  This means the multiple threads can safely
 3786** attempt to use the same database connection at the same time.
 3787** (Mutexes will block any actual concurrency, but in this mode
 3788** there is no harm in trying.)
 3789**
 3790** ^(<dt>[SQLITE_OPEN_SHAREDCACHE]</dt>
 3791** <dd>The database is opened with [shared cache] enabled, overriding
 3792** the default shared cache setting provided by
 3793** [sqlite3_enable_shared_cache()].)^
 3794** The [use of shared cache mode is discouraged] and hence shared cache
 3795** capabilities may be omitted from many builds of SQLite.  In such cases,
 3796** this option is a no-op.
 3797**
 3798** ^(<dt>[SQLITE_OPEN_PRIVATECACHE]</dt>
 3799** <dd>The database is opened with [shared cache] disabled, overriding
 3800** the default shared cache setting provided by
 3801** [sqlite3_enable_shared_cache()].)^
 3802**
 3803** [[OPEN_EXRESCODE]] ^(<dt>[SQLITE_OPEN_EXRESCODE]</dt>
 3804** <dd>The database connection comes up in "extended result code mode".
 3805** In other words, the database behaves as if
 3806** [sqlite3_extended_result_codes(db,1)] were called on the database
 3807** connection as soon as the connection is created. In addition to setting
 3808** the extended result code mode, this flag also causes [sqlite3_open_v2()]
 3809** to return an extended result code.</dd>
 3810**
 3811** [[OPEN_NOFOLLOW]] ^(<dt>[SQLITE_OPEN_NOFOLLOW]</dt>
 3812** <dd>The database filename is not allowed to contain a symbolic link</dd>
 3813** </dl>)^
 3814**
 3815** If the 3rd parameter to sqlite3_open_v2() is not one of the
 3816** required combinations shown above optionally combined with other
 3817** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
 3818** then the behavior is undefined.  Historic versions of SQLite
 3819** have silently ignored surplus bits in the flags parameter to
 3820** sqlite3_open_v2(), however that behavior might not be carried through
 3821** into future versions of SQLite and so applications should not rely
 3822** upon it.  Note in particular that the SQLITE_OPEN_EXCLUSIVE flag is a no-op
 3823** for sqlite3_open_v2().  The SQLITE_OPEN_EXCLUSIVE does *not* cause
 3824** the open to fail if the database already exists.  The SQLITE_OPEN_EXCLUSIVE
 3825** flag is intended for use by the [sqlite3_vfs|VFS interface] only, and not
 3826** by sqlite3_open_v2().
 3827**
 3828** ^The fourth parameter to sqlite3_open_v2() is the name of the
 3829** [sqlite3_vfs] object that defines the operating system interface that
 3830** the new database connection should use.  ^If the fourth parameter is
 3831** a NULL pointer then the default [sqlite3_vfs] object is used.
 3832**
 3833** ^If the filename is ":memory:", then a private, temporary in-memory database
 3834** is created for the connection.  ^This in-memory database will vanish when
 3835** the database connection is closed.  Future versions of SQLite might
 3836** make use of additional special filenames that begin with the ":" character.
 3837** It is recommended that when a database filename actually does begin with
 3838** a ":" character you should prefix the filename with a pathname such as
 3839** "./" to avoid ambiguity.
 3840**
 3841** ^If the filename is an empty string, then a private, temporary
 3842** on-disk database will be created.  ^This private database will be
 3843** automatically deleted as soon as the database connection is closed.
 3844**
 3845** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
 3846**
 3847** ^If [URI filename] interpretation is enabled, and the filename argument
 3848** begins with "file:", then the filename is interpreted as a URI. ^URI
 3849** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
 3850** set in the third argument to sqlite3_open_v2(), or if it has
 3851** been enabled globally using the [SQLITE_CONFIG_URI] option with the
 3852** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
 3853** URI filename interpretation is turned off
 3854** by default, but future releases of SQLite might enable URI filename
 3855** interpretation by default.  See "[URI filenames]" for additional
 3856** information.
 3857**
 3858** URI filenames are parsed according to RFC 3986. ^If the URI contains an
 3859** authority, then it must be either an empty string or the string
 3860** "localhost". ^If the authority is not an empty string or "localhost", an
 3861** error is returned to the caller. ^The fragment component of a URI, if
 3862** present, is ignored.
 3863**
 3864** ^SQLite uses the path component of the URI as the name of the disk file
 3865** which contains the database. ^If the path begins with a '/' character,
 3866** then it is interpreted as an absolute path. ^If the path does not begin
 3867** with a '/' (meaning that the authority section is omitted from the URI)
 3868** then the path is interpreted as a relative path.
 3869** ^(On windows, the first component of an absolute path
 3870** is a drive specification (e.g. "C:").)^
 3871**
 3872** [[core URI query parameters]]
 3873** The query component of a URI may contain parameters that are interpreted
 3874** either by SQLite itself, or by a [VFS | custom VFS implementation].
 3875** SQLite and its built-in [VFSes] interpret the
 3876** following query parameters:
 3877**
 3878** <ul>
 3879**   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
 3880**     a VFS object that provides the operating system interface that should
 3881**     be used to access the database file on disk. ^If this option is set to
 3882**     an empty string the default VFS object is used. ^Specifying an unknown
 3883**     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
 3884**     present, then the VFS specified by the option takes precedence over
 3885**     the value passed as the fourth parameter to sqlite3_open_v2().
 3886**
 3887**   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
 3888**     "rwc", or "memory". Attempting to set it to any other value is
 3889**     an error)^.
 3890**     ^If "ro" is specified, then the database is opened for read-only
 3891**     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the
 3892**     third argument to sqlite3_open_v2(). ^If the mode option is set to
 3893**     "rw", then the database is opened for read-write (but not create)
 3894**     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had
 3895**     been set. ^Value "rwc" is equivalent to setting both
 3896**     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE.  ^If the mode option is
 3897**     set to "memory" then a pure [in-memory database] that never reads
 3898**     or writes from disk is used. ^It is an error to specify a value for
 3899**     the mode parameter that is less restrictive than that specified by
 3900**     the flags passed in the third parameter to sqlite3_open_v2().
 3901**
 3902**   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
 3903**     "private". ^Setting it to "shared" is equivalent to setting the
 3904**     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
 3905**     sqlite3_open_v2(). ^Setting the cache parameter to "private" is
 3906**     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
 3907**     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
 3908**     a URI filename, its value overrides any behavior requested by setting
 3909**     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
 3910**
 3911**  <li> <b>psow</b>: ^The psow parameter indicates whether or not the
 3912**     [powersafe overwrite] property does or does not apply to the
 3913**     storage media on which the database file resides.
 3914**
 3915**  <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
 3916**     which if set disables file locking in rollback journal modes.  This
 3917**     is useful for accessing a database on a filesystem that does not
 3918**     support locking.  Caution:  Database corruption might result if two
 3919**     or more processes write to the same database and any one of those
 3920**     processes uses nolock=1.
 3921**
 3922**  <li> <b>immutable</b>: ^The immutable parameter is a boolean query
 3923**     parameter that indicates that the database file is stored on
 3924**     read-only media.  ^When immutable is set, SQLite assumes that the
 3925**     database file cannot be changed, even by a process with higher
 3926**     privilege, and so the database is opened read-only and all locking
 3927**     and change detection is disabled.  Caution: Setting the immutable
 3928**     property on a database file that does in fact change can result
 3929**     in incorrect query results and/or [SQLITE_CORRUPT] errors.
 3930**     See also: [SQLITE_IOCAP_IMMUTABLE].
 3931**
 3932** </ul>
 3933**
 3934** ^Specifying an unknown parameter in the query component of a URI is not an
 3935** error.  Future versions of SQLite might understand additional query
 3936** parameters.  See "[query parameters with special meaning to SQLite]" for
 3937** additional information.
 3938**
 3939** [[URI filename examples]] <h3>URI filename examples</h3>
 3940**
 3941** <table border="1" align=center cellpadding=5>
 3942** <tr><th> URI filenames <th> Results
 3943** <tr><td> file:data.db <td>
 3944**          Open the file "data.db" in the current directory.
 3945** <tr><td> file:/home/fred/data.db<br>
 3946**          file:///home/fred/data.db <br>
 3947**          file://localhost/home/fred/data.db <br> <td>
 3948**          Open the database file "/home/fred/data.db".
 3949** <tr><td> file://darkstar/home/fred/data.db <td>
 3950**          An error. "darkstar" is not a recognized authority.
 3951** <tr><td style="white-space:nowrap">
 3952**          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
 3953**     <td> Windows only: Open the file "data.db" on fred's desktop on drive
 3954**          C:. Note that the %20 escaping in this example is not strictly
 3955**          necessary - space characters can be used literally
 3956**          in URI filenames.
 3957** <tr><td> file:data.db?mode=ro&cache=private <td>
 3958**          Open file "data.db" in the current directory for read-only access.
 3959**          Regardless of whether or not shared-cache mode is enabled by
 3960**          default, use a private cache.
 3961** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
 3962**          Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
 3963**          that uses dot-files in place of posix advisory locking.
 3964** <tr><td> file:data.db?mode=readonly <td>
 3965**          An error. "readonly" is not a valid option for the "mode" parameter.
 3966**          Use "ro" instead:  "file:data.db?mode=ro".
 3967** </table>
 3968**
 3969** ^URI hexadecimal escape sequences (%HH) are supported within the path and
 3970** query components of a URI. A hexadecimal escape sequence consists of a
 3971** percent sign - "%" - followed by exactly two hexadecimal digits
 3972** specifying an octet value. ^Before the path or query components of a
 3973** URI filename are interpreted, they are encoded using UTF-8 and all
 3974** hexadecimal escape sequences replaced by a single byte containing the
 3975** corresponding octet. If this process generates an invalid UTF-8 encoding,
 3976** the results are undefined.
 3977**
 3978** <b>Note to Windows users:</b>  The encoding used for the filename argument
 3979** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
 3980** codepage is currently defined.  Filenames containing international
 3981** characters must be converted to UTF-8 prior to passing them into
 3982** sqlite3_open() or sqlite3_open_v2().
 3983**
 3984** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
 3985** prior to calling sqlite3_open() or sqlite3_open_v2().  Otherwise, various
 3986** features that require the use of temporary files may fail.
 3987**
 3988** See also: [sqlite3_temp_directory]
 3989*/
 3990SQLITE_API int sqlite3_open(
 3991  const char *filename,   /* Database filename (UTF-8) */
 3992  sqlite3 **ppDb          /* OUT: SQLite db handle */
 3993);
 3994SQLITE_API int sqlite3_open16(
 3995  const void *filename,   /* Database filename (UTF-16) */
 3996  sqlite3 **ppDb          /* OUT: SQLite db handle */
 3997);
 3998SQLITE_API int sqlite3_open_v2(
 3999  const char *filename,   /* Database filename (UTF-8) */
 4000  sqlite3 **ppDb,         /* OUT: SQLite db handle */
 4001  int flags,              /* Flags */
 4002  const char *zVfs        /* Name of VFS module to use */
 4003);
 4004
 4005/*
 4006** CAPI3REF: Obtain Values For URI Parameters
 4007**
 4008** These are utility routines, useful to [VFS|custom VFS implementations],
 4009** that check if a database file was a URI that contained a specific query
 4010** parameter, and if so obtains the value of that query parameter.
 4011**
 4012** The first parameter to these interfaces (hereafter referred to
 4013** as F) must be one of:
 4014** <ul>
 4015** <li> A database filename pointer created by the SQLite core and
 4016** passed into the xOpen() method of a VFS implementation, or
 4017** <li> A filename obtained from [sqlite3_db_filename()], or
 4018** <li> A new filename constructed using [sqlite3_create_filename()].
 4019** </ul>
 4020** If the F parameter is not one of the above, then the behavior is
 4021** undefined and probably undesirable.  Older versions of SQLite were
 4022** more tolerant of invalid F parameters than newer versions.
 4023**
 4024** If F is a suitable filename (as described in the previous paragraph)
 4025** and if P is the name of the query parameter, then
 4026** sqlite3_uri_parameter(F,P) returns the value of the P
 4027** parameter if it exists or a NULL pointer if P does not appear as a
 4028** query parameter on F.  If P is a query parameter of F and it
 4029** has no explicit value, then sqlite3_uri_parameter(F,P) returns
 4030** a pointer to an empty string.
 4031**
 4032** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
 4033** parameter and returns true (1) or false (0) according to the value
 4034** of P.  The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
 4035** value of query parameter P is one of "yes", "true", or "on" in any
 4036** case or if the value begins with a non-zero number.  The
 4037** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
 4038** query parameter P is one of "no", "false", or "off" in any case or
 4039** if the value begins with a numeric zero.  If P is not a query
 4040** parameter on F or if the value of P does not match any of the
 4041** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
 4042**
 4043** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
 4044** 64-bit signed integer and returns that integer, or D if P does not
 4045** exist.  If the value of P is something other than an integer, then
 4046** zero is returned.
 4047**
 4048** The sqlite3_uri_key(F,N) returns a pointer to the name (not
 4049** the value) of the N-th query parameter for filename F, or a NULL
 4050** pointer if N is less than zero or greater than the number of query
 4051** parameters minus 1.  The N value is zero-based so N should be 0 to obtain
 4052** the name of the first query parameter, 1 for the second parameter, and
 4053** so forth.
 4054**
 4055** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
 4056** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
 4057** is not a database file pathname pointer that the SQLite core passed
 4058** into the xOpen VFS method, then the behavior of this routine is undefined
 4059** and probably undesirable.
 4060**
 4061** Beginning with SQLite [version 3.31.0] ([dateof:3.31.0]) the input F
 4062** parameter can also be the name of a rollback journal file or WAL file
 4063** in addition to the main database file.  Prior to version 3.31.0, these
 4064** routines would only work if F was the name of the main database file.
 4065** When the F parameter is the name of the rollback journal or WAL file,
 4066** it has access to all the same query parameters as were found on the
 4067** main database file.
 4068**
 4069** See the [URI filename] documentation for additional information.
 4070*/
 4071SQLITE_API const char *sqlite3_uri_parameter(sqlite3_filename z, const char *zParam);
 4072SQLITE_API int sqlite3_uri_boolean(sqlite3_filename z, const char *zParam, int bDefault);
 4073SQLITE_API sqlite3_int64 sqlite3_uri_int64(sqlite3_filename, const char*, sqlite3_int64);
 4074SQLITE_API const char *sqlite3_uri_key(sqlite3_filename z, int N);
 4075
 4076/*
 4077** CAPI3REF:  Translate filenames
 4078**
 4079** These routines are available to [VFS|custom VFS implementations] for
 4080** translating filenames between the main database file, the journal file,
 4081** and the WAL file.
 4082**
 4083** If F is the name of an sqlite database file, journal file, or WAL file
 4084** passed by the SQLite core into the VFS, then sqlite3_filename_database(F)
 4085** returns the name of the corresponding database file.
 4086**
 4087** If F is the name of an sqlite database file, journal file, or WAL file
 4088** passed by the SQLite core into the VFS, or if F is a database filename
 4089** obtained from [sqlite3_db_filename()], then sqlite3_filename_journal(F)
 4090** returns the name of the corresponding rollback journal file.
 4091**
 4092** If F is the name of an sqlite database file, journal file, or WAL file
 4093** that was passed by the SQLite core into the VFS, or if F is a database
 4094** filename obtained from [sqlite3_db_filename()], then
 4095** sqlite3_filename_wal(F) returns the name of the corresponding
 4096** WAL file.
 4097**
 4098** In all of the above, if F is not the name of a database, journal or WAL
 4099** filename passed into the VFS from the SQLite core and F is not the
 4100** return value from [sqlite3_db_filename()], then the result is
 4101** undefined and is likely a memory access violation.
 4102*/
 4103SQLITE_API const char *sqlite3_filename_database(sqlite3_filename);
 4104SQLITE_API const char *sqlite3_filename_journal(sqlite3_filename);
 4105SQLITE_API const char *sqlite3_filename_wal(sqlite3_filename);
 4106
 4107/*
 4108** CAPI3REF:  Database File Corresponding To A Journal
 4109**
 4110** ^If X is the name of a rollback or WAL-mode journal file that is
 4111** passed into the xOpen method of [sqlite3_vfs], then
 4112** sqlite3_database_file_object(X) returns a pointer to the [sqlite3_file]
 4113** object that represents the main database file.
 4114**
 4115** This routine is intended for use in custom [VFS] implementations
 4116** only.  It is not a general-purpose interface.
 4117** The argument sqlite3_file_object(X) must be a filename pointer that
 4118** has been passed into [sqlite3_vfs].xOpen method where the
 4119** flags parameter to xOpen contains one of the bits
 4120** [SQLITE_OPEN_MAIN_JOURNAL] or [SQLITE_OPEN_WAL].  Any other use
 4121** of this routine results in undefined and probably undesirable
 4122** behavior.
 4123*/
 4124SQLITE_API sqlite3_file *sqlite3_database_file_object(const char*);
 4125
 4126/*
 4127** CAPI3REF: Create and Destroy VFS Filenames
 4128**
 4129** These interfaces are provided for use by [VFS shim] implementations and
 4130** are not useful outside of that context.
 4131**
 4132** The sqlite3_create_filename(D,J,W,N,P) allocates memory to hold a version of
 4133** database filename D with corresponding journal file J and WAL file W and
 4134** an array P of N URI Key/Value pairs.  The result from
 4135** sqlite3_create_filename(D,J,W,N,P) is a pointer to a database filename that
 4136** is safe to pass to routines like:
 4137** <ul>
 4138** <li> [sqlite3_uri_parameter()],
 4139** <li> [sqlite3_uri_boolean()],
 4140** <li> [sqlite3_uri_int64()],
 4141** <li> [sqlite3_uri_key()],
 4142** <li> [sqlite3_filename_database()],
 4143** <li> [sqlite3_filename_journal()], or
 4144** <li> [sqlite3_filename_wal()].
 4145** </ul>
 4146** If a memory allocation error occurs, sqlite3_create_filename() might
 4147** return a NULL pointer.  The memory obtained from sqlite3_create_filename(X)
 4148** must be released by a corresponding call to sqlite3_free_filename(Y).
 4149**
 4150** The P parameter in sqlite3_create_filename(D,J,W,N,P) should be an array
 4151** of 2*N pointers to strings.  Each pair of pointers in this array corresponds
 4152** to a key and value for a query parameter.  The P parameter may be a NULL
 4153** pointer if N is zero.  None of the 2*N pointers in the P array may be
 4154** NULL pointers and key pointers should not be empty strings.
 4155** None of the D, J, or W parameters to sqlite3_create_filename(D,J,W,N,P) may
 4156** be NULL pointers, though they can be empty strings.
 4157**
 4158** The sqlite3_free_filename(Y) routine releases a memory allocation
 4159** previously obtained from sqlite3_create_filename().  Invoking
 4160** sqlite3_free_filename(Y) where Y is a NULL pointer is a harmless no-op.
 4161**
 4162** If the Y parameter to sqlite3_free_filename(Y) is anything other
 4163** than a NULL pointer or a pointer previously acquired from
 4164** sqlite3_create_filename(), then bad things such as heap
 4165** corruption or segfaults may occur. The value Y should not be
 4166** used again after sqlite3_free_filename(Y) has been called.  This means
 4167** that if the [sqlite3_vfs.xOpen()] method of a VFS has been called using Y,
 4168** then the corresponding [sqlite3_module.xClose() method should also be
 4169** invoked prior to calling sqlite3_free_filename(Y).
 4170*/
 4171SQLITE_API sqlite3_filename sqlite3_create_filename(
 4172  const char *zDatabase,
 4173  const char *zJournal,
 4174  const char *zWal,
 4175  int nParam,
 4176  const char **azParam
 4177);
 4178SQLITE_API void sqlite3_free_filename(sqlite3_filename);
 4179
 4180/*
 4181** CAPI3REF: Error Codes And Messages
 4182** METHOD: sqlite3
 4183**
 4184** ^If the most recent sqlite3_* API call associated with
 4185** [database connection] D failed, then the sqlite3_errcode(D) interface
 4186** returns the numeric [result code] or [extended result code] for that
 4187** API call.
 4188** ^The sqlite3_extended_errcode()
 4189** interface is the same except that it always returns the
 4190** [extended result code] even when extended result codes are
 4191** disabled.
 4192**
 4193** The values returned by sqlite3_errcode() and/or
 4194** sqlite3_extended_errcode() might change with each API call.
 4195** Except, there are some interfaces that are guaranteed to never
 4196** change the value of the error code.  The error-code preserving
 4197** interfaces include the following:
 4198**
 4199** <ul>
 4200** <li> sqlite3_errcode()
 4201** <li> sqlite3_extended_errcode()
 4202** <li> sqlite3_errmsg()
 4203** <li> sqlite3_errmsg16()
 4204** <li> sqlite3_error_offset()
 4205** <li> sqlite3_db_handle()
 4206** </ul>
 4207**
 4208** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
 4209** text that describes the error, as either UTF-8 or UTF-16 respectively,
 4210** or NULL if no error message is available.
 4211** (See how SQLite handles [invalid UTF] for exceptions to this rule.)
 4212** ^(Memory to hold the error message string is managed internally.
 4213** The application does not need to worry about freeing the result.
 4214** However, the error string might be overwritten or deallocated by
 4215** subsequent calls to other SQLite interface functions.)^
 4216**
 4217** ^The sqlite3_errstr(E) interface returns the English-language text
 4218** that describes the [result code] E, as UTF-8, or NULL if E is not a
 4219** result code for which a text error message is available.
 4220** ^(Memory to hold the error message string is managed internally
 4221** and must not be freed by the application)^.
 4222**
 4223** ^If the most recent error references a specific token in the input
 4224** SQL, the sqlite3_error_offset() interface returns the byte offset
 4225** of the start of that token.  ^The byte offset returned by
 4226** sqlite3_error_offset() assumes that the input SQL is UTF-8.
 4227** ^If the most recent error does not reference a specific token in the input
 4228** SQL, then the sqlite3_error_offset() function returns -1.
 4229**
 4230** When the serialized [threading mode] is in use, it might be the
 4231** case that a second error occurs on a separate thread in between
 4232** the time of the first error and the call to these interfaces.
 4233** When that happens, the second error will be reported since these
 4234** interfaces always report the most recent result.  To avoid
 4235** this, each thread can obtain exclusive use of the [database connection] D
 4236** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
 4237** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
 4238** all calls to the interfaces listed here are completed.
 4239**
 4240** If an interface fails with SQLITE_MISUSE, that means the interface
 4241** was invoked incorrectly by the application.  In that case, the
 4242** error code and message may or may not be set.
 4243*/
 4244SQLITE_API int sqlite3_errcode(sqlite3 *db);
 4245SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
 4246SQLITE_API const char *sqlite3_errmsg(sqlite3*);
 4247SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
 4248SQLITE_API const char *sqlite3_errstr(int);
 4249SQLITE_API int sqlite3_error_offset(sqlite3 *db);
 4250
 4251/*
 4252** CAPI3REF: Set Error Code And Message
 4253** METHOD: sqlite3
 4254**
 4255** Set the error code of the database handle passed as the first argument
 4256** to errcode, and the error message to a copy of nul-terminated string
 4257** zErrMsg. If zErrMsg is passed NULL, then the error message is set to
 4258** the default message associated with the supplied error code.  Subsequent
 4259** calls to [sqlite3_errcode()] and [sqlite3_errmsg()] and similar will
 4260** return the values set by this routine in place of what was previously
 4261** set by SQLite itself.
 4262**
 4263** This function returns SQLITE_OK if the error code and error message are
 4264** successfully set, SQLITE_NOMEM if an OOM occurs, and SQLITE_MISUSE if
 4265** the database handle is NULL or invalid.
 4266**
 4267** The error code and message set by this routine remains in effect until
 4268** they are changed, either by another call to this routine or until they are
 4269** changed to by SQLite itself to reflect the result of some subsquent
 4270** API call.
 4271**
 4272** This function is intended for use by SQLite extensions or wrappers.  The
 4273** idea is that an extension or wrapper can use this routine to set error
 4274** messages and error codes and thus behave more like a core SQLite
 4275** feature from the point of view of an application.
 4276*/
 4277SQLITE_API int sqlite3_set_errmsg(sqlite3 *db, int errcode, const char *zErrMsg);
 4278
 4279/*
 4280** CAPI3REF: Prepared Statement Object
 4281** KEYWORDS: {prepared statement} {prepared statements}
 4282**
 4283** An instance of this object represents a single SQL statement that
 4284** has been compiled into binary form and is ready to be evaluated.
 4285**
 4286** Think of each SQL statement as a separate computer program.  The
 4287** original SQL text is source code.  A prepared statement object
 4288** is the compiled object code.  All SQL must be converted into a
 4289** prepared statement before it can be run.
 4290**
 4291** The life-cycle of a prepared statement object usually goes like this:
 4292**
 4293** <ol>
 4294** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
 4295** <li> Bind values to [parameters] using the sqlite3_bind_*()
 4296**      interfaces.
 4297** <li> Run the SQL by calling [sqlite3_step()] one or more times.
 4298** <li> Reset the prepared statement using [sqlite3_reset()] then go back
 4299**      to step 2.  Do this zero or more times.
 4300** <li> Destroy the object using [sqlite3_finalize()].
 4301** </ol>
 4302*/
 4303typedef struct sqlite3_stmt sqlite3_stmt;
 4304
 4305/*
 4306** CAPI3REF: Run-time Limits
 4307** METHOD: sqlite3
 4308**
 4309** ^(This interface allows the size of various constructs to be limited
 4310** on a connection by connection basis.  The first parameter is the
 4311** [database connection] whose limit is to be set or queried.  The
 4312** second parameter is one of the [limit categories] that define a
 4313** class of constructs to be size limited.  The third parameter is the
 4314** new limit for that construct.)^
 4315**
 4316** ^If the new limit is a negative number, the limit is unchanged.
 4317** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a
 4318** [limits | hard upper bound]
 4319** set at compile-time by a C preprocessor macro called
 4320** [limits | SQLITE_MAX_<i>NAME</i>].
 4321** (The "_LIMIT_" in the name is changed to "_MAX_".))^
 4322** ^Attempts to increase a limit above its hard upper bound are
 4323** silently truncated to the hard upper bound.
 4324**
 4325** ^Regardless of whether or not the limit was changed, the
 4326** [sqlite3_limit()] interface returns the prior value of the limit.
 4327** ^Hence, to find the current value of a limit without changing it,
 4328** simply invoke this interface with the third parameter set to -1.
 4329**
 4330** Run-time limits are intended for use in applications that manage
 4331** both their own internal database and also databases that are controlled
 4332** by untrusted external sources.  An example application might be a
 4333** web browser that has its own databases for storing history and
 4334** separate databases controlled by JavaScript applications downloaded
 4335** off the Internet.  The internal databases can be given the
 4336** large, default limits.  Databases managed by external sources can
 4337** be given much smaller limits designed to prevent a denial of service
 4338** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
 4339** interface to further control untrusted SQL.  The size of the database
 4340** created by an untrusted script can be contained using the
 4341** [max_page_count] [PRAGMA].
 4342**
 4343** New run-time limit categories may be added in future releases.
 4344*/
 4345SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
 4346
 4347/*
 4348** CAPI3REF: Run-Time Limit Categories
 4349** KEYWORDS: {limit category} {*limit categories}
 4350**
 4351** These constants define various performance limits
 4352** that can be lowered at run-time using [sqlite3_limit()].
 4353** A concise description of these limits follows, and additional information
 4354** is available at [limits | Limits in SQLite].
 4355**
 4356** <dl>
 4357** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
 4358** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
 4359**
 4360** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
 4361** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
 4362**
 4363** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
 4364** <dd>The maximum number of columns in a table definition or in the
 4365** result set of a [SELECT] or the maximum number of columns in an index
 4366** or in an ORDER BY or GROUP BY clause.</dd>)^
 4367**
 4368** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
 4369** <dd>The maximum depth of the parse tree on any expression.</dd>)^
 4370**
 4371** [[SQLITE_LIMIT_PARSER_DEPTH]] ^(<dt>SQLITE_LIMIT_PARSER_DEPTH</dt>
 4372** <dd>The maximum depth of the LALR(1) parser stack used to analyze
 4373** input SQL statements.</dd>)^
 4374**
 4375** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
 4376** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
 4377**
 4378** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
 4379** <dd>The maximum number of instructions in a virtual machine program
 4380** used to implement an SQL statement.  If [sqlite3_prepare_v2()] or
 4381** the equivalent tries to allocate space for more than this many opcodes
 4382** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^
 4383**
 4384** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
 4385** <dd>The maximum number of arguments on a function.</dd>)^
 4386**
 4387** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
 4388** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
 4389**
 4390** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
 4391** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
 4392** <dd>The maximum length of the pattern argument to the [LIKE] or
 4393** [GLOB] operators.</dd>)^
 4394**
 4395** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
 4396** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
 4397** <dd>The maximum index number of any [parameter] in an SQL statement.)^
 4398**
 4399** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
 4400** <dd>The maximum depth of recursion for triggers.</dd>)^
 4401**
 4402** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
 4403** <dd>The maximum number of auxiliary worker threads that a single
 4404** [prepared statement] may start.</dd>)^
 4405** </dl>
 4406*/
 4407#define SQLITE_LIMIT_LENGTH                    0
 4408#define SQLITE_LIMIT_SQL_LENGTH                1
 4409#define SQLITE_LIMIT_COLUMN                    2
 4410#define SQLITE_LIMIT_EXPR_DEPTH                3
 4411#define SQLITE_LIMIT_COMPOUND_SELECT           4
 4412#define SQLITE_LIMIT_VDBE_OP                   5
 4413#define SQLITE_LIMIT_FUNCTION_ARG              6
 4414#define SQLITE_LIMIT_ATTACHED                  7
 4415#define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
 4416#define SQLITE_LIMIT_VARIABLE_NUMBER           9
 4417#define SQLITE_LIMIT_TRIGGER_DEPTH            10
 4418#define SQLITE_LIMIT_WORKER_THREADS           11
 4419#define SQLITE_LIMIT_PARSER_DEPTH             12
 4420
 4421/*
 4422** CAPI3REF: Prepare Flags
 4423**
 4424** These constants define various flags that can be passed into the
 4425** "prepFlags" parameter of the [sqlite3_prepare_v3()] and
 4426** [sqlite3_prepare16_v3()] interfaces.
 4427**
 4428** New flags may be added in future releases of SQLite.
 4429**
 4430** <dl>
 4431** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt>
 4432** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
 4433** that the prepared statement will be retained for a long time and
 4434** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()]
 4435** and [sqlite3_prepare16_v3()] assume that the prepared statement will
 4436** be used just once or at most a few times and then destroyed using
 4437** [sqlite3_finalize()] relatively soon. The current implementation acts
 4438** on this hint by avoiding the use of [lookaside memory] so as not to
 4439** deplete the limited store of lookaside memory. Future versions of
 4440** SQLite may act on this hint differently.
 4441**
 4442** [[SQLITE_PREPARE_NORMALIZE]] <dt>SQLITE_PREPARE_NORMALIZE</dt>
 4443** <dd>The SQLITE_PREPARE_NORMALIZE flag is a no-op. This flag used
 4444** to be required for any prepared statement that wanted to use the
 4445** [sqlite3_normalized_sql()] interface.  However, the
 4446** [sqlite3_normalized_sql()] interface is now available to all
 4447** prepared statements, regardless of whether or not they use this
 4448** flag.
 4449**
 4450** [[SQLITE_PREPARE_NO_VTAB]] <dt>SQLITE_PREPARE_NO_VTAB</dt>
 4451** <dd>The SQLITE_PREPARE_NO_VTAB flag causes the SQL compiler
 4452** to return an error (error code SQLITE_ERROR) if the statement uses
 4453** any virtual tables.
 4454**
 4455** [[SQLITE_PREPARE_DONT_LOG]] <dt>SQLITE_PREPARE_DONT_LOG</dt>
 4456** <dd>The SQLITE_PREPARE_DONT_LOG flag prevents SQL compiler
 4457** errors from being sent to the error log defined by
 4458** [SQLITE_CONFIG_LOG].  This can be used, for example, to do test
 4459** compiles to see if some SQL syntax is well-formed, without generating
 4460** messages on the global error log when it is not.  If the test compile
 4461** fails, the sqlite3_prepare_v3() call returns the same error indications
 4462** with or without this flag; it just omits the call to [sqlite3_log()] that
 4463** logs the error.
 4464**
 4465** [[SQLITE_PREPARE_FROM_DDL]] <dt>SQLITE_PREPARE_FROM_DDL</dt>
 4466** <dd>The SQLITE_PREPARE_FROM_DDL flag causes the SQL compiler to enforce
 4467** security constraints that would otherwise only be enforced when parsing
 4468** the database schema.  In other words, the SQLITE_PREPARE_FROM_DDL flag
 4469** causes the SQL compiler to treat the SQL statement being prepared as if
 4470** it had come from an attacker.  When SQLITE_PREPARE_FROM_DDL is used and
 4471** [SQLITE_DBCONFIG_TRUSTED_SCHEMA] is off, SQL functions may only be called
 4472** if they are tagged with [SQLITE_INNOCUOUS] and virtual tables may only
 4473** be used if they are tagged with [SQLITE_VTAB_INNOCUOUS].  Best practice
 4474** is to use the SQLITE_PREPARE_FROM_DDL option when preparing any SQL that
 4475** is derived from parts of the database schema. In particular, virtual
 4476** table implementations that run SQL statements that are derived from
 4477** arguments to their CREATE VIRTUAL TABLE statement should always use
 4478** [sqlite3_prepare_v3()] and set the SQLITE_PREPARE_FROM_DDL flag to
 4479** prevent bypass of the [SQLITE_DBCONFIG_TRUSTED_SCHEMA] security checks.
 4480** </dl>
 4481*/
 4482#define SQLITE_PREPARE_PERSISTENT              0x01
 4483#define SQLITE_PREPARE_NORMALIZE               0x02
 4484#define SQLITE_PREPARE_NO_VTAB                 0x04
 4485#define SQLITE_PREPARE_DONT_LOG                0x10
 4486#define SQLITE_PREPARE_FROM_DDL                0x20
 4487
 4488/*
 4489** CAPI3REF: Compiling An SQL Statement
 4490** KEYWORDS: {SQL statement compiler}
 4491** METHOD: sqlite3
 4492** CONSTRUCTOR: sqlite3_stmt
 4493**
 4494** To execute an SQL statement, it must first be compiled into a byte-code
 4495** program using one of these routines.  Or, in other words, these routines
 4496** are constructors for the [prepared statement] object.
 4497**
 4498** The preferred routine to use is [sqlite3_prepare_v2()].  The
 4499** [sqlite3_prepare()] interface is legacy and should be avoided.
 4500** [sqlite3_prepare_v3()] has an extra
 4501** [SQLITE_PREPARE_FROM_DDL|"prepFlags" option] that is sometimes
 4502** needed for special purpose or to pass along security restrictions.
 4503**
 4504** The use of the UTF-8 interfaces is preferred, as SQLite currently
 4505** does all parsing using UTF-8.  The UTF-16 interfaces are provided
 4506** as a convenience.  The UTF-16 interfaces work by converting the
 4507** input text into UTF-8, then invoking the corresponding UTF-8 interface.
 4508**
 4509** The first argument, "db", is a [database connection] obtained from a
 4510** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
 4511** [sqlite3_open16()].  The database connection must not have been closed.
 4512**
 4513** The second argument, "zSql", is the statement to be compiled, encoded
 4514** as either UTF-8 or UTF-16.  The sqlite3_prepare(), sqlite3_prepare_v2(),
 4515** and sqlite3_prepare_v3()
 4516** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
 4517** and sqlite3_prepare16_v3() use UTF-16.
 4518**
 4519** ^If the nByte argument is negative, then zSql is read up to the
 4520** first zero terminator. ^If nByte is positive, then it is the maximum
 4521** number of bytes read from zSql.  When nByte is positive, zSql is read
 4522** up to the first zero terminator or until the nByte bytes have been read,
 4523** whichever comes first.  ^If nByte is zero, then no prepared
 4524** statement is generated.
 4525** If the caller knows that the supplied string is nul-terminated, then
 4526** there is a small performance advantage to passing an nByte parameter that
 4527** is the number of bytes in the input string <i>including</i>
 4528** the nul-terminator.
 4529** Note that nByte measures the length of the input in bytes, not
 4530** characters, even for the UTF-16 interfaces.
 4531**
 4532** ^If pzTail is not NULL then *pzTail is made to point to the first byte
 4533** past the end of the first SQL statement in zSql.  These routines only
 4534** compile the first statement in zSql, so *pzTail is left pointing to
 4535** what remains uncompiled.
 4536**
 4537** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
 4538** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
 4539** to NULL.  ^If the input text contains no SQL (if the input is an empty
 4540** string or a comment) then *ppStmt is set to NULL.
 4541** The calling procedure is responsible for deleting the compiled
 4542** SQL statement using [sqlite3_finalize()] after it has finished with it.
 4543** ppStmt may not be NULL.
 4544**
 4545** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
 4546** otherwise an [error code] is returned.
 4547**
 4548** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
 4549** and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
 4550** The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
 4551** are retained for backwards compatibility, but their use is discouraged.
 4552** ^In the "vX" interfaces, the prepared statement
 4553** that is returned (the [sqlite3_stmt] object) contains a copy of the
 4554** original SQL text. This causes the [sqlite3_step()] interface to
 4555** behave differently in three ways:
 4556**
 4557** <ol>
 4558** <li>
 4559** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
 4560** always used to do, [sqlite3_step()] will automatically recompile the SQL
 4561** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
 4562** retries will occur before sqlite3_step() gives up and returns an error.
 4563** </li>
 4564**
 4565** <li>
 4566** ^When an error occurs, [sqlite3_step()] will return one of the detailed
 4567** [error codes] or [extended error codes].  ^The legacy behavior was that
 4568** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
 4569** and the application would have to make a second call to [sqlite3_reset()]
 4570** in order to find the underlying cause of the problem. With the "v2" prepare
 4571** interfaces, the underlying reason for the error is returned immediately.
 4572** </li>
 4573**
 4574** <li>
 4575** ^If the specific value bound to a [parameter | host parameter] in the
 4576** WHERE clause might influence the choice of query plan for a statement,
 4577** then the statement will be automatically recompiled, as if there had been
 4578** a schema change, on the first [sqlite3_step()] call following any change
 4579** to the [sqlite3_bind_text | bindings] of that [parameter].
 4580** ^The specific value of a WHERE-clause [parameter] might influence the
 4581** choice of query plan if the parameter is the left-hand side of a [LIKE]
 4582** or [GLOB] operator or if the parameter is compared to an indexed column
 4583** and the [SQLITE_ENABLE_STAT4] compile-time option is enabled.
 4584** </li>
 4585** </ol>
 4586**
 4587** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
 4588** the extra prepFlags parameter, which is a bit array consisting of zero or
 4589** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags.  ^The
 4590** sqlite3_prepare_v2() interface works exactly the same as
 4591** sqlite3_prepare_v3() with a zero prepFlags parameter.
 4592*/
 4593SQLITE_API int sqlite3_prepare(
 4594  sqlite3 *db,            /* Database handle */
 4595  const char *zSql,       /* SQL statement, UTF-8 encoded */
 4596  int nByte,              /* Maximum length of zSql in bytes. */
 4597  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
 4598  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
 4599);
 4600SQLITE_API int sqlite3_prepare_v2(
 4601  sqlite3 *db,            /* Database handle */
 4602  const char *zSql,       /* SQL statement, UTF-8 encoded */
 4603  int nByte,              /* Maximum length of zSql in bytes. */
 4604  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
 4605  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
 4606);
 4607SQLITE_API int sqlite3_prepare_v3(
 4608  sqlite3 *db,            /* Database handle */
 4609  const char *zSql,       /* SQL statement, UTF-8 encoded */
 4610  int nByte,              /* Maximum length of zSql in bytes. */
 4611  unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
 4612  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
 4613  const char **pzTail     /* OUT: Pointer to unused portion of zSql */
 4614);
 4615SQLITE_API int sqlite3_prepare16(
 4616  sqlite3 *db,            /* Database handle */
 4617  const void *zSql,       /* SQL statement, UTF-16 encoded */
 4618  int nByte,              /* Maximum length of zSql in bytes. */
 4619  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
 4620  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
 4621);
 4622SQLITE_API int sqlite3_prepare16_v2(
 4623  sqlite3 *db,            /* Database handle */
 4624  const void *zSql,       /* SQL statement, UTF-16 encoded */
 4625  int nByte,              /* Maximum length of zSql in bytes. */
 4626  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
 4627  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
 4628);
 4629SQLITE_API int sqlite3_prepare16_v3(
 4630  sqlite3 *db,            /* Database handle */
 4631  const void *zSql,       /* SQL statement, UTF-16 encoded */
 4632  int nByte,              /* Maximum length of zSql in bytes. */
 4633  unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
 4634  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
 4635  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
 4636);
 4637
 4638/*
 4639** CAPI3REF: Retrieving Statement SQL
 4640** METHOD: sqlite3_stmt
 4641**
 4642** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
 4643** SQL text used to create [prepared statement] P if P was
 4644** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()],
 4645** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
 4646** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
 4647** string containing the SQL text of prepared statement P with
 4648** [bound parameters] expanded.
 4649** ^The sqlite3_normalized_sql(P) interface returns a pointer to a UTF-8
 4650** string containing the normalized SQL text of prepared statement P.  The
 4651** semantics used to normalize a SQL statement are unspecified and subject
 4652** to change.  At a minimum, literal values will be replaced with suitable
 4653** placeholders.
 4654**
 4655** ^(For example, if a prepared statement is created using the SQL
 4656** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
 4657** and parameter :xyz is unbound, then sqlite3_sql() will return
 4658** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
 4659** will return "SELECT 2345,NULL".)^
 4660**
 4661** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory
 4662** is available to hold the result, or if the result would exceed the
 4663** maximum string length determined by the [SQLITE_LIMIT_LENGTH].
 4664**
 4665** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of
 4666** bound parameter expansions.  ^The [SQLITE_OMIT_TRACE] compile-time
 4667** option causes sqlite3_expanded_sql() to always return NULL.
 4668**
 4669** ^The strings returned by sqlite3_sql(P) and sqlite3_normalized_sql(P)
 4670** are managed by SQLite and are automatically freed when the prepared
 4671** statement is finalized.
 4672** ^The string returned by sqlite3_expanded_sql(P), on the other hand,
 4673** is obtained from [sqlite3_malloc()] and must be freed by the application
 4674** by passing it to [sqlite3_free()].
 4675**
 4676** ^The sqlite3_normalized_sql() interface is only available if
 4677** the [SQLITE_ENABLE_NORMALIZE] compile-time option is defined.
 4678*/
 4679SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
 4680SQLITE_API char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
 4681#ifdef SQLITE_ENABLE_NORMALIZE
 4682SQLITE_API const char *sqlite3_normalized_sql(sqlite3_stmt *pStmt);
 4683#endif
 4684
 4685/*
 4686** CAPI3REF: Determine If An SQL Statement Writes The Database
 4687** METHOD: sqlite3_stmt
 4688**
 4689** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
 4690** and only if the [prepared statement] X makes no direct changes to
 4691** the content of the database file.
 4692**
 4693** Note that [application-defined SQL functions] or
 4694** [virtual tables] might change the database indirectly as a side effect.
 4695** ^(For example, if an application defines a function "eval()" that
 4696** calls [sqlite3_exec()], then the following SQL statement would
 4697** change the database file through side-effects:
 4698**
 4699** <blockquote><pre>
 4700**    SELECT eval('DELETE FROM t1') FROM t2;
 4701** </pre></blockquote>
 4702**
 4703** But because the [SELECT] statement does not change the database file
 4704** directly, sqlite3_stmt_readonly() would still return true.)^
 4705**
 4706** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
 4707** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
 4708** since the statements themselves do not actually modify the database but
 4709** rather they control the timing of when other statements modify the
 4710** database.  ^The [ATTACH] and [DETACH] statements also cause
 4711** sqlite3_stmt_readonly() to return true since, while those statements
 4712** change the configuration of a database connection, they do not make
 4713** changes to the content of the database files on disk.
 4714** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
 4715** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
 4716** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
 4717** sqlite3_stmt_readonly() returns false for those commands.
 4718**
 4719** ^This routine returns false if there is any possibility that the
 4720** statement might change the database file.  ^A false return does
 4721** not guarantee that the statement will change the database file.
 4722** ^For example, an UPDATE statement might have a WHERE clause that
 4723** makes it a no-op, but the sqlite3_stmt_readonly() result would still
 4724** be false.  ^Similarly, a CREATE TABLE IF NOT EXISTS statement is a
 4725** read-only no-op if the table already exists, but
 4726** sqlite3_stmt_readonly() still returns false for such a statement.
 4727**
 4728** ^If prepared statement X is an [EXPLAIN] or [EXPLAIN QUERY PLAN]
 4729** statement, then sqlite3_stmt_readonly(X) returns the same value as
 4730** if the EXPLAIN or EXPLAIN QUERY PLAN prefix were omitted.
 4731*/
 4732SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
 4733
 4734/*
 4735** CAPI3REF: Query The EXPLAIN Setting For A Prepared Statement
 4736** METHOD: sqlite3_stmt
 4737**
 4738** ^The sqlite3_stmt_isexplain(S) interface returns 1 if the
 4739** prepared statement S is an EXPLAIN statement, or 2 if the
 4740** statement S is an EXPLAIN QUERY PLAN.
 4741** ^The sqlite3_stmt_isexplain(S) interface returns 0 if S is
 4742** an ordinary statement or a NULL pointer.
 4743*/
 4744SQLITE_API int sqlite3_stmt_isexplain(sqlite3_stmt *pStmt);
 4745
 4746/*
 4747** CAPI3REF: Change The EXPLAIN Setting For A Prepared Statement
 4748** METHOD: sqlite3_stmt
 4749**
 4750** The sqlite3_stmt_explain(S,E) interface changes the EXPLAIN
 4751** setting for [prepared statement] S.  If E is zero, then S becomes
 4752** a normal prepared statement.  If E is 1, then S behaves as if
 4753** its SQL text began with "[EXPLAIN]".  If E is 2, then S behaves as if
 4754** its SQL text began with "[EXPLAIN QUERY PLAN]".
 4755**
 4756** Calling sqlite3_stmt_explain(S,E) might cause S to be reprepared.
 4757** SQLite tries to avoid a reprepare, but a reprepare might be necessary
 4758** on the first transition into EXPLAIN or EXPLAIN QUERY PLAN mode.
 4759**
 4760** Because of the potential need to reprepare, a call to
 4761** sqlite3_stmt_explain(S,E) will fail with SQLITE_ERROR if S cannot be
 4762** reprepared because it was created using [sqlite3_prepare()] instead of
 4763** the newer [sqlite3_prepare_v2()] or [sqlite3_prepare_v3()] interfaces and
 4764** hence has no saved SQL text with which to reprepare.
 4765**
 4766** Changing the explain setting for a prepared statement does not change
 4767** the original SQL text for the statement.  Hence, if the SQL text originally
 4768** began with EXPLAIN or EXPLAIN QUERY PLAN, but sqlite3_stmt_explain(S,0)
 4769** is called to convert the statement into an ordinary statement, the EXPLAIN
 4770** or EXPLAIN QUERY PLAN keywords will still appear in the sqlite3_sql(S)
 4771** output, even though the statement now acts like a normal SQL statement.
 4772**
 4773** This routine returns SQLITE_OK if the explain mode is successfully
 4774** changed, or an error code if the explain mode could not be changed.
 4775** The explain mode cannot be changed while a statement is active.
 4776** Hence, it is good practice to call [sqlite3_reset(S)]
 4777** immediately prior to calling sqlite3_stmt_explain(S,E).
 4778*/
 4779SQLITE_API int sqlite3_stmt_explain(sqlite3_stmt *pStmt, int eMode);
 4780
 4781/*
 4782** CAPI3REF: Determine If A Prepared Statement Has Been Reset
 4783** METHOD: sqlite3_stmt
 4784**
 4785** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
 4786** [prepared statement] S has been stepped at least once using
 4787** [sqlite3_step(S)] but has neither run to completion (returned
 4788** [SQLITE_DONE] from [sqlite3_step(S)]) nor
 4789** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
 4790** interface returns false if S is a NULL pointer.  If S is not a
 4791** NULL pointer and is not a pointer to a valid [prepared statement]
 4792** object, then the behavior is undefined and probably undesirable.
 4793**
 4794** This interface can be used in combination [sqlite3_next_stmt()]
 4795** to locate all prepared statements associated with a database
 4796** connection that are in need of being reset.  This can be used,
 4797** for example, in diagnostic routines to search for prepared
 4798** statements that are holding a transaction open.
 4799*/
 4800SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
 4801
 4802/*
 4803** CAPI3REF: Dynamically Typed Value Object
 4804** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
 4805**
 4806** SQLite uses the sqlite3_value object to represent all values
 4807** that can be stored in a database table. SQLite uses dynamic typing
 4808** for the values it stores.  ^Values stored in sqlite3_value objects
 4809** can be integers, floating point values, strings, BLOBs, or NULL.
 4810**
 4811** An sqlite3_value object may be either "protected" or "unprotected".
 4812** Some interfaces require a protected sqlite3_value.  Other interfaces
 4813** will accept either a protected or an unprotected sqlite3_value.
 4814** Every interface that accepts sqlite3_value arguments specifies
 4815** whether or not it requires a protected sqlite3_value.  The
 4816** [sqlite3_value_dup()] interface can be used to construct a new
 4817** protected sqlite3_value from an unprotected sqlite3_value.
 4818**
 4819** The terms "protected" and "unprotected" refer to whether or not
 4820** a mutex is held.  An internal mutex is held for a protected
 4821** sqlite3_value object but no mutex is held for an unprotected
 4822** sqlite3_value object.  If SQLite is compiled to be single-threaded
 4823** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
 4824** or if SQLite is run in one of reduced mutex modes
 4825** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
 4826** then there is no distinction between protected and unprotected
 4827** sqlite3_value objects and they can be used interchangeably.  However,
 4828** for maximum code portability it is recommended that applications
 4829** still make the distinction between protected and unprotected
 4830** sqlite3_value objects even when not strictly required.
 4831**
 4832** ^The sqlite3_value objects that are passed as parameters into the
 4833** implementation of [application-defined SQL functions] are protected.
 4834** ^The sqlite3_value objects returned by [sqlite3_vtab_rhs_value()]
 4835** are protected.
 4836** ^The sqlite3_value object returned by
 4837** [sqlite3_column_value()] is unprotected.
 4838** Unprotected sqlite3_value objects may only be used as arguments
 4839** to [sqlite3_result_value()], [sqlite3_bind_value()], and
 4840** [sqlite3_value_dup()].
 4841** The [sqlite3_value_blob | sqlite3_value_type()] family of
 4842** interfaces require protected sqlite3_value objects.
 4843*/
 4844typedef struct sqlite3_value sqlite3_value;
 4845
 4846/*
 4847** CAPI3REF: SQL Function Context Object
 4848**
 4849** The context in which an SQL function executes is stored in an
 4850** sqlite3_context object.  ^A pointer to an sqlite3_context object
 4851** is always the first parameter to [application-defined SQL functions].
 4852** The application-defined SQL function implementation will pass this
 4853** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
 4854** [sqlite3_aggregate_context()], [sqlite3_user_data()],
 4855** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
 4856** and/or [sqlite3_set_auxdata()].
 4857*/
 4858typedef struct sqlite3_context sqlite3_context;
 4859
 4860/*
 4861** CAPI3REF: Binding Values To Prepared Statements
 4862** KEYWORDS: {host parameter} {host parameters} {host parameter name}
 4863** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
 4864** METHOD: sqlite3_stmt
 4865**
 4866** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
 4867** literals may be replaced by a [parameter] that matches one of the following
 4868** templates:
 4869**
 4870** <ul>
 4871** <li>  ?
 4872** <li>  ?NNN
 4873** <li>  :VVV
 4874** <li>  @VVV
 4875** <li>  $VVV
 4876** </ul>
 4877**
 4878** In the templates above, NNN represents an integer literal,
 4879** and VVV represents an alphanumeric identifier.)^  ^The values of these
 4880** parameters (also called "host parameter names" or "SQL parameters")
 4881** can be set using the sqlite3_bind_*() routines defined here.
 4882**
 4883** ^The first argument to the sqlite3_bind_*() routines is always
 4884** a pointer to the [sqlite3_stmt] object returned from
 4885** [sqlite3_prepare_v2()] or its variants.
 4886**
 4887** ^The second argument is the index of the SQL parameter to be set.
 4888** ^The leftmost SQL parameter has an index of 1.  ^When the same named
 4889** SQL parameter is used more than once, second and subsequent
 4890** occurrences have the same index as the first occurrence.
 4891** ^The index for named parameters can be looked up using the
 4892** [sqlite3_bind_parameter_index()] API if desired.  ^The index
 4893** for "?NNN" parameters is the value of NNN.
 4894** ^The NNN value must be between 1 and the [sqlite3_limit()]
 4895** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 32766).
 4896**
 4897** ^The third argument is the value to bind to the parameter.
 4898** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
 4899** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
 4900** is ignored and the end result is the same as sqlite3_bind_null().
 4901** ^If the third parameter to sqlite3_bind_text() is not NULL, then
 4902** it should be a pointer to well-formed UTF8 text.
 4903** ^If the third parameter to sqlite3_bind_text16() is not NULL, then
 4904** it should be a pointer to well-formed UTF16 text.
 4905** ^If the third parameter to sqlite3_bind_text64() is not NULL, then
 4906** it should be a pointer to a well-formed unicode string that is
 4907** either UTF8 if the sixth parameter is SQLITE_UTF8 or SQLITE_UTF8_ZT,
 4908** or UTF16 otherwise.
 4909**
 4910** [[byte-order determination rules]] ^The byte-order of
 4911** UTF16 input text is determined by the byte-order mark (BOM, U+FEFF)
 4912** found in the first character, which is removed, or in the absence of a BOM
 4913** the byte order is the native byte order of the host
 4914** machine for sqlite3_bind_text16() or the byte order specified in
 4915** the 6th parameter for sqlite3_bind_text64().)^
 4916** ^If UTF16 input text contains invalid unicode
 4917** characters, then SQLite might change those invalid characters
 4918** into the unicode replacement character: U+FFFD.
 4919**
 4920** ^(In those routines that have a fourth argument, its value is the
 4921** number of bytes in the parameter.  To be clear: the value is the
 4922** number of <u>bytes</u> in the value, not the number of characters.)^
 4923** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
 4924** is negative, then the length of the string is
 4925** the number of bytes up to the first zero terminator.
 4926** If the fourth parameter to sqlite3_bind_blob() is negative, then
 4927** the behavior is undefined.
 4928** If a non-negative fourth parameter is provided to sqlite3_bind_text()
 4929** or sqlite3_bind_text16() or sqlite3_bind_text64() then
 4930** that parameter must be the byte offset
 4931** where the NUL terminator would occur assuming the string were NUL
 4932** terminated.  If any NUL characters occur at byte offsets less than
 4933** the value of the fourth parameter then the resulting string value will
 4934** contain embedded NULs.  The result of expressions involving strings
 4935** with embedded NULs is undefined.
 4936**
 4937** ^The fifth argument to the BLOB and string binding interfaces controls
 4938** or indicates the lifetime of the object referenced by the third parameter.
 4939** These three options exist:
 4940** ^ (1) A destructor to dispose of the BLOB or string after SQLite has finished
 4941** with it may be passed. ^It is called to dispose of the BLOB or string even
 4942** if the call to the bind API fails, except the destructor is not called if
 4943** the third parameter is a NULL pointer or the fourth parameter is negative.
 4944** ^ (2) The special constant, [SQLITE_STATIC], may be passed to indicate that
 4945** the application remains responsible for disposing of the object. ^In this
 4946** case, the object and the provided pointer to it must remain valid until
 4947** either the prepared statement is finalized or the same SQL parameter is
 4948** bound to something else, whichever occurs sooner.
 4949** ^ (3) The constant, [SQLITE_TRANSIENT], may be passed to indicate that the
 4950** object is to be copied prior to the return from sqlite3_bind_*(). ^The
 4951** object and pointer to it must remain valid until then. ^SQLite will then
 4952** manage the lifetime of its private copy.
 4953**
 4954** ^The sixth argument (the E argument)
 4955** to sqlite3_bind_text64(S,K,Z,N,D,E) must be one of
 4956** [SQLITE_UTF8], [SQLITE_UTF8_ZT], [SQLITE_UTF16], [SQLITE_UTF16BE],
 4957** or [SQLITE_UTF16LE] to specify the encoding of the text in the
 4958** third parameter, Z.  The special value [SQLITE_UTF8_ZT] means that the
 4959** string argument is both UTF-8 encoded and is zero-terminated.  In other
 4960** words, SQLITE_UTF8_ZT means that the Z array is allocated to hold at
 4961** least N+1 bytes and that the Z&#91;N&#93; byte is zero.  If
 4962** the E argument to sqlite3_bind_text64(S,K,Z,N,D,E) is not one of the
 4963** allowed values shown above, or if the text encoding is different
 4964** from the encoding specified by the sixth parameter, then the behavior
 4965** is undefined.
 4966**
 4967** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
 4968** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
 4969** (just an integer to hold its size) while it is being processed.
 4970** Zeroblobs are intended to serve as placeholders for BLOBs whose
 4971** content is later written using
 4972** [sqlite3_blob_open | incremental BLOB I/O] routines.
 4973** ^A negative value for the zeroblob results in a zero-length BLOB.
 4974**
 4975** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
 4976** [prepared statement] S to have an SQL value of NULL, but to also be
 4977** associated with the pointer P of type T.  ^D is either a NULL pointer or
 4978** a pointer to a destructor function for P. ^SQLite will invoke the
 4979** destructor D with a single argument of P when it is finished using
 4980** P, even if the call to sqlite3_bind_pointer() fails.  Due to a
 4981** historical design quirk, results are undefined if D is
 4982** SQLITE_TRANSIENT. The T parameter should be a static string,
 4983** preferably a string literal. The sqlite3_bind_pointer() routine is
 4984** part of the [pointer passing interface] added for SQLite 3.20.0.
 4985**
 4986** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
 4987** for the [prepared statement] or with a prepared statement for which
 4988** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
 4989** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
 4990** routine is passed a [prepared statement] that has been finalized, the
 4991** result is undefined and probably harmful.
 4992**
 4993** ^Bindings are not cleared by the [sqlite3_reset()] routine.
 4994** ^Unbound parameters are interpreted as NULL.
 4995**
 4996** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
 4997** [error code] if anything goes wrong.
 4998** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
 4999** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
 5000** [SQLITE_MAX_LENGTH].
 5001** ^[SQLITE_RANGE] is returned if the parameter
 5002** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
 5003**
 5004** See also: [sqlite3_bind_parameter_count()],
 5005** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
 5006*/
 5007SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
 5008SQLITE_API int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
 5009                        void(*)(void*));
 5010SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
 5011SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
 5012SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
 5013SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
 5014SQLITE_API int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
 5015SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
 5016SQLITE_API int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
 5017                         void(*)(void*), unsigned char encoding);
 5018SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
 5019SQLITE_API int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
 5020SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
 5021SQLITE_API int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
 5022
 5023/*
 5024** CAPI3REF: Number Of SQL Parameters
 5025** METHOD: sqlite3_stmt
 5026**
 5027** ^This routine can be used to find the number of [SQL parameters]
 5028** in a [prepared statement].  SQL parameters are tokens of the
 5029** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
 5030** placeholders for values that are [sqlite3_bind_blob | bound]
 5031** to the parameters at a later time.
 5032**
 5033** ^(This routine actually returns the index of the largest (rightmost)
 5034** parameter. For all forms except ?NNN, this will correspond to the
 5035** number of unique parameters.  If parameters of the ?NNN form are used,
 5036** there may be gaps in the list.)^
 5037**
 5038** See also: [sqlite3_bind_blob|sqlite3_bind()],
 5039** [sqlite3_bind_parameter_name()], and
 5040** [sqlite3_bind_parameter_index()].
 5041*/
 5042SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
 5043
 5044/*
 5045** CAPI3REF: Name Of A Host Parameter
 5046** METHOD: sqlite3_stmt
 5047**
 5048** ^The sqlite3_bind_parameter_name(P,N) interface returns
 5049** the name of the N-th [SQL parameter] in the [prepared statement] P.
 5050** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
 5051** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
 5052** respectively.
 5053** In other words, the initial ":" or "$" or "@" or "?"
 5054** is included as part of the name.)^
 5055** ^Parameters of the form "?" without a following integer have no name
 5056** and are referred to as "nameless" or "anonymous parameters".
 5057**
 5058** ^The first host parameter has an index of 1, not 0.
 5059**
 5060** ^If the value N is out of range or if the N-th parameter is
 5061** nameless, then NULL is returned.  ^The returned string is
 5062** always in UTF-8 encoding even if the named parameter was
 5063** originally specified as UTF-16 in [sqlite3_prepare16()],
 5064** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
 5065**
 5066** See also: [sqlite3_bind_blob|sqlite3_bind()],
 5067** [sqlite3_bind_parameter_count()], and
 5068** [sqlite3_bind_parameter_index()].
 5069*/
 5070SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
 5071
 5072/*
 5073** CAPI3REF: Index Of A Parameter With A Given Name
 5074** METHOD: sqlite3_stmt
 5075**
 5076** ^Return the index of an SQL parameter given its name.  ^The
 5077** index value returned is suitable for use as the second
 5078** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
 5079** is returned if no matching parameter is found.  ^The parameter
 5080** name must be given in UTF-8 even if the original statement
 5081** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or
 5082** [sqlite3_prepare16_v3()].
 5083**
 5084** See also: [sqlite3_bind_blob|sqlite3_bind()],
 5085** [sqlite3_bind_parameter_count()], and
 5086** [sqlite3_bind_parameter_name()].
 5087*/
 5088SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
 5089
 5090/*
 5091** CAPI3REF: Reset All Bindings On A Prepared Statement
 5092** METHOD: sqlite3_stmt
 5093**
 5094** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
 5095** the [sqlite3_bind_blob | bindings] on a [prepared statement].
 5096** ^Use this routine to reset all host parameters to NULL.
 5097*/
 5098SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
 5099
 5100/*
 5101** CAPI3REF: Number Of Columns In A Result Set
 5102** METHOD: sqlite3_stmt
 5103**
 5104** ^Return the number of columns in the result set returned by the
 5105** [prepared statement]. ^If this routine returns 0, that means the
 5106** [prepared statement] returns no data (for example an [UPDATE]).
 5107** ^However, just because this routine returns a positive number does not
 5108** mean that one or more rows of data will be returned.  ^A SELECT statement
 5109** will always have a positive sqlite3_column_count() but depending on the
 5110** WHERE clause constraints and the table content, it might return no rows.
 5111**
 5112** See also: [sqlite3_data_count()]
 5113*/
 5114SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
 5115
 5116/*
 5117** CAPI3REF: Column Names In A Result Set
 5118** METHOD: sqlite3_stmt
 5119**
 5120** ^These routines return the name assigned to a particular column
 5121** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
 5122** interface returns a pointer to a zero-terminated UTF-8 string
 5123** and sqlite3_column_name16() returns a pointer to a zero-terminated
 5124** UTF-16 string.  ^The first parameter is the [prepared statement]
 5125** that implements the [SELECT] statement. ^The second parameter is the
 5126** column number.  ^The leftmost column is number 0.
 5127**
 5128** ^The returned string pointer is valid until either the [prepared statement]
 5129** is destroyed by [sqlite3_finalize()] or until the statement is automatically
 5130** reprepared by the first call to [sqlite3_step()] for a particular run
 5131** or until the next call to
 5132** sqlite3_column_name() or sqlite3_column_name16() on the same column.
 5133**
 5134** ^If sqlite3_malloc() fails during the processing of either routine
 5135** (for example during a conversion from UTF-8 to UTF-16) then a
 5136** NULL pointer is returned.
 5137**
 5138** ^The name of a result column is the value of the "AS" clause for
 5139** that column, if there is an AS clause.  If there is no AS clause
 5140** then the name of the column is unspecified and may change from
 5141** one release of SQLite to the next.
 5142*/
 5143SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
 5144SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
 5145
 5146/*
 5147** CAPI3REF: Source Of Data In A Query Result
 5148** METHOD: sqlite3_stmt
 5149**
 5150** ^These routines provide a means to determine the database, table, and
 5151** table column that is the origin of a particular result column in a
 5152** [SELECT] statement.
 5153** ^The name of the database or table or column can be returned as
 5154** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
 5155** the database name, the _table_ routines return the table name, and
 5156** the origin_ routines return the column name.
 5157** ^The returned string is valid until the [prepared statement] is destroyed
 5158** using [sqlite3_finalize()] or until the statement is automatically
 5159** reprepared by the first call to [sqlite3_step()] for a particular run
 5160** or until the same information is requested
 5161** again in a different encoding.
 5162**
 5163** ^The names returned are the original un-aliased names of the
 5164** database, table, and column.
 5165**
 5166** ^The first argument to these interfaces is a [prepared statement].
 5167** ^These functions return information about the Nth result column returned by
 5168** the statement, where N is the second function argument.
 5169** ^The left-most column is column 0 for these routines.
 5170**
 5171** ^If the Nth column returned by the statement is an expression or
 5172** subquery and is not a column value, then all of these functions return
 5173** NULL.  ^These routines might also return NULL if a memory allocation error
 5174** occurs.  ^Otherwise, they return the name of the attached database, table,
 5175** or column that query result column was extracted from.
 5176**
 5177** ^As with all other SQLite APIs, those whose names end with "16" return
 5178** UTF-16 encoded strings and the other functions return UTF-8.
 5179**
 5180** ^These APIs are only available if the library was compiled with the
 5181** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
 5182**
 5183** If two or more threads call one or more
 5184** [sqlite3_column_database_name | column metadata interfaces]
 5185** for the same [prepared statement] and result column
 5186** at the same time then the results are undefined.
 5187*/
 5188SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
 5189SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
 5190SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
 5191SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
 5192SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
 5193SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
 5194
 5195/*
 5196** CAPI3REF: Declared Datatype Of A Query Result
 5197** METHOD: sqlite3_stmt
 5198**
 5199** ^(The first parameter is a [prepared statement].
 5200** If this statement is a [SELECT] statement and the Nth column of the
 5201** returned result set of that [SELECT] is a table column (not an
 5202** expression or subquery) then the declared type of the table
 5203** column is returned.)^  ^If the Nth column of the result set is an
 5204** expression or subquery, then a NULL pointer is returned.
 5205** ^The returned string is always UTF-8 encoded.
 5206**
 5207** ^(For example, given the database schema:
 5208**
 5209** CREATE TABLE t1(c1 VARIANT);
 5210**
 5211** and the following statement to be compiled:
 5212**
 5213** SELECT c1 + 1, c1 FROM t1;
 5214**
 5215** this routine would return the string "VARIANT" for the second result
 5216** column (i==1), and a NULL pointer for the first result column (i==0).)^
 5217**
 5218** ^SQLite uses dynamic run-time typing.  ^So just because a column
 5219** is declared to contain a particular type does not mean that the
 5220** data stored in that column is of the declared type.  SQLite is
 5221** strongly typed, but the typing is dynamic not static.  ^Type
 5222** is associated with individual values, not with the containers
 5223** used to hold those values.
 5224*/
 5225SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
 5226SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
 5227
 5228/*
 5229** CAPI3REF: Evaluate An SQL Statement
 5230** METHOD: sqlite3_stmt
 5231**
 5232** After a [prepared statement] has been prepared using any of
 5233** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()],
 5234** or [sqlite3_prepare16_v3()] or one of the legacy
 5235** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
 5236** must be called one or more times to evaluate the statement.
 5237**
 5238** The details of the behavior of the sqlite3_step() interface depend
 5239** on whether the statement was prepared using the newer "vX" interfaces
 5240** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()],
 5241** [sqlite3_prepare16_v2()] or the older legacy
 5242** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
 5243** new "vX" interface is recommended for new applications but the legacy
 5244** interface will continue to be supported.
 5245**
 5246** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
 5247** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
 5248** ^With the "v2" interface, any of the other [result codes] or
 5249** [extended result codes] might be returned as well.
 5250**
 5251** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
 5252** database locks it needs to do its job.  ^If the statement is a [COMMIT]
 5253** or occurs outside of an explicit transaction, then you can retry the
 5254** statement.  If the statement is not a [COMMIT] and occurs within an
 5255** explicit transaction then you should rollback the transaction before
 5256** continuing.
 5257**
 5258** ^[SQLITE_DONE] means that the statement has finished executing
 5259** successfully.  sqlite3_step() should not be called again on this virtual
 5260** machine without first calling [sqlite3_reset()] to reset the virtual
 5261** machine back to its initial state.
 5262**
 5263** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
 5264** is returned each time a new row of data is ready for processing by the
 5265** caller. The values may be accessed using the [column access functions].
 5266** sqlite3_step() is called again to retrieve the next row of data.
 5267**
 5268** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
 5269** violation) has occurred.  sqlite3_step() should not be called again on
 5270** the VM. More information may be found by calling [sqlite3_errmsg()].
 5271** ^With the legacy interface, a more specific error code (for example,
 5272** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
 5273** can be obtained by calling [sqlite3_reset()] on the
 5274** [prepared statement].  ^In the "v2" interface,
 5275** the more specific error code is returned directly by sqlite3_step().
 5276**
 5277** [SQLITE_MISUSE] means that the this routine was called inappropriately.
 5278** Perhaps it was called on a [prepared statement] that has
 5279** already been [sqlite3_finalize | finalized] or on one that had
 5280** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
 5281** be the case that the same database connection is being used by two or
 5282** more threads at the same moment in time.
 5283**
 5284** For all versions of SQLite up to and including 3.6.23.1, a call to
 5285** [sqlite3_reset()] was required after sqlite3_step() returned anything
 5286** other than [SQLITE_ROW] before any subsequent invocation of
 5287** sqlite3_step().  Failure to reset the prepared statement using
 5288** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
 5289** sqlite3_step().  But after [version 3.6.23.1] ([dateof:3.6.23.1]),
 5290** sqlite3_step() began
 5291** calling [sqlite3_reset()] automatically in this circumstance rather
 5292** than returning [SQLITE_MISUSE].  This is not considered a compatibility
 5293** break because any application that ever receives an SQLITE_MISUSE error
 5294** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
 5295** can be used to restore the legacy behavior.
 5296**
 5297** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
 5298** API always returns a generic error code, [SQLITE_ERROR], following any
 5299** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
 5300** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
 5301** specific [error codes] that better describes the error.
 5302** We admit that this is a goofy design.  The problem has been fixed
 5303** with the "v2" interface.  If you prepare all of your SQL statements
 5304** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()]
 5305** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead
 5306** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
 5307** then the more specific [error codes] are returned directly
 5308** by sqlite3_step().  The use of the "vX" interfaces is recommended.
 5309*/
 5310SQLITE_API int sqlite3_step(sqlite3_stmt*);
 5311
 5312/*
 5313** CAPI3REF: Number of columns in a result set
 5314** METHOD: sqlite3_stmt
 5315**
 5316** ^The sqlite3_data_count(P) interface returns the number of columns in the
 5317** current row of the result set of [prepared statement] P.
 5318** ^If prepared statement P does not have results ready to return
 5319** (via calls to the [sqlite3_column_int | sqlite3_column()] family of
 5320** interfaces) then sqlite3_data_count(P) returns 0.
 5321** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
 5322** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
 5323** [sqlite3_step](P) returned [SQLITE_DONE].  ^The sqlite3_data_count(P)
 5324** will return non-zero if previous call to [sqlite3_step](P) returned
 5325** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
 5326** where it always returns zero since each step of that multi-step
 5327** pragma returns 0 columns of data.
 5328**
 5329** See also: [sqlite3_column_count()]
 5330*/
 5331SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
 5332
 5333/*
 5334** CAPI3REF: Fundamental Datatypes
 5335** KEYWORDS: SQLITE_TEXT
 5336**
 5337** ^(Every value in SQLite has one of five fundamental datatypes:
 5338**
 5339** <ul>
 5340** <li> 64-bit signed integer
 5341** <li> 64-bit IEEE floating point number
 5342** <li> string
 5343** <li> BLOB
 5344** <li> NULL
 5345** </ul>)^
 5346**
 5347** These constants are codes for each of those types.
 5348**
 5349** Note that the SQLITE_TEXT constant was also used in SQLite version 2
 5350** for a completely different meaning.  Software that links against both
 5351** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
 5352** SQLITE_TEXT.
 5353*/
 5354#define SQLITE_INTEGER  1
 5355#define SQLITE_FLOAT    2
 5356#define SQLITE_BLOB     4
 5357#define SQLITE_NULL     5
 5358#ifdef SQLITE_TEXT
 5359# undef SQLITE_TEXT
 5360#else
 5361# define SQLITE_TEXT     3
 5362#endif
 5363#define SQLITE3_TEXT     3
 5364
 5365/*
 5366** CAPI3REF: Result Values From A Query
 5367** KEYWORDS: {column access functions}
 5368** METHOD: sqlite3_stmt
 5369**
 5370** <b>Summary:</b>
 5371** <blockquote><table border=0 cellpadding=0 cellspacing=0>
 5372** <tr><td><b>sqlite3_column_blob</b><td>&rarr;<td>BLOB result
 5373** <tr><td><b>sqlite3_column_double</b><td>&rarr;<td>REAL result
 5374** <tr><td><b>sqlite3_column_int</b><td>&rarr;<td>32-bit INTEGER result
 5375** <tr><td><b>sqlite3_column_int64</b><td>&rarr;<td>64-bit INTEGER result
 5376** <tr><td><b>sqlite3_column_text</b><td>&rarr;<td>UTF-8 TEXT result
 5377** <tr><td><b>sqlite3_column_text16</b><td>&rarr;<td>UTF-16 TEXT result
 5378** <tr><td><b>sqlite3_column_value</b><td>&rarr;<td>The result as an
 5379** [sqlite3_value|unprotected sqlite3_value] object.
 5380** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
 5381** <tr><td><b>sqlite3_column_bytes</b><td>&rarr;<td>Size of a BLOB
 5382** or a UTF-8 TEXT result in bytes
 5383** <tr><td><b>sqlite3_column_bytes16&nbsp;&nbsp;</b>
 5384** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
 5385** TEXT in bytes
 5386** <tr><td><b>sqlite3_column_type</b><td>&rarr;<td>Default
 5387** datatype of the result
 5388** </table></blockquote>
 5389**
 5390** <b>Details:</b>
 5391**
 5392** ^These routines return information about a single column of the current
 5393** result row of a query.  ^In every case the first argument is a pointer
 5394** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
 5395** that was returned from [sqlite3_prepare_v2()] or one of its variants)
 5396** and the second argument is the index of the column for which information
 5397** should be returned. ^The leftmost column of the result set has the index 0.
 5398** ^The number of columns in the result can be determined using
 5399** [sqlite3_column_count()].
 5400**
 5401** If the SQL statement does not currently point to a valid row, or if the
 5402** column index is out of range, the result is undefined.
 5403** These routines may only be called when the most recent call to
 5404** [sqlite3_step()] has returned [SQLITE_ROW] and neither
 5405** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
 5406** If any of these routines are called after [sqlite3_reset()] or
 5407** [sqlite3_finalize()] or after [sqlite3_step()] has returned
 5408** something other than [SQLITE_ROW], the results are undefined.
 5409** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
 5410** are called from a different thread while any of these routines
 5411** are pending, then the results are undefined.
 5412**
 5413** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
 5414** each return the value of a result column in a specific data format.  If
 5415** the result column is not initially in the requested format (for example,
 5416** if the query returns an integer but the sqlite3_column_text() interface
 5417** is used to extract the value) then an automatic type conversion is performed.
 5418**
 5419** ^The sqlite3_column_type() routine returns the
 5420** [SQLITE_INTEGER | datatype code] for the initial data type
 5421** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
 5422** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].
 5423** The return value of sqlite3_column_type() can be used to decide which
 5424** of the first six interface should be used to extract the column value.
 5425** The value returned by sqlite3_column_type() is only meaningful if no
 5426** automatic type conversions have occurred for the value in question.
 5427** After a type conversion, the result of calling sqlite3_column_type()
 5428** is undefined, though harmless.  Future
 5429** versions of SQLite may change the behavior of sqlite3_column_type()
 5430** following a type conversion.
 5431**
 5432** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
 5433** or sqlite3_column_bytes16() interfaces can be used to determine the size
 5434** of that BLOB or string.
 5435**
 5436** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
 5437** routine returns the number of bytes in that BLOB or string.
 5438** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
 5439** the string to UTF-8 and then returns the number of bytes.
 5440** ^If the result is a numeric value then sqlite3_column_bytes() uses
 5441** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
 5442** the number of bytes in that string.
 5443** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
 5444**
 5445** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
 5446** routine returns the number of bytes in that BLOB or string.
 5447** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
 5448** the string to UTF-16 and then returns the number of bytes.
 5449** ^If the result is a numeric value then sqlite3_column_bytes16() uses
 5450** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
 5451** the number of bytes in that string.
 5452** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
 5453**
 5454** ^The values returned by [sqlite3_column_bytes()] and
 5455** [sqlite3_column_bytes16()] do not include the zero terminators at the end
 5456** of the string.  ^For clarity: the values returned by
 5457** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
 5458** bytes in the string, not the number of characters.
 5459**
 5460** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
 5461** even empty strings, are always zero-terminated.  ^The return
 5462** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
 5463**
 5464** ^Strings returned by sqlite3_column_text16() always have the endianness
 5465** which is native to the platform, regardless of the text encoding set
 5466** for the database.
 5467**
 5468** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
 5469** [unprotected sqlite3_value] object.  In a multithreaded environment,
 5470** an unprotected sqlite3_value object may only be used safely with
 5471** [sqlite3_bind_value()] and [sqlite3_result_value()].
 5472** If the [unprotected sqlite3_value] object returned by
 5473** [sqlite3_column_value()] is used in any other way, including calls
 5474** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
 5475** or [sqlite3_value_bytes()], the behavior is not threadsafe.
 5476** Hence, the sqlite3_column_value() interface
 5477** is normally only useful within the implementation of
 5478** [application-defined SQL functions] or [virtual tables], not within
 5479** top-level application code.
 5480**
 5481** These routines may attempt to convert the datatype of the result.
 5482** ^For example, if the internal representation is FLOAT and a text result
 5483** is requested, [sqlite3_snprintf()] is used internally to perform the
 5484** conversion automatically.  ^(The following table details the conversions
 5485** that are applied:
 5486**
 5487** <blockquote>
 5488** <table border="1">
 5489** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
 5490**
 5491** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
 5492** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
 5493** <tr><td>  NULL    <td>   TEXT    <td> Result is a NULL pointer
 5494** <tr><td>  NULL    <td>   BLOB    <td> Result is a NULL pointer
 5495** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
 5496** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
 5497** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
 5498** <tr><td>  FLOAT   <td> INTEGER   <td> [CAST] to INTEGER
 5499** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
 5500** <tr><td>  FLOAT   <td>   BLOB    <td> [CAST] to BLOB
 5501** <tr><td>  TEXT    <td> INTEGER   <td> [CAST] to INTEGER
 5502** <tr><td>  TEXT    <td>  FLOAT    <td> [CAST] to REAL
 5503** <tr><td>  TEXT    <td>   BLOB    <td> No change
 5504** <tr><td>  BLOB    <td> INTEGER   <td> [CAST] to INTEGER
 5505** <tr><td>  BLOB    <td>  FLOAT    <td> [CAST] to REAL
 5506** <tr><td>  BLOB    <td>   TEXT    <td> [CAST] to TEXT, ensure zero terminator
 5507** </table>
 5508** </blockquote>)^
 5509**
 5510** Note that when type conversions occur, pointers returned by prior
 5511** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
 5512** sqlite3_column_text16() may be invalidated.
 5513** Type conversions and pointer invalidations might occur
 5514** in the following cases:
 5515**
 5516** <ul>
 5517** <li> The initial content is a BLOB and sqlite3_column_text() or
 5518**      sqlite3_column_text16() is called.  A zero-terminator might
 5519**      need to be added to the string.</li>
 5520** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
 5521**      sqlite3_column_text16() is called.  The content must be converted
 5522**      to UTF-16.</li>
 5523** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
 5524**      sqlite3_column_text() is called.  The content must be converted
 5525**      to UTF-8.</li>
 5526** </ul>
 5527**
 5528** ^Conversions between UTF-16be and UTF-16le are always done in place and do
 5529** not invalidate a prior pointer, though of course the content of the buffer
 5530** that the prior pointer references will have been modified.  Other kinds
 5531** of conversion are done in place when it is possible, but sometimes they
 5532** are not possible and in those cases prior pointers are invalidated.
 5533**
 5534** The safest policy is to invoke these routines
 5535** in one of the following ways:
 5536**
 5537** <ul>
 5538**  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
 5539**  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
 5540**  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
 5541** </ul>
 5542**
 5543** In other words, you should call sqlite3_column_text(),
 5544** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
 5545** into the desired format, then invoke sqlite3_column_bytes() or
 5546** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
 5547** to sqlite3_column_text() or sqlite3_column_blob() with calls to
 5548** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
 5549** with calls to sqlite3_column_bytes().
 5550**
 5551** ^The pointers returned are valid until a type conversion occurs as
 5552** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
 5553** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
 5554** and BLOBs is freed automatically.  Do not pass the pointers returned
 5555** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
 5556** [sqlite3_free()].
 5557**
 5558** As long as the input parameters are correct, these routines will only
 5559** fail if an out-of-memory error occurs during a format conversion.
 5560** Only the following subset of interfaces are subject to out-of-memory
 5561** errors:
 5562**
 5563** <ul>
 5564** <li> sqlite3_column_blob()
 5565** <li> sqlite3_column_text()
 5566** <li> sqlite3_column_text16()
 5567** <li> sqlite3_column_bytes()
 5568** <li> sqlite3_column_bytes16()
 5569** </ul>
 5570**
 5571** If an out-of-memory error occurs, then the return value from these
 5572** routines is the same as if the column had contained an SQL NULL value.
 5573** Valid SQL NULL returns can be distinguished from out-of-memory errors
 5574** by invoking the [sqlite3_errcode()] immediately after the suspect
 5575** return value is obtained and before any
 5576** other SQLite interface is called on the same [database connection].
 5577*/
 5578SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
 5579SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
 5580SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
 5581SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
 5582SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
 5583SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
 5584SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
 5585SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
 5586SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
 5587SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
 5588
 5589/*
 5590** CAPI3REF: Destroy A Prepared Statement Object
 5591** DESTRUCTOR: sqlite3_stmt
 5592**
 5593** ^The sqlite3_finalize() function is called to delete a [prepared statement].
 5594** ^If the most recent evaluation of the statement encountered no errors
 5595** or if the statement has never been evaluated, then sqlite3_finalize() returns
 5596** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
 5597** sqlite3_finalize(S) returns the appropriate [error code] or
 5598** [extended error code].
 5599**
 5600** ^The sqlite3_finalize(S) routine can be called at any point during
 5601** the life cycle of [prepared statement] S:
 5602** before statement S is ever evaluated, after
 5603** one or more calls to [sqlite3_reset()], or after any call
 5604** to [sqlite3_step()] regardless of whether or not the statement has
 5605** completed execution.
 5606**
 5607** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
 5608**
 5609** The application must finalize every [prepared statement] in order to avoid
 5610** resource leaks.  It is a grievous error for the application to try to use
 5611** a prepared statement after it has been finalized.  Any use of a prepared
 5612** statement after it has been finalized can result in undefined and
 5613** undesirable behavior such as segfaults and heap corruption.
 5614*/
 5615SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
 5616
 5617/*
 5618** CAPI3REF: Reset A Prepared Statement Object
 5619** METHOD: sqlite3_stmt
 5620**
 5621** The sqlite3_reset() function is called to reset a [prepared statement]
 5622** object back to its initial state, ready to be re-executed.
 5623** ^Any SQL statement variables that had values bound to them using
 5624** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
 5625** Use [sqlite3_clear_bindings()] to reset the bindings.
 5626**
 5627** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
 5628** back to the beginning of its program.
 5629**
 5630** ^The return code from [sqlite3_reset(S)] indicates whether or not
 5631** the previous evaluation of prepared statement S completed successfully.
 5632** ^If [sqlite3_step(S)] has never before been called on S or if
 5633** [sqlite3_step(S)] has not been called since the previous call
 5634** to [sqlite3_reset(S)], then [sqlite3_reset(S)] will return
 5635** [SQLITE_OK].
 5636**
 5637** ^If the most recent call to [sqlite3_step(S)] for the
 5638** [prepared statement] S indicated an error, then
 5639** [sqlite3_reset(S)] returns an appropriate [error code].
 5640** ^The [sqlite3_reset(S)] interface might also return an [error code]
 5641** if there were no prior errors but the process of resetting
 5642** the prepared statement caused a new error. ^For example, if an
 5643** [INSERT] statement with a [RETURNING] clause is only stepped one time,
 5644** that one call to [sqlite3_step(S)] might return SQLITE_ROW but
 5645** the overall statement might still fail and the [sqlite3_reset(S)] call
 5646** might return SQLITE_BUSY if locking constraints prevent the
 5647** database change from committing.  Therefore, it is important that
 5648** applications check the return code from [sqlite3_reset(S)] even if
 5649** no prior call to [sqlite3_step(S)] indicated a problem.
 5650**
 5651** ^The [sqlite3_reset(S)] interface does not change the values
 5652** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
 5653*/
 5654SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
 5655
 5656
 5657/*
 5658** CAPI3REF: Create Or Redefine SQL Functions
 5659** KEYWORDS: {function creation routines}
 5660** METHOD: sqlite3
 5661**
 5662** ^These functions (collectively known as "function creation routines")
 5663** are used to add SQL functions or aggregates or to redefine the behavior
 5664** of existing SQL functions or aggregates. The only differences between
 5665** the three "sqlite3_create_function*" routines are the text encoding
 5666** expected for the second parameter (the name of the function being
 5667** created) and the presence or absence of a destructor callback for
 5668** the application data pointer. Function sqlite3_create_window_function()
 5669** is similar, but allows the user to supply the extra callback functions
 5670** needed by [aggregate window functions].
 5671**
 5672** ^The first parameter is the [database connection] to which the SQL
 5673** function is to be added.  ^If an application uses more than one database
 5674** connection then application-defined SQL functions must be added
 5675** to each database connection separately.
 5676**
 5677** ^The second parameter is the name of the SQL function to be created or
 5678** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
 5679** representation, exclusive of the zero-terminator.  ^Note that the name
 5680** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.
 5681** ^Any attempt to create a function with a longer name
 5682** will result in [SQLITE_MISUSE] being returned.
 5683**
 5684** ^The third parameter (nArg)
 5685** is the number of arguments that the SQL function or
 5686** aggregate takes. ^If this parameter is -1, then the SQL function or
 5687** aggregate may take any number of arguments between 0 and the limit
 5688** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
 5689** parameter is less than -1 or greater than 127 then the behavior is
 5690** undefined.
 5691**
 5692** ^The fourth parameter, eTextRep, specifies what
 5693** [SQLITE_UTF8 | text encoding] this SQL function prefers for
 5694** its parameters.  The application should set this parameter to
 5695** [SQLITE_UTF16LE] if the function implementation invokes
 5696** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
 5697** implementation invokes [sqlite3_value_text16be()] on an input, or
 5698** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
 5699** otherwise.  ^The same SQL function may be registered multiple times using
 5700** different preferred text encodings, with different implementations for
 5701** each encoding.
 5702** ^When multiple implementations of the same function are available, SQLite
 5703** will pick the one that involves the least amount of data conversion.
 5704**
 5705** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
 5706** to signal that the function will always return the same result given
 5707** the same inputs within a single SQL statement.  Most SQL functions are
 5708** deterministic.  The built-in [random()] SQL function is an example of a
 5709** function that is not deterministic.  The SQLite query planner is able to
 5710** perform additional optimizations on deterministic functions, so use
 5711** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
 5712**
 5713** ^The fourth parameter may also optionally include the [SQLITE_DIRECTONLY]
 5714** flag, which if present prevents the function from being invoked from
 5715** within VIEWs, TRIGGERs, CHECK constraints, generated column expressions,
 5716** index expressions, or the WHERE clause of partial indexes.
 5717**
 5718** For best security, the [SQLITE_DIRECTONLY] flag is recommended for
 5719** all application-defined SQL functions that do not need to be
 5720** used inside of triggers, views, CHECK constraints, or other elements of
 5721** the database schema.  This flag is especially recommended for SQL
 5722** functions that have side effects or reveal internal application state.
 5723** Without this flag, an attacker might be able to modify the schema of
 5724** a database file to include invocations of the function with parameters
 5725** chosen by the attacker, which the application will then execute when
 5726** the database file is opened and read.
 5727**
 5728** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
 5729** function can gain access to this pointer using [sqlite3_user_data()].)^
 5730**
 5731** ^The sixth, seventh and eighth parameters passed to the three
 5732** "sqlite3_create_function*" functions, xFunc, xStep and xFinal, are
 5733** pointers to C-language functions that implement the SQL function or
 5734** aggregate. ^A scalar SQL function requires an implementation of the xFunc
 5735** callback only; NULL pointers must be passed as the xStep and xFinal
 5736** parameters. ^An aggregate SQL function requires an implementation of xStep
 5737** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
 5738** SQL function or aggregate, pass NULL pointers for all three function
 5739** callbacks.
 5740**
 5741** ^The sixth, seventh, eighth and ninth parameters (xStep, xFinal, xValue
 5742** and xInverse) passed to sqlite3_create_window_function are pointers to
 5743** C-language callbacks that implement the new function. xStep and xFinal
 5744** must both be non-NULL. xValue and xInverse may either both be NULL, in
 5745** which case a regular aggregate function is created, or must both be
 5746** non-NULL, in which case the new function may be used as either an aggregate
 5747** or aggregate window function. More details regarding the implementation
 5748** of aggregate window functions are
 5749** [user-defined window functions|available here].
 5750**
 5751** ^(If the final parameter to sqlite3_create_function_v2() or
 5752** sqlite3_create_window_function() is not NULL, then it is the destructor for
 5753** the application data pointer. The destructor is invoked when the function
 5754** is deleted, either by being overloaded or when the database connection
 5755** closes.)^ ^The destructor is also invoked if the call to
 5756** sqlite3_create_function_v2() fails.  ^When the destructor callback is
 5757** invoked, it is passed a single argument which is a copy of the application
 5758** data pointer which was the fifth parameter to sqlite3_create_function_v2().
 5759**
 5760** ^It is permitted to register multiple implementations of the same
 5761** functions with the same name but with either differing numbers of
 5762** arguments or differing preferred text encodings.  ^SQLite will use
 5763** the implementation that most closely matches the way in which the
 5764** SQL function is used.  ^A function implementation with a non-negative
 5765** nArg parameter is a better match than a function implementation with
 5766** a negative nArg.  ^A function where the preferred text encoding
 5767** matches the database encoding is a better
 5768** match than a function where the encoding is different.
 5769** ^A function where the encoding difference is between UTF16le and UTF16be
 5770** is a closer match than a function where the encoding difference is
 5771** between UTF8 and UTF16.
 5772**
 5773** ^Built-in functions may be overloaded by new application-defined functions.
 5774**
 5775** ^An application-defined function is permitted to call other
 5776** SQLite interfaces.  However, such calls must not
 5777** close the database connection nor finalize or reset the prepared
 5778** statement in which the function is running.
 5779*/
 5780SQLITE_API int sqlite3_create_function(
 5781  sqlite3 *db,
 5782  const char *zFunctionName,
 5783  int nArg,
 5784  int eTextRep,
 5785  void *pApp,
 5786  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
 5787  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
 5788  void (*xFinal)(sqlite3_context*)
 5789);
 5790SQLITE_API int sqlite3_create_function16(
 5791  sqlite3 *db,
 5792  const void *zFunctionName,
 5793  int nArg,
 5794  int eTextRep,
 5795  void *pApp,
 5796  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
 5797  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
 5798  void (*xFinal)(sqlite3_context*)
 5799);
 5800SQLITE_API int sqlite3_create_function_v2(
 5801  sqlite3 *db,
 5802  const char *zFunctionName,
 5803  int nArg,
 5804  int eTextRep,
 5805  void *pApp,
 5806  void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
 5807  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
 5808  void (*xFinal)(sqlite3_context*),
 5809  void(*xDestroy)(void*)
 5810);
 5811SQLITE_API int sqlite3_create_window_function(
 5812  sqlite3 *db,
 5813  const char *zFunctionName,
 5814  int nArg,
 5815  int eTextRep,
 5816  void *pApp,
 5817  void (*xStep)(sqlite3_context*,int,sqlite3_value**),
 5818  void (*xFinal)(sqlite3_context*),
 5819  void (*xValue)(sqlite3_context*),
 5820  void (*xInverse)(sqlite3_context*,int,sqlite3_value**),
 5821  void(*xDestroy)(void*)
 5822);
 5823
 5824/*
 5825** CAPI3REF: Text Encodings
 5826**
 5827** These constants define integer codes that represent the various
 5828** text encodings supported by SQLite.
 5829**
 5830** <dl>
 5831** [[SQLITE_UTF8]] <dt>SQLITE_UTF8</dt><dd>Text is encoding as UTF-8</dd>
 5832**
 5833** [[SQLITE_UTF16LE]] <dt>SQLITE_UTF16LE</dt><dd>Text is encoding as UTF-16
 5834** with each code point being expressed "little endian" - the least significant
 5835** byte first.  This is the usual encoding, for example on Windows.</dd>
 5836**
 5837** [[SQLITE_UTF16BE]] <dt>SQLITE_UTF16BE</dt><dd>Text is encoding as UTF-16
 5838** with each code point being expressed "big endian" - the most significant
 5839** byte first.  This encoding is less common, but is still sometimes seen,
 5840** specially on older systems.
 5841**
 5842** [[SQLITE_UTF16]] <dt>SQLITE_UTF16</dt><dd>Text is encoding as UTF-16
 5843** with each code point being expressed either little endian or as big
 5844** endian, according to the native endianness of the host computer.
 5845**
 5846** [[SQLITE_ANY]] <dt>SQLITE_ANY</dt><dd>This encoding value may only be used
 5847** to declare the preferred text for [application-defined SQL functions]
 5848** created using [sqlite3_create_function()] and similar.  If the preferred
 5849** encoding (the 4th parameter to sqlite3_create_function() - the eTextRep
 5850** parameter) is SQLITE_ANY, that indicates that the function does not have
 5851** a preference regarding the text encoding of its parameters and can take
 5852** any text encoding that the SQLite core find convenient to supply.  This
 5853** option is deprecated.  Please do not use it in new applications.
 5854**
 5855** [[SQLITE_UTF16_ALIGNED]] <dt>SQLITE_UTF16_ALIGNED</dt><dd>This encoding
 5856** value may be used as the 3rd parameter (the eTextRep parameter) to
 5857** [sqlite3_create_collation()] and similar.  This encoding value means
 5858** that the application-defined collating sequence created expects its
 5859** input strings to be in UTF16 in native byte order, and that the start
 5860** of the strings must be aligned to a 2-byte boundary.
 5861**
 5862** [[SQLITE_UTF8_ZT]] <dt>SQLITE_UTF8_ZT</dt><dd>This option can only be
 5863** used to specify the text encoding to strings input to
 5864** [sqlite3_result_text64()] and [sqlite3_bind_text64()].
 5865** The SQLITE_UTF8_ZT encoding means that the input string (call it "z")
 5866** is UTF-8 encoded and that it is zero-terminated.  If the length parameter
 5867** (call it "n") is non-negative, this encoding option means that the caller
 5868** guarantees that z array contains at least n+1 bytes and that the z&#91;n&#93;
 5869** byte has a value of zero.
 5870** This option gives the same output as SQLITE_UTF8, but can be more efficient
 5871** by avoiding the need to make a copy of the input string, in some cases.
 5872** However, if z is allocated to hold fewer than n+1 bytes or if the
 5873** z&#91;n&#93; byte is not zero, undefined behavior may result.
 5874** </dl>
 5875*/
 5876#define SQLITE_UTF8           1    /* IMP: R-37514-35566 */
 5877#define SQLITE_UTF16LE        2    /* IMP: R-03371-37637 */
 5878#define SQLITE_UTF16BE        3    /* IMP: R-51971-34154 */
 5879#define SQLITE_UTF16          4    /* Use native byte order */
 5880#define SQLITE_ANY            5    /* Deprecated */
 5881#define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
 5882#define SQLITE_UTF8_ZT       16    /* Zero-terminated UTF8 */
 5883
 5884/*
 5885** CAPI3REF: Function Flags
 5886**
 5887** These constants may be ORed together with the
 5888** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
 5889** to [sqlite3_create_function()], [sqlite3_create_function16()], or
 5890** [sqlite3_create_function_v2()].
 5891**
 5892** <dl>
 5893** [[SQLITE_DETERMINISTIC]] <dt>SQLITE_DETERMINISTIC</dt><dd>
 5894** The SQLITE_DETERMINISTIC flag means that the new function always gives
 5895** the same output when the input parameters are the same.
 5896** The [abs|abs() function] is deterministic, for example, but
 5897** [randomblob|randomblob()] is not.  Functions must
 5898** be deterministic in order to be used in certain contexts such as
 5899** with the WHERE clause of [partial indexes] or in [generated columns].
 5900** SQLite might also optimize deterministic functions by factoring them
 5901** out of inner loops.
 5902** </dd>
 5903**
 5904** [[SQLITE_DIRECTONLY]] <dt>SQLITE_DIRECTONLY</dt><dd>
 5905** The SQLITE_DIRECTONLY flag means that the function may only be invoked
 5906** from top-level SQL, and cannot be used in VIEWs or TRIGGERs nor in
 5907** schema structures such as [CHECK constraints], [DEFAULT clauses],
 5908** [expression indexes], [partial indexes], or [generated columns].
 5909** <p>
 5910** The SQLITE_DIRECTONLY flag is recommended for any
 5911** [application-defined SQL function]
 5912** that has side-effects or that could potentially leak sensitive information.
 5913** This will prevent attacks in which an application is tricked
 5914** into using a database file that has had its schema surreptitiously
 5915** modified to invoke the application-defined function in ways that are
 5916** harmful.
 5917** <p>
 5918** Some people say it is good practice to set SQLITE_DIRECTONLY on all
 5919** [application-defined SQL functions], regardless of whether or not they
 5920** are security sensitive, as doing so prevents those functions from being used
 5921** inside of the database schema, and thus ensures that the database
 5922** can be inspected and modified using generic tools (such as the [CLI])
 5923** that do not have access to the application-defined functions.
 5924** </dd>
 5925**
 5926** [[SQLITE_INNOCUOUS]] <dt>SQLITE_INNOCUOUS</dt><dd>
 5927** The SQLITE_INNOCUOUS flag means that the function is unlikely
 5928** to cause problems even if misused.  An innocuous function should have
 5929** no side effects and should not depend on any values other than its
 5930** input parameters. The [abs|abs() function] is an example of an
 5931** innocuous function.
 5932** The [load_extension() SQL function] is not innocuous because of its
 5933** side effects.
 5934** <p> SQLITE_INNOCUOUS is similar to SQLITE_DETERMINISTIC, but is not
 5935** exactly the same.  The [random|random() function] is an example of a
 5936** function that is innocuous but not deterministic.
 5937** <p>Some heightened security settings
 5938** ([SQLITE_DBCONFIG_TRUSTED_SCHEMA] and [PRAGMA trusted_schema=OFF])
 5939** disable the use of SQL functions inside views and triggers and in
 5940** schema structures such as [CHECK constraints], [DEFAULT clauses],
 5941** [expression indexes], [partial indexes], and [generated columns] unless
 5942** the function is tagged with SQLITE_INNOCUOUS.  Most built-in functions
 5943** are innocuous.  Developers are advised to avoid using the
 5944** SQLITE_INNOCUOUS flag for application-defined functions unless the
 5945** function has been carefully audited and found to be free of potentially
 5946** security-adverse side-effects and information-leaks.
 5947** </dd>
 5948**
 5949** [[SQLITE_SUBTYPE]] <dt>SQLITE_SUBTYPE</dt><dd>
 5950** The SQLITE_SUBTYPE flag indicates to SQLite that a function might call
 5951** [sqlite3_value_subtype()] to inspect the sub-types of its arguments.
 5952** This flag instructs SQLite to omit some corner-case optimizations that
 5953** might disrupt the operation of the [sqlite3_value_subtype()] function,
 5954** causing it to return zero rather than the correct subtype().
 5955** All SQL functions that invoke [sqlite3_value_subtype()] should have this
 5956** property.  If the SQLITE_SUBTYPE property is omitted, then the return
 5957** value from [sqlite3_value_subtype()] might sometimes be zero even though
 5958** a non-zero subtype was specified by the function argument expression.
 5959**
 5960** [[SQLITE_RESULT_SUBTYPE]] <dt>SQLITE_RESULT_SUBTYPE</dt><dd>
 5961** The SQLITE_RESULT_SUBTYPE flag indicates to SQLite that a function might call
 5962** [sqlite3_result_subtype()] to cause a sub-type to be associated with its
 5963** result.
 5964** Every function that invokes [sqlite3_result_subtype()] should have this
 5965** property.  If it does not, then the call to [sqlite3_result_subtype()]
 5966** might become a no-op if the function is used as a term in an
 5967** [expression index].  On the other hand, SQL functions that never invoke
 5968** [sqlite3_result_subtype()] should avoid setting this property, as the
 5969** purpose of this property is to disable certain optimizations that are
 5970** incompatible with subtypes.
 5971**
 5972** [[SQLITE_SELFORDER1]] <dt>SQLITE_SELFORDER1</dt><dd>
 5973** The SQLITE_SELFORDER1 flag indicates that the function is an aggregate
 5974** that internally orders the values provided to the first argument.  The
 5975** ordered-set aggregate SQL notation with a single ORDER BY term can be
 5976** used to invoke this function.  If the ordered-set aggregate notation is
 5977** used on a function that lacks this flag, then an error is raised. Note
 5978** that the ordered-set aggregate syntax is only available if SQLite is
 5979** built using the -DSQLITE_ENABLE_ORDERED_SET_AGGREGATES compile-time option.
 5980** </dd>
 5981** </dl>
 5982*/
 5983#define SQLITE_DETERMINISTIC    0x000000800
 5984#define SQLITE_DIRECTONLY       0x000080000
 5985#define SQLITE_SUBTYPE          0x000100000
 5986#define SQLITE_INNOCUOUS        0x000200000
 5987#define SQLITE_RESULT_SUBTYPE   0x001000000
 5988#define SQLITE_SELFORDER1       0x002000000
 5989
 5990/*
 5991** CAPI3REF: Deprecated Functions
 5992** DEPRECATED
 5993**
 5994** These functions are [deprecated].  In order to maintain
 5995** backwards compatibility with older code, these functions continue
 5996** to be supported.  However, new applications should avoid
 5997** the use of these functions.  To encourage programmers to avoid
 5998** these functions, we will not explain what they do.
 5999*/
 6000#ifndef SQLITE_OMIT_DEPRECATED
 6001SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
 6002SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
 6003SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
 6004SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
 6005SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
 6006SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
 6007                      void*,sqlite3_int64);
 6008#endif
 6009
 6010/*
 6011** CAPI3REF: Obtaining SQL Values
 6012** METHOD: sqlite3_value
 6013**
 6014** <b>Summary:</b>
 6015** <blockquote><table border=0 cellpadding=0 cellspacing=0>
 6016** <tr><td><b>sqlite3_value_blob</b><td>&rarr;<td>BLOB value
 6017** <tr><td><b>sqlite3_value_double</b><td>&rarr;<td>REAL value
 6018** <tr><td><b>sqlite3_value_int</b><td>&rarr;<td>32-bit INTEGER value
 6019** <tr><td><b>sqlite3_value_int64</b><td>&rarr;<td>64-bit INTEGER value
 6020** <tr><td><b>sqlite3_value_pointer</b><td>&rarr;<td>Pointer value
 6021** <tr><td><b>sqlite3_value_text</b><td>&rarr;<td>UTF-8 TEXT value
 6022** <tr><td><b>sqlite3_value_text16</b><td>&rarr;<td>UTF-16 TEXT value in
 6023** the native byteorder
 6024** <tr><td><b>sqlite3_value_text16be</b><td>&rarr;<td>UTF-16be TEXT value
 6025** <tr><td><b>sqlite3_value_text16le</b><td>&rarr;<td>UTF-16le TEXT value
 6026** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
 6027** <tr><td><b>sqlite3_value_bytes</b><td>&rarr;<td>Size of a BLOB
 6028** or a UTF-8 TEXT in bytes
 6029** <tr><td><b>sqlite3_value_bytes16&nbsp;&nbsp;</b>
 6030** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
 6031** TEXT in bytes
 6032** <tr><td><b>sqlite3_value_type</b><td>&rarr;<td>Default
 6033** datatype of the value
 6034** <tr><td><b>sqlite3_value_numeric_type&nbsp;&nbsp;</b>
 6035** <td>&rarr;&nbsp;&nbsp;<td>Best numeric datatype of the value
 6036** <tr><td><b>sqlite3_value_nochange&nbsp;&nbsp;</b>
 6037** <td>&rarr;&nbsp;&nbsp;<td>True if the column is unchanged in an UPDATE
 6038** against a virtual table.
 6039** <tr><td><b>sqlite3_value_frombind&nbsp;&nbsp;</b>
 6040** <td>&rarr;&nbsp;&nbsp;<td>True if value originated from a [bound parameter]
 6041** </table></blockquote>
 6042**
 6043** <b>Details:</b>
 6044**
 6045** These routines extract type, size, and content information from
 6046** [protected sqlite3_value] objects.  Protected sqlite3_value objects
 6047** are used to pass parameter information into the functions that
 6048** implement [application-defined SQL functions] and [virtual tables].
 6049**
 6050** These routines work only with [protected sqlite3_value] objects.
 6051** Any attempt to use these routines on an [unprotected sqlite3_value]
 6052** is not threadsafe.
 6053**
 6054** ^These routines work just like the corresponding [column access functions]
 6055** except that these routines take a single [protected sqlite3_value] object
 6056** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
 6057**
 6058** ^The sqlite3_value_text16() interface extracts a UTF-16 string
 6059** in the native byte-order of the host machine.  ^The
 6060** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
 6061** extract UTF-16 strings as big-endian and little-endian respectively.
 6062**
 6063** ^If [sqlite3_value] object V was initialized
 6064** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)]
 6065** and if X and Y are strings that compare equal according to strcmp(X,Y),
 6066** then sqlite3_value_pointer(V,Y) will return the pointer P.  ^Otherwise,
 6067** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer()
 6068** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
 6069**
 6070** ^(The sqlite3_value_type(V) interface returns the
 6071** [SQLITE_INTEGER | datatype code] for the initial datatype of the
 6072** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER],
 6073** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^
 6074** Other interfaces might change the datatype for an sqlite3_value object.
 6075** For example, if the datatype is initially SQLITE_INTEGER and
 6076** sqlite3_value_text(V) is called to extract a text value for that
 6077** integer, then subsequent calls to sqlite3_value_type(V) might return
 6078** SQLITE_TEXT.  Whether or not a persistent internal datatype conversion
 6079** occurs is undefined and may change from one release of SQLite to the next.
 6080**
 6081** ^(The sqlite3_value_numeric_type() interface attempts to apply
 6082** numeric affinity to the value.  This means that an attempt is
 6083** made to convert the value to an integer or floating point.  If
 6084** such a conversion is possible without loss of information (in other
 6085** words, if the value is a string that looks like a number)
 6086** then the conversion is performed.  Otherwise no conversion occurs.
 6087** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
 6088**
 6089** ^Within the [xUpdate] method of a [virtual table], the
 6090** sqlite3_value_nochange(X) interface returns true if and only if
 6091** the column corresponding to X is unchanged by the UPDATE operation
 6092** that the xUpdate method call was invoked to implement and if
 6093** the prior [xColumn] method call that was invoked to extract
 6094** the value for that column returned without setting a result (probably
 6095** because it queried [sqlite3_vtab_nochange()] and found that the column
 6096** was unchanging).  ^Within an [xUpdate] method, any value for which
 6097** sqlite3_value_nochange(X) is true will in all other respects appear
 6098** to be a NULL value.  If sqlite3_value_nochange(X) is invoked anywhere other
 6099** than within an [xUpdate] method call for an UPDATE statement, then
 6100** the return value is arbitrary and meaningless.
 6101**
 6102** ^The sqlite3_value_frombind(X) interface returns non-zero if the
 6103** value X originated from one of the [sqlite3_bind_int|sqlite3_bind()]
 6104** interfaces.  ^If X comes from an SQL literal value, or a table column,
 6105** or an expression, then sqlite3_value_frombind(X) returns zero.
 6106**
 6107** Please pay particular attention to the fact that the pointer returned
 6108** from [sqlite3_value_blob()], [sqlite3_value_text()], or
 6109** [sqlite3_value_text16()] can be invalidated by a subsequent call to
 6110** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
 6111** or [sqlite3_value_text16()].
 6112**
 6113** These routines must be called from the same thread as
 6114** the SQL function that supplied the [sqlite3_value*] parameters.
 6115**
 6116** As long as the input parameter is correct, these routines can only
 6117** fail if an out-of-memory error occurs while trying to do a
 6118** UTF8&rarr;UTF16 or UTF16&rarr;UTF8 conversion.
 6119** If an out-of-memory error occurs, then the return value from these
 6120** routines is the same as if the column had contained an SQL NULL value.
 6121** If the input sqlite3_value was not obtained from [sqlite3_value_dup()],
 6122** then valid SQL NULL returns can also be distinguished from
 6123** out-of-memory errors after extracting the value
 6124** by invoking the [sqlite3_errcode()] immediately after the suspicious
 6125** return value is obtained and before any
 6126** other SQLite interface is called on the same [database connection].
 6127** If the input sqlite3_value was obtained from sqlite3_value_dup() then
 6128** it is disconnected from the database connection and so sqlite3_errcode()
 6129** will not work.
 6130** In that case, the only way to distinguish an out-of-memory
 6131** condition from a true SQL NULL is to invoke sqlite3_value_type() on the
 6132** input to see if it is NULL prior to trying to extract the value.
 6133*/
 6134SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
 6135SQLITE_API double sqlite3_value_double(sqlite3_value*);
 6136SQLITE_API int sqlite3_value_int(sqlite3_value*);
 6137SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
 6138SQLITE_API void *sqlite3_value_pointer(sqlite3_value*, const char*);
 6139SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
 6140SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
 6141SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
 6142SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
 6143SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
 6144SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
 6145SQLITE_API int sqlite3_value_type(sqlite3_value*);
 6146SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
 6147SQLITE_API int sqlite3_value_nochange(sqlite3_value*);
 6148SQLITE_API int sqlite3_value_frombind(sqlite3_value*);
 6149
 6150/*
 6151** CAPI3REF: Report the internal text encoding state of an sqlite3_value object
 6152** METHOD: sqlite3_value
 6153**
 6154** ^(The sqlite3_value_encoding(X) interface returns one of [SQLITE_UTF8],
 6155** [SQLITE_UTF16BE], or [SQLITE_UTF16LE] according to the current text encoding
 6156** of the value X, assuming that X has type TEXT.)^  If sqlite3_value_type(X)
 6157** returns something other than SQLITE_TEXT, then the return value from
 6158** sqlite3_value_encoding(X) is meaningless.  ^Calls to
 6159** [sqlite3_value_text(X)], [sqlite3_value_text16(X)],
 6160** [sqlite3_value_text16be(X)],
 6161** [sqlite3_value_text16le(X)], [sqlite3_value_bytes(X)], or
 6162** [sqlite3_value_bytes16(X)] might change the encoding of the value X and
 6163** thus change the return from subsequent calls to sqlite3_value_encoding(X).
 6164**
 6165** This routine is intended for used by applications that test and validate
 6166** the SQLite implementation.  This routine is inquiring about the opaque
 6167** internal state of an [sqlite3_value] object.  Ordinary applications should
 6168** not need to know what the internal state of an sqlite3_value object is and
 6169** hence should not need to use this interface.
 6170*/
 6171SQLITE_API int sqlite3_value_encoding(sqlite3_value*);
 6172
 6173/*
 6174** CAPI3REF: Finding The Subtype Of SQL Values
 6175** METHOD: sqlite3_value
 6176**
 6177** The sqlite3_value_subtype(V) function returns the subtype for
 6178** an [application-defined SQL function] argument V.  The subtype
 6179** information can be used to pass a limited amount of context from
 6180** one SQL function to another.  Use the [sqlite3_result_subtype()]
 6181** routine to set the subtype for the return value of an SQL function.
 6182**
 6183** Every [application-defined SQL function] that invokes this interface
 6184** should include the [SQLITE_SUBTYPE] property in the text
 6185** encoding argument when the function is [sqlite3_create_function|registered].
 6186** If the [SQLITE_SUBTYPE] property is omitted, then sqlite3_value_subtype()
 6187** might return zero instead of the upstream subtype in some corner cases.
 6188*/
 6189SQLITE_API unsigned int sqlite3_value_subtype(sqlite3_value*);
 6190
 6191/*
 6192** CAPI3REF: Copy And Free SQL Values
 6193** METHOD: sqlite3_value
 6194**
 6195** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
 6196** object V and returns a pointer to that copy.  ^The [sqlite3_value] returned
 6197** is a [protected sqlite3_value] object even if the input is not.
 6198** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
 6199** memory allocation fails. ^If V is a [pointer value], then the result
 6200** of sqlite3_value_dup(V) is a NULL value.
 6201**
 6202** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
 6203** previously obtained from [sqlite3_value_dup()].  ^If V is a NULL pointer
 6204** then sqlite3_value_free(V) is a harmless no-op.
 6205*/
 6206SQLITE_API sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
 6207SQLITE_API void sqlite3_value_free(sqlite3_value*);
 6208
 6209/*
 6210** CAPI3REF: Obtain Aggregate Function Context
 6211** METHOD: sqlite3_context
 6212**
 6213** Implementations of aggregate SQL functions use this
 6214** routine to allocate memory for storing their state.
 6215**
 6216** ^The first time the sqlite3_aggregate_context(C,N) routine is called
 6217** for a particular aggregate function, SQLite allocates
 6218** N bytes of memory, zeroes out that memory, and returns a pointer
 6219** to the new memory. ^On second and subsequent calls to
 6220** sqlite3_aggregate_context() for the same aggregate function instance,
 6221** the same buffer is returned.  Sqlite3_aggregate_context() is normally
 6222** called once for each invocation of the xStep callback and then one
 6223** last time when the xFinal callback is invoked.  ^(When no rows match
 6224** an aggregate query, the xStep() callback of the aggregate function
 6225** implementation is never called and xFinal() is called exactly once.
 6226** In those cases, sqlite3_aggregate_context() might be called for the
 6227** first time from within xFinal().)^
 6228**
 6229** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer
 6230** when first called if N is less than or equal to zero or if a memory
 6231** allocation error occurs.
 6232**
 6233** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
 6234** determined by the N parameter on the first successful call.  Changing the
 6235** value of N in any subsequent call to sqlite3_aggregate_context() within
 6236** the same aggregate function instance will not resize the memory
 6237** allocation.)^  Within the xFinal callback, it is customary to set
 6238** N=0 in calls to sqlite3_aggregate_context(C,N) so that no
 6239** pointless memory allocations occur.
 6240**
 6241** ^SQLite automatically frees the memory allocated by
 6242** sqlite3_aggregate_context() when the aggregate query concludes.
 6243**
 6244** The first parameter must be a copy of the
 6245** [sqlite3_context | SQL function context] that is the first parameter
 6246** to the xStep or xFinal callback routine that implements the aggregate
 6247** function.
 6248**
 6249** This routine must be called from the same thread in which
 6250** the aggregate SQL function is running.
 6251*/
 6252SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
 6253
 6254/*
 6255** CAPI3REF: User Data For Functions
 6256** METHOD: sqlite3_context
 6257**
 6258** ^The sqlite3_user_data() interface returns a copy of
 6259** the pointer that was the pUserData parameter (the 5th parameter)
 6260** of the [sqlite3_create_function()]
 6261** and [sqlite3_create_function16()] routines that originally
 6262** registered the application defined function.
 6263**
 6264** This routine must be called from the same thread in which
 6265** the application-defined function is running.
 6266*/
 6267SQLITE_API void *sqlite3_user_data(sqlite3_context*);
 6268
 6269/*
 6270** CAPI3REF: Database Connection For Functions
 6271** METHOD: sqlite3_context
 6272**
 6273** ^The sqlite3_context_db_handle() interface returns a copy of
 6274** the pointer to the [database connection] (the 1st parameter)
 6275** of the [sqlite3_create_function()]
 6276** and [sqlite3_create_function16()] routines that originally
 6277** registered the application defined function.
 6278*/
 6279SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
 6280
 6281/*
 6282** CAPI3REF: Function Auxiliary Data
 6283** METHOD: sqlite3_context
 6284**
 6285** These functions may be used by (non-aggregate) SQL functions to
 6286** associate auxiliary data with argument values. If the same argument
 6287** value is passed to multiple invocations of the same SQL function during
 6288** query execution, under some circumstances the associated auxiliary data
 6289** might be preserved.  An example of where this might be useful is in a
 6290** regular-expression matching function. The compiled version of the regular
 6291** expression can be stored as auxiliary data associated with the pattern
 6292** string. Then as long as the pattern string remains the same,
 6293** the compiled regular expression can be reused on multiple
 6294** invocations of the same function.
 6295**
 6296** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the auxiliary
 6297** data associated by the sqlite3_set_auxdata(C,N,P,X) function with the
 6298** Nth argument value to the application-defined function.  ^N is zero
 6299** for the left-most function argument.  ^If there is no auxiliary data
 6300** associated with the function argument, the sqlite3_get_auxdata(C,N)
 6301** interface returns a NULL pointer.
 6302**
 6303** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as auxiliary data for the
 6304** N-th argument of the application-defined function.  ^Subsequent
 6305** calls to sqlite3_get_auxdata(C,N) return P from the most recent
 6306** sqlite3_set_auxdata(C,N,P,X) call if the auxiliary data is still valid or
 6307** NULL if the auxiliary data has been discarded.
 6308** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
 6309** SQLite will invoke the destructor function X with parameter P exactly
 6310** once, when the auxiliary data is discarded.
 6311** SQLite is free to discard the auxiliary data at any time, including: <ul>
 6312** <li> ^(when the corresponding function parameter changes)^, or
 6313** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
 6314**      SQL statement)^, or
 6315** <li> ^(when sqlite3_set_auxdata() is invoked again on the same
 6316**       parameter)^, or
 6317** <li> ^(during the original sqlite3_set_auxdata() call when a memory
 6318**      allocation error occurs.)^
 6319** <li> ^(during the original sqlite3_set_auxdata() call if the function
 6320**      is evaluated during query planning instead of during query execution,
 6321**      as sometimes happens with [SQLITE_ENABLE_STAT4].)^ </ul>
 6322**
 6323** Note the last two bullets in particular.  The destructor X in
 6324** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
 6325** sqlite3_set_auxdata() interface even returns.  Hence sqlite3_set_auxdata()
 6326** should be called near the end of the function implementation and the
 6327** function implementation should not make any use of P after
 6328** sqlite3_set_auxdata() has been called.  Furthermore, a call to
 6329** sqlite3_get_auxdata() that occurs immediately after a corresponding call
 6330** to sqlite3_set_auxdata() might still return NULL if an out-of-memory
 6331** condition occurred during the sqlite3_set_auxdata() call or if the
 6332** function is being evaluated during query planning rather than during
 6333** query execution.
 6334**
 6335** ^(In practice, auxiliary data is preserved between function calls for
 6336** function parameters that are compile-time constants, including literal
 6337** values and [parameters] and expressions composed from the same.)^
 6338**
 6339** The value of the N parameter to these interfaces should be non-negative.
 6340** Future enhancements may make use of negative N values to define new
 6341** kinds of function caching behavior.
 6342**
 6343** These routines must be called from the same thread in which
 6344** the SQL function is running.
 6345**
 6346** See also: [sqlite3_get_clientdata()] and [sqlite3_set_clientdata()].
 6347*/
 6348SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
 6349SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
 6350
 6351/*
 6352** CAPI3REF: Database Connection Client Data
 6353** METHOD: sqlite3
 6354**
 6355** These functions are used to associate one or more named pointers
 6356** with a [database connection].
 6357** A call to sqlite3_set_clientdata(D,N,P,X) causes the pointer P
 6358** to be attached to [database connection] D using name N.  Subsequent
 6359** calls to sqlite3_get_clientdata(D,N) will return a copy of pointer P
 6360** or a NULL pointer if there were no prior calls to
 6361** sqlite3_set_clientdata() with the same values of D and N.
 6362** Names are compared using strcmp() and are thus case sensitive.
 6363** It returns 0 on success and SQLITE_NOMEM on allocation failure.
 6364**
 6365** If P and X are both non-NULL, then the destructor X is invoked with
 6366** argument P on the first of the following occurrences:
 6367** <ul>
 6368** <li> An out-of-memory error occurs during the call to
 6369**      sqlite3_set_clientdata() which attempts to register pointer P.
 6370** <li> A subsequent call to sqlite3_set_clientdata(D,N,P,X) is made
 6371**      with the same D and N parameters.
 6372** <li> The database connection closes.  SQLite does not make any guarantees
 6373**      about the order in which destructors are called, only that all
 6374**      destructors will be called exactly once at some point during the
 6375**      database connection closing process.
 6376** </ul>
 6377**
 6378** SQLite does not do anything with client data other than invoke
 6379** destructors on the client data at the appropriate time.  The intended
 6380** use for client data is to provide a mechanism for wrapper libraries
 6381** to store additional information about an SQLite database connection.
 6382**
 6383** There is no limit (other than available memory) on the number of different
 6384** client data pointers (with different names) that can be attached to a
 6385** single database connection.  However, the current implementation stores
 6386** the content on a linked list.  Insert and retrieval performance will
 6387** be proportional to the number of entries.  The design use case, and
 6388** the use case for which the implementation is optimized, is
 6389** that an application will store only small number of client data names,
 6390** typically just one or two.  This interface is not intended to be a
 6391** generalized key/value store for thousands or millions of keys.  It
 6392** will work for that, but performance might be disappointing.
 6393**
 6394** There is no way to enumerate the client data pointers
 6395** associated with a database connection.  The N parameter can be thought
 6396** of as a secret key such that only code that knows the secret key is able
 6397** to access the associated data.
 6398**
 6399** Security Warning:  These interfaces should not be exposed in scripting
 6400** languages or in other circumstances where it might be possible for an
 6401** attacker to invoke them.  Any agent that can invoke these interfaces
 6402** can probably also take control of the process.
 6403**
 6404** Database connection client data is only available for SQLite
 6405** version 3.44.0 ([dateof:3.44.0]) and later.
 6406**
 6407** See also: [sqlite3_set_auxdata()] and [sqlite3_get_auxdata()].
 6408*/
 6409SQLITE_API void *sqlite3_get_clientdata(sqlite3*,const char*);
 6410SQLITE_API int sqlite3_set_clientdata(sqlite3*, const char*, void*, void(*)(void*));
 6411
 6412/*
 6413** CAPI3REF: Constants Defining Special Destructor Behavior
 6414**
 6415** These are special values for the destructor that is passed in as the
 6416** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
 6417** argument is SQLITE_STATIC, it means that the content pointer is constant
 6418** and will never change.  It does not need to be destroyed.  ^The
 6419** SQLITE_TRANSIENT value means that the content will likely change in
 6420** the near future and that SQLite should make its own private copy of
 6421** the content before returning.
 6422**
 6423** The typedef is necessary to work around problems in certain
 6424** C++ compilers.
 6425*/
 6426typedef void (*sqlite3_destructor_type)(void*);
 6427#define SQLITE_STATIC      ((sqlite3_destructor_type)0)
 6428#define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
 6429
 6430/*
 6431** CAPI3REF: Setting The Result Of An SQL Function
 6432** METHOD: sqlite3_context
 6433**
 6434** These routines are used by the xFunc or xFinal callbacks that
 6435** implement SQL functions and aggregates.  See
 6436** [sqlite3_create_function()] and [sqlite3_create_function16()]
 6437** for additional information.
 6438**
 6439** These functions work very much like the [parameter binding] family of
 6440** functions used to bind values to host parameters in prepared statements.
 6441** Refer to the [SQL parameter] documentation for additional information.
 6442**
 6443** ^The sqlite3_result_blob() interface sets the result from
 6444** an application-defined function to be the BLOB whose content is pointed
 6445** to by the second parameter and which is N bytes long where N is the
 6446** third parameter.
 6447**
 6448** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
 6449** interfaces set the result of the application-defined function to be
 6450** a BLOB containing all zero bytes and N bytes in size.
 6451**
 6452** ^The sqlite3_result_double() interface sets the result from
 6453** an application-defined function to be a floating point value specified
 6454** by its 2nd argument.
 6455**
 6456** ^The sqlite3_result_error() and sqlite3_result_error16() functions
 6457** cause the implemented SQL function to throw an exception.
 6458** ^SQLite uses the string pointed to by the
 6459** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
 6460** as the text of an error message.  ^SQLite interprets the error
 6461** message string from sqlite3_result_error() as UTF-8. ^SQLite
 6462** interprets the string from sqlite3_result_error16() as UTF-16 using
 6463** the same [byte-order determination rules] as [sqlite3_bind_text16()].
 6464** ^If the third parameter to sqlite3_result_error()
 6465** or sqlite3_result_error16() is negative then SQLite takes as the error
 6466** message all text up through the first zero character.
 6467** ^If the third parameter to sqlite3_result_error() or
 6468** sqlite3_result_error16() is non-negative then SQLite takes that many
 6469** bytes (not characters) from the 2nd parameter as the error message.
 6470** ^The sqlite3_result_error() and sqlite3_result_error16()
 6471** routines make a private copy of the error message text before
 6472** they return.  Hence, the calling function can deallocate or
 6473** modify the text after they return without harm.
 6474** ^The sqlite3_result_error_code() function changes the error code
 6475** returned by SQLite as a result of an error in a function.  ^By default,
 6476** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
 6477** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
 6478**
 6479** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
 6480** error indicating that a string or BLOB is too long to represent.
 6481**
 6482** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
 6483** error indicating that a memory allocation failed.
 6484**
 6485** ^The sqlite3_result_int() interface sets the return value
 6486** of the application-defined function to be the 32-bit signed integer
 6487** value given in the 2nd argument.
 6488** ^The sqlite3_result_int64() interface sets the return value
 6489** of the application-defined function to be the 64-bit signed integer
 6490** value given in the 2nd argument.
 6491**
 6492** ^The sqlite3_result_null() interface sets the return value
 6493** of the application-defined function to be NULL.
 6494**
 6495** ^The sqlite3_result_text(), sqlite3_result_text16(),
 6496** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
 6497** set the return value of the application-defined function to be
 6498** a text string which is represented as UTF-8, UTF-16 native byte order,
 6499** UTF-16 little endian, or UTF-16 big endian, respectively.
 6500** ^The sqlite3_result_text64(C,Z,N,D,E) interface sets the return value of an
 6501** application-defined function to be a text string in an encoding
 6502** specified the E parameter, which must be one
 6503** of [SQLITE_UTF8], [SQLITE_UTF8_ZT], [SQLITE_UTF16], [SQLITE_UTF16BE],
 6504** or [SQLITE_UTF16LE].  ^The special value [SQLITE_UTF8_ZT] means that
 6505** the result text is both UTF-8 and zero-terminated.  In other words,
 6506** SQLITE_UTF8_ZT means that the Z array holds at least N+1 bytes and that
 6507** the Z&#91;N&#93; is zero.
 6508** ^SQLite takes the text result from the application from
 6509** the 2nd parameter of the sqlite3_result_text* interfaces.
 6510** ^If the 3rd parameter to any of the sqlite3_result_text* interfaces
 6511** other than sqlite3_result_text64() is negative, then SQLite computes
 6512** the string length itself by searching the 2nd parameter for the first
 6513** zero character.
 6514** ^If the 3rd parameter to the sqlite3_result_text* interfaces
 6515** is non-negative, then as many bytes (not characters) of the text
 6516** pointed to by the 2nd parameter are taken as the application-defined
 6517** function result.  If the 3rd parameter is non-negative, then it
 6518** must be the byte offset into the string where the NUL terminator would
 6519** appear if the string were NUL terminated.  If any NUL characters occur
 6520** in the string at a byte offset that is less than the value of the 3rd
 6521** parameter, then the resulting string will contain embedded NULs and the
 6522** result of expressions operating on strings with embedded NULs is undefined.
 6523** ^If the 4th parameter to the sqlite3_result_text* interfaces
 6524** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
 6525** function as the destructor on the text or BLOB result when it has
 6526** finished using that result.
 6527** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
 6528** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
 6529** assumes that the text or BLOB result is in constant space and does not
 6530** copy the content of the parameter nor call a destructor on the content
 6531** when it has finished using that result.
 6532** ^If the 4th parameter to the sqlite3_result_text* interfaces
 6533** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
 6534** then SQLite makes a copy of the result into space obtained
 6535** from [sqlite3_malloc()] before it returns.
 6536**
 6537** ^For the sqlite3_result_text16(), sqlite3_result_text16le(), and
 6538** sqlite3_result_text16be() routines, and for sqlite3_result_text64()
 6539** when the encoding is not UTF8, if the input UTF16 begins with a
 6540** byte-order mark (BOM, U+FEFF) then the BOM is removed from the
 6541** string and the rest of the string is interpreted according to the
 6542** byte-order specified by the BOM.  ^The byte-order specified by
 6543** the BOM at the beginning of the text overrides the byte-order
 6544** specified by the interface procedure.  ^So, for example, if
 6545** sqlite3_result_text16le() is invoked with text that begins
 6546** with bytes 0xfe, 0xff (a big-endian byte-order mark) then the
 6547** first two bytes of input are skipped and the remaining input
 6548** is interpreted as UTF16BE text.
 6549**
 6550** ^For UTF16 input text to the sqlite3_result_text16(),
 6551** sqlite3_result_text16be(), sqlite3_result_text16le(), and
 6552** sqlite3_result_text64() routines, if the text contains invalid
 6553** UTF16 characters, the invalid characters might be converted
 6554** into the unicode replacement character, U+FFFD.
 6555**
 6556** ^The sqlite3_result_value() interface sets the result of
 6557** the application-defined function to be a copy of the
 6558** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
 6559** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
 6560** so that the [sqlite3_value] specified in the parameter may change or
 6561** be deallocated after sqlite3_result_value() returns without harm.
 6562** ^A [protected sqlite3_value] object may always be used where an
 6563** [unprotected sqlite3_value] object is required, so either
 6564** kind of [sqlite3_value] object can be used with this interface.
 6565**
 6566** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
 6567** SQL NULL value, just like [sqlite3_result_null(C)], except that it
 6568** also associates the host-language pointer P or type T with that
 6569** NULL value such that the pointer can be retrieved within an
 6570** [application-defined SQL function] using [sqlite3_value_pointer()].
 6571** ^If the D parameter is not NULL, then it is a pointer to a destructor
 6572** for the P parameter.  ^SQLite invokes D with P as its only argument
 6573** when SQLite is finished with P.  The T parameter should be a static
 6574** string and preferably a string literal. The sqlite3_result_pointer()
 6575** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
 6576**
 6577** If these routines are called from within a different thread
 6578** than the one containing the application-defined function that received
 6579** the [sqlite3_context] pointer, the results are undefined.
 6580*/
 6581SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
 6582SQLITE_API void sqlite3_result_blob64(sqlite3_context*,const void*,
 6583                           sqlite3_uint64,void(*)(void*));
 6584SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
 6585SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
 6586SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
 6587SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
 6588SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
 6589SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
 6590SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
 6591SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
 6592SQLITE_API void sqlite3_result_null(sqlite3_context*);
 6593SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
 6594SQLITE_API void sqlite3_result_text64(sqlite3_context*, const char *z, sqlite3_uint64 n,
 6595                           void(*)(void*), unsigned char encoding);
 6596SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
 6597SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
 6598SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
 6599SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
 6600SQLITE_API void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*));
 6601SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
 6602SQLITE_API int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
 6603
 6604
 6605/*
 6606** CAPI3REF: Setting The Subtype Of An SQL Function
 6607** METHOD: sqlite3_context
 6608**
 6609** The sqlite3_result_subtype(C,T) function causes the subtype of
 6610** the result from the [application-defined SQL function] with
 6611** [sqlite3_context] C to be the value T.  Only the lower 8 bits
 6612** of the subtype T are preserved in current versions of SQLite;
 6613** higher order bits are discarded.
 6614** The number of subtype bytes preserved by SQLite might increase
 6615** in future releases of SQLite.
 6616**
 6617** Every [application-defined SQL function] that invokes this interface
 6618** should include the [SQLITE_RESULT_SUBTYPE] property in its
 6619** text encoding argument when the SQL function is
 6620** [sqlite3_create_function|registered].  If the [SQLITE_RESULT_SUBTYPE]
 6621** property is omitted from the function that invokes sqlite3_result_subtype(),
 6622** then in some cases the sqlite3_result_subtype() might fail to set
 6623** the result subtype.
 6624**
 6625** If SQLite is compiled with -DSQLITE_STRICT_SUBTYPE=1, then any
 6626** SQL function that invokes the sqlite3_result_subtype() interface
 6627** and that does not have the SQLITE_RESULT_SUBTYPE property will raise
 6628** an error.  Future versions of SQLite might enable -DSQLITE_STRICT_SUBTYPE=1
 6629** by default.
 6630*/
 6631SQLITE_API void sqlite3_result_subtype(sqlite3_context*,unsigned int);
 6632
 6633/*
 6634** CAPI3REF: Define New Collating Sequences
 6635** METHOD: sqlite3
 6636**
 6637** ^These functions add, remove, or modify a [collation] associated
 6638** with the [database connection] specified as the first argument.
 6639**
 6640** ^The name of the collation is a UTF-8 string
 6641** for sqlite3_create_collation() and sqlite3_create_collation_v2()
 6642** and a UTF-16 string in native byte order for sqlite3_create_collation16().
 6643** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
 6644** considered to be the same name.
 6645**
 6646** ^(The third argument (eTextRep) must be one of the constants:
 6647** <ul>
 6648** <li> [SQLITE_UTF8],
 6649** <li> [SQLITE_UTF16LE],
 6650** <li> [SQLITE_UTF16BE],
 6651** <li> [SQLITE_UTF16], or
 6652** <li> [SQLITE_UTF16_ALIGNED].
 6653** </ul>)^
 6654** ^The eTextRep argument determines the encoding of strings passed
 6655** to the collating function callback, xCompare.
 6656** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
 6657** force strings to be UTF16 with native byte order.
 6658** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
 6659** on an even byte address.
 6660**
 6661** ^The fourth argument, pArg, is an application data pointer that is passed
 6662** through as the first argument to the collating function callback.
 6663**
 6664** ^The fifth argument, xCompare, is a pointer to the collating function.
 6665** ^Multiple collating functions can be registered using the same name but
 6666** with different eTextRep parameters and SQLite will use whichever
 6667** function requires the least amount of data transformation.
 6668** ^If the xCompare argument is NULL then the collating function is
 6669** deleted.  ^When all collating functions having the same name are deleted,
 6670** that collation is no longer usable.
 6671**
 6672** ^The collating function callback is invoked with a copy of the pArg
 6673** application data pointer and with two strings in the encoding specified
 6674** by the eTextRep argument.  The two integer parameters to the collating
 6675** function callback are the length of the two strings, in bytes. The collating
 6676** function must return an integer that is negative, zero, or positive
 6677** if the first string is less than, equal to, or greater than the second,
 6678** respectively.  A collating function must always return the same answer
 6679** given the same inputs.  If two or more collating functions are registered
 6680** to the same collation name (using different eTextRep values) then all
 6681** must give an equivalent answer when invoked with equivalent strings.
 6682** The collating function must obey the following properties for all
 6683** strings A, B, and C:
 6684**
 6685** <ol>
 6686** <li> If A==B then B==A.
 6687** <li> If A==B and B==C then A==C.
 6688** <li> If A&lt;B THEN B&gt;A.
 6689** <li> If A&lt;B and B&lt;C then A&lt;C.
 6690** </ol>
 6691**
 6692** If a collating function fails any of the above constraints and that
 6693** collating function is registered and used, then the behavior of SQLite
 6694** is undefined.
 6695**
 6696** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
 6697** with the addition that the xDestroy callback is invoked on pArg when
 6698** the collating function is deleted.
 6699** ^Collating functions are deleted when they are overridden by later
 6700** calls to the collation creation functions or when the
 6701** [database connection] is closed using [sqlite3_close()].
 6702**
 6703** ^The xDestroy callback is <u>not</u> called if the
 6704** sqlite3_create_collation_v2() function fails.  Applications that invoke
 6705** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should
 6706** check the return code and dispose of the application data pointer
 6707** themselves rather than expecting SQLite to deal with it for them.
 6708** This is different from every other SQLite interface.  The inconsistency
 6709** is unfortunate but cannot be changed without breaking backwards
 6710** compatibility.
 6711**
 6712** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
 6713*/
 6714SQLITE_API int sqlite3_create_collation(
 6715  sqlite3*,
 6716  const char *zName,
 6717  int eTextRep,
 6718  void *pArg,
 6719  int(*xCompare)(void*,int,const void*,int,const void*)
 6720);
 6721SQLITE_API int sqlite3_create_collation_v2(
 6722  sqlite3*,
 6723  const char *zName,
 6724  int eTextRep,
 6725  void *pArg,
 6726  int(*xCompare)(void*,int,const void*,int,const void*),
 6727  void(*xDestroy)(void*)
 6728);
 6729SQLITE_API int sqlite3_create_collation16(
 6730  sqlite3*,
 6731  const void *zName,
 6732  int eTextRep,
 6733  void *pArg,
 6734  int(*xCompare)(void*,int,const void*,int,const void*)
 6735);
 6736
 6737/*
 6738** CAPI3REF: Collation Needed Callbacks
 6739** METHOD: sqlite3
 6740**
 6741** ^To avoid having to register all collation sequences before a database
 6742** can be used, a single callback function may be registered with the
 6743** [database connection] to be invoked whenever an undefined collation
 6744** sequence is required.
 6745**
 6746** ^If the function is registered using the sqlite3_collation_needed() API,
 6747** then it is passed the names of undefined collation sequences as strings
 6748** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
 6749** the names are passed as UTF-16 in machine native byte order.
 6750** ^A call to either function replaces the existing collation-needed callback.
 6751**
 6752** ^(When the callback is invoked, the first argument passed is a copy
 6753** of the second argument to sqlite3_collation_needed() or
 6754** sqlite3_collation_needed16().  The second argument is the database
 6755** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
 6756** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
 6757** sequence function required.  The fourth parameter is the name of the
 6758** required collation sequence.)^
 6759**
 6760** The callback function should register the desired collation using
 6761** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
 6762** [sqlite3_create_collation_v2()].
 6763*/
 6764SQLITE_API int sqlite3_collation_needed(
 6765  sqlite3*,
 6766  void*,
 6767  void(*)(void*,sqlite3*,int eTextRep,const char*)
 6768);
 6769SQLITE_API int sqlite3_collation_needed16(
 6770  sqlite3*,
 6771  void*,
 6772  void(*)(void*,sqlite3*,int eTextRep,const void*)
 6773);
 6774
 6775#ifdef SQLITE_ENABLE_CEROD
 6776/*
 6777** Specify the activation key for a CEROD database.  Unless
 6778** activated, none of the CEROD routines will work.
 6779*/
 6780SQLITE_API void sqlite3_activate_cerod(
 6781  const char *zPassPhrase        /* Activation phrase */
 6782);
 6783#endif
 6784
 6785/*
 6786** CAPI3REF: Suspend Execution For A Short Time
 6787**
 6788** The sqlite3_sleep() function causes the current thread to suspend execution
 6789** for at least a number of milliseconds specified in its parameter.
 6790**
 6791** If the operating system does not support sleep requests with
 6792** millisecond time resolution, then the time will be rounded up to
 6793** the nearest second. The number of milliseconds of sleep actually
 6794** requested from the operating system is returned.
 6795**
 6796** ^SQLite implements this interface by calling the xSleep()
 6797** method of the default [sqlite3_vfs] object.  If the xSleep() method
 6798** of the default VFS is not implemented correctly, or not implemented at
 6799** all, then the behavior of sqlite3_sleep() may deviate from the description
 6800** in the previous paragraphs.
 6801**
 6802** If a negative argument is passed to sqlite3_sleep() the results vary by
 6803** VFS and operating system.  Some system treat a negative argument as an
 6804** instruction to sleep forever.  Others understand it to mean do not sleep
 6805** at all. ^In SQLite version 3.42.0 and later, a negative
 6806** argument passed into sqlite3_sleep() is changed to zero before it is relayed
 6807** down into the xSleep method of the VFS.
 6808*/
 6809SQLITE_API int sqlite3_sleep(int);
 6810
 6811/*
 6812** CAPI3REF: Name Of The Folder Holding Temporary Files
 6813**
 6814** ^(If this global variable is made to point to a string which is
 6815** the name of a folder (a.k.a. directory), then all temporary files
 6816** created by SQLite when using a built-in [sqlite3_vfs | VFS]
 6817** will be placed in that directory.)^  ^If this variable
 6818** is a NULL pointer, then SQLite performs a search for an appropriate
 6819** temporary file directory.
 6820**
 6821** Applications are strongly discouraged from using this global variable.
 6822** It is required to set a temporary folder on Windows Runtime (WinRT).
 6823** But for all other platforms, it is highly recommended that applications
 6824** neither read nor write this variable.  This global variable is a relic
 6825** that exists for backwards compatibility of legacy applications and should
 6826** be avoided in new projects.
 6827**
 6828** It is not safe to read or modify this variable in more than one
 6829** thread at a time.  It is not safe to read or modify this variable
 6830** if a [database connection] is being used at the same time in a separate
 6831** thread.
 6832** It is intended that this variable be set once
 6833** as part of process initialization and before any SQLite interface
 6834** routines have been called and that this variable remain unchanged
 6835** thereafter.
 6836**
 6837** ^The [temp_store_directory pragma] may modify this variable and cause
 6838** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
 6839** the [temp_store_directory pragma] always assumes that any string
 6840** that this variable points to is held in memory obtained from
 6841** [sqlite3_malloc] and the pragma may attempt to free that memory
 6842** using [sqlite3_free].
 6843** Hence, if this variable is modified directly, either it should be
 6844** made NULL or made to point to memory obtained from [sqlite3_malloc]
 6845** or else the use of the [temp_store_directory pragma] should be avoided.
 6846** Except when requested by the [temp_store_directory pragma], SQLite
 6847** does not free the memory that sqlite3_temp_directory points to.  If
 6848** the application wants that memory to be freed, it must do
 6849** so itself, taking care to only do so after all [database connection]
 6850** objects have been destroyed.
 6851**
 6852** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
 6853** prior to calling [sqlite3_open] or [sqlite3_open_v2].  Otherwise, various
 6854** features that require the use of temporary files may fail.  Here is an
 6855** example of how to do this using C++ with the Windows Runtime:
 6856**
 6857** <blockquote><pre>
 6858** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
 6859** &nbsp;     TemporaryFolder->Path->Data();
 6860** char zPathBuf&#91;MAX_PATH + 1&#93;;
 6861** memset(zPathBuf, 0, sizeof(zPathBuf));
 6862** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
 6863** &nbsp;     NULL, NULL);
 6864** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
 6865** </pre></blockquote>
 6866*/
 6867SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
 6868
 6869/*
 6870** CAPI3REF: Name Of The Folder Holding Database Files
 6871**
 6872** ^(If this global variable is made to point to a string which is
 6873** the name of a folder (a.k.a. directory), then all database files
 6874** specified with a relative pathname and created or accessed by
 6875** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
 6876** to be relative to that directory.)^ ^If this variable is a NULL
 6877** pointer, then SQLite assumes that all database files specified
 6878** with a relative pathname are relative to the current directory
 6879** for the process.  Only the windows VFS makes use of this global
 6880** variable; it is ignored by the unix VFS.
 6881**
 6882** Changing the value of this variable while a database connection is
 6883** open can result in a corrupt database.
 6884**
 6885** It is not safe to read or modify this variable in more than one
 6886** thread at a time.  It is not safe to read or modify this variable
 6887** if a [database connection] is being used at the same time in a separate
 6888** thread.
 6889** It is intended that this variable be set once
 6890** as part of process initialization and before any SQLite interface
 6891** routines have been called and that this variable remain unchanged
 6892** thereafter.
 6893**
 6894** ^The [data_store_directory pragma] may modify this variable and cause
 6895** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
 6896** the [data_store_directory pragma] always assumes that any string
 6897** that this variable points to is held in memory obtained from
 6898** [sqlite3_malloc] and the pragma may attempt to free that memory
 6899** using [sqlite3_free].
 6900** Hence, if this variable is modified directly, either it should be
 6901** made NULL or made to point to memory obtained from [sqlite3_malloc]
 6902** or else the use of the [data_store_directory pragma] should be avoided.
 6903*/
 6904SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
 6905
 6906/*
 6907** CAPI3REF: Win32 Specific Interface
 6908**
 6909** These interfaces are available only on Windows.  The
 6910** [sqlite3_win32_set_directory] interface is used to set the value associated
 6911** with the [sqlite3_temp_directory] or [sqlite3_data_directory] variable, to
 6912** zValue, depending on the value of the type parameter.  The zValue parameter
 6913** should be NULL to cause the previous value to be freed via [sqlite3_free];
 6914** a non-NULL value will be copied into memory obtained from [sqlite3_malloc]
 6915** prior to being used.  The [sqlite3_win32_set_directory] interface returns
 6916** [SQLITE_OK] to indicate success, [SQLITE_ERROR] if the type is unsupported,
 6917** or [SQLITE_NOMEM] if memory could not be allocated.  The value of the
 6918** [sqlite3_data_directory] variable is intended to act as a replacement for
 6919** the current directory on the sub-platforms of Win32 where that concept is
 6920** not present, e.g. WinRT and UWP.  The [sqlite3_win32_set_directory8] and
 6921** [sqlite3_win32_set_directory16] interfaces behave exactly the same as the
 6922** sqlite3_win32_set_directory interface except the string parameter must be
 6923** UTF-8 or UTF-16, respectively.
 6924*/
 6925SQLITE_API int sqlite3_win32_set_directory(
 6926  unsigned long type, /* Identifier for directory being set or reset */
 6927  void *zValue        /* New value for directory being set or reset */
 6928);
 6929SQLITE_API int sqlite3_win32_set_directory8(unsigned long type, const char *zValue);
 6930SQLITE_API int sqlite3_win32_set_directory16(unsigned long type, const void *zValue);
 6931
 6932/*
 6933** CAPI3REF: Win32 Directory Types
 6934**
 6935** These macros are only available on Windows.  They define the allowed values
 6936** for the type argument to the [sqlite3_win32_set_directory] interface.
 6937*/
 6938#define SQLITE_WIN32_DATA_DIRECTORY_TYPE  1
 6939#define SQLITE_WIN32_TEMP_DIRECTORY_TYPE  2
 6940
 6941/*
 6942** CAPI3REF: Test For Auto-Commit Mode
 6943** KEYWORDS: {autocommit mode}
 6944** METHOD: sqlite3
 6945**
 6946** ^The sqlite3_get_autocommit() interface returns non-zero or
 6947** zero if the given database connection is or is not in autocommit mode,
 6948** respectively.  ^Autocommit mode is on by default.
 6949** ^Autocommit mode is disabled by a [BEGIN] statement.
 6950** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
 6951**
 6952** If certain kinds of errors occur on a statement within a multi-statement
 6953** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
 6954** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
 6955** transaction might be rolled back automatically.  The only way to
 6956** find out whether SQLite automatically rolled back the transaction after
 6957** an error is to use this function.
 6958**
 6959** If another thread changes the autocommit status of the database
 6960** connection while this routine is running, then the return value
 6961** is undefined.
 6962*/
 6963SQLITE_API int sqlite3_get_autocommit(sqlite3*);
 6964
 6965/*
 6966** CAPI3REF: Find The Database Handle Of A Prepared Statement
 6967** METHOD: sqlite3_stmt
 6968**
 6969** ^The sqlite3_db_handle interface returns the [database connection] handle
 6970** to which a [prepared statement] belongs.  ^The [database connection]
 6971** returned by sqlite3_db_handle is the same [database connection]
 6972** that was the first argument
 6973** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
 6974** create the statement in the first place.
 6975*/
 6976SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
 6977
 6978/*
 6979** CAPI3REF: Return The Schema Name For A Database Connection
 6980** METHOD: sqlite3
 6981**
 6982** ^The sqlite3_db_name(D,N) interface returns a pointer to the schema name
 6983** for the N-th database on database connection D, or a NULL pointer if N is
 6984** out of range.  An N value of 0 means the main database file.  An N of 1 is
 6985** the "temp" schema.  Larger values of N correspond to various ATTACH-ed
 6986** databases.
 6987**
 6988** Space to hold the string that is returned by sqlite3_db_name() is managed
 6989** by SQLite itself.  The string might be deallocated by any operation that
 6990** changes the schema, including [ATTACH] or [DETACH] or calls to
 6991** [sqlite3_serialize()] or [sqlite3_deserialize()], even operations that
 6992** occur on a different thread.  Applications that need to
 6993** remember the string long-term should make their own copy.  Applications that
 6994** are accessing the same database connection simultaneously on multiple
 6995** threads should mutex-protect calls to this API and should make their own
 6996** private copy of the result prior to releasing the mutex.
 6997*/
 6998SQLITE_API const char *sqlite3_db_name(sqlite3 *db, int N);
 6999
 7000/*
 7001** CAPI3REF: Return The Filename For A Database Connection
 7002** METHOD: sqlite3
 7003**
 7004** ^The sqlite3_db_filename(D,N) interface returns a pointer to the filename
 7005** associated with database N of connection D.
 7006** ^If there is no attached database N on the database
 7007** connection D, or if database N is a temporary or in-memory database, then
 7008** this function will return either a NULL pointer or an empty string.
 7009**
 7010** ^The string value returned by this routine is owned and managed by
 7011** the database connection.  ^The value will be valid until the database N
 7012** is [DETACH]-ed or until the database connection closes.
 7013**
 7014** ^The filename returned by this function is the output of the
 7015** xFullPathname method of the [VFS].  ^In other words, the filename
 7016** will be an absolute pathname, even if the filename used
 7017** to open the database originally was a URI or relative pathname.
 7018**
 7019** If the filename pointer returned by this routine is not NULL, then it
 7020** can be used as the filename input parameter to these routines:
 7021** <ul>
 7022** <li> [sqlite3_uri_parameter()]
 7023** <li> [sqlite3_uri_boolean()]
 7024** <li> [sqlite3_uri_int64()]
 7025** <li> [sqlite3_filename_database()]
 7026** <li> [sqlite3_filename_journal()]
 7027** <li> [sqlite3_filename_wal()]
 7028** </ul>
 7029*/
 7030SQLITE_API sqlite3_filename sqlite3_db_filename(sqlite3 *db, const char *zDbName);
 7031
 7032/*
 7033** CAPI3REF: Determine if a database is read-only
 7034** METHOD: sqlite3
 7035**
 7036** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
 7037** of connection D is read-only, 0 if it is read/write, or -1 if N is not
 7038** the name of a database on connection D.
 7039*/
 7040SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
 7041
 7042/*
 7043** CAPI3REF: Determine the transaction state of a database
 7044** METHOD: sqlite3
 7045**
 7046** ^The sqlite3_txn_state(D,S) interface returns the current
 7047** [transaction state] of schema S in database connection D.  ^If S is NULL,
 7048** then the highest transaction state of any schema on database connection D
 7049** is returned.  Transaction states are (in order of lowest to highest):
 7050** <ol>
 7051** <li value="0"> SQLITE_TXN_NONE
 7052** <li value="1"> SQLITE_TXN_READ
 7053** <li value="2"> SQLITE_TXN_WRITE
 7054** </ol>
 7055** ^If the S argument to sqlite3_txn_state(D,S) is not the name of
 7056** a valid schema, then -1 is returned.
 7057*/
 7058SQLITE_API int sqlite3_txn_state(sqlite3*,const char *zSchema);
 7059
 7060/*
 7061** CAPI3REF: Allowed return values from sqlite3_txn_state()
 7062** KEYWORDS: {transaction state}
 7063**
 7064** These constants define the current transaction state of a database file.
 7065** ^The [sqlite3_txn_state(D,S)] interface returns one of these
 7066** constants in order to describe the transaction state of schema S
 7067** in [database connection] D.
 7068**
 7069** <dl>
 7070** [[SQLITE_TXN_NONE]] <dt>SQLITE_TXN_NONE</dt>
 7071** <dd>The SQLITE_TXN_NONE state means that no transaction is currently
 7072** pending.</dd>
 7073**
 7074** [[SQLITE_TXN_READ]] <dt>SQLITE_TXN_READ</dt>
 7075** <dd>The SQLITE_TXN_READ state means that the database is currently
 7076** in a read transaction.  Content has been read from the database file
 7077** but nothing in the database file has changed.  The transaction state
 7078** will be advanced to SQLITE_TXN_WRITE if any changes occur and there are
 7079** no other conflicting concurrent write transactions.  The transaction
 7080** state will revert to SQLITE_TXN_NONE following a [ROLLBACK] or
 7081** [COMMIT].</dd>
 7082**
 7083** [[SQLITE_TXN_WRITE]] <dt>SQLITE_TXN_WRITE</dt>
 7084** <dd>The SQLITE_TXN_WRITE state means that the database is currently
 7085** in a write transaction.  Content has been written to the database file
 7086** but has not yet committed.  The transaction state will change to
 7087** SQLITE_TXN_NONE at the next [ROLLBACK] or [COMMIT].</dd>
 7088*/
 7089#define SQLITE_TXN_NONE  0
 7090#define SQLITE_TXN_READ  1
 7091#define SQLITE_TXN_WRITE 2
 7092
 7093/*
 7094** CAPI3REF: Find the next prepared statement
 7095** METHOD: sqlite3
 7096**
 7097** ^This interface returns a pointer to the next [prepared statement] after
 7098** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
 7099** then this interface returns a pointer to the first prepared statement
 7100** associated with the database connection pDb.  ^If no prepared statement
 7101** satisfies the conditions of this routine, it returns NULL.
 7102**
 7103** The [database connection] pointer D in a call to
 7104** [sqlite3_next_stmt(D,S)] must refer to an open database
 7105** connection and in particular must not be a NULL pointer.
 7106*/
 7107SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
 7108
 7109/*
 7110** CAPI3REF: Commit And Rollback Notification Callbacks
 7111** METHOD: sqlite3
 7112**
 7113** ^The sqlite3_commit_hook() interface registers a callback
 7114** function to be invoked whenever a transaction is [COMMIT | committed].
 7115** ^Any callback set by a previous call to sqlite3_commit_hook()
 7116** for the same database connection is overridden.
 7117** ^The sqlite3_rollback_hook() interface registers a callback
 7118** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
 7119** ^Any callback set by a previous call to sqlite3_rollback_hook()
 7120** for the same database connection is overridden.
 7121** ^The pArg argument is passed through to the callback.
 7122** ^If the callback on a commit hook function returns non-zero,
 7123** then the commit is converted into a rollback.
 7124**
 7125** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
 7126** return the P argument from the previous call of the same function
 7127** on the same [database connection] D, or NULL for
 7128** the first call for each function on D.
 7129**
 7130** The commit and rollback hook callbacks are not reentrant.
 7131** The callback implementation must not do anything that will modify
 7132** the database connection that invoked the callback.  Any actions
 7133** to modify the database connection must be deferred until after the
 7134** completion of the [sqlite3_step()] call that triggered the commit
 7135** or rollback hook in the first place.
 7136** Note that running any other SQL statements, including SELECT statements,
 7137** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
 7138** the database connections for the meaning of "modify" in this paragraph.
 7139**
 7140** ^Registering a NULL function disables the callback.
 7141**
 7142** ^When the commit hook callback routine returns zero, the [COMMIT]
 7143** operation is allowed to continue normally.  ^If the commit hook
 7144** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
 7145** ^The rollback hook is invoked on a rollback that results from a commit
 7146** hook returning non-zero, just as it would be with any other rollback.
 7147**
 7148** ^For the purposes of this API, a transaction is said to have been
 7149** rolled back if an explicit "ROLLBACK" statement is executed, or
 7150** an error or constraint causes an implicit rollback to occur.
 7151** ^The rollback callback is not invoked if a transaction is
 7152** automatically rolled back because the database connection is closed.
 7153**
 7154** See also the [sqlite3_update_hook()] interface.
 7155*/
 7156SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
 7157SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
 7158
 7159/*
 7160** CAPI3REF: Autovacuum Compaction Amount Callback
 7161** METHOD: sqlite3
 7162**
 7163** ^The sqlite3_autovacuum_pages(D,C,P,X) interface registers a callback
 7164** function C that is invoked prior to each autovacuum of the database
 7165** file.  ^The callback is passed a copy of the generic data pointer (P),
 7166** the schema-name of the attached database that is being autovacuumed,
 7167** the size of the database file in pages, the number of free pages,
 7168** and the number of bytes per page, respectively.  The callback should
 7169** return the number of free pages that should be removed by the
 7170** autovacuum.  ^If the callback returns zero, then no autovacuum happens.
 7171** ^If the value returned is greater than or equal to the number of
 7172** free pages, then a complete autovacuum happens.
 7173**
 7174** <p>^If there are multiple ATTACH-ed database files that are being
 7175** modified as part of a transaction commit, then the autovacuum pages
 7176** callback is invoked separately for each file.
 7177**
 7178** <p><b>The callback is not reentrant.</b> The callback function should
 7179** not attempt to invoke any other SQLite interface.  If it does, bad
 7180** things may happen, including segmentation faults and corrupt database
 7181** files.  The callback function should be a simple function that
 7182** does some arithmetic on its input parameters and returns a result.
 7183**
 7184** ^The X parameter to sqlite3_autovacuum_pages(D,C,P,X) is an optional
 7185** destructor for the P parameter.  ^If X is not NULL, then X(P) is
 7186** invoked whenever the database connection closes or when the callback
 7187** is overwritten by another invocation of sqlite3_autovacuum_pages().
 7188**
 7189** <p>^There is only one autovacuum pages callback per database connection.
 7190** ^Each call to the sqlite3_autovacuum_pages() interface overrides all
 7191** previous invocations for that database connection.  ^If the callback
 7192** argument (C) to sqlite3_autovacuum_pages(D,C,P,X) is a NULL pointer,
 7193** then the autovacuum steps callback is canceled.  The return value
 7194** from sqlite3_autovacuum_pages() is normally SQLITE_OK, but might
 7195** be some other error code if something goes wrong.  The current
 7196** implementation will only return SQLITE_OK or SQLITE_MISUSE, but other
 7197** return codes might be added in future releases.
 7198**
 7199** <p>If no autovacuum pages callback is specified (the usual case) or
 7200** a NULL pointer is provided for the callback,
 7201** then the default behavior is to vacuum all free pages.  So, in other
 7202** words, the default behavior is the same as if the callback function
 7203** were something like this:
 7204**
 7205** <blockquote><pre>
 7206** &nbsp;   unsigned int demonstration_autovac_pages_callback(
 7207** &nbsp;     void *pClientData,
 7208** &nbsp;     const char *zSchema,
 7209** &nbsp;     unsigned int nDbPage,
 7210** &nbsp;     unsigned int nFreePage,
 7211** &nbsp;     unsigned int nBytePerPage
 7212** &nbsp;   ){
 7213** &nbsp;     return nFreePage;
 7214** &nbsp;   }
 7215** </pre></blockquote>
 7216*/
 7217SQLITE_API int sqlite3_autovacuum_pages(
 7218  sqlite3 *db,
 7219  unsigned int(*)(void*,const char*,unsigned int,unsigned int,unsigned int),
 7220  void*,
 7221  void(*)(void*)
 7222);
 7223
 7224
 7225/*
 7226** CAPI3REF: Data Change Notification Callbacks
 7227** METHOD: sqlite3
 7228**
 7229** ^The sqlite3_update_hook() interface registers a callback function
 7230** with the [database connection] identified by the first argument
 7231** to be invoked whenever a row is updated, inserted or deleted in
 7232** a [rowid table].
 7233** ^Any callback set by a previous call to this function
 7234** for the same database connection is overridden.
 7235**
 7236** ^The second argument is a pointer to the function to invoke when a
 7237** row is updated, inserted or deleted in a rowid table.
 7238** ^The update hook is disabled by invoking sqlite3_update_hook()
 7239** with a NULL pointer as the second parameter.
 7240** ^The first argument to the callback is a copy of the third argument
 7241** to sqlite3_update_hook().
 7242** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
 7243** or [SQLITE_UPDATE], depending on the operation that caused the callback
 7244** to be invoked.
 7245** ^The third and fourth arguments to the callback contain pointers to the
 7246** database and table name containing the affected row.
 7247** ^The final callback parameter is the [rowid] of the row.
 7248** ^In the case of an update, this is the [rowid] after the update takes place.
 7249**
 7250** ^(The update hook is not invoked when internal system tables are
 7251** modified (i.e. sqlite_sequence).)^
 7252** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
 7253**
 7254** ^In the current implementation, the update hook
 7255** is not invoked when conflicting rows are deleted because of an
 7256** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
 7257** invoked when rows are deleted using the [truncate optimization].
 7258** The exceptions defined in this paragraph might change in a future
 7259** release of SQLite.
 7260**
 7261** Whether the update hook is invoked before or after the
 7262** corresponding change is currently unspecified and may differ
 7263** depending on the type of change. Do not rely on the order of the
 7264** hook call with regards to the final result of the operation which
 7265** triggers the hook.
 7266**
 7267** The update hook implementation must not do anything that will modify
 7268** the database connection that invoked the update hook.  Any actions
 7269** to modify the database connection must be deferred until after the
 7270** completion of the [sqlite3_step()] call that triggered the update hook.
 7271** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
 7272** database connections for the meaning of "modify" in this paragraph.
 7273**
 7274** ^The sqlite3_update_hook(D,C,P) function
 7275** returns the P argument from the previous call
 7276** on the same [database connection] D, or NULL for
 7277** the first call on D.
 7278**
 7279** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()],
 7280** and [sqlite3_preupdate_hook()] interfaces.
 7281*/
 7282SQLITE_API void *sqlite3_update_hook(
 7283  sqlite3*,
 7284  void(*)(void *,int ,char const *,char const *,sqlite3_int64),
 7285  void*
 7286);
 7287
 7288/*
 7289** CAPI3REF: Enable Or Disable Shared Pager Cache
 7290**
 7291** ^(This routine enables or disables the sharing of the database cache
 7292** and schema data structures between [database connection | connections]
 7293** to the same database. Sharing is enabled if the argument is true
 7294** and disabled if the argument is false.)^
 7295**
 7296** This interface is omitted if SQLite is compiled with
 7297** [-DSQLITE_OMIT_SHARED_CACHE].  The [-DSQLITE_OMIT_SHARED_CACHE]
 7298** compile-time option is recommended because the
 7299** [use of shared cache mode is discouraged].
 7300**
 7301** ^Cache sharing is enabled and disabled for an entire process.
 7302** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]).
 7303** In prior versions of SQLite,
 7304** sharing was enabled or disabled for each thread separately.
 7305**
 7306** ^(The cache sharing mode set by this interface effects all subsequent
 7307** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
 7308** Existing database connections continue to use the sharing mode
 7309** that was in effect at the time they were opened.)^
 7310**
 7311** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
 7312** successfully.  An [error code] is returned otherwise.)^
 7313**
 7314** ^Shared cache is disabled by default. It is recommended that it stay
 7315** that way.  In other words, do not use this routine.  This interface
 7316** continues to be provided for historical compatibility, but its use is
 7317** discouraged.  Any use of shared cache is discouraged.  If shared cache
 7318** must be used, it is recommended that shared cache only be enabled for
 7319** individual database connections using the [sqlite3_open_v2()] interface
 7320** with the [SQLITE_OPEN_SHAREDCACHE] flag.
 7321**
 7322** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
 7323** and will always return SQLITE_MISUSE. On those systems,
 7324** shared cache mode should be enabled per-database connection via
 7325** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
 7326**
 7327** This interface is threadsafe on processors where writing a
 7328** 32-bit integer is atomic.
 7329**
 7330** See Also:  [SQLite Shared-Cache Mode]
 7331*/
 7332SQLITE_API int sqlite3_enable_shared_cache(int);
 7333
 7334/*
 7335** CAPI3REF: Attempt To Free Heap Memory
 7336**
 7337** ^The sqlite3_release_memory() interface attempts to free N bytes
 7338** of heap memory by deallocating non-essential memory allocations
 7339** held by the database library.   Memory used to cache database
 7340** pages to improve performance is an example of non-essential memory.
 7341** ^sqlite3_release_memory() returns the number of bytes actually freed,
 7342** which might be more or less than the amount requested.
 7343** ^The sqlite3_release_memory() routine is a no-op returning zero
 7344** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
 7345**
 7346** See also: [sqlite3_db_release_memory()]
 7347*/
 7348SQLITE_API int sqlite3_release_memory(int);
 7349
 7350/*
 7351** CAPI3REF: Free Memory Used By A Database Connection
 7352** METHOD: sqlite3
 7353**
 7354** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
 7355** memory as possible from database connection D. Unlike the
 7356** [sqlite3_release_memory()] interface, this interface is in effect even
 7357** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
 7358** omitted.
 7359**
 7360** See also: [sqlite3_release_memory()]
 7361*/
 7362SQLITE_API int sqlite3_db_release_memory(sqlite3*);
 7363
 7364/*
 7365** CAPI3REF: Impose A Limit On Heap Size
 7366**
 7367** These interfaces impose limits on the amount of heap memory that will be
 7368** used by all database connections within a single process.
 7369**
 7370** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
 7371** soft limit on the amount of heap memory that may be allocated by SQLite.
 7372** ^SQLite strives to keep heap memory utilization below the soft heap
 7373** limit by reducing the number of pages held in the page cache
 7374** as heap memory usages approaches the limit.
 7375** ^The soft heap limit is "soft" because even though SQLite strives to stay
 7376** below the limit, it will exceed the limit rather than generate
 7377** an [SQLITE_NOMEM] error.  In other words, the soft heap limit
 7378** is advisory only.
 7379**
 7380** ^The sqlite3_hard_heap_limit64(N) interface sets a hard upper bound of
 7381** N bytes on the amount of memory that will be allocated.  ^The
 7382** sqlite3_hard_heap_limit64(N) interface is similar to
 7383** sqlite3_soft_heap_limit64(N) except that memory allocations will fail
 7384** when the hard heap limit is reached.
 7385**
 7386** ^The return value from both sqlite3_soft_heap_limit64() and
 7387** sqlite3_hard_heap_limit64() is the size of
 7388** the heap limit prior to the call, or negative in the case of an
 7389** error.  ^If the argument N is negative
 7390** then no change is made to the heap limit.  Hence, the current
 7391** size of heap limits can be determined by invoking
 7392** sqlite3_soft_heap_limit64(-1) or sqlite3_hard_heap_limit(-1).
 7393**
 7394** ^Setting the heap limits to zero disables the heap limiter mechanism.
 7395**
 7396** ^The soft heap limit may not be greater than the hard heap limit.
 7397** ^If the hard heap limit is enabled and if sqlite3_soft_heap_limit(N)
 7398** is invoked with a value of N that is greater than the hard heap limit,
 7399** the soft heap limit is set to the value of the hard heap limit.
 7400** ^The soft heap limit is automatically enabled whenever the hard heap
 7401** limit is enabled. ^When sqlite3_hard_heap_limit64(N) is invoked and
 7402** the soft heap limit is outside the range of 1..N, then the soft heap
 7403** limit is set to N.  ^Invoking sqlite3_soft_heap_limit64(0) when the
 7404** hard heap limit is enabled makes the soft heap limit equal to the
 7405** hard heap limit.
 7406**
 7407** The memory allocation limits can also be adjusted using
 7408** [PRAGMA soft_heap_limit] and [PRAGMA hard_heap_limit].
 7409**
 7410** ^(The heap limits are not enforced in the current implementation
 7411** if one or more of following conditions are true:
 7412**
 7413** <ul>
 7414** <li> The limit value is set to zero.
 7415** <li> Memory accounting is disabled using a combination of the
 7416**      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
 7417**      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
 7418** <li> An alternative page cache implementation is specified using
 7419**      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
 7420** <li> The page cache allocates from its own memory pool supplied
 7421**      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
 7422**      from the heap.
 7423** </ul>)^
 7424**
 7425** The circumstances under which SQLite will enforce the heap limits may
 7426** change in future releases of SQLite.
 7427*/
 7428SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
 7429SQLITE_API sqlite3_int64 sqlite3_hard_heap_limit64(sqlite3_int64 N);
 7430
 7431/*
 7432** CAPI3REF: Deprecated Soft Heap Limit Interface
 7433** DEPRECATED
 7434**
 7435** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
 7436** interface.  This routine is provided for historical compatibility
 7437** only.  All new applications should use the
 7438** [sqlite3_soft_heap_limit64()] interface rather than this one.
 7439*/
 7440SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
 7441
 7442
 7443/*
 7444** CAPI3REF: Extract Metadata About A Column Of A Table
 7445** METHOD: sqlite3
 7446**
 7447** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
 7448** information about column C of table T in database D
 7449** on [database connection] X.)^  ^The sqlite3_table_column_metadata()
 7450** interface returns SQLITE_OK and fills in the non-NULL pointers in
 7451** the final five arguments with appropriate values if the specified
 7452** column exists.  ^The sqlite3_table_column_metadata() interface returns
 7453** SQLITE_ERROR if the specified column does not exist.
 7454** ^If the column-name parameter to sqlite3_table_column_metadata() is a
 7455** NULL pointer, then this routine simply checks for the existence of the
 7456** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
 7457** does not.  If the table name parameter T in a call to
 7458** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
 7459** undefined behavior.
 7460**
 7461** ^The column is identified by the second, third and fourth parameters to
 7462** this function. ^(The second parameter is either the name of the database
 7463** (i.e. "main", "temp", or an attached database) containing the specified
 7464** table or NULL.)^ ^If it is NULL, then all attached databases are searched
 7465** for the table using the same algorithm used by the database engine to
 7466** resolve unqualified table references.
 7467**
 7468** ^The third and fourth parameters to this function are the table and column
 7469** name of the desired column, respectively.
 7470**
 7471** ^Metadata is returned by writing to the memory locations passed as the 5th
 7472** and subsequent parameters to this function. ^Any of these arguments may be
 7473** NULL, in which case the corresponding element of metadata is omitted.
 7474**
 7475** ^(<blockquote>
 7476** <table border="1">
 7477** <tr><th> Parameter <th> Output<br>Type <th>  Description
 7478**
 7479** <tr><td> 5th <td> const char* <td> Data type
 7480** <tr><td> 6th <td> const char* <td> Name of default collation sequence
 7481** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
 7482** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
 7483** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
 7484** </table>
 7485** </blockquote>)^
 7486**
 7487** ^The memory pointed to by the character pointers returned for the
 7488** declaration type and collation sequence is valid until the next
 7489** call to any SQLite API function.
 7490**
 7491** ^If the specified table is actually a view, an [error code] is returned.
 7492**
 7493** ^If the specified column is "rowid", "oid" or "_rowid_" and the table
 7494** is not a [WITHOUT ROWID] table and an
 7495** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
 7496** parameters are set for the explicitly declared column. ^(If there is no
 7497** [INTEGER PRIMARY KEY] column, then the outputs
 7498** for the [rowid] are set as follows:
 7499**
 7500** <pre>
 7501**     data type: "INTEGER"
 7502**     collation sequence: "BINARY"
 7503**     not null: 0
 7504**     primary key: 1
 7505**     auto increment: 0
 7506** </pre>)^
 7507**
 7508** ^This function causes all database schemas to be read from disk and
 7509** parsed, if that has not already been done, and returns an error if
 7510** any errors are encountered while loading the schema.
 7511*/
 7512SQLITE_API int sqlite3_table_column_metadata(
 7513  sqlite3 *db,                /* Connection handle */
 7514  const char *zDbName,        /* Database name or NULL */
 7515  const char *zTableName,     /* Table name */
 7516  const char *zColumnName,    /* Column name */
 7517  char const **pzDataType,    /* OUTPUT: Declared data type */
 7518  char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
 7519  int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
 7520  int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
 7521  int *pAutoinc               /* OUTPUT: True if column is auto-increment */
 7522);
 7523
 7524/*
 7525** CAPI3REF: Load An Extension
 7526** METHOD: sqlite3
 7527**
 7528** ^This interface loads an SQLite extension library from the named file.
 7529**
 7530** ^The sqlite3_load_extension() interface attempts to load an
 7531** [SQLite extension] library contained in the file zFile.  If
 7532** the file cannot be loaded directly, attempts are made to load
 7533** with various operating-system specific filename extensions added.
 7534** So for example, if "samplelib" cannot be loaded, then names like
 7535** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
 7536** be tried also.
 7537**
 7538** ^The entry point is zProc.
 7539** ^(zProc may be 0, in which case SQLite will try to come up with an
 7540** entry point name on its own.  It first tries "sqlite3_extension_init".
 7541** If that does not work, it tries names of the form "sqlite3_X_init"
 7542** where X consists of the lower-case equivalent of all ASCII alphabetic
 7543** characters or all ASCII alphanumeric characters in the filename from
 7544** the last "/" to the first following "." and omitting any initial "lib".)^
 7545** ^The sqlite3_load_extension() interface returns
 7546** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
 7547** ^If an error occurs and pzErrMsg is not 0, then the
 7548** [sqlite3_load_extension()] interface shall attempt to
 7549** fill *pzErrMsg with error message text stored in memory
 7550** obtained from [sqlite3_malloc()]. The calling function
 7551** should free this memory by calling [sqlite3_free()].
 7552**
 7553** ^Extension loading must be enabled using
 7554** [sqlite3_enable_load_extension()] or
 7555** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL)
 7556** prior to calling this API,
 7557** otherwise an error will be returned.
 7558**
 7559** <b>Security warning:</b> It is recommended that the
 7560** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this
 7561** interface.  The use of the [sqlite3_enable_load_extension()] interface
 7562** should be avoided.  This will keep the SQL function [load_extension()]
 7563** disabled and prevent SQL injections from giving attackers
 7564** access to extension loading capabilities.
 7565**
 7566** See also the [load_extension() SQL function].
 7567*/
 7568SQLITE_API int sqlite3_load_extension(
 7569  sqlite3 *db,          /* Load the extension into this database connection */
 7570  const char *zFile,    /* Name of the shared library containing extension */
 7571  const char *zProc,    /* Entry point.  Derived from zFile if 0 */
 7572  char **pzErrMsg       /* Put error message here if not 0 */
 7573);
 7574
 7575/*
 7576** CAPI3REF: Enable Or Disable Extension Loading
 7577** METHOD: sqlite3
 7578**
 7579** ^So as not to open security holes in older applications that are
 7580** unprepared to deal with [extension loading], and as a means of disabling
 7581** [extension loading] while evaluating user-entered SQL, the following API
 7582** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
 7583**
 7584** ^Extension loading is off by default.
 7585** ^Call the sqlite3_enable_load_extension() routine with onoff==1
 7586** to turn extension loading on and call it with onoff==0 to turn
 7587** it back off again.
 7588**
 7589** ^This interface enables or disables both the C-API
 7590** [sqlite3_load_extension()] and the SQL function [load_extension()].
 7591** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..)
 7592** to enable or disable only the C-API.)^
 7593**
 7594** <b>Security warning:</b> It is recommended that extension loading
 7595** be enabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method
 7596** rather than this interface, so the [load_extension()] SQL function
 7597** remains disabled. This will prevent SQL injections from giving attackers
 7598** access to extension loading capabilities.
 7599*/
 7600SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
 7601
 7602/*
 7603** CAPI3REF: Automatically Load Statically Linked Extensions
 7604**
 7605** ^This interface causes the xEntryPoint() function to be invoked for
 7606** each new [database connection] that is created.  The idea here is that
 7607** xEntryPoint() is the entry point for a statically linked [SQLite extension]
 7608** that is to be automatically loaded into all new database connections.
 7609**
 7610** ^(Even though the function prototype shows that xEntryPoint() takes
 7611** no arguments and returns void, SQLite invokes xEntryPoint() with three
 7612** arguments and expects an integer result as if the signature of the
 7613** entry point were as follows:
 7614**
 7615** <blockquote><pre>
 7616** &nbsp;  int xEntryPoint(
 7617** &nbsp;    sqlite3 *db,
 7618** &nbsp;    char **pzErrMsg,
 7619** &nbsp;    const struct sqlite3_api_routines *pThunk
 7620** &nbsp;  );
 7621** </pre></blockquote>)^
 7622**
 7623** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
 7624** point to an appropriate error message (obtained from [sqlite3_mprintf()])
 7625** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
 7626** is NULL before calling the xEntryPoint().  ^SQLite will invoke
 7627** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
 7628** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
 7629** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
 7630**
 7631** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
 7632** on the list of automatic extensions is a harmless no-op. ^No entry point
 7633** will be called more than once for each database connection that is opened.
 7634**
 7635** See also: [sqlite3_reset_auto_extension()]
 7636** and [sqlite3_cancel_auto_extension()]
 7637*/
 7638SQLITE_API int sqlite3_auto_extension(void(*xEntryPoint)(void));
 7639
 7640/*
 7641** CAPI3REF: Cancel Automatic Extension Loading
 7642**
 7643** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
 7644** initialization routine X that was registered using a prior call to
 7645** [sqlite3_auto_extension(X)].  ^The [sqlite3_cancel_auto_extension(X)]
 7646** routine returns 1 if initialization routine X was successfully
 7647** unregistered and it returns 0 if X was not on the list of initialization
 7648** routines.
 7649*/
 7650SQLITE_API int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
 7651
 7652/*
 7653** CAPI3REF: Reset Automatic Extension Loading
 7654**
 7655** ^This interface disables all automatic extensions previously
 7656** registered using [sqlite3_auto_extension()].
 7657*/
 7658SQLITE_API void sqlite3_reset_auto_extension(void);
 7659
 7660/*
 7661** Structures used by the virtual table interface
 7662*/
 7663typedef struct sqlite3_vtab sqlite3_vtab;
 7664typedef struct sqlite3_index_info sqlite3_index_info;
 7665typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
 7666typedef struct sqlite3_module sqlite3_module;
 7667
 7668/*
 7669** CAPI3REF: Virtual Table Object
 7670** KEYWORDS: sqlite3_module {virtual table module}
 7671**
 7672** This structure, sometimes called a "virtual table module",
 7673** defines the implementation of a [virtual table].
 7674** This structure consists mostly of methods for the module.
 7675**
 7676** ^A virtual table module is created by filling in a persistent
 7677** instance of this structure and passing a pointer to that instance
 7678** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
 7679** ^The registration remains valid until it is replaced by a different
 7680** module or until the [database connection] closes.  The content
 7681** of this structure must not change while it is registered with
 7682** any database connection.
 7683*/
 7684struct sqlite3_module {
 7685  int iVersion;
 7686  int (*xCreate)(sqlite3*, void *pAux,
 7687               int argc, const char *const*argv,
 7688               sqlite3_vtab **ppVTab, char**);
 7689  int (*xConnect)(sqlite3*, void *pAux,
 7690               int argc, const char *const*argv,
 7691               sqlite3_vtab **ppVTab, char**);
 7692  int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
 7693  int (*xDisconnect)(sqlite3_vtab *pVTab);
 7694  int (*xDestroy)(sqlite3_vtab *pVTab);
 7695  int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
 7696  int (*xClose)(sqlite3_vtab_cursor*);
 7697  int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
 7698                int argc, sqlite3_value **argv);
 7699  int (*xNext)(sqlite3_vtab_cursor*);
 7700  int (*xEof)(sqlite3_vtab_cursor*);
 7701  int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
 7702  int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
 7703  int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
 7704  int (*xBegin)(sqlite3_vtab *pVTab);
 7705  int (*xSync)(sqlite3_vtab *pVTab);
 7706  int (*xCommit)(sqlite3_vtab *pVTab);
 7707  int (*xRollback)(sqlite3_vtab *pVTab);
 7708  int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
 7709                       void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
 7710                       void **ppArg);
 7711  int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
 7712  /* The methods above are in version 1 of the sqlite_module object. Those
 7713  ** below are for version 2 and greater. */
 7714  int (*xSavepoint)(sqlite3_vtab *pVTab, int);
 7715  int (*xRelease)(sqlite3_vtab *pVTab, int);
 7716  int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
 7717  /* The methods above are in versions 1 and 2 of the sqlite_module object.
 7718  ** Those below are for version 3 and greater. */
 7719  int (*xShadowName)(const char*);
 7720  /* The methods above are in versions 1 through 3 of the sqlite_module object.
 7721  ** Those below are for version 4 and greater. */
 7722  int (*xIntegrity)(sqlite3_vtab *pVTab, const char *zSchema,
 7723                    const char *zTabName, int mFlags, char **pzErr);
 7724};
 7725
 7726/*
 7727** CAPI3REF: Virtual Table Indexing Information
 7728** KEYWORDS: sqlite3_index_info
 7729**
 7730** The sqlite3_index_info structure and its substructures is used as part
 7731** of the [virtual table] interface to
 7732** pass information into and receive the reply from the [xBestIndex]
 7733** method of a [virtual table module].  The fields under **Inputs** are the
 7734** inputs to xBestIndex and are read-only.  xBestIndex inserts its
 7735** results into the **Outputs** fields.
 7736**
 7737** ^(The aConstraint[] array records WHERE clause constraints of the form:
 7738**
 7739** <blockquote>column OP expr</blockquote>
 7740**
 7741** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^  ^(The particular operator is
 7742** stored in aConstraint[].op using one of the
 7743** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
 7744** ^(The index of the column is stored in
 7745** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
 7746** expr on the right-hand side can be evaluated (and thus the constraint
 7747** is usable) and false if it cannot.)^
 7748**
 7749** ^The optimizer automatically inverts terms of the form "expr OP column"
 7750** and makes other simplifications to the WHERE clause in an attempt to
 7751** get as many WHERE clause terms into the form shown above as possible.
 7752** ^The aConstraint[] array only reports WHERE clause terms that are
 7753** relevant to the particular virtual table being queried.
 7754**
 7755** ^Information about the ORDER BY clause is stored in aOrderBy[].
 7756** ^Each term of aOrderBy records a column of the ORDER BY clause.
 7757**
 7758** The colUsed field indicates which columns of the virtual table may be
 7759** required by the current scan. Virtual table columns are numbered from
 7760** zero in the order in which they appear within the CREATE TABLE statement
 7761** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
 7762** the corresponding bit is set within the colUsed mask if the column may be
 7763** required by SQLite. If the table has at least 64 columns and any column
 7764** to the right of the first 63 is required, then bit 63 of colUsed is also
 7765** set. In other words, column iCol may be required if the expression
 7766** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to
 7767** non-zero.
 7768**
 7769** The [xBestIndex] method must fill aConstraintUsage[] with information
 7770** about what parameters to pass to xFilter.  ^If argvIndex>0 then
 7771** the right-hand side of the corresponding aConstraint[] is evaluated
 7772** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
 7773** is true, then the constraint is assumed to be fully handled by the
 7774** virtual table and might not be checked again by the byte code.)^ ^(The
 7775** aConstraintUsage[].omit flag is an optimization hint. When the omit flag
 7776** is left in its default setting of false, the constraint will always be
 7777** checked separately in byte code.  If the omit flag is changed to true, then
 7778** the constraint may or may not be checked in byte code.  In other words,
 7779** when the omit flag is true there is no guarantee that the constraint will
 7780** not be checked again using byte code.)^
 7781**
 7782** ^The idxNum and idxStr values are recorded and passed into the
 7783** [xFilter] method.
 7784** ^[sqlite3_free()] is used to free idxStr if and only if
 7785** needToFreeIdxStr is true.
 7786**
 7787** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
 7788** the correct order to satisfy the ORDER BY clause so that no separate
 7789** sorting step is required.
 7790**
 7791** ^The estimatedCost value is an estimate of the cost of a particular
 7792** strategy. A cost of N indicates that the cost of the strategy is similar
 7793** to a linear scan of an SQLite table with N rows. A cost of log(N)
 7794** indicates that the expense of the operation is similar to that of a
 7795** binary search on a unique indexed field of an SQLite table with N rows.
 7796**
 7797** ^The estimatedRows value is an estimate of the number of rows that
 7798** will be returned by the strategy.
 7799**
 7800** The xBestIndex method may optionally populate the idxFlags field with a
 7801** mask of SQLITE_INDEX_SCAN_* flags. One such flag is
 7802** [SQLITE_INDEX_SCAN_HEX], which if set causes the [EXPLAIN QUERY PLAN]
 7803** output to show the idxNum as hex instead of as decimal.  Another flag is
 7804** SQLITE_INDEX_SCAN_UNIQUE, which if set indicates that the query plan will
 7805** return at most one row.
 7806**
 7807** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
 7808** SQLite also assumes that if a call to the xUpdate() method is made as
 7809** part of the same statement to delete or update a virtual table row and the
 7810** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
 7811** any database changes. In other words, if the xUpdate() returns
 7812** SQLITE_CONSTRAINT, the database contents must be exactly as they were
 7813** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
 7814** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
 7815** the xUpdate method are automatically rolled back by SQLite.
 7816**
 7817** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
 7818** structure for SQLite [version 3.8.2] ([dateof:3.8.2]).
 7819** If a virtual table extension is
 7820** used with an SQLite version earlier than 3.8.2, the results of attempting
 7821** to read or write the estimatedRows field are undefined (but are likely
 7822** to include crashing the application). The estimatedRows field should
 7823** therefore only be used if [sqlite3_libversion_number()] returns a
 7824** value greater than or equal to 3008002. Similarly, the idxFlags field
 7825** was added for [version 3.9.0] ([dateof:3.9.0]).
 7826** It may therefore only be used if
 7827** sqlite3_libversion_number() returns a value greater than or equal to
 7828** 3009000.
 7829*/
 7830struct sqlite3_index_info {
 7831  /* Inputs */
 7832  int nConstraint;           /* Number of entries in aConstraint */
 7833  struct sqlite3_index_constraint {
 7834     int iColumn;              /* Column constrained.  -1 for ROWID */
 7835     unsigned char op;         /* Constraint operator */
 7836     unsigned char usable;     /* True if this constraint is usable */
 7837     int iTermOffset;          /* Used internally - xBestIndex should ignore */
 7838  } *aConstraint;            /* Table of WHERE clause constraints */
 7839  int nOrderBy;              /* Number of terms in the ORDER BY clause */
 7840  struct sqlite3_index_orderby {
 7841     int iColumn;              /* Column number */
 7842     unsigned char desc;       /* True for DESC.  False for ASC. */
 7843  } *aOrderBy;               /* The ORDER BY clause */
 7844  /* Outputs */
 7845  struct sqlite3_index_constraint_usage {
 7846    int argvIndex;           /* if >0, constraint is part of argv to xFilter */
 7847    unsigned char omit;      /* Do not code a test for this constraint */
 7848  } *aConstraintUsage;
 7849  int idxNum;                /* Number used to identify the index */
 7850  char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
 7851  int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
 7852  int orderByConsumed;       /* True if output is already ordered */
 7853  double estimatedCost;           /* Estimated cost of using this index */
 7854  /* Fields below are only available in SQLite 3.8.2 and later */
 7855  sqlite3_int64 estimatedRows;    /* Estimated number of rows returned */
 7856  /* Fields below are only available in SQLite 3.9.0 and later */
 7857  int idxFlags;              /* Mask of SQLITE_INDEX_SCAN_* flags */
 7858  /* Fields below are only available in SQLite 3.10.0 and later */
 7859  sqlite3_uint64 colUsed;    /* Input: Mask of columns used by statement */
 7860};
 7861
 7862/*
 7863** CAPI3REF: Virtual Table Scan Flags
 7864**
 7865** Virtual table implementations are allowed to set the
 7866** [sqlite3_index_info].idxFlags field to some combination of
 7867** these bits.
 7868*/
 7869#define SQLITE_INDEX_SCAN_UNIQUE 0x00000001 /* Scan visits at most 1 row */
 7870#define SQLITE_INDEX_SCAN_HEX    0x00000002 /* Display idxNum as hex */
 7871                                            /* in EXPLAIN QUERY PLAN */
 7872
 7873/*
 7874** CAPI3REF: Virtual Table Constraint Operator Codes
 7875**
 7876** These macros define the allowed values for the
 7877** [sqlite3_index_info].aConstraint[].op field.  Each value represents
 7878** an operator that is part of a constraint term in the WHERE clause of
 7879** a query that uses a [virtual table].
 7880**
 7881** ^The left-hand operand of the operator is given by the corresponding
 7882** aConstraint[].iColumn field.  ^An iColumn of -1 indicates the left-hand
 7883** operand is the rowid.
 7884** The SQLITE_INDEX_CONSTRAINT_LIMIT and SQLITE_INDEX_CONSTRAINT_OFFSET
 7885** operators have no left-hand operand, and so for those operators the
 7886** corresponding aConstraint[].iColumn is meaningless and should not be
 7887** used.
 7888**
 7889** All operator values from SQLITE_INDEX_CONSTRAINT_FUNCTION through
 7890** value 255 are reserved to represent functions that are overloaded
 7891** by the [xFindFunction|xFindFunction method] of the virtual table
 7892** implementation.
 7893**
 7894** The right-hand operands for each constraint might be accessible using
 7895** the [sqlite3_vtab_rhs_value()] interface.  Usually the right-hand
 7896** operand is only available if it appears as a single constant literal
 7897** in the input SQL.  If the right-hand operand is another column or an
 7898** expression (even a constant expression) or a parameter, then the
 7899** sqlite3_vtab_rhs_value() probably will not be able to extract it.
 7900** ^The SQLITE_INDEX_CONSTRAINT_ISNULL and
 7901** SQLITE_INDEX_CONSTRAINT_ISNOTNULL operators have no right-hand operand
 7902** and hence calls to sqlite3_vtab_rhs_value() for those operators will
 7903** always return SQLITE_NOTFOUND.
 7904**
 7905** The collating sequence to be used for comparison can be found using
 7906** the [sqlite3_vtab_collation()] interface.  For most real-world virtual
 7907** tables, the collating sequence of constraints does not matter (for example
 7908** because the constraints are numeric) and so the sqlite3_vtab_collation()
 7909** interface is not commonly needed.
 7910*/
 7911#define SQLITE_INDEX_CONSTRAINT_EQ          2
 7912#define SQLITE_INDEX_CONSTRAINT_GT          4
 7913#define SQLITE_INDEX_CONSTRAINT_LE          8
 7914#define SQLITE_INDEX_CONSTRAINT_LT         16
 7915#define SQLITE_INDEX_CONSTRAINT_GE         32
 7916#define SQLITE_INDEX_CONSTRAINT_MATCH      64
 7917#define SQLITE_INDEX_CONSTRAINT_LIKE       65
 7918#define SQLITE_INDEX_CONSTRAINT_GLOB       66
 7919#define SQLITE_INDEX_CONSTRAINT_REGEXP     67
 7920#define SQLITE_INDEX_CONSTRAINT_NE         68
 7921#define SQLITE_INDEX_CONSTRAINT_ISNOT      69
 7922#define SQLITE_INDEX_CONSTRAINT_ISNOTNULL  70
 7923#define SQLITE_INDEX_CONSTRAINT_ISNULL     71
 7924#define SQLITE_INDEX_CONSTRAINT_IS         72
 7925#define SQLITE_INDEX_CONSTRAINT_LIMIT      73
 7926#define SQLITE_INDEX_CONSTRAINT_OFFSET     74
 7927#define SQLITE_INDEX_CONSTRAINT_FUNCTION  150
 7928
 7929/*
 7930** CAPI3REF: Register A Virtual Table Implementation
 7931** METHOD: sqlite3
 7932**
 7933** ^These routines are used to register a new [virtual table module] name.
 7934** ^Module names must be registered before
 7935** creating a new [virtual table] using the module and before using a
 7936** preexisting [virtual table] for the module.
 7937**
 7938** ^The module name is registered on the [database connection] specified
 7939** by the first parameter.  ^The name of the module is given by the
 7940** second parameter.  ^The third parameter is a pointer to
 7941** the implementation of the [virtual table module].   ^The fourth
 7942** parameter is an arbitrary client data pointer that is passed through
 7943** into the [xCreate] and [xConnect] methods of the virtual table module
 7944** when a new virtual table is being created or reinitialized.
 7945**
 7946** ^The sqlite3_create_module_v2() interface has a fifth parameter which
 7947** is a pointer to a destructor for the pClientData.  ^SQLite will
 7948** invoke the destructor function (if it is not NULL) when SQLite
 7949** no longer needs the pClientData pointer.  ^The destructor will also
 7950** be invoked if the call to sqlite3_create_module_v2() fails.
 7951** ^The sqlite3_create_module()
 7952** interface is equivalent to sqlite3_create_module_v2() with a NULL
 7953** destructor.
 7954**
 7955** ^If the third parameter (the pointer to the sqlite3_module object) is
 7956** NULL then no new module is created and any existing modules with the
 7957** same name are dropped.
 7958**
 7959** See also: [sqlite3_drop_modules()]
 7960*/
 7961SQLITE_API int sqlite3_create_module(
 7962  sqlite3 *db,               /* SQLite connection to register module with */
 7963  const char *zName,         /* Name of the module */
 7964  const sqlite3_module *p,   /* Methods for the module */
 7965  void *pClientData          /* Client data for xCreate/xConnect */
 7966);
 7967SQLITE_API int sqlite3_create_module_v2(
 7968  sqlite3 *db,               /* SQLite connection to register module with */
 7969  const char *zName,         /* Name of the module */
 7970  const sqlite3_module *p,   /* Methods for the module */
 7971  void *pClientData,         /* Client data for xCreate/xConnect */
 7972  void(*xDestroy)(void*)     /* Module destructor function */
 7973);
 7974
 7975/*
 7976** CAPI3REF: Remove Unnecessary Virtual Table Implementations
 7977** METHOD: sqlite3
 7978**
 7979** ^The sqlite3_drop_modules(D,L) interface removes all virtual
 7980** table modules from database connection D except those named on list L.
 7981** The L parameter must be either NULL or a pointer to an array of pointers
 7982** to strings where the array is terminated by a single NULL pointer.
 7983** ^If the L parameter is NULL, then all virtual table modules are removed.
 7984**
 7985** See also: [sqlite3_create_module()]
 7986*/
 7987SQLITE_API int sqlite3_drop_modules(
 7988  sqlite3 *db,                /* Remove modules from this connection */
 7989  const char **azKeep         /* Except, do not remove the ones named here */
 7990);
 7991
 7992/*
 7993** CAPI3REF: Virtual Table Instance Object
 7994** KEYWORDS: sqlite3_vtab
 7995**
 7996** Every [virtual table module] implementation uses a subclass
 7997** of this object to describe a particular instance
 7998** of the [virtual table].  Each subclass will
 7999** be tailored to the specific needs of the module implementation.
 8000** The purpose of this superclass is to define certain fields that are
 8001** common to all module implementations.
 8002**
 8003** ^Virtual tables methods can set an error message by assigning a
 8004** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
 8005** take care that any prior string is freed by a call to [sqlite3_free()]
 8006** prior to assigning a new string to zErrMsg.  ^After the error message
 8007** is delivered up to the client application, the string will be automatically
 8008** freed by sqlite3_free() and the zErrMsg field will be zeroed.
 8009*/
 8010struct sqlite3_vtab {
 8011  const sqlite3_module *pModule;  /* The module for this virtual table */
 8012  int nRef;                       /* Number of open cursors */
 8013  char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
 8014  /* Virtual table implementations will typically add additional fields */
 8015};
 8016
 8017/*
 8018** CAPI3REF: Virtual Table Cursor Object
 8019** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
 8020**
 8021** Every [virtual table module] implementation uses a subclass of the
 8022** following structure to describe cursors that point into the
 8023** [virtual table] and are used
 8024** to loop through the virtual table.  Cursors are created using the
 8025** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
 8026** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
 8027** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
 8028** of the module.  Each module implementation will define
 8029** the content of a cursor structure to suit its own needs.
 8030**
 8031** This superclass exists in order to define fields of the cursor that
 8032** are common to all implementations.
 8033*/
 8034struct sqlite3_vtab_cursor {
 8035  sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
 8036  /* Virtual table implementations will typically add additional fields */
 8037};
 8038
 8039/*
 8040** CAPI3REF: Declare The Schema Of A Virtual Table
 8041**
 8042** ^The [xCreate] and [xConnect] methods of a
 8043** [virtual table module] call this interface
 8044** to declare the format (the names and datatypes of the columns) of
 8045** the virtual tables they implement.
 8046*/
 8047SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
 8048
 8049/*
 8050** CAPI3REF: Overload A Function For A Virtual Table
 8051** METHOD: sqlite3
 8052**
 8053** ^(Virtual tables can provide alternative implementations of functions
 8054** using the [xFindFunction] method of the [virtual table module].
 8055** But global versions of those functions
 8056** must exist in order to be overloaded.)^
 8057**
 8058** ^(This API makes sure a global version of a function with a particular
 8059** name and number of parameters exists.  If no such function exists
 8060** before this API is called, a new function is created.)^  ^The implementation
 8061** of the new function always causes an exception to be thrown.  So
 8062** the new function is not good for anything by itself.  Its only
 8063** purpose is to be a placeholder function that can be overloaded
 8064** by a [virtual table].
 8065*/
 8066SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
 8067
 8068/*
 8069** CAPI3REF: A Handle To An Open BLOB
 8070** KEYWORDS: {BLOB handle} {BLOB handles}
 8071**
 8072** An instance of this object represents an open BLOB on which
 8073** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
 8074** ^Objects of this type are created by [sqlite3_blob_open()]
 8075** and destroyed by [sqlite3_blob_close()].
 8076** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
 8077** can be used to read or write small subsections of the BLOB.
 8078** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
 8079*/
 8080typedef struct sqlite3_blob sqlite3_blob;
 8081
 8082/*
 8083** CAPI3REF: Open A BLOB For Incremental I/O
 8084** METHOD: sqlite3
 8085** CONSTRUCTOR: sqlite3_blob
 8086**
 8087** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
 8088** in row iRow, column zColumn, table zTable in database zDb;
 8089** in other words, the same BLOB that would be selected by:
 8090**
 8091** <pre>
 8092**     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
 8093** </pre>)^
 8094**
 8095** ^(Parameter zDb is not the filename that contains the database, but
 8096** rather the symbolic name of the database. For attached databases, this is
 8097** the name that appears after the AS keyword in the [ATTACH] statement.
 8098** For the main database file, the database name is "main". For TEMP
 8099** tables, the database name is "temp".)^
 8100**
 8101** ^If the flags parameter is non-zero, then the BLOB is opened for read
 8102** and write access. ^If the flags parameter is zero, the BLOB is opened for
 8103** read-only access.
 8104**
 8105** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
 8106** in *ppBlob. Otherwise an [error code] is returned and, unless the error
 8107** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
 8108** the API is not misused, it is always safe to call [sqlite3_blob_close()]
 8109** on *ppBlob after this function returns.
 8110**
 8111** This function fails with SQLITE_ERROR if any of the following are true:
 8112** <ul>
 8113**   <li> ^(Database zDb does not exist)^,
 8114**   <li> ^(Table zTable does not exist within database zDb)^,
 8115**   <li> ^(Table zTable is a WITHOUT ROWID table)^,
 8116**   <li> ^(Column zColumn does not exist)^,
 8117**   <li> ^(Row iRow is not present in the table)^,
 8118**   <li> ^(The specified column of row iRow contains a value that is not
 8119**         a TEXT or BLOB value)^,
 8120**   <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE
 8121**         constraint and the blob is being opened for read/write access)^,
 8122**   <li> ^([foreign key constraints | Foreign key constraints] are enabled,
 8123**         column zColumn is part of a [child key] definition and the blob is
 8124**         being opened for read/write access)^.
 8125** </ul>
 8126**
 8127** ^Unless it returns SQLITE_MISUSE, this function sets the
 8128** [database connection] error code and message accessible via
 8129** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
 8130**
 8131** A BLOB referenced by sqlite3_blob_open() may be read using the
 8132** [sqlite3_blob_read()] interface and modified by using
 8133** [sqlite3_blob_write()].  The [BLOB handle] can be moved to a
 8134** different row of the same table using the [sqlite3_blob_reopen()]
 8135** interface.  However, the column, table, or database of a [BLOB handle]
 8136** cannot be changed after the [BLOB handle] is opened.
 8137**
 8138** ^(If the row that a BLOB handle points to is modified by an
 8139** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
 8140** then the BLOB handle is marked as "expired".
 8141** This is true if any column of the row is changed, even a column
 8142** other than the one the BLOB handle is open on.)^
 8143** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
 8144** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
 8145** ^(Changes written into a BLOB prior to the BLOB expiring are not
 8146** rolled back by the expiration of the BLOB.  Such changes will eventually
 8147** commit if the transaction continues to completion.)^
 8148**
 8149** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
 8150** the opened blob.  ^The size of a blob may not be changed by this
 8151** interface.  Use the [UPDATE] SQL command to change the size of a
 8152** blob.
 8153**
 8154** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
 8155** and the built-in [zeroblob] SQL function may be used to create a
 8156** zero-filled blob to read or write using the incremental-blob interface.
 8157**
 8158** To avoid a resource leak, every open [BLOB handle] should eventually
 8159** be released by a call to [sqlite3_blob_close()].
 8160**
 8161** See also: [sqlite3_blob_close()],
 8162** [sqlite3_blob_reopen()], [sqlite3_blob_read()],
 8163** [sqlite3_blob_bytes()], [sqlite3_blob_write()].
 8164*/
 8165SQLITE_API int sqlite3_blob_open(
 8166  sqlite3*,
 8167  const char *zDb,
 8168  const char *zTable,
 8169  const char *zColumn,
 8170  sqlite3_int64 iRow,
 8171  int flags,
 8172  sqlite3_blob **ppBlob
 8173);
 8174
 8175/*
 8176** CAPI3REF: Move a BLOB Handle to a New Row
 8177** METHOD: sqlite3_blob
 8178**
 8179** ^This function is used to move an existing [BLOB handle] so that it points
 8180** to a different row of the same database table. ^The new row is identified
 8181** by the rowid value passed as the second argument. Only the row can be
 8182** changed. ^The database, table and column on which the blob handle is open
 8183** remain the same. Moving an existing [BLOB handle] to a new row is
 8184** faster than closing the existing handle and opening a new one.
 8185**
 8186** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
 8187** it must exist and there must be either a blob or text value stored in
 8188** the nominated column.)^ ^If the new row is not present in the table, or if
 8189** it does not contain a blob or text value, or if another error occurs, an
 8190** SQLite error code is returned and the blob handle is considered aborted.
 8191** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
 8192** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
 8193** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
 8194** always returns zero.
 8195**
 8196** ^This function sets the database handle error code and message.
 8197*/
 8198SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
 8199
 8200/*
 8201** CAPI3REF: Close A BLOB Handle
 8202** DESTRUCTOR: sqlite3_blob
 8203**
 8204** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
 8205** unconditionally.  Even if this routine returns an error code, the
 8206** handle is still closed.)^
 8207**
 8208** ^If the blob handle being closed was opened for read-write access, and if
 8209** the database is in auto-commit mode and there are no other open read-write
 8210** blob handles or active write statements, the current transaction is
 8211** committed. ^If an error occurs while committing the transaction, an error
 8212** code is returned and the transaction rolled back.
 8213**
 8214** Calling this function with an argument that is not a NULL pointer or an
 8215** open blob handle results in undefined behavior. ^Calling this routine
 8216** with a null pointer (such as would be returned by a failed call to
 8217** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
 8218** is passed a valid open blob handle, the values returned by the
 8219** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
 8220*/
 8221SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
 8222
 8223/*
 8224** CAPI3REF: Return The Size Of An Open BLOB
 8225** METHOD: sqlite3_blob
 8226**
 8227** ^Returns the size in bytes of the BLOB accessible via the
 8228** successfully opened [BLOB handle] in its only argument.  ^The
 8229** incremental blob I/O routines can only read or overwrite existing
 8230** blob content; they cannot change the size of a blob.
 8231**
 8232** This routine only works on a [BLOB handle] which has been created
 8233** by a prior successful call to [sqlite3_blob_open()] and which has not
 8234** been closed by [sqlite3_blob_close()].  Passing any other pointer in
 8235** to this routine results in undefined and probably undesirable behavior.
 8236*/
 8237SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
 8238
 8239/*
 8240** CAPI3REF: Read Data From A BLOB Incrementally
 8241** METHOD: sqlite3_blob
 8242**
 8243** ^(This function is used to read data from an open [BLOB handle] into a
 8244** caller-supplied buffer. N bytes of data are copied into buffer Z
 8245** from the open BLOB, starting at offset iOffset.)^
 8246**
 8247** ^If offset iOffset is less than N bytes from the end of the BLOB,
 8248** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
 8249** less than zero, [SQLITE_ERROR] is returned and no data is read.
 8250** ^The size of the blob (and hence the maximum value of N+iOffset)
 8251** can be determined using the [sqlite3_blob_bytes()] interface.
 8252**
 8253** ^An attempt to read from an expired [BLOB handle] fails with an
 8254** error code of [SQLITE_ABORT].
 8255**
 8256** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
 8257** Otherwise, an [error code] or an [extended error code] is returned.)^
 8258**
 8259** This routine only works on a [BLOB handle] which has been created
 8260** by a prior successful call to [sqlite3_blob_open()] and which has not
 8261** been closed by [sqlite3_blob_close()].  Passing any other pointer in
 8262** to this routine results in undefined and probably undesirable behavior.
 8263**
 8264** See also: [sqlite3_blob_write()].
 8265*/
 8266SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
 8267
 8268/*
 8269** CAPI3REF: Write Data Into A BLOB Incrementally
 8270** METHOD: sqlite3_blob
 8271**
 8272** ^(This function is used to write data into an open [BLOB handle] from a
 8273** caller-supplied buffer. N bytes of data are copied from the buffer Z
 8274** into the open BLOB, starting at offset iOffset.)^
 8275**
 8276** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
 8277** Otherwise, an  [error code] or an [extended error code] is returned.)^
 8278** ^Unless SQLITE_MISUSE is returned, this function sets the
 8279** [database connection] error code and message accessible via
 8280** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions.
 8281**
 8282** ^If the [BLOB handle] passed as the first argument was not opened for
 8283** writing (the flags parameter to [sqlite3_blob_open()] was zero),
 8284** this function returns [SQLITE_READONLY].
 8285**
 8286** This function may only modify the contents of the BLOB; it is
 8287** not possible to increase the size of a BLOB using this API.
 8288** ^If offset iOffset is less than N bytes from the end of the BLOB,
 8289** [SQLITE_ERROR] is returned and no data is written. The size of the
 8290** BLOB (and hence the maximum value of N+iOffset) can be determined
 8291** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less
 8292** than zero [SQLITE_ERROR] is returned and no data is written.
 8293**
 8294** ^An attempt to write to an expired [BLOB handle] fails with an
 8295** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
 8296** before the [BLOB handle] expired are not rolled back by the
 8297** expiration of the handle, though of course those changes might
 8298** have been overwritten by the statement that expired the BLOB handle
 8299** or by other independent statements.
 8300**
 8301** This routine only works on a [BLOB handle] which has been created
 8302** by a prior successful call to [sqlite3_blob_open()] and which has not
 8303** been closed by [sqlite3_blob_close()].  Passing any other pointer in
 8304** to this routine results in undefined and probably undesirable behavior.
 8305**
 8306** See also: [sqlite3_blob_read()].
 8307*/
 8308SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
 8309
 8310/*
 8311** CAPI3REF: Virtual File System Objects
 8312**
 8313** A virtual filesystem (VFS) is an [sqlite3_vfs] object
 8314** that SQLite uses to interact
 8315** with the underlying operating system.  Most SQLite builds come with a
 8316** single default VFS that is appropriate for the host computer.
 8317** New VFSes can be registered and existing VFSes can be unregistered.
 8318** The following interfaces are provided.
 8319**
 8320** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
 8321** ^Names are case sensitive.
 8322** ^Names are zero-terminated UTF-8 strings.
 8323** ^If there is no match, a NULL pointer is returned.
 8324** ^If zVfsName is NULL then the default VFS is returned.
 8325**
 8326** ^New VFSes are registered with sqlite3_vfs_register().
 8327** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
 8328** ^The same VFS can be registered multiple times without injury.
 8329** ^To make an existing VFS into the default VFS, register it again
 8330** with the makeDflt flag set.  If two different VFSes with the
 8331** same name are registered, the behavior is undefined.  If a
 8332** VFS is registered with a name that is NULL or an empty string,
 8333** then the behavior is undefined.
 8334**
 8335** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
 8336** ^(If the default VFS is unregistered, another VFS is chosen as
 8337** the default.  The choice for the new VFS is arbitrary.)^
 8338*/
 8339SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
 8340SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
 8341SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
 8342
 8343/*
 8344** CAPI3REF: Mutexes
 8345**
 8346** The SQLite core uses these routines for thread
 8347** synchronization. Though they are intended for internal
 8348** use by SQLite, code that links against SQLite is
 8349** permitted to use any of these routines.
 8350**
 8351** The SQLite source code contains multiple implementations
 8352** of these mutex routines.  An appropriate implementation
 8353** is selected automatically at compile-time.  The following
 8354** implementations are available in the SQLite core:
 8355**
 8356** <ul>
 8357** <li>   SQLITE_MUTEX_PTHREADS
 8358** <li>   SQLITE_MUTEX_W32
 8359** <li>   SQLITE_MUTEX_NOOP
 8360** </ul>
 8361**
 8362** The SQLITE_MUTEX_NOOP implementation is a set of routines
 8363** that does no real locking and is appropriate for use in
 8364** a single-threaded application.  The SQLITE_MUTEX_PTHREADS and
 8365** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
 8366** and Windows.
 8367**
 8368**
 8369** ^The sqlite3_mutex_alloc() routine allocates a new
 8370** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
 8371** routine returns NULL if it is unable to allocate the requested
 8372** mutex.  The argument to sqlite3_mutex_alloc() must be one of these
 8373** integer constants:
 8374**
 8375** <ul>
 8376** <li>  SQLITE_MUTEX_FAST
 8377** <li>  SQLITE_MUTEX_RECURSIVE
 8378** <li>  SQLITE_MUTEX_STATIC_MAIN
 8379** <li>  SQLITE_MUTEX_STATIC_MEM
 8380** <li>  SQLITE_MUTEX_STATIC_OPEN
 8381** <li>  SQLITE_MUTEX_STATIC_PRNG
 8382** <li>  SQLITE_MUTEX_STATIC_LRU
 8383** <li>  SQLITE_MUTEX_STATIC_PMEM
 8384** <li>  SQLITE_MUTEX_STATIC_APP1
 8385** <li>  SQLITE_MUTEX_STATIC_APP2
 8386** <li>  SQLITE_MUTEX_STATIC_APP3
 8387** <li>  SQLITE_MUTEX_STATIC_VFS1
 8388** <li>  SQLITE_MUTEX_STATIC_VFS2
 8389** <li>  SQLITE_MUTEX_STATIC_VFS3
 8390** </ul>
 8391**
 8392** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
 8393** cause sqlite3_mutex_alloc() to create
 8394** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
 8395** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
 8396** The mutex implementation does not need to make a distinction
 8397** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
 8398** not want to.  SQLite will only request a recursive mutex in
 8399** cases where it really needs one.  If a faster non-recursive mutex
 8400** implementation is available on the host platform, the mutex subsystem
 8401** might return such a mutex in response to SQLITE_MUTEX_FAST.
 8402**
 8403** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
 8404** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
 8405** a pointer to a static preexisting mutex.  ^Nine static mutexes are
 8406** used by the current version of SQLite.  Future versions of SQLite
 8407** may add additional static mutexes.  Static mutexes are for internal
 8408** use by SQLite only.  Applications that use SQLite mutexes should
 8409** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
 8410** SQLITE_MUTEX_RECURSIVE.
 8411**
 8412** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
 8413** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
 8414** returns a different mutex on every call.  ^For the static
 8415** mutex types, the same mutex is returned on every call that has
 8416** the same type number.
 8417**
 8418** ^The sqlite3_mutex_free() routine deallocates a previously
 8419** allocated dynamic mutex.  Attempting to deallocate a static
 8420** mutex results in undefined behavior.
 8421**
 8422** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
 8423** to enter a mutex.  ^If another thread is already within the mutex,
 8424** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
 8425** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
 8426** upon successful entry.  ^(Mutexes created using
 8427** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
 8428** In such cases, the
 8429** mutex must be exited an equal number of times before another thread
 8430** can enter.)^  If the same thread tries to enter any mutex other
 8431** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
 8432**
 8433** ^(Some systems (for example, Windows 95) do not support the operation
 8434** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
 8435** will always return SQLITE_BUSY. In most cases the SQLite core only uses
 8436** sqlite3_mutex_try() as an optimization, so this is acceptable
 8437** behavior. The exceptions are unix builds that set the
 8438** SQLITE_ENABLE_SETLK_TIMEOUT build option. In that case a working
 8439** sqlite3_mutex_try() is required.)^
 8440**
 8441** ^The sqlite3_mutex_leave() routine exits a mutex that was
 8442** previously entered by the same thread.   The behavior
 8443** is undefined if the mutex is not currently entered by the
 8444** calling thread or is not currently allocated.
 8445**
 8446** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(),
 8447** sqlite3_mutex_leave(), or sqlite3_mutex_free() is a NULL pointer,
 8448** then any of the four routines behaves as a no-op.
 8449**
 8450** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
 8451*/
 8452SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
 8453SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
 8454SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
 8455SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
 8456SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
 8457
 8458/*
 8459** CAPI3REF: Mutex Methods Object
 8460**
 8461** An instance of this structure defines the low-level routines
 8462** used to allocate and use mutexes.
 8463**
 8464** Usually, the default mutex implementations provided by SQLite are
 8465** sufficient, however the application has the option of substituting a custom
 8466** implementation for specialized deployments or systems for which SQLite
 8467** does not provide a suitable implementation. In this case, the application
 8468** creates and populates an instance of this structure to pass
 8469** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
 8470** Additionally, an instance of this structure can be used as an
 8471** output variable when querying the system for the current mutex
 8472** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
 8473**
 8474** ^The xMutexInit method defined by this structure is invoked as
 8475** part of system initialization by the sqlite3_initialize() function.
 8476** ^The xMutexInit routine is called by SQLite exactly once for each
 8477** effective call to [sqlite3_initialize()].
 8478**
 8479** ^The xMutexEnd method defined by this structure is invoked as
 8480** part of system shutdown by the sqlite3_shutdown() function. The
 8481** implementation of this method is expected to release all outstanding
 8482** resources obtained by the mutex methods implementation, especially
 8483** those obtained by the xMutexInit method.  ^The xMutexEnd()
 8484** interface is invoked exactly once for each call to [sqlite3_shutdown()].
 8485**
 8486** ^(The remaining seven methods defined by this structure (xMutexAlloc,
 8487** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
 8488** xMutexNotheld) implement the following interfaces (respectively):
 8489**
 8490** <ul>
 8491**   <li>  [sqlite3_mutex_alloc()] </li>
 8492**   <li>  [sqlite3_mutex_free()] </li>
 8493**   <li>  [sqlite3_mutex_enter()] </li>
 8494**   <li>  [sqlite3_mutex_try()] </li>
 8495**   <li>  [sqlite3_mutex_leave()] </li>
 8496**   <li>  [sqlite3_mutex_held()] </li>
 8497**   <li>  [sqlite3_mutex_notheld()] </li>
 8498** </ul>)^
 8499**
 8500** The only difference is that the public sqlite3_XXX functions enumerated
 8501** above silently ignore any invocations that pass a NULL pointer instead
 8502** of a valid mutex handle. The implementations of the methods defined
 8503** by this structure are not required to handle this case. The results
 8504** of passing a NULL pointer instead of a valid mutex handle are undefined
 8505** (i.e. it is acceptable to provide an implementation that segfaults if
 8506** it is passed a NULL pointer).
 8507**
 8508** The xMutexInit() method must be threadsafe.  It must be harmless to
 8509** invoke xMutexInit() multiple times within the same process and without
 8510** intervening calls to xMutexEnd().  Second and subsequent calls to
 8511** xMutexInit() must be no-ops.
 8512**
 8513** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
 8514** and its associates).  Similarly, xMutexAlloc() must not use SQLite memory
 8515** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
 8516** memory allocation for a fast or recursive mutex.
 8517**
 8518** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
 8519** called, but only if the prior call to xMutexInit returned SQLITE_OK.
 8520** If xMutexInit fails in any way, it is expected to clean up after itself
 8521** prior to returning.
 8522*/
 8523typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
 8524struct sqlite3_mutex_methods {
 8525  int (*xMutexInit)(void);
 8526  int (*xMutexEnd)(void);
 8527  sqlite3_mutex *(*xMutexAlloc)(int);
 8528  void (*xMutexFree)(sqlite3_mutex *);
 8529  void (*xMutexEnter)(sqlite3_mutex *);
 8530  int (*xMutexTry)(sqlite3_mutex *);
 8531  void (*xMutexLeave)(sqlite3_mutex *);
 8532  int (*xMutexHeld)(sqlite3_mutex *);
 8533  int (*xMutexNotheld)(sqlite3_mutex *);
 8534};
 8535
 8536/*
 8537** CAPI3REF: Mutex Verification Routines
 8538**
 8539** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
 8540** are intended for use inside assert() statements.  The SQLite core
 8541** never uses these routines except inside an assert() and applications
 8542** are advised to follow the lead of the core.  The SQLite core only
 8543** provides implementations for these routines when it is compiled
 8544** with the SQLITE_DEBUG flag.  External mutex implementations
 8545** are only required to provide these routines if SQLITE_DEBUG is
 8546** defined and if NDEBUG is not defined.
 8547**
 8548** These routines should return true if the mutex in their argument
 8549** is held or not held, respectively, by the calling thread.
 8550**
 8551** The implementation is not required to provide versions of these
 8552** routines that actually work. If the implementation does not provide working
 8553** versions of these routines, it should at least provide stubs that always
 8554** return true so that one does not get spurious assertion failures.
 8555**
 8556** If the argument to sqlite3_mutex_held() is a NULL pointer then
 8557** the routine should return 1.   This seems counter-intuitive since
 8558** clearly the mutex cannot be held if it does not exist.  But
 8559** the reason the mutex does not exist is because the build is not
 8560** using mutexes.  And we do not want the assert() containing the
 8561** call to sqlite3_mutex_held() to fail, so a non-zero return is
 8562** the appropriate thing to do.  The sqlite3_mutex_notheld()
 8563** interface should also return 1 when given a NULL pointer.
 8564*/
 8565#ifndef NDEBUG
 8566SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
 8567SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
 8568#endif
 8569
 8570/*
 8571** CAPI3REF: Mutex Types
 8572**
 8573** The [sqlite3_mutex_alloc()] interface takes a single argument
 8574** which is one of these integer constants.
 8575**
 8576** The set of static mutexes may change from one SQLite release to the
 8577** next.  Applications that override the built-in mutex logic must be
 8578** prepared to accommodate additional static mutexes.
 8579*/
 8580#define SQLITE_MUTEX_FAST             0
 8581#define SQLITE_MUTEX_RECURSIVE        1
 8582#define SQLITE_MUTEX_STATIC_MAIN      2
 8583#define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
 8584#define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
 8585#define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
 8586#define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_randomness() */
 8587#define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
 8588#define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
 8589#define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
 8590#define SQLITE_MUTEX_STATIC_APP1      8  /* For use by application */
 8591#define SQLITE_MUTEX_STATIC_APP2      9  /* For use by application */
 8592#define SQLITE_MUTEX_STATIC_APP3     10  /* For use by application */
 8593#define SQLITE_MUTEX_STATIC_VFS1     11  /* For use by built-in VFS */
 8594#define SQLITE_MUTEX_STATIC_VFS2     12  /* For use by extension VFS */
 8595#define SQLITE_MUTEX_STATIC_VFS3     13  /* For use by application VFS */
 8596
 8597/* Legacy compatibility: */
 8598#define SQLITE_MUTEX_STATIC_MASTER    2
 8599
 8600
 8601/*
 8602** CAPI3REF: Retrieve the mutex for a database connection
 8603** METHOD: sqlite3
 8604**
 8605** ^This interface returns a pointer to the [sqlite3_mutex] object that
 8606** serializes access to the [database connection] given in the argument
 8607** when the [threading mode] is Serialized.
 8608** ^If the [threading mode] is Single-thread or Multi-thread then this
 8609** routine returns a NULL pointer.
 8610*/
 8611SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
 8612
 8613/*
 8614** CAPI3REF: Low-Level Control Of Database Files
 8615** METHOD: sqlite3
 8616** KEYWORDS: {file control}
 8617**
 8618** ^The [sqlite3_file_control()] interface makes a direct call to the
 8619** xFileControl method for the [sqlite3_io_methods] object associated
 8620** with a particular database identified by the second argument. ^The
 8621** name of the database is "main" for the main database or "temp" for the
 8622** TEMP database, or the name that appears after the AS keyword for
 8623** databases that are added using the [ATTACH] SQL command.
 8624** ^A NULL pointer can be used in place of "main" to refer to the
 8625** main database file.
 8626** ^The third and fourth parameters to this routine
 8627** are passed directly through to the second and third parameters of
 8628** the xFileControl method.  ^The return value of the xFileControl
 8629** method becomes the return value of this routine.
 8630**
 8631** A few opcodes for [sqlite3_file_control()] are handled directly
 8632** by the SQLite core and never invoke the
 8633** sqlite3_io_methods.xFileControl method.
 8634** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes
 8635** a pointer to the underlying [sqlite3_file] object to be written into
 8636** the space pointed to by the 4th parameter.  The
 8637** [SQLITE_FCNTL_JOURNAL_POINTER] works similarly except that it returns
 8638** the [sqlite3_file] object associated with the journal file instead of
 8639** the main database.  The [SQLITE_FCNTL_VFS_POINTER] opcode returns
 8640** a pointer to the underlying [sqlite3_vfs] object for the file.
 8641** The [SQLITE_FCNTL_DATA_VERSION] returns the data version counter
 8642** from the pager.
 8643**
 8644** ^If the second parameter (zDbName) does not match the name of any
 8645** open database file, then SQLITE_ERROR is returned.  ^This error
 8646** code is not remembered and will not be recalled by [sqlite3_errcode()]
 8647** or [sqlite3_errmsg()].  The underlying xFileControl method might
 8648** also return SQLITE_ERROR.  There is no way to distinguish between
 8649** an incorrect zDbName and an SQLITE_ERROR return from the underlying
 8650** xFileControl method.
 8651**
 8652** See also: [file control opcodes]
 8653*/
 8654SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
 8655
 8656/*
 8657** CAPI3REF: Testing Interface
 8658**
 8659** ^The sqlite3_test_control() interface is used to read out internal
 8660** state of SQLite and to inject faults into SQLite for testing
 8661** purposes.  ^The first parameter is an operation code that determines
 8662** the number, meaning, and operation of all subsequent parameters.
 8663**
 8664** This interface is not for use by applications.  It exists solely
 8665** for verifying the correct operation of the SQLite library.  Depending
 8666** on how the SQLite library is compiled, this interface might not exist.
 8667**
 8668** The details of the operation codes, their meanings, the parameters
 8669** they take, and what they do are all subject to change without notice.
 8670** Unlike most of the SQLite API, this function is not guaranteed to
 8671** operate consistently from one release to the next.
 8672*/
 8673SQLITE_API int sqlite3_test_control(int op, ...);
 8674
 8675/*
 8676** CAPI3REF: Testing Interface Operation Codes
 8677**
 8678** These constants are the valid operation code parameters used
 8679** as the first argument to [sqlite3_test_control()].
 8680**
 8681** These parameters and their meanings are subject to change
 8682** without notice.  These values are for testing purposes only.
 8683** Applications should not use any of these parameters or the
 8684** [sqlite3_test_control()] interface.
 8685*/
 8686#define SQLITE_TESTCTRL_FIRST                    5
 8687#define SQLITE_TESTCTRL_PRNG_SAVE                5
 8688#define SQLITE_TESTCTRL_PRNG_RESTORE             6
 8689#define SQLITE_TESTCTRL_PRNG_RESET               7  /* NOT USED */
 8690#define SQLITE_TESTCTRL_FK_NO_ACTION             7
 8691#define SQLITE_TESTCTRL_BITVEC_TEST              8
 8692#define SQLITE_TESTCTRL_FAULT_INSTALL            9
 8693#define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
 8694#define SQLITE_TESTCTRL_PENDING_BYTE            11
 8695#define SQLITE_TESTCTRL_ASSERT                  12
 8696#define SQLITE_TESTCTRL_ALWAYS                  13
 8697#define SQLITE_TESTCTRL_RESERVE                 14  /* NOT USED */
 8698#define SQLITE_TESTCTRL_JSON_SELFCHECK          14
 8699#define SQLITE_TESTCTRL_OPTIMIZATIONS           15
 8700#define SQLITE_TESTCTRL_ISKEYWORD               16  /* NOT USED */
 8701#define SQLITE_TESTCTRL_GETOPT                  16
 8702#define SQLITE_TESTCTRL_SCRATCHMALLOC           17  /* NOT USED */
 8703#define SQLITE_TESTCTRL_INTERNAL_FUNCTIONS      17
 8704#define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
 8705#define SQLITE_TESTCTRL_EXPLAIN_STMT            19  /* NOT USED */
 8706#define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD    19
 8707#define SQLITE_TESTCTRL_NEVER_CORRUPT           20
 8708#define SQLITE_TESTCTRL_VDBE_COVERAGE           21
 8709#define SQLITE_TESTCTRL_BYTEORDER               22
 8710#define SQLITE_TESTCTRL_ISINIT                  23
 8711#define SQLITE_TESTCTRL_SORTER_MMAP             24
 8712#define SQLITE_TESTCTRL_IMPOSTER                25
 8713#define SQLITE_TESTCTRL_PARSER_COVERAGE         26
 8714#define SQLITE_TESTCTRL_RESULT_INTREAL          27
 8715#define SQLITE_TESTCTRL_PRNG_SEED               28
 8716#define SQLITE_TESTCTRL_EXTRA_SCHEMA_CHECKS     29
 8717#define SQLITE_TESTCTRL_SEEK_COUNT              30
 8718#define SQLITE_TESTCTRL_TRACEFLAGS              31
 8719#define SQLITE_TESTCTRL_TUNE                    32
 8720#define SQLITE_TESTCTRL_LOGEST                  33
 8721#define SQLITE_TESTCTRL_USELONGDOUBLE           34  /* NOT USED */
 8722#define SQLITE_TESTCTRL_ATOF                    34
 8723#define SQLITE_TESTCTRL_LAST                    34  /* Largest TESTCTRL */
 8724
 8725/*
 8726** CAPI3REF: SQL Keyword Checking
 8727**
 8728** These routines provide access to the set of SQL language keywords
 8729** recognized by SQLite.  Applications can use these routines to determine
 8730** whether or not a specific identifier needs to be escaped (for example,
 8731** by enclosing in double-quotes) so as not to confuse the parser.
 8732**
 8733** The sqlite3_keyword_count() interface returns the number of distinct
 8734** keywords understood by SQLite.
 8735**
 8736** The sqlite3_keyword_name(N,Z,L) interface finds the 0-based N-th keyword and
 8737** makes *Z point to that keyword expressed as UTF8 and writes the number
 8738** of bytes in the keyword into *L.  The string that *Z points to is not
 8739** zero-terminated.  The sqlite3_keyword_name(N,Z,L) routine returns
 8740** SQLITE_OK if N is within bounds and SQLITE_ERROR if not. If either Z
 8741** or L are NULL or invalid pointers then calls to
 8742** sqlite3_keyword_name(N,Z,L) result in undefined behavior.
 8743**
 8744** The sqlite3_keyword_check(Z,L) interface checks to see whether or not
 8745** the L-byte UTF8 identifier that Z points to is a keyword, returning non-zero
 8746** if it is and zero if not.
 8747**
 8748** The parser used by SQLite is forgiving.  It is often possible to use
 8749** a keyword as an identifier as long as such use does not result in a
 8750** parsing ambiguity.  For example, the statement
 8751** "CREATE TABLE BEGIN(REPLACE,PRAGMA,END);" is accepted by SQLite, and
 8752** creates a new table named "BEGIN" with three columns named
 8753** "REPLACE", "PRAGMA", and "END".  Nevertheless, best practice is to avoid
 8754** using keywords as identifiers.  Common techniques used to avoid keyword
 8755** name collisions include:
 8756** <ul>
 8757** <li> Put all identifier names inside double-quotes.  This is the official
 8758**      SQL way to escape identifier names.
 8759** <li> Put identifier names inside &#91;...&#93;.  This is not standard SQL,
 8760**      but it is what SQL Server does and so lots of programmers use this
 8761**      technique.
 8762** <li> Begin every identifier with the letter "Z" as no SQL keywords start
 8763**      with "Z".
 8764** <li> Include a digit somewhere in every identifier name.
 8765** </ul>
 8766**
 8767** Note that the number of keywords understood by SQLite can depend on
 8768** compile-time options.  For example, "VACUUM" is not a keyword if
 8769** SQLite is compiled with the [-DSQLITE_OMIT_VACUUM] option.  Also,
 8770** new keywords may be added to future releases of SQLite.
 8771*/
 8772SQLITE_API int sqlite3_keyword_count(void);
 8773SQLITE_API int sqlite3_keyword_name(int,const char**,int*);
 8774SQLITE_API int sqlite3_keyword_check(const char*,int);
 8775
 8776/*
 8777** CAPI3REF: Dynamic String Object
 8778** KEYWORDS: {dynamic string}
 8779**
 8780** An instance of the sqlite3_str object contains a dynamically-sized
 8781** string under construction.
 8782**
 8783** The lifecycle of an sqlite3_str object is as follows:
 8784** <ol>
 8785** <li> ^The sqlite3_str object is created using [sqlite3_str_new()].
 8786** <li> ^Text is appended to the sqlite3_str object using various
 8787** methods, such as [sqlite3_str_appendf()].
 8788** <li> ^The sqlite3_str object is destroyed and the string it created
 8789** is returned using the [sqlite3_str_finish()] interface.
 8790** </ol>
 8791*/
 8792typedef struct sqlite3_str sqlite3_str;
 8793
 8794/*
 8795** CAPI3REF: Create A New Dynamic String Object
 8796** CONSTRUCTOR: sqlite3_str
 8797**
 8798** ^The [sqlite3_str_new(D)] interface allocates and initializes
 8799** a new [sqlite3_str] object.  To avoid memory leaks, the object returned by
 8800** [sqlite3_str_new()] must be freed by a subsequent call to
 8801** [sqlite3_str_finish(X)].
 8802**
 8803** ^The [sqlite3_str_new(D)] interface always returns a pointer to a
 8804** valid [sqlite3_str] object, though in the event of an out-of-memory
 8805** error the returned object might be a special singleton that will
 8806** silently reject new text, always return SQLITE_NOMEM from
 8807** [sqlite3_str_errcode()], always return 0 for
 8808** [sqlite3_str_length()], and always return NULL from
 8809** [sqlite3_str_finish(X)].  It is always safe to use the value
 8810** returned by [sqlite3_str_new(D)] as the sqlite3_str parameter
 8811** to any of the other [sqlite3_str] methods.
 8812**
 8813** The D parameter to [sqlite3_str_new(D)] may be NULL.  If the
 8814** D parameter in [sqlite3_str_new(D)] is not NULL, then the maximum
 8815** length of the string contained in the [sqlite3_str] object will be
 8816** the value set for [sqlite3_limit](D,[SQLITE_LIMIT_LENGTH]) instead
 8817** of [SQLITE_MAX_LENGTH].
 8818*/
 8819SQLITE_API sqlite3_str *sqlite3_str_new(sqlite3*);
 8820
 8821/*
 8822** CAPI3REF: Finalize A Dynamic String
 8823** DESTRUCTOR: sqlite3_str
 8824**
 8825** ^The [sqlite3_str_finish(X)] interface destroys the sqlite3_str object X
 8826** and returns a pointer to a memory buffer obtained from [sqlite3_malloc64()]
 8827** that contains the constructed string.  The calling application should
 8828** pass the returned value to [sqlite3_free()] to avoid a memory leak.
 8829** ^The [sqlite3_str_finish(X)] interface may return a NULL pointer if any
 8830** errors were encountered during construction of the string.  ^The
 8831** [sqlite3_str_finish(X)] interface might also return a NULL pointer if the
 8832** string in [sqlite3_str] object X is zero bytes long.
 8833**
 8834** ^The [sqlite3_str_free(X)] interface destroys both the sqlite3_str object
 8835** X and the string content it contains.  Calling sqlite3_str_free(X) is
 8836** the equivalent of calling [sqlite3_free](sqlite3_str_finish(X)).
 8837*/
 8838SQLITE_API char *sqlite3_str_finish(sqlite3_str*);
 8839SQLITE_API void sqlite3_str_free(sqlite3_str*);
 8840
 8841/*
 8842** CAPI3REF: Add Content To A Dynamic String
 8843** METHOD: sqlite3_str
 8844**
 8845** These interfaces add or remove content to an sqlite3_str object
 8846** previously obtained from [sqlite3_str_new()].
 8847**
 8848** ^The [sqlite3_str_appendf(X,F,...)] and
 8849** [sqlite3_str_vappendf(X,F,V)] interfaces uses the [built-in printf]
 8850** functionality of SQLite to append formatted text onto the end of
 8851** [sqlite3_str] object X.
 8852**
 8853** ^The [sqlite3_str_append(X,S,N)] method appends exactly N bytes from string S
 8854** onto the end of the [sqlite3_str] object X.  N must be non-negative.
 8855** S must contain at least N non-zero bytes of content.  To append a
 8856** zero-terminated string in its entirety, use the [sqlite3_str_appendall()]
 8857** method instead.
 8858**
 8859** ^The [sqlite3_str_appendall(X,S)] method appends the complete content of
 8860** zero-terminated string S onto the end of [sqlite3_str] object X.
 8861**
 8862** ^The [sqlite3_str_appendchar(X,N,C)] method appends N copies of the
 8863** single-byte character C onto the end of [sqlite3_str] object X.
 8864** ^This method can be used, for example, to add whitespace indentation.
 8865**
 8866** ^The [sqlite3_str_reset(X)] method resets the string under construction
 8867** inside [sqlite3_str] object X back to zero bytes in length.
 8868**
 8869** ^The [sqlite3_str_truncate(X,N)] method changes the length of the string
 8870** under construction to be N bytes or less.  This routine is a no-op if
 8871** N is negative or if the string is already N bytes or smaller in size.
 8872**
 8873** These methods do not return a result code.  ^If an error occurs, that fact
 8874** is recorded in the [sqlite3_str] object and can be recovered by a
 8875** subsequent call to [sqlite3_str_errcode(X)].
 8876*/
 8877SQLITE_API void sqlite3_str_appendf(sqlite3_str*, const char *zFormat, ...);
 8878SQLITE_API void sqlite3_str_vappendf(sqlite3_str*, const char *zFormat, va_list);
 8879SQLITE_API void sqlite3_str_append(sqlite3_str*, const char *zIn, int N);
 8880SQLITE_API void sqlite3_str_appendall(sqlite3_str*, const char *zIn);
 8881SQLITE_API void sqlite3_str_appendchar(sqlite3_str*, int N, char C);
 8882SQLITE_API void sqlite3_str_reset(sqlite3_str*);
 8883SQLITE_API void sqlite3_str_truncate(sqlite3_str*,int N);
 8884
 8885/*
 8886** CAPI3REF: Status Of A Dynamic String
 8887** METHOD: sqlite3_str
 8888**
 8889** These interfaces return the current status of an [sqlite3_str] object.
 8890**
 8891** ^If any prior errors have occurred while constructing the dynamic string
 8892** in sqlite3_str X, then the [sqlite3_str_errcode(X)] method will return
 8893** an appropriate error code.  ^The [sqlite3_str_errcode(X)] method returns
 8894** [SQLITE_NOMEM] following any out-of-memory error, or
 8895** [SQLITE_TOOBIG] if the size of the dynamic string exceeds
 8896** [SQLITE_MAX_LENGTH], or [SQLITE_OK] if there have been no errors.
 8897**
 8898** ^The [sqlite3_str_length(X)] method returns the current length, in bytes,
 8899** of the dynamic string under construction in [sqlite3_str] object X.
 8900** ^The length returned by [sqlite3_str_length(X)] does not include the
 8901** zero-termination byte.
 8902**
 8903** ^The [sqlite3_str_value(X)] method returns a pointer to the current
 8904** content of the dynamic string under construction in X.  The value
 8905** returned by [sqlite3_str_value(X)] is managed by the sqlite3_str object X
 8906** and might be freed or altered by any subsequent method on the same
 8907** [sqlite3_str] object.  Applications must not use the pointer returned by
 8908** [sqlite3_str_value(X)] after any subsequent method call on the same
 8909** object.  ^Applications may change the content of the string returned
 8910** by [sqlite3_str_value(X)] as long as they do not write into any bytes
 8911** outside the range of 0 to [sqlite3_str_length(X)] and do not read or
 8912** write any byte after any subsequent sqlite3_str method call.
 8913*/
 8914SQLITE_API int sqlite3_str_errcode(sqlite3_str*);
 8915SQLITE_API int sqlite3_str_length(sqlite3_str*);
 8916SQLITE_API char *sqlite3_str_value(sqlite3_str*);
 8917
 8918/*
 8919** CAPI3REF: SQLite Runtime Status
 8920**
 8921** ^These interfaces are used to retrieve runtime status information
 8922** about the performance of SQLite, and optionally to reset various
 8923** highwater marks.  ^The first argument is an integer code for
 8924** the specific parameter to measure.  ^(Recognized integer codes
 8925** are of the form [status parameters | SQLITE_STATUS_...].)^
 8926** ^The current value of the parameter is returned into *pCurrent.
 8927** ^The highest recorded value is returned in *pHighwater.  ^If the
 8928** resetFlag is true, then the highest record value is reset after
 8929** *pHighwater is written.  ^(Some parameters do not record the highest
 8930** value.  For those parameters
 8931** nothing is written into *pHighwater and the resetFlag is ignored.)^
 8932** ^(Other parameters record only the highwater mark and not the current
 8933** value.  For these latter parameters nothing is written into *pCurrent.)^
 8934**
 8935** ^The sqlite3_status() and sqlite3_status64() routines return
 8936** SQLITE_OK on success and a non-zero [error code] on failure.
 8937**
 8938** If either the current value or the highwater mark is too large to
 8939** be represented by a 32-bit integer, then the values returned by
 8940** sqlite3_status() are undefined.
 8941**
 8942** See also: [sqlite3_db_status()]
 8943*/
 8944SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
 8945SQLITE_API int sqlite3_status64(
 8946  int op,
 8947  sqlite3_int64 *pCurrent,
 8948  sqlite3_int64 *pHighwater,
 8949  int resetFlag
 8950);
 8951
 8952
 8953/*
 8954** CAPI3REF: Status Parameters
 8955** KEYWORDS: {status parameters}
 8956**
 8957** These integer constants designate various run-time status parameters
 8958** that can be returned by [sqlite3_status()].
 8959**
 8960** <dl>
 8961** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
 8962** <dd>This parameter is the current amount of memory checked out
 8963** using [sqlite3_malloc()], either directly or indirectly.  The
 8964** figure includes calls made to [sqlite3_malloc()] by the application
 8965** and internal memory usage by the SQLite library.  Auxiliary page-cache
 8966** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
 8967** this parameter.  The amount returned is the sum of the allocation
 8968** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
 8969**
 8970** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
 8971** <dd>This parameter records the largest memory allocation request
 8972** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
 8973** internal equivalents).  Only the value returned in the
 8974** *pHighwater parameter to [sqlite3_status()] is of interest.
 8975** The value written into the *pCurrent parameter is undefined.</dd>)^
 8976**
 8977** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
 8978** <dd>This parameter records the number of separate memory allocations
 8979** currently checked out.</dd>)^
 8980**
 8981** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
 8982** <dd>This parameter returns the number of pages used out of the
 8983** [pagecache memory allocator] that was configured using
 8984** [SQLITE_CONFIG_PAGECACHE].  The
 8985** value returned is in pages, not in bytes.</dd>)^
 8986**
 8987** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]]
 8988** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
 8989** <dd>This parameter returns the number of bytes of page cache
 8990** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
 8991** buffer and where forced to overflow to [sqlite3_malloc()].  The
 8992** returned value includes allocations that overflowed because they
 8993** were too large (they were larger than the "sz" parameter to
 8994** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
 8995** no space was left in the page cache.</dd>)^
 8996**
 8997** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
 8998** <dd>This parameter records the largest memory allocation request
 8999** handed to the [pagecache memory allocator].  Only the value returned in the
 9000** *pHighwater parameter to [sqlite3_status()] is of interest.
 9001** The value written into the *pCurrent parameter is undefined.</dd>)^
 9002**
 9003** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt>
 9004** <dd>No longer used.</dd>
 9005**
 9006** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
 9007** <dd>No longer used.</dd>
 9008**
 9009** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
 9010** <dd>No longer used.</dd>
 9011**
 9012** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
 9013** <dd>The *pHighwater parameter records the deepest parser stack.
 9014** The *pCurrent value is undefined.  The *pHighwater value is only
 9015** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
 9016** </dl>
 9017**
 9018** New status parameters may be added from time to time.
 9019*/
 9020#define SQLITE_STATUS_MEMORY_USED          0
 9021#define SQLITE_STATUS_PAGECACHE_USED       1
 9022#define SQLITE_STATUS_PAGECACHE_OVERFLOW   2
 9023#define SQLITE_STATUS_SCRATCH_USED         3  /* NOT USED */
 9024#define SQLITE_STATUS_SCRATCH_OVERFLOW     4  /* NOT USED */
 9025#define SQLITE_STATUS_MALLOC_SIZE          5
 9026#define SQLITE_STATUS_PARSER_STACK         6
 9027#define SQLITE_STATUS_PAGECACHE_SIZE       7
 9028#define SQLITE_STATUS_SCRATCH_SIZE         8  /* NOT USED */
 9029#define SQLITE_STATUS_MALLOC_COUNT         9
 9030
 9031/*
 9032** CAPI3REF: Database Connection Status
 9033** METHOD: sqlite3
 9034**
 9035** ^This interface is used to retrieve runtime status information
 9036** about a single [database connection].  ^The first argument is the
 9037** database connection object to be interrogated.  ^The second argument
 9038** is an integer constant, taken from the set of
 9039** [SQLITE_DBSTATUS options], that
 9040** determines the parameter to interrogate.  The set of
 9041** [SQLITE_DBSTATUS options] is likely
 9042** to grow in future releases of SQLite.
 9043**
 9044** ^The current value of the requested parameter is written into *pCur
 9045** and the highest instantaneous value is written into *pHiwtr.  ^If
 9046** the resetFlg is true, then the highest instantaneous value is
 9047** reset back down to the current value.
 9048**
 9049** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
 9050** non-zero [error code] on failure.
 9051**
 9052** ^The sqlite3_db_status64(D,O,C,H,R) routine works exactly the same
 9053** way as sqlite3_db_status(D,O,C,H,R) routine except that the C and H
 9054** parameters are pointer to 64-bit integers (type: sqlite3_int64) instead
 9055** of pointers to 32-bit integers, which allows larger status values
 9056** to be returned.  If a status value exceeds 2,147,483,647 then
 9057** sqlite3_db_status() will truncate the value whereas sqlite3_db_status64()
 9058** will return the full value.
 9059**
 9060** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
 9061*/
 9062SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
 9063SQLITE_API int sqlite3_db_status64(sqlite3*,int,sqlite3_int64*,sqlite3_int64*,int);
 9064
 9065/*
 9066** CAPI3REF: Status Parameters for database connections
 9067** KEYWORDS: {SQLITE_DBSTATUS options}
 9068**
 9069** These constants are the available integer "verbs" that can be passed as
 9070** the second argument to the [sqlite3_db_status()] interface.
 9071**
 9072** New verbs may be added in future releases of SQLite. Existing verbs
 9073** might be discontinued. Applications should check the return code from
 9074** [sqlite3_db_status()] to make sure that the call worked.
 9075** The [sqlite3_db_status()] interface will return a non-zero error code
 9076** if a discontinued or unsupported verb is invoked.
 9077**
 9078** <dl>
 9079** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
 9080** <dd>This parameter returns the number of lookaside memory slots currently
 9081** checked out.</dd>)^
 9082**
 9083** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
 9084** <dd>This parameter returns the number of malloc attempts that were
 9085** satisfied using lookaside memory. Only the high-water value is meaningful;
 9086** the current value is always zero.</dd>)^
 9087**
 9088** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
 9089** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
 9090** <dd>This parameter returns the number of malloc attempts that might have
 9091** been satisfied using lookaside memory but failed due to the amount of
 9092** memory requested being larger than the lookaside slot size.
 9093** Only the high-water value is meaningful;
 9094** the current value is always zero.</dd>)^
 9095**
 9096** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
 9097** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
 9098** <dd>This parameter returns the number of malloc attempts that might have
 9099** been satisfied using lookaside memory but failed due to all lookaside
 9100** memory already being in use.
 9101** Only the high-water value is meaningful;
 9102** the current value is always zero.</dd>)^
 9103**
 9104** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
 9105** <dd>This parameter returns the approximate number of bytes of heap
 9106** memory used by all pager caches associated with the database connection.)^
 9107** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
 9108** </dd>
 9109**
 9110** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]]
 9111** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt>
 9112** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
 9113** pager cache is shared between two or more connections the bytes of heap
 9114** memory used by that pager cache is divided evenly between the attached
 9115** connections.)^  In other words, if none of the pager caches associated
 9116** with the database connection are shared, this request returns the same
 9117** value as DBSTATUS_CACHE_USED. Or, if one or more of the pager caches are
 9118** shared, the value returned by this call will be smaller than that returned
 9119** by DBSTATUS_CACHE_USED. ^The highwater mark associated with
 9120** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0.</dd>
 9121**
 9122** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
 9123** <dd>This parameter returns the approximate number of bytes of heap
 9124** memory used to store the schema for all databases associated
 9125** with the connection - main, temp, and any [ATTACH]-ed databases.)^
 9126** ^The full amount of memory used by the schemas is reported, even if the
 9127** schema memory is shared with other database connections due to
 9128** [shared cache mode] being enabled.
 9129** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
 9130** </dd>
 9131**
 9132** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
 9133** <dd>This parameter returns the approximate number of bytes of heap
 9134** and lookaside memory used by all prepared statements associated with
 9135** the database connection.)^
 9136** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
 9137** </dd>
 9138**
 9139** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
 9140** <dd>This parameter returns the number of pager cache hits that have
 9141** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT
 9142** is always 0.
 9143** </dd>
 9144**
 9145** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
 9146** <dd>This parameter returns the number of pager cache misses that have
 9147** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS
 9148** is always 0.
 9149** </dd>
 9150**
 9151** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
 9152** <dd>This parameter returns the number of dirty cache entries that have
 9153** been written to disk. Specifically, the number of pages written to the
 9154** wal file in wal mode databases, or the number of pages written to the
 9155** database file in rollback mode databases. Any pages written as part of
 9156** transaction rollback or database recovery operations are not included.
 9157** If an IO or other error occurs while writing a page to disk, the effect
 9158** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
 9159** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
 9160** <p>
 9161** ^(There is overlap between the quantities measured by this parameter
 9162** (SQLITE_DBSTATUS_CACHE_WRITE) and SQLITE_DBSTATUS_TEMPBUF_SPILL.
 9163** Resetting one will reduce the other.)^
 9164** </dd>
 9165**
 9166** [[SQLITE_DBSTATUS_CACHE_SPILL]] ^(<dt>SQLITE_DBSTATUS_CACHE_SPILL</dt>
 9167** <dd>This parameter returns the number of dirty cache entries that have
 9168** been written to disk in the middle of a transaction due to the page
 9169** cache overflowing. Transactions are more efficient if they are written
 9170** to disk all at once. When pages spill mid-transaction, that introduces
 9171** additional overhead. This parameter can be used to help identify
 9172** inefficiencies that can be resolved by increasing the cache size.
 9173** </dd>
 9174**
 9175** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
 9176** <dd>This parameter returns zero for the current value if and only if
 9177** all foreign key constraints (deferred or immediate) have been
 9178** resolved.)^  ^The highwater mark is always 0.
 9179**
 9180** [[SQLITE_DBSTATUS_TEMPBUF_SPILL] ^(<dt>SQLITE_DBSTATUS_TEMPBUF_SPILL</dt>
 9181** <dd>^(This parameter returns the number of bytes written to temporary
 9182** files on disk that could have been kept in memory had sufficient memory
 9183** been available.  This value includes writes to intermediate tables that
 9184** are part of complex queries, external sorts that spill to disk, and
 9185** writes to TEMP tables.)^
 9186** ^The highwater mark is always 0.
 9187** <p>
 9188** ^(There is overlap between the quantities measured by this parameter
 9189** (SQLITE_DBSTATUS_TEMPBUF_SPILL) and SQLITE_DBSTATUS_CACHE_WRITE.
 9190** Resetting one will reduce the other.)^
 9191** </dd>
 9192** </dl>
 9193*/
 9194#define SQLITE_DBSTATUS_LOOKASIDE_USED       0
 9195#define SQLITE_DBSTATUS_CACHE_USED           1
 9196#define SQLITE_DBSTATUS_SCHEMA_USED          2
 9197#define SQLITE_DBSTATUS_STMT_USED            3
 9198#define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
 9199#define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
 9200#define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
 9201#define SQLITE_DBSTATUS_CACHE_HIT            7
 9202#define SQLITE_DBSTATUS_CACHE_MISS           8
 9203#define SQLITE_DBSTATUS_CACHE_WRITE          9
 9204#define SQLITE_DBSTATUS_DEFERRED_FKS        10
 9205#define SQLITE_DBSTATUS_CACHE_USED_SHARED   11
 9206#define SQLITE_DBSTATUS_CACHE_SPILL         12
 9207#define SQLITE_DBSTATUS_TEMPBUF_SPILL       13
 9208#define SQLITE_DBSTATUS_MAX                 13   /* Largest defined DBSTATUS */
 9209
 9210
 9211/*
 9212** CAPI3REF: Prepared Statement Status
 9213** METHOD: sqlite3_stmt
 9214**
 9215** ^(Each prepared statement maintains various
 9216** [SQLITE_STMTSTATUS counters] that measure the number
 9217** of times it has performed specific operations.)^  These counters can
 9218** be used to monitor the performance characteristics of the prepared
 9219** statements.  For example, if the number of table steps greatly exceeds
 9220** the number of table searches or result rows, that would tend to indicate
 9221** that the prepared statement is using a full table scan rather than
 9222** an index.
 9223**
 9224** ^(This interface is used to retrieve and reset counter values from
 9225** a [prepared statement].  The first argument is the prepared statement
 9226** object to be interrogated.  The second argument
 9227** is an integer code for a specific [SQLITE_STMTSTATUS counter]
 9228** to be interrogated.)^
 9229** ^The current value of the requested counter is returned.
 9230** ^If the resetFlg is true, then the counter is reset to zero after this
 9231** interface call returns.
 9232**
 9233** See also: [sqlite3_status()] and [sqlite3_db_status()].
 9234*/
 9235SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
 9236
 9237/*
 9238** CAPI3REF: Status Parameters for prepared statements
 9239** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
 9240**
 9241** These preprocessor macros define integer codes that name counter
 9242** values associated with the [sqlite3_stmt_status()] interface.
 9243** The meanings of the various counters are as follows:
 9244**
 9245** <dl>
 9246** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
 9247** <dd>^This is the number of times that SQLite has stepped forward in
 9248** a table as part of a full table scan.  Large numbers for this counter
 9249** may indicate opportunities for performance improvement through
 9250** careful use of indices.</dd>
 9251**
 9252** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
 9253** <dd>^This is the number of sort operations that have occurred.
 9254** A non-zero value in this counter may indicate an opportunity to
 9255** improve performance through careful use of indices.</dd>
 9256**
 9257** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
 9258** <dd>^This is the number of rows inserted into transient indices that
 9259** were created automatically in order to help joins run faster.
 9260** A non-zero value in this counter may indicate an opportunity to
 9261** improve performance by adding permanent indices that do not
 9262** need to be reinitialized each time the statement is run.</dd>
 9263**
 9264** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
 9265** <dd>^This is the number of virtual machine operations executed
 9266** by the prepared statement if that number is less than or equal
 9267** to 2147483647.  The number of virtual machine operations can be
 9268** used as a proxy for the total work done by the prepared statement.
 9269** If the number of virtual machine operations exceeds 2147483647
 9270** then the value returned by this statement status code is undefined.</dd>
 9271**
 9272** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt>
 9273** <dd>^This is the number of times that the prepare statement has been
 9274** automatically regenerated due to schema changes or changes to
 9275** [bound parameters] that might affect the query plan.</dd>
 9276**
 9277** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt>
 9278** <dd>^This is the number of times that the prepared statement has
 9279** been run.  A single "run" for the purposes of this counter is one
 9280** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()].
 9281** The counter is incremented on the first [sqlite3_step()] call of each
 9282** cycle.</dd>
 9283**
 9284** [[SQLITE_STMTSTATUS_FILTER_MISS]]
 9285** [[SQLITE_STMTSTATUS_FILTER HIT]]
 9286** <dt>SQLITE_STMTSTATUS_FILTER_HIT<br>
 9287** SQLITE_STMTSTATUS_FILTER_MISS</dt>
 9288** <dd>^SQLITE_STMTSTATUS_FILTER_HIT is the number of times that a join
 9289** step was bypassed because a Bloom filter returned not-found.  The
 9290** corresponding SQLITE_STMTSTATUS_FILTER_MISS value is the number of
 9291** times that the Bloom filter returned a find, and thus the join step
 9292** had to be processed as normal.</dd>
 9293**
 9294** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt>
 9295** <dd>^This is the approximate number of bytes of heap memory
 9296** used to store the prepared statement.  ^This value is not actually
 9297** a counter, and so the resetFlg parameter to sqlite3_stmt_status()
 9298** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED.
 9299** </dd>
 9300** </dl>
 9301*/
 9302#define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
 9303#define SQLITE_STMTSTATUS_SORT              2
 9304#define SQLITE_STMTSTATUS_AUTOINDEX         3
 9305#define SQLITE_STMTSTATUS_VM_STEP           4
 9306#define SQLITE_STMTSTATUS_REPREPARE         5
 9307#define SQLITE_STMTSTATUS_RUN               6
 9308#define SQLITE_STMTSTATUS_FILTER_MISS       7
 9309#define SQLITE_STMTSTATUS_FILTER_HIT        8
 9310#define SQLITE_STMTSTATUS_MEMUSED           99
 9311
 9312/*
 9313** CAPI3REF: Custom Page Cache Object
 9314**
 9315** The sqlite3_pcache type is opaque.  It is implemented by
 9316** the pluggable module.  The SQLite core has no knowledge of
 9317** its size or internal structure and never deals with the
 9318** sqlite3_pcache object except by holding and passing pointers
 9319** to the object.
 9320**
 9321** See [sqlite3_pcache_methods2] for additional information.
 9322*/
 9323typedef struct sqlite3_pcache sqlite3_pcache;
 9324
 9325/*
 9326** CAPI3REF: Custom Page Cache Object
 9327**
 9328** The sqlite3_pcache_page object represents a single page in the
 9329** page cache.  The page cache will allocate instances of this
 9330** object.  Various methods of the page cache use pointers to instances
 9331** of this object as parameters or as their return value.
 9332**
 9333** See [sqlite3_pcache_methods2] for additional information.
 9334*/
 9335typedef struct sqlite3_pcache_page sqlite3_pcache_page;
 9336struct sqlite3_pcache_page {
 9337  void *pBuf;        /* The content of the page */
 9338  void *pExtra;      /* Extra information associated with the page */
 9339};
 9340
 9341/*
 9342** CAPI3REF: Application Defined Page Cache.
 9343** KEYWORDS: {page cache}
 9344**
 9345** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
 9346** register an alternative page cache implementation by passing in an
 9347** instance of the sqlite3_pcache_methods2 structure.)^
 9348** In many applications, most of the heap memory allocated by
 9349** SQLite is used for the page cache.
 9350** By implementing a
 9351** custom page cache using this API, an application can better control
 9352** the amount of memory consumed by SQLite, the way in which
 9353** that memory is allocated and released, and the policies used to
 9354** determine exactly which parts of a database file are cached and for
 9355** how long.
 9356**
 9357** The alternative page cache mechanism is an
 9358** extreme measure that is only needed by the most demanding applications.
 9359** The built-in page cache is recommended for most uses.
 9360**
 9361** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
 9362** internal buffer by SQLite within the call to [sqlite3_config].  Hence
 9363** the application may discard the parameter after the call to
 9364** [sqlite3_config()] returns.)^
 9365**
 9366** [[the xInit() page cache method]]
 9367** ^(The xInit() method is called once for each effective
 9368** call to [sqlite3_initialize()])^
 9369** (usually only once during the lifetime of the process). ^(The xInit()
 9370** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
 9371** The intent of the xInit() method is to set up global data structures
 9372** required by the custom page cache implementation.
 9373** ^(If the xInit() method is NULL, then the
 9374** built-in default page cache is used instead of the application defined
 9375** page cache.)^
 9376**
 9377** [[the xShutdown() page cache method]]
 9378** ^The xShutdown() method is called by [sqlite3_shutdown()].
 9379** It can be used to clean up
 9380** any outstanding resources before process shutdown, if required.
 9381** ^The xShutdown() method may be NULL.
 9382**
 9383** ^SQLite automatically serializes calls to the xInit method,
 9384** so the xInit method need not be threadsafe.  ^The
 9385** xShutdown method is only called from [sqlite3_shutdown()] so it does
 9386** not need to be threadsafe either.  All other methods must be threadsafe
 9387** in multithreaded applications.
 9388**
 9389** ^SQLite will never invoke xInit() more than once without an intervening
 9390** call to xShutdown().
 9391**
 9392** [[the xCreate() page cache methods]]
 9393** ^SQLite invokes the xCreate() method to construct a new cache instance.
 9394** SQLite will typically create one cache instance for each open database file,
 9395** though this is not guaranteed. ^The
 9396** first parameter, szPage, is the size in bytes of the pages that must
 9397** be allocated by the cache.  ^szPage will always be a power of two.  ^The
 9398** second parameter szExtra is a number of bytes of extra storage
 9399** associated with each page cache entry.  ^The szExtra parameter will be
 9400** a number less than 250.  SQLite will use the
 9401** extra szExtra bytes on each page to store metadata about the underlying
 9402** database page on disk.  The value passed into szExtra depends
 9403** on the SQLite version, the target platform, and how SQLite was compiled.
 9404** ^The third argument to xCreate(), bPurgeable, is true if the cache being
 9405** created will be used to cache database pages of a file stored on disk, or
 9406** false if it is used for an in-memory database. The cache implementation
 9407** does not have to do anything special based upon the value of bPurgeable;
 9408** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
 9409** never invoke xUnpin() except to deliberately delete a page.
 9410** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
 9411** false will always have the "discard" flag set to true.
 9412** ^Hence, a cache created with bPurgeable set to false will
 9413** never contain any unpinned pages.
 9414**
 9415** [[the xCachesize() page cache method]]
 9416** ^(The xCachesize() method may be called at any time by SQLite to set the
 9417** suggested maximum cache-size (number of pages stored) for the cache
 9418** instance passed as the first argument. This is the value configured using
 9419** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
 9420** parameter, the implementation is not required to do anything with this
 9421** value; it is advisory only.
 9422**
 9423** [[the xPagecount() page cache methods]]
 9424** The xPagecount() method must return the number of pages currently
 9425** stored in the cache, both pinned and unpinned.
 9426**
 9427** [[the xFetch() page cache methods]]
 9428** The xFetch() method locates a page in the cache and returns a pointer to
 9429** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
 9430** The pBuf element of the returned sqlite3_pcache_page object will be a
 9431** pointer to a buffer of szPage bytes used to store the content of a
 9432** single database page.  The pExtra element of sqlite3_pcache_page will be
 9433** a pointer to the szExtra bytes of extra storage that SQLite has requested
 9434** for each entry in the page cache.
 9435**
 9436** The page to be fetched is determined by the key. ^The minimum key value
 9437** is 1.  After it has been retrieved using xFetch, the page is considered
 9438** to be "pinned".
 9439**
 9440** If the requested page is already in the page cache, then the page cache
 9441** implementation must return a pointer to the page buffer with its content
 9442** intact.  If the requested page is not already in the cache, then the
 9443** cache implementation should use the value of the createFlag
 9444** parameter to help it determine what action to take:
 9445**
 9446** <table border=1 width=85% align=center>
 9447** <tr><th> createFlag <th> Behavior when page is not already in cache
 9448** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
 9449** <tr><td> 1 <td> Allocate a new page if it is easy and convenient to do so.
 9450**                 Otherwise return NULL.
 9451** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
 9452**                 NULL if allocating a new page is effectively impossible.
 9453** </table>
 9454**
 9455** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
 9456** will only use a createFlag of 2 after a prior call with a createFlag of 1
 9457** failed.)^  In between the xFetch() calls, SQLite may
 9458** attempt to unpin one or more cache pages by spilling the content of
 9459** pinned pages to disk and synching the operating system disk cache.
 9460**
 9461** [[the xUnpin() page cache method]]
 9462** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
 9463** as its second argument.  If the third parameter, discard, is non-zero,
 9464** then the page must be evicted from the cache.
 9465** ^If the discard parameter is
 9466** zero, then the page may be discarded or retained at the discretion of the
 9467** page cache implementation. ^The page cache implementation
 9468** may choose to evict unpinned pages at any time.
 9469**
 9470** The cache must not perform any reference counting. A single
 9471** call to xUnpin() unpins the page regardless of the number of prior calls
 9472** to xFetch().
 9473**
 9474** [[the xRekey() page cache methods]]
 9475** The xRekey() method is used to change the key value associated with the
 9476** page passed as the second argument. If the cache
 9477** previously contains an entry associated with newKey, it must be
 9478** discarded. ^Any prior cache entry associated with newKey is guaranteed not
 9479** to be pinned.
 9480**
 9481** When SQLite calls the xTruncate() method, the cache must discard all
 9482** existing cache entries with page numbers (keys) greater than or equal
 9483** to the value of the iLimit parameter passed to xTruncate(). If any
 9484** of these pages are pinned, they become implicitly unpinned, meaning that
 9485** they can be safely discarded.
 9486**
 9487** [[the xDestroy() page cache method]]
 9488** ^The xDestroy() method is used to delete a cache allocated by xCreate().
 9489** All resources associated with the specified cache should be freed. ^After
 9490** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
 9491** handle invalid, and will not use it with any other sqlite3_pcache_methods2
 9492** functions.
 9493**
 9494** [[the xShrink() page cache method]]
 9495** ^SQLite invokes the xShrink() method when it wants the page cache to
 9496** free up as much of heap memory as possible.  The page cache implementation
 9497** is not obligated to free any memory, but well-behaved implementations should
 9498** do their best.
 9499*/
 9500typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
 9501struct sqlite3_pcache_methods2 {
 9502  int iVersion;
 9503  void *pArg;
 9504  int (*xInit)(void*);
 9505  void (*xShutdown)(void*);
 9506  sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
 9507  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
 9508  int (*xPagecount)(sqlite3_pcache*);
 9509  sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
 9510  void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
 9511  void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*,
 9512      unsigned oldKey, unsigned newKey);
 9513  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
 9514  void (*xDestroy)(sqlite3_pcache*);
 9515  void (*xShrink)(sqlite3_pcache*);
 9516};
 9517
 9518/*
 9519** This is the obsolete pcache_methods object that has now been replaced
 9520** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
 9521** retained in the header file for backwards compatibility only.
 9522*/
 9523typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
 9524struct sqlite3_pcache_methods {
 9525  void *pArg;
 9526  int (*xInit)(void*);
 9527  void (*xShutdown)(void*);
 9528  sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
 9529  void (*xCachesize)(sqlite3_pcache*, int nCachesize);
 9530  int (*xPagecount)(sqlite3_pcache*);
 9531  void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
 9532  void (*xUnpin)(sqlite3_pcache*, void*, int discard);
 9533  void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
 9534  void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
 9535  void (*xDestroy)(sqlite3_pcache*);
 9536};
 9537
 9538
 9539/*
 9540** CAPI3REF: Online Backup Object
 9541**
 9542** The sqlite3_backup object records state information about an ongoing
 9543** online backup operation.  ^The sqlite3_backup object is created by
 9544** a call to [sqlite3_backup_init()] and is destroyed by a call to
 9545** [sqlite3_backup_finish()].
 9546**
 9547** See Also: [Using the SQLite Online Backup API]
 9548*/
 9549typedef struct sqlite3_backup sqlite3_backup;
 9550
 9551/*
 9552** CAPI3REF: Online Backup API.
 9553**
 9554** The backup API copies the content of one database into another.
 9555** It is useful either for creating backups of databases or
 9556** for copying in-memory databases to or from persistent files.
 9557**
 9558** See Also: [Using the SQLite Online Backup API]
 9559**
 9560** ^SQLite holds a write transaction open on the destination database file
 9561** for the duration of the backup operation.
 9562** ^The source database is read-locked only while it is being read;
 9563** it is not locked continuously for the entire backup operation.
 9564** ^Thus, the backup may be performed on a live source database without
 9565** preventing other database connections from
 9566** reading or writing to the source database while the backup is underway.
 9567**
 9568** ^(To perform a backup operation:
 9569**   <ol>
 9570**     <li><b>sqlite3_backup_init()</b> is called once to initialize the
 9571**         backup,
 9572**     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer
 9573**         the data between the two databases, and finally
 9574**     <li><b>sqlite3_backup_finish()</b> is called to release all resources
 9575**         associated with the backup operation.
 9576**   </ol>)^
 9577** There should be exactly one call to sqlite3_backup_finish() for each
 9578** successful call to sqlite3_backup_init().
 9579**
 9580** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
 9581**
 9582** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the
 9583** [database connection] associated with the destination database
 9584** and the database name, respectively.
 9585** ^The database name is "main" for the main database, "temp" for the
 9586** temporary database, or the name specified after the AS keyword in
 9587** an [ATTACH] statement for an attached database.
 9588** ^The S and M arguments passed to
 9589** sqlite3_backup_init(D,N,S,M) identify the [database connection]
 9590** and database name of the source database, respectively.
 9591** ^The source and destination [database connections] (parameters S and D)
 9592** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
 9593** an error.
 9594**
 9595** ^A call to sqlite3_backup_init() will fail, returning NULL, if
 9596** there is already a read or read-write transaction open on the
 9597** destination database.
 9598**
 9599** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
 9600** returned and an error code and error message are stored in the
 9601** destination [database connection] D.
 9602** ^The error code and message for the failed call to sqlite3_backup_init()
 9603** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
 9604** [sqlite3_errmsg16()] functions.
 9605** ^A successful call to sqlite3_backup_init() returns a pointer to an
 9606** [sqlite3_backup] object.
 9607** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
 9608** sqlite3_backup_finish() functions to perform the specified backup
 9609** operation.
 9610**
 9611** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
 9612**
 9613** ^Function sqlite3_backup_step(B,N) will copy up to N pages between
 9614** the source and destination databases specified by [sqlite3_backup] object B.
 9615** ^If N is negative, all remaining source pages are copied.
 9616** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
 9617** are still more pages to be copied, then the function returns [SQLITE_OK].
 9618** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
 9619** from source to destination, then it returns [SQLITE_DONE].
 9620** ^If an error occurs while running sqlite3_backup_step(B,N),
 9621** then an [error code] is returned. ^As well as [SQLITE_OK] and
 9622** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
 9623** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
 9624** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
 9625**
 9626** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
 9627** <ol>
 9628** <li> the destination database was opened read-only, or
 9629** <li> the destination database is using write-ahead-log journaling
 9630** and the destination and source page sizes differ, or
 9631** <li> the destination database is an in-memory database and the
 9632** destination and source page sizes differ.
 9633** </ol>)^
 9634**
 9635** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
 9636** the [sqlite3_busy_handler | busy-handler function]
 9637** is invoked (if one is specified). ^If the
 9638** busy-handler returns non-zero before the lock is available, then
 9639** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
 9640** sqlite3_backup_step() can be retried later. ^If the source
 9641** [database connection]
 9642** is being used to write to the source database when sqlite3_backup_step()
 9643** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
 9644** case the call to sqlite3_backup_step() can be retried later on. ^(If
 9645** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
 9646** [SQLITE_READONLY] is returned, then
 9647** there is no point in retrying the call to sqlite3_backup_step(). These
 9648** errors are considered fatal.)^  The application must accept
 9649** that the backup operation has failed and pass the backup operation handle
 9650** to the sqlite3_backup_finish() to release associated resources.
 9651**
 9652** ^The first call to sqlite3_backup_step() obtains an exclusive lock
 9653** on the destination file. ^The exclusive lock is not released until either
 9654** sqlite3_backup_finish() is called or the backup operation is complete
 9655** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
 9656** sqlite3_backup_step() obtains a [shared lock] on the source database that
 9657** lasts for the duration of the sqlite3_backup_step() call.
 9658** ^Because the source database is not locked between calls to
 9659** sqlite3_backup_step(), the source database may be modified mid-way
 9660** through the backup process.  ^If the source database is modified by an
 9661** external process or via a database connection other than the one being
 9662** used by the backup operation, then the backup will be automatically
 9663** restarted by the next call to sqlite3_backup_step(). ^If the source
 9664** database is modified by using the same database connection as is used
 9665** by the backup operation, then the backup database is automatically
 9666** updated at the same time.
 9667**
 9668** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
 9669**
 9670** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the
 9671** application wishes to abandon the backup operation, the application
 9672** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
 9673** ^The sqlite3_backup_finish() interfaces releases all
 9674** resources associated with the [sqlite3_backup] object.
 9675** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
 9676** active write-transaction on the destination database is rolled back.
 9677** The [sqlite3_backup] object is invalid
 9678** and may not be used following a call to sqlite3_backup_finish().
 9679**
 9680** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
 9681** sqlite3_backup_step() errors occurred, regardless of whether or not
 9682** sqlite3_backup_step() completed.
 9683** ^If an out-of-memory condition or IO error occurred during any prior
 9684** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
 9685** sqlite3_backup_finish() returns the corresponding [error code].
 9686**
 9687** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
 9688** is not a permanent error and does not affect the return value of
 9689** sqlite3_backup_finish().
 9690**
 9691** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
 9692** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
 9693**
 9694** ^The sqlite3_backup_remaining() routine returns the number of pages still
 9695** to be backed up at the conclusion of the most recent sqlite3_backup_step().
 9696** ^The sqlite3_backup_pagecount() routine returns the total number of pages
 9697** in the source database at the conclusion of the most recent
 9698** sqlite3_backup_step().
 9699** ^(The values returned by these functions are only updated by
 9700** sqlite3_backup_step(). If the source database is modified in a way that
 9701** changes the size of the source database or the number of pages remaining,
 9702** those changes are not reflected in the output of sqlite3_backup_pagecount()
 9703** and sqlite3_backup_remaining() until after the next
 9704** sqlite3_backup_step().)^
 9705**
 9706** <b>Concurrent Usage of Database Handles</b>
 9707**
 9708** ^The source [database connection] may be used by the application for other
 9709** purposes while a backup operation is underway or being initialized.
 9710** ^If SQLite is compiled and configured to support threadsafe database
 9711** connections, then the source database connection may be used concurrently
 9712** from within other threads.
 9713**
 9714** However, the application must guarantee that the destination
 9715** [database connection] is not passed to any other API (by any thread) after
 9716** sqlite3_backup_init() is called and before the corresponding call to
 9717** sqlite3_backup_finish().  SQLite does not currently check to see
 9718** if the application incorrectly accesses the destination [database connection]
 9719** and so no error code is reported, but the operations may malfunction
 9720** nevertheless.  Use of the destination database connection while a
 9721** backup is in progress might also cause a mutex deadlock.
 9722**
 9723** If running in [shared cache mode], the application must
 9724** guarantee that the shared cache used by the destination database
 9725** is not accessed while the backup is running. In practice this means
 9726** that the application must guarantee that the disk file being
 9727** backed up to is not accessed by any connection within the process,
 9728** not just the specific connection that was passed to sqlite3_backup_init().
 9729**
 9730** The [sqlite3_backup] object itself is partially threadsafe. Multiple
 9731** threads may safely make multiple concurrent calls to sqlite3_backup_step().
 9732** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
 9733** APIs are not strictly speaking threadsafe. If they are invoked at the
 9734** same time as another thread is invoking sqlite3_backup_step() it is
 9735** possible that they return invalid values.
 9736**
 9737** <b>Alternatives To Using The Backup API</b>
 9738**
 9739** Other techniques for safely creating a consistent backup of an SQLite
 9740** database include:
 9741**
 9742** <ul>
 9743** <li> The [VACUUM INTO] command.
 9744** <li> The [sqlite3_rsync] utility program.
 9745** </ul>
 9746*/
 9747SQLITE_API sqlite3_backup *sqlite3_backup_init(
 9748  sqlite3 *pDest,                        /* Destination database handle */
 9749  const char *zDestName,                 /* Destination database name */
 9750  sqlite3 *pSource,                      /* Source database handle */
 9751  const char *zSourceName                /* Source database name */
 9752);
 9753SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
 9754SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
 9755SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
 9756SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
 9757
 9758/*
 9759** CAPI3REF: Unlock Notification
 9760** METHOD: sqlite3
 9761**
 9762** ^When running in shared-cache mode, a database operation may fail with
 9763** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
 9764** individual tables within the shared-cache cannot be obtained. See
 9765** [SQLite Shared-Cache Mode] for a description of shared-cache locking.
 9766** ^This API may be used to register a callback that SQLite will invoke
 9767** when the connection currently holding the required lock relinquishes it.
 9768** ^This API is only available if the library was compiled with the
 9769** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
 9770**
 9771** See Also: [Using the SQLite Unlock Notification Feature].
 9772**
 9773** ^Shared-cache locks are released when a database connection concludes
 9774** its current transaction, either by committing it or rolling it back.
 9775**
 9776** ^When a connection (known as the blocked connection) fails to obtain a
 9777** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
 9778** identity of the database connection (the blocking connection) that
 9779** has locked the required resource is stored internally. ^After an
 9780** application receives an SQLITE_LOCKED error, it may call the
 9781** sqlite3_unlock_notify() method with the blocked connection handle as
 9782** the first argument to register for a callback that will be invoked
 9783** when the blocking connection's current transaction is concluded. ^The
 9784** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
 9785** call that concludes the blocking connection's transaction.
 9786**
 9787** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
 9788** there is a chance that the blocking connection will have already
 9789** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
 9790** If this happens, then the specified callback is invoked immediately,
 9791** from within the call to sqlite3_unlock_notify().)^
 9792**
 9793** ^If the blocked connection is attempting to obtain a write-lock on a
 9794** shared-cache table, and more than one other connection currently holds
 9795** a read-lock on the same table, then SQLite arbitrarily selects one of
 9796** the other connections to use as the blocking connection.
 9797**
 9798** ^(There may be at most one unlock-notify callback registered by a
 9799** blocked connection. If sqlite3_unlock_notify() is called when the
 9800** blocked connection already has a registered unlock-notify callback,
 9801** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
 9802** called with a NULL pointer as its second argument, then any existing
 9803** unlock-notify callback is canceled. ^The blocked connection's
 9804** unlock-notify callback may also be canceled by closing the blocked
 9805** connection using [sqlite3_close()].
 9806**
 9807** The unlock-notify callback is not reentrant. If an application invokes
 9808** any sqlite3_xxx API functions from within an unlock-notify callback, a
 9809** crash or deadlock may be the result.
 9810**
 9811** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
 9812** returns SQLITE_OK.
 9813**
 9814** <b>Callback Invocation Details</b>
 9815**
 9816** When an unlock-notify callback is registered, the application provides a
 9817** single void* pointer that is passed to the callback when it is invoked.
 9818** However, the signature of the callback function allows SQLite to pass
 9819** it an array of void* context pointers. The first argument passed to
 9820** an unlock-notify callback is a pointer to an array of void* pointers,
 9821** and the second is the number of entries in the array.
 9822**
 9823** When a blocking connection's transaction is concluded, there may be
 9824** more than one blocked connection that has registered for an unlock-notify
 9825** callback. ^If two or more such blocked connections have specified the
 9826** same callback function, then instead of invoking the callback function
 9827** multiple times, it is invoked once with the set of void* context pointers
 9828** specified by the blocked connections bundled together into an array.
 9829** This gives the application an opportunity to prioritize any actions
 9830** related to the set of unblocked database connections.
 9831**
 9832** <b>Deadlock Detection</b>
 9833**
 9834** Assuming that after registering for an unlock-notify callback a
 9835** database waits for the callback to be issued before taking any further
 9836** action (a reasonable assumption), then using this API may cause the
 9837** application to deadlock. For example, if connection X is waiting for
 9838** connection Y's transaction to be concluded, and similarly connection
 9839** Y is waiting on connection X's transaction, then neither connection
 9840** will proceed and the system may remain deadlocked indefinitely.
 9841**
 9842** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
 9843** detection. ^If a given call to sqlite3_unlock_notify() would put the
 9844** system in a deadlocked state, then SQLITE_LOCKED is returned and no
 9845** unlock-notify callback is registered. The system is said to be in
 9846** a deadlocked state if connection A has registered for an unlock-notify
 9847** callback on the conclusion of connection B's transaction, and connection
 9848** B has itself registered for an unlock-notify callback when connection
 9849** A's transaction is concluded. ^Indirect deadlock is also detected, so
 9850** the system is also considered to be deadlocked if connection B has
 9851** registered for an unlock-notify callback on the conclusion of connection
 9852** C's transaction, where connection C is waiting on connection A. ^Any
 9853** number of levels of indirection are allowed.
 9854**
 9855** <b>The "DROP TABLE" Exception</b>
 9856**
 9857** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost
 9858** always appropriate to call sqlite3_unlock_notify(). There is however,
 9859** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
 9860** SQLite checks if there are any currently executing SELECT statements
 9861** that belong to the same connection. If there are, SQLITE_LOCKED is
 9862** returned. In this case there is no "blocking connection", so invoking
 9863** sqlite3_unlock_notify() results in the unlock-notify callback being
 9864** invoked immediately. If the application then re-attempts the "DROP TABLE"
 9865** or "DROP INDEX" query, an infinite loop might be the result.
 9866**
 9867** One way around this problem is to check the extended error code returned
 9868** by an sqlite3_step() call. ^(If there is a blocking connection, then the
 9869** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
 9870** the special "DROP TABLE/INDEX" case, the extended error code is just
 9871** SQLITE_LOCKED.)^
 9872*/
 9873SQLITE_API int sqlite3_unlock_notify(
 9874  sqlite3 *pBlocked,                          /* Waiting connection */
 9875  void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
 9876  void *pNotifyArg                            /* Argument to pass to xNotify */
 9877);
 9878
 9879
 9880/*
 9881** CAPI3REF: String Comparison
 9882**
 9883** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
 9884** and extensions to compare the contents of two buffers containing UTF-8
 9885** strings in a case-independent fashion, using the same definition of "case
 9886** independence" that SQLite uses internally when comparing identifiers.
 9887*/
 9888SQLITE_API int sqlite3_stricmp(const char *, const char *);
 9889SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
 9890
 9891/*
 9892** CAPI3REF: String Globbing
 9893*
 9894** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if
 9895** string X matches the [GLOB] pattern P.
 9896** ^The definition of [GLOB] pattern matching used in
 9897** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
 9898** SQL dialect understood by SQLite.  ^The [sqlite3_strglob(P,X)] function
 9899** is case sensitive.
 9900**
 9901** Note that this routine returns zero on a match and non-zero if the strings
 9902** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
 9903**
 9904** See also: [sqlite3_strlike()].
 9905*/
 9906SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr);
 9907
 9908/*
 9909** CAPI3REF: String LIKE Matching
 9910*
 9911** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if
 9912** string X matches the [LIKE] pattern P with escape character E.
 9913** ^The definition of [LIKE] pattern matching used in
 9914** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E"
 9915** operator in the SQL dialect understood by SQLite.  ^For "X LIKE P" without
 9916** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0.
 9917** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case
 9918** insensitive - equivalent upper and lower case ASCII characters match
 9919** one another.
 9920**
 9921** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though
 9922** only ASCII characters are case folded.
 9923**
 9924** Note that this routine returns zero on a match and non-zero if the strings
 9925** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
 9926**
 9927** See also: [sqlite3_strglob()].
 9928*/
 9929SQLITE_API int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc);
 9930
 9931/*
 9932** CAPI3REF: Error Logging Interface
 9933**
 9934** ^The [sqlite3_log()] interface writes a message into the [error log]
 9935** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
 9936** ^If logging is enabled, the zFormat string and subsequent arguments are
 9937** used with [sqlite3_snprintf()] to generate the final output string.
 9938**
 9939** The sqlite3_log() interface is intended for use by extensions such as
 9940** virtual tables, collating functions, and SQL functions.  While there is
 9941** nothing to prevent an application from calling sqlite3_log(), doing so
 9942** is considered bad form.
 9943**
 9944** The zFormat string must not be NULL.
 9945**
 9946** To avoid deadlocks and other threading problems, the sqlite3_log() routine
 9947** will not use dynamically allocated memory.  The log message is stored in
 9948** a fixed-length buffer on the stack.  If the log message is longer than
 9949** a few hundred characters, it will be truncated to the length of the
 9950** buffer.
 9951*/
 9952SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
 9953
 9954/*
 9955** CAPI3REF: Write-Ahead Log Commit Hook
 9956** METHOD: sqlite3
 9957**
 9958** ^The [sqlite3_wal_hook()] function is used to register a callback that
 9959** is invoked each time data is committed to a database in wal mode.
 9960**
 9961** ^(The callback is invoked by SQLite after the commit has taken place and
 9962** the associated write-lock on the database released)^, so the implementation
 9963** may read, write or [checkpoint] the database as required.
 9964**
 9965** ^The first parameter passed to the callback function when it is invoked
 9966** is a copy of the third parameter passed to sqlite3_wal_hook() when
 9967** registering the callback. ^The second is a copy of the database handle.
 9968** ^The third parameter is the name of the database that was written to -
 9969** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
 9970** is the number of pages currently in the write-ahead log file,
 9971** including those that were just committed.
 9972**
 9973** ^The callback function should normally return [SQLITE_OK].  ^If an error
 9974** code is returned, that error will propagate back up through the
 9975** SQLite code base to cause the statement that provoked the callback
 9976** to report an error, though the commit will have still occurred. If the
 9977** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
 9978** that does not correspond to any valid SQLite error code, the results
 9979** are undefined.
 9980**
 9981** ^A single database handle may have at most a single write-ahead log
 9982** callback registered at one time. ^Calling [sqlite3_wal_hook()]
 9983** replaces the default behavior or previously registered write-ahead
 9984** log callback.
 9985**
 9986** ^The return value is a copy of the third parameter from the
 9987** previous call, if any, or 0.
 9988**
 9989** ^The [sqlite3_wal_autocheckpoint()] interface and the
 9990** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and
 9991** will overwrite any prior [sqlite3_wal_hook()] settings.
 9992**
 9993** ^If a write-ahead log callback is set using this function then
 9994** [sqlite3_wal_checkpoint_v2()] or [PRAGMA wal_checkpoint]
 9995** should be invoked periodically to keep the write-ahead log file
 9996** from growing without bound.
 9997**
 9998** ^Passing a NULL pointer for the callback disables automatic
 9999** checkpointing entirely. To re-enable the default behavior, call
10000** sqlite3_wal_autocheckpoint(db,1000) or use [PRAGMA wal_checkpoint].
10001*/
10002SQLITE_API void *sqlite3_wal_hook(
10003  sqlite3*,
10004  int(*)(void *,sqlite3*,const char*,int),
10005  void*
10006);
10007
10008/*
10009** CAPI3REF: Configure an auto-checkpoint
10010** METHOD: sqlite3
10011**
10012** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
10013** [sqlite3_wal_hook()] that causes any database on [database connection] D
10014** to automatically [checkpoint]
10015** after committing a transaction if there are N or
10016** more frames in the [write-ahead log] file.  ^Passing zero or
10017** a negative value as the N parameter disables automatic
10018** checkpoints entirely.
10019**
10020** ^The callback registered by this function replaces any existing callback
10021** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
10022** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
10023** configured by this function.
10024**
10025** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
10026** from SQL.
10027**
10028** ^Checkpoints initiated by this mechanism are
10029** [sqlite3_wal_checkpoint_v2|PASSIVE].
10030**
10031** ^Every new [database connection] defaults to having the auto-checkpoint
10032** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
10033** pages.
10034**
10035** ^The use of this interface is only necessary if the default setting
10036** is found to be suboptimal for a particular application.
10037*/
10038SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
10039
10040/*
10041** CAPI3REF: Checkpoint a database
10042** METHOD: sqlite3
10043**
10044** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
10045** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
10046**
10047** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the
10048** [write-ahead log] for database X on [database connection] D to be
10049** transferred into the database file and for the write-ahead log to
10050** be reset.  See the [checkpointing] documentation for addition
10051** information.
10052**
10053** This interface used to be the only way to cause a checkpoint to
10054** occur.  But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
10055** interface was added.  This interface is retained for backwards
10056** compatibility and as a convenience for applications that need to manually
10057** start a callback but which do not need the full power (and corresponding
10058** complication) of [sqlite3_wal_checkpoint_v2()].
10059*/
10060SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
10061
10062/*
10063** CAPI3REF: Checkpoint a database
10064** METHOD: sqlite3
10065**
10066** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
10067** operation on database X of [database connection] D in mode M.  Status
10068** information is written back into integers pointed to by L and C.)^
10069** ^(The M parameter must be a valid [checkpoint mode]:)^
10070**
10071** <dl>
10072** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
10073**   ^Checkpoint as many frames as possible without waiting for any database
10074**   readers or writers to finish, then sync the database file if all frames
10075**   in the log were checkpointed. ^The [busy-handler callback]
10076**   is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.
10077**   ^On the other hand, passive mode might leave the checkpoint unfinished
10078**   if there are concurrent readers or writers.
10079**
10080** <dt>SQLITE_CHECKPOINT_FULL<dd>
10081**   ^This mode blocks (it invokes the
10082**   [sqlite3_busy_handler|busy-handler callback]) until there is no
10083**   database writer and all readers are reading from the most recent database
10084**   snapshot. ^It then checkpoints all frames in the log file and syncs the
10085**   database file. ^This mode blocks new database writers while it is pending,
10086**   but new database readers are allowed to continue unimpeded.
10087**
10088** <dt>SQLITE_CHECKPOINT_RESTART<dd>
10089**   ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
10090**   that after checkpointing the log file it blocks (calls the
10091**   [busy-handler callback])
10092**   until all readers are reading from the database file only. ^This ensures
10093**   that the next writer will restart the log file from the beginning.
10094**   ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
10095**   database writer attempts while it is pending, but does not impede readers.
10096**
10097** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
10098**   ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
10099**   addition that it also truncates the log file to zero bytes just prior
10100**   to a successful return.
10101**
10102** <dt>SQLITE_CHECKPOINT_NOOP<dd>
10103**   ^This mode always checkpoints zero frames. The only reason to invoke
10104**   a NOOP checkpoint is to access the values returned by
10105**   sqlite3_wal_checkpoint_v2() via output parameters *pnLog and *pnCkpt.
10106** </dl>
10107**
10108** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
10109** the log file or to -1 if the checkpoint could not run because
10110** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
10111** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
10112** log file (including any that were already checkpointed before the function
10113** was called) or to -1 if the checkpoint could not run due to an error or
10114** because the database is not in WAL mode. ^Note that upon successful
10115** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
10116** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
10117**
10118** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
10119** any other process is running a checkpoint operation at the same time, the
10120** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a
10121** busy-handler configured, it will not be invoked in this case.
10122**
10123** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the
10124** exclusive "writer" lock on the database file. ^If the writer lock cannot be
10125** obtained immediately, and a busy-handler is configured, it is invoked and
10126** the writer lock retried until either the busy-handler returns 0 or the lock
10127** is successfully obtained. ^The busy-handler is also invoked while waiting for
10128** database readers as described above. ^If the busy-handler returns 0 before
10129** the writer lock is obtained or while waiting for database readers, the
10130** checkpoint operation proceeds from that point in the same way as
10131** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible
10132** without blocking any further. ^SQLITE_BUSY is returned in this case.
10133**
10134** ^If parameter zDb is NULL or points to a zero length string, then the
10135** specified operation is attempted on all WAL databases [attached] to
10136** [database connection] db.  In this case the
10137** values written to output parameters *pnLog and *pnCkpt are undefined. ^If
10138** an SQLITE_BUSY error is encountered when processing one or more of the
10139** attached WAL databases, the operation is still attempted on any remaining
10140** attached databases and SQLITE_BUSY is returned at the end. ^If any other
10141** error occurs while processing an attached database, processing is abandoned
10142** and the error code is returned to the caller immediately. ^If no error
10143** (SQLITE_BUSY or otherwise) is encountered while processing the attached
10144** databases, SQLITE_OK is returned.
10145**
10146** ^If database zDb is the name of an attached database that is not in WAL
10147** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
10148** zDb is not NULL (or a zero length string) and is not the name of any
10149** attached database, SQLITE_ERROR is returned to the caller.
10150**
10151** ^Unless it returns SQLITE_MISUSE,
10152** the sqlite3_wal_checkpoint_v2() interface
10153** sets the error information that is queried by
10154** [sqlite3_errcode()] and [sqlite3_errmsg()].
10155**
10156** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
10157** from SQL.
10158*/
10159SQLITE_API int sqlite3_wal_checkpoint_v2(
10160  sqlite3 *db,                    /* Database handle */
10161  const char *zDb,                /* Name of attached database (or NULL) */
10162  int eMode,                      /* SQLITE_CHECKPOINT_* value */
10163  int *pnLog,                     /* OUT: Size of WAL log in frames */
10164  int *pnCkpt                     /* OUT: Total number of frames checkpointed */
10165);
10166
10167/*
10168** CAPI3REF: Checkpoint Mode Values
10169** KEYWORDS: {checkpoint mode}
10170**
10171** These constants define all valid values for the "checkpoint mode" passed
10172** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
10173** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
10174** meaning of each of these checkpoint modes.
10175*/
10176#define SQLITE_CHECKPOINT_NOOP    -1  /* Do no work at all */
10177#define SQLITE_CHECKPOINT_PASSIVE  0  /* Do as much as possible w/o blocking */
10178#define SQLITE_CHECKPOINT_FULL     1  /* Wait for writers, then checkpoint */
10179#define SQLITE_CHECKPOINT_RESTART  2  /* Like FULL but wait for readers */
10180#define SQLITE_CHECKPOINT_TRUNCATE 3  /* Like RESTART but also truncate WAL */
10181
10182/*
10183** CAPI3REF: Virtual Table Interface Configuration
10184**
10185** This function may be called by either the [xConnect] or [xCreate] method
10186** of a [virtual table] implementation to configure
10187** various facets of the virtual table interface.
10188**
10189** If this interface is invoked outside the context of an xConnect or
10190** xCreate virtual table method then the behavior is undefined.
10191**
10192** In the call sqlite3_vtab_config(D,C,...) the D parameter is the
10193** [database connection] in which the virtual table is being created and
10194** which is passed in as the first argument to the [xConnect] or [xCreate]
10195** method that is invoking sqlite3_vtab_config().  The C parameter is one
10196** of the [virtual table configuration options].  The presence and meaning
10197** of parameters after C depend on which [virtual table configuration option]
10198** is used.
10199*/
10200SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
10201
10202/*
10203** CAPI3REF: Virtual Table Configuration Options
10204** KEYWORDS: {virtual table configuration options}
10205** KEYWORDS: {virtual table configuration option}
10206**
10207** These macros define the various options to the
10208** [sqlite3_vtab_config()] interface that [virtual table] implementations
10209** can use to customize and optimize their behavior.
10210**
10211** <dl>
10212** [[SQLITE_VTAB_CONSTRAINT_SUPPORT]]
10213** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT</dt>
10214** <dd>Calls of the form
10215** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
10216** where X is an integer.  If X is zero, then the [virtual table] whose
10217** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
10218** support constraints.  In this configuration (which is the default) if
10219** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
10220** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
10221** specified as part of the user's SQL statement, regardless of the actual
10222** ON CONFLICT mode specified.
10223**
10224** If X is non-zero, then the virtual table implementation guarantees
10225** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
10226** any modifications to internal or persistent data structures have been made.
10227** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite
10228** is able to roll back a statement or database transaction, and abandon
10229** or continue processing the current SQL statement as appropriate.
10230** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
10231** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
10232** had been ABORT.
10233**
10234** Virtual table implementations that are required to handle OR REPLACE
10235** must do so within the [xUpdate] method. If a call to the
10236** [sqlite3_vtab_on_conflict()] function indicates that the current ON
10237** CONFLICT policy is REPLACE, the virtual table implementation should
10238** silently replace the appropriate rows within the xUpdate callback and
10239** return SQLITE_OK. Or, if this is not possible, it may return
10240** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT
10241** constraint handling.
10242** </dd>
10243**
10244** [[SQLITE_VTAB_DIRECTONLY]]<dt>SQLITE_VTAB_DIRECTONLY</dt>
10245** <dd>Calls of the form
10246** [sqlite3_vtab_config](db,SQLITE_VTAB_DIRECTONLY) from within the
10247** the [xConnect] or [xCreate] methods of a [virtual table] implementation
10248** prohibits that virtual table from being used from within triggers and
10249** views.
10250** </dd>
10251**
10252** [[SQLITE_VTAB_INNOCUOUS]]<dt>SQLITE_VTAB_INNOCUOUS</dt>
10253** <dd>Calls of the form
10254** [sqlite3_vtab_config](db,SQLITE_VTAB_INNOCUOUS) from within the
10255** [xConnect] or [xCreate] methods of a [virtual table] implementation
10256** identify that virtual table as being safe to use from within triggers
10257** and views.  Conceptually, the SQLITE_VTAB_INNOCUOUS tag means that the
10258** virtual table can do no serious harm even if it is controlled by a
10259** malicious hacker.  Developers should avoid setting the SQLITE_VTAB_INNOCUOUS
10260** flag unless absolutely necessary.
10261** </dd>
10262**
10263** [[SQLITE_VTAB_USES_ALL_SCHEMAS]]<dt>SQLITE_VTAB_USES_ALL_SCHEMAS</dt>
10264** <dd>Calls of the form
10265** [sqlite3_vtab_config](db,SQLITE_VTAB_USES_ALL_SCHEMA) from within the
10266** the [xConnect] or [xCreate] methods of a [virtual table] implementation
10267** instruct the query planner to begin at least a read transaction on
10268** all schemas ("main", "temp", and any ATTACH-ed databases) whenever the
10269** virtual table is used.
10270** </dd>
10271** </dl>
10272*/
10273#define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
10274#define SQLITE_VTAB_INNOCUOUS          2
10275#define SQLITE_VTAB_DIRECTONLY         3
10276#define SQLITE_VTAB_USES_ALL_SCHEMAS   4
10277
10278/*
10279** CAPI3REF: Determine The Virtual Table Conflict Policy
10280**
10281** This function may only be called from within a call to the [xUpdate] method
10282** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
10283** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
10284** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
10285** of the SQL statement that triggered the call to the [xUpdate] method of the
10286** [virtual table].
10287*/
10288SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
10289
10290/*
10291** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE
10292**
10293** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn]
10294** method of a [virtual table], then it might return true if the
10295** column is being fetched as part of an UPDATE operation during which the
10296** column value will not change.  The virtual table implementation can use
10297** this hint as permission to substitute a return value that is less
10298** expensive to compute and that the corresponding
10299** [xUpdate] method understands as a "no-change" value.
10300**
10301** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that
10302** the column is not changed by the UPDATE statement, then the xColumn
10303** method can optionally return without setting a result, without calling
10304** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces].
10305** In that case, [sqlite3_value_nochange(X)] will return true for the
10306** same column in the [xUpdate] method.
10307**
10308** The sqlite3_vtab_nochange() routine is an optimization.  Virtual table
10309** implementations should continue to give a correct answer even if the
10310** sqlite3_vtab_nochange() interface were to always return false.  In the
10311** current implementation, the sqlite3_vtab_nochange() interface does always
10312** returns false for the enhanced [UPDATE FROM] statement.
10313*/
10314SQLITE_API int sqlite3_vtab_nochange(sqlite3_context*);
10315
10316/*
10317** CAPI3REF: Determine The Collation For a Virtual Table Constraint
10318** METHOD: sqlite3_index_info
10319**
10320** This function may only be called from within a call to the [xBestIndex]
10321** method of a [virtual table].  This function returns a pointer to a string
10322** that is the name of the appropriate collation sequence to use for text
10323** comparisons on the constraint identified by its arguments.
10324**
10325** The first argument must be the pointer to the [sqlite3_index_info] object
10326** that is the first parameter to the xBestIndex() method. The second argument
10327** must be an index into the aConstraint[] array belonging to the
10328** sqlite3_index_info structure passed to xBestIndex.
10329**
10330** Important:
10331** The first parameter must be the same pointer that is passed into the
10332** xBestMethod() method.  The first parameter may not be a pointer to a
10333** different [sqlite3_index_info] object, even an exact copy.
10334**
10335** The return value is computed as follows:
10336**
10337** <ol>
10338** <li><p> If the constraint comes from a WHERE clause expression that contains
10339**         a [COLLATE operator], then the name of the collation specified by
10340**         that COLLATE operator is returned.
10341** <li><p> If there is no COLLATE operator, but the column that is the subject
10342**         of the constraint specifies an alternative collating sequence via
10343**         a [COLLATE clause] on the column definition within the CREATE TABLE
10344**         statement that was passed into [sqlite3_declare_vtab()], then the
10345**         name of that alternative collating sequence is returned.
10346** <li><p> Otherwise, "BINARY" is returned.
10347** </ol>
10348*/
10349SQLITE_API const char *sqlite3_vtab_collation(sqlite3_index_info*,int);
10350
10351/*
10352** CAPI3REF: Determine if a virtual table query is DISTINCT
10353** METHOD: sqlite3_index_info
10354**
10355** This API may only be used from within an [xBestIndex|xBestIndex method]
10356** of a [virtual table] implementation. The result of calling this
10357** interface from outside of xBestIndex() is undefined and probably harmful.
10358**
10359** ^The sqlite3_vtab_distinct() interface returns an integer between 0 and
10360** 3.  The integer returned by sqlite3_vtab_distinct()
10361** gives the virtual table additional information about how the query
10362** planner wants the output to be ordered. As long as the virtual table
10363** can meet the ordering requirements of the query planner, it may set
10364** the "orderByConsumed" flag.
10365**
10366** <ol><li value="0"><p>
10367** ^If the sqlite3_vtab_distinct() interface returns 0, that means
10368** that the query planner needs the virtual table to return all rows in the
10369** sort order defined by the "nOrderBy" and "aOrderBy" fields of the
10370** [sqlite3_index_info] object.  This is the default expectation.  If the
10371** virtual table outputs all rows in sorted order, then it is always safe for
10372** the xBestIndex method to set the "orderByConsumed" flag, regardless of
10373** the return value from sqlite3_vtab_distinct().
10374** <li value="1"><p>
10375** ^(If the sqlite3_vtab_distinct() interface returns 1, that means
10376** that the query planner does not need the rows to be returned in sorted order
10377** as long as all rows with the same values in all columns identified by the
10378** "aOrderBy" field are adjacent.)^  This mode is used when the query planner
10379** is doing a GROUP BY.
10380** <li value="2"><p>
10381** ^(If the sqlite3_vtab_distinct() interface returns 2, that means
10382** that the query planner does not need the rows returned in any particular
10383** order, as long as rows with the same values in all columns identified
10384** by "aOrderBy" are adjacent.)^  ^(Furthermore, when two or more rows
10385** contain the same values for all columns identified by "colUsed", all but
10386** one such row may optionally be omitted from the result.)^
10387** The virtual table is not required to omit rows that are duplicates
10388** over the "colUsed" columns, but if the virtual table can do that without
10389** too much extra effort, it could potentially help the query to run faster.
10390** This mode is used for a DISTINCT query.
10391** <li value="3"><p>
10392** ^(If the sqlite3_vtab_distinct() interface returns 3, that means the
10393** virtual table must return rows in the order defined by "aOrderBy" as
10394** if the sqlite3_vtab_distinct() interface had returned 0.  However if
10395** two or more rows in the result have the same values for all columns
10396** identified by "colUsed", then all but one such row may optionally be
10397** omitted.)^  Like when the return value is 2, the virtual table
10398** is not required to omit rows that are duplicates over the "colUsed"
10399** columns, but if the virtual table can do that without
10400** too much extra effort, it could potentially help the query to run faster.
10401** This mode is used for queries
10402** that have both DISTINCT and ORDER BY clauses.
10403** </ol>
10404**
10405** <p>The following table summarizes the conditions under which the
10406** virtual table is allowed to set the "orderByConsumed" flag based on
10407** the value returned by sqlite3_vtab_distinct().  This table is a
10408** restatement of the previous four paragraphs:
10409**
10410** <table border=1 cellspacing=0 cellpadding=10 width="90%">
10411** <tr>
10412** <td valign="top">sqlite3_vtab_distinct() return value
10413** <td valign="top">Rows are returned in aOrderBy order
10414** <td valign="top">Rows with the same value in all aOrderBy columns are
10415**                  adjacent
10416** <td valign="top">Duplicates over all colUsed columns may be omitted
10417** <tr><td>0<td>yes<td>yes<td>no
10418** <tr><td>1<td>no<td>yes<td>no
10419** <tr><td>2<td>no<td>yes<td>yes
10420** <tr><td>3<td>yes<td>yes<td>yes
10421** </table>
10422**
10423** ^For the purposes of comparing virtual table output values to see if the
10424** values are the same value for sorting purposes, two NULL values are
10425** considered to be the same.  In other words, the comparison operator is "IS"
10426** (or "IS NOT DISTINCT FROM") and not "==".
10427**
10428** If a virtual table implementation is unable to meet the requirements
10429** specified above, then it must not set the "orderByConsumed" flag in the
10430** [sqlite3_index_info] object or an incorrect answer may result.
10431**
10432** ^A virtual table implementation is always free to return rows in any order
10433** it wants, as long as the "orderByConsumed" flag is not set.  ^When the
10434** "orderByConsumed" flag is unset, the query planner will add extra
10435** [bytecode] to ensure that the final results returned by the SQL query are
10436** ordered correctly.  The use of the "orderByConsumed" flag and the
10437** sqlite3_vtab_distinct() interface is merely an optimization.  ^Careful
10438** use of the sqlite3_vtab_distinct() interface and the "orderByConsumed"
10439** flag might help queries against a virtual table to run faster.  Being
10440** overly aggressive and setting the "orderByConsumed" flag when it is not
10441** valid to do so, on the other hand, might cause SQLite to return incorrect
10442** results.
10443*/
10444SQLITE_API int sqlite3_vtab_distinct(sqlite3_index_info*);
10445
10446/*
10447** CAPI3REF: Identify and handle IN constraints in xBestIndex
10448**
10449** This interface may only be used from within an
10450** [xBestIndex|xBestIndex() method] of a [virtual table] implementation.
10451** The result of invoking this interface from any other context is
10452** undefined and probably harmful.
10453**
10454** ^(A constraint on a virtual table of the form
10455** "[IN operator|column IN (...)]" is
10456** communicated to the xBestIndex method as a
10457** [SQLITE_INDEX_CONSTRAINT_EQ] constraint.)^  If xBestIndex wants to use
10458** this constraint, it must set the corresponding
10459** aConstraintUsage[].argvIndex to a positive integer.  ^(Then, under
10460** the usual mode of handling IN operators, SQLite generates [bytecode]
10461** that invokes the [xFilter|xFilter() method] once for each value
10462** on the right-hand side of the IN operator.)^  Thus the virtual table
10463** only sees a single value from the right-hand side of the IN operator
10464** at a time.
10465**
10466** In some cases, however, it would be advantageous for the virtual
10467** table to see all values on the right-hand of the IN operator all at
10468** once.  The sqlite3_vtab_in() interfaces facilitates this in two ways:
10469**
10470** <ol>
10471** <li><p>
10472**   ^A call to sqlite3_vtab_in(P,N,-1) will return true (non-zero)
10473**   if and only if the [sqlite3_index_info|P->aConstraint][N] constraint
10474**   is an [IN operator] that can be processed all at once.  ^In other words,
10475**   sqlite3_vtab_in() with -1 in the third argument is a mechanism
10476**   by which the virtual table can ask SQLite if all-at-once processing
10477**   of the IN operator is even possible.
10478**
10479** <li><p>
10480**   ^A call to sqlite3_vtab_in(P,N,F) with F==1 or F==0 indicates
10481**   to SQLite that the virtual table does or does not want to process
10482**   the IN operator all-at-once, respectively.  ^Thus when the third
10483**   parameter (F) is non-negative, this interface is the mechanism by
10484**   which the virtual table tells SQLite how it wants to process the
10485**   IN operator.
10486** </ol>
10487**
10488** ^The sqlite3_vtab_in(P,N,F) interface can be invoked multiple times
10489** within the same xBestIndex method call.  ^For any given P,N pair,
10490** the return value from sqlite3_vtab_in(P,N,F) will always be the same
10491** within the same xBestIndex call.  ^If the interface returns true
10492** (non-zero), that means that the constraint is an IN operator
10493** that can be processed all-at-once.  ^If the constraint is not an IN
10494** operator or cannot be processed all-at-once, then the interface returns
10495** false.
10496**
10497** ^(All-at-once processing of the IN operator is selected if both of the
10498** following conditions are met:
10499**
10500** <ol>
10501** <li><p> The P->aConstraintUsage[N].argvIndex value is set to a positive
10502** integer.  This is how the virtual table tells SQLite that it wants to
10503** use the N-th constraint.
10504**
10505** <li><p> The last call to sqlite3_vtab_in(P,N,F) for which F was
10506** non-negative had F>=1.
10507** </ol>)^
10508**
10509** ^If either or both of the conditions above are false, then SQLite uses
10510** the traditional one-at-a-time processing strategy for the IN constraint.
10511** ^If both conditions are true, then the argvIndex-th parameter to the
10512** xFilter method will be an [sqlite3_value] that appears to be NULL,
10513** but which can be passed to [sqlite3_vtab_in_first()] and
10514** [sqlite3_vtab_in_next()] to find all values on the right-hand side
10515** of the IN constraint.
10516*/
10517SQLITE_API int sqlite3_vtab_in(sqlite3_index_info*, int iCons, int bHandle);
10518
10519/*
10520** CAPI3REF: Find all elements on the right-hand side of an IN constraint.
10521**
10522** These interfaces are only useful from within the
10523** [xFilter|xFilter() method] of a [virtual table] implementation.
10524** The result of invoking these interfaces from any other context
10525** is undefined and probably harmful.
10526**
10527** The X parameter in a call to sqlite3_vtab_in_first(X,P) or
10528** sqlite3_vtab_in_next(X,P) should be one of the parameters to the
10529** xFilter method which invokes these routines, and specifically
10530** a parameter that was previously selected for all-at-once IN constraint
10531** processing using the [sqlite3_vtab_in()] interface in the
10532** [xBestIndex|xBestIndex method].  ^(If the X parameter is not
10533** an xFilter argument that was selected for all-at-once IN constraint
10534** processing, then these routines return [SQLITE_ERROR].)^
10535**
10536** ^(Use these routines to access all values on the right-hand side
10537** of the IN constraint using code like the following:
10538**
10539** <blockquote><pre>
10540** &nbsp;  for(rc=sqlite3_vtab_in_first(pList, &pVal);
10541** &nbsp;      rc==SQLITE_OK && pVal;
10542** &nbsp;      rc=sqlite3_vtab_in_next(pList, &pVal)
10543** &nbsp;  ){
10544** &nbsp;    // do something with pVal
10545** &nbsp;  }
10546** &nbsp;  if( rc!=SQLITE_DONE ){
10547** &nbsp;    // an error has occurred
10548** &nbsp;  }
10549** </pre></blockquote>)^
10550**
10551** ^On success, the sqlite3_vtab_in_first(X,P) and sqlite3_vtab_in_next(X,P)
10552** routines return SQLITE_OK and set *P to point to the first or next value
10553** on the RHS of the IN constraint.  ^If there are no more values on the
10554** right hand side of the IN constraint, then *P is set to NULL and these
10555** routines return [SQLITE_DONE].  ^The return value might be
10556** some other value, such as SQLITE_NOMEM, in the event of a malfunction.
10557**
10558** The *ppOut values returned by these routines are only valid until the
10559** next call to either of these routines or until the end of the xFilter
10560** method from which these routines were called.  If the virtual table
10561** implementation needs to retain the *ppOut values for longer, it must make
10562** copies.  The *ppOut values are [protected sqlite3_value|protected].
10563*/
10564SQLITE_API int sqlite3_vtab_in_first(sqlite3_value *pVal, sqlite3_value **ppOut);
10565SQLITE_API int sqlite3_vtab_in_next(sqlite3_value *pVal, sqlite3_value **ppOut);
10566
10567/*
10568** CAPI3REF: Constraint values in xBestIndex()
10569** METHOD: sqlite3_index_info
10570**
10571** This API may only be used from within the [xBestIndex|xBestIndex method]
10572** of a [virtual table] implementation. The result of calling this interface
10573** from outside of an xBestIndex method are undefined and probably harmful.
10574**
10575** ^When the sqlite3_vtab_rhs_value(P,J,V) interface is invoked from within
10576** the [xBestIndex] method of a [virtual table] implementation, with P being
10577** a copy of the [sqlite3_index_info] object pointer passed into xBestIndex and
10578** J being a 0-based index into P->aConstraint[], then this routine
10579** attempts to set *V to the value of the right-hand operand of
10580** that constraint if the right-hand operand is known.  ^If the
10581** right-hand operand is not known, then *V is set to a NULL pointer.
10582** ^The sqlite3_vtab_rhs_value(P,J,V) interface returns SQLITE_OK if
10583** and only if *V is set to a value.  ^The sqlite3_vtab_rhs_value(P,J,V)
10584** inteface returns SQLITE_NOTFOUND if the right-hand side of the J-th
10585** constraint is not available.  ^The sqlite3_vtab_rhs_value() interface
10586** can return a result code other than SQLITE_OK or SQLITE_NOTFOUND if
10587** something goes wrong.
10588**
10589** The sqlite3_vtab_rhs_value() interface is usually only successful if
10590** the right-hand operand of a constraint is a literal value in the original
10591** SQL statement.  If the right-hand operand is an expression or a reference
10592** to some other column or a [host parameter], then sqlite3_vtab_rhs_value()
10593** will probably return [SQLITE_NOTFOUND].
10594**
10595** ^(Some constraints, such as [SQLITE_INDEX_CONSTRAINT_ISNULL] and
10596** [SQLITE_INDEX_CONSTRAINT_ISNOTNULL], have no right-hand operand.  For such
10597** constraints, sqlite3_vtab_rhs_value() always returns SQLITE_NOTFOUND.)^
10598**
10599** ^The [sqlite3_value] object returned in *V is a protected sqlite3_value
10600** and remains valid for the duration of the xBestIndex method call.
10601** ^When xBestIndex returns, the sqlite3_value object returned by
10602** sqlite3_vtab_rhs_value() is automatically deallocated.
10603**
10604** The "_rhs_" in the name of this routine is an abbreviation for
10605** "Right-Hand Side".
10606*/
10607SQLITE_API int sqlite3_vtab_rhs_value(sqlite3_index_info*, int, sqlite3_value **ppVal);
10608
10609/*
10610** CAPI3REF: Conflict resolution modes
10611** KEYWORDS: {conflict resolution mode}
10612**
10613** These constants are returned by [sqlite3_vtab_on_conflict()] to
10614** inform a [virtual table] implementation of the [ON CONFLICT] mode
10615** for the SQL statement being evaluated.
10616**
10617** Note that the [SQLITE_IGNORE] constant is also used as a potential
10618** return value from the [sqlite3_set_authorizer()] callback and that
10619** [SQLITE_ABORT] is also a [result code].
10620*/
10621#define SQLITE_ROLLBACK 1
10622/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
10623#define SQLITE_FAIL     3
10624/* #define SQLITE_ABORT 4  // Also an error code */
10625#define SQLITE_REPLACE  5
10626
10627/*
10628** CAPI3REF: Prepared Statement Scan Status Opcodes
10629** KEYWORDS: {scanstatus options}
10630**
10631** The following constants can be used for the T parameter to the
10632** [sqlite3_stmt_scanstatus(S,X,T,V)] interface.  Each constant designates a
10633** different metric for sqlite3_stmt_scanstatus() to return.
10634**
10635** When the value returned to V is a string, space to hold that string is
10636** managed by the prepared statement S and will be automatically freed when
10637** S is finalized.
10638**
10639** Not all values are available for all query elements. When a value is
10640** not available, the output variable is set to -1 if the value is numeric,
10641** or to NULL if it is a string (SQLITE_SCANSTAT_NAME).
10642**
10643** <dl>
10644** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
10645** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be
10646** set to the total number of times that the X-th loop has run.</dd>
10647**
10648** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
10649** <dd>^The [sqlite3_int64] variable pointed to by the V parameter will be set
10650** to the total number of rows examined by all iterations of the X-th loop.</dd>
10651**
10652** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
10653** <dd>^The "double" variable pointed to by the V parameter will be set to the
10654** query planner's estimate for the average number of rows output from each
10655** iteration of the X-th loop.  If the query planner's estimate was accurate,
10656** then this value will approximate the quotient NVISIT/NLOOP and the
10657** product of this value for all prior loops with the same SELECTID will
10658** be the NLOOP value for the current loop.</dd>
10659**
10660** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
10661** <dd>^The "const char *" variable pointed to by the V parameter will be set
10662** to a zero-terminated UTF-8 string containing the name of the index or table
10663** used for the X-th loop.</dd>
10664**
10665** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
10666** <dd>^The "const char *" variable pointed to by the V parameter will be set
10667** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
10668** description for the X-th loop.</dd>
10669**
10670** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECTID</dt>
10671** <dd>^The "int" variable pointed to by the V parameter will be set to the
10672** id for the X-th query plan element. The id value is unique within the
10673** statement. The select-id is the same value as is output in the first
10674** column of an [EXPLAIN QUERY PLAN] query.</dd>
10675**
10676** [[SQLITE_SCANSTAT_PARENTID]] <dt>SQLITE_SCANSTAT_PARENTID</dt>
10677** <dd>The "int" variable pointed to by the V parameter will be set to the
10678** id of the parent of the current query element, if applicable, or
10679** to zero if the query element has no parent. This is the same value as
10680** returned in the second column of an [EXPLAIN QUERY PLAN] query.</dd>
10681**
10682** [[SQLITE_SCANSTAT_NCYCLE]] <dt>SQLITE_SCANSTAT_NCYCLE</dt>
10683** <dd>The sqlite3_int64 output value is set to the number of cycles,
10684** according to the processor time-stamp counter, that elapsed while the
10685** query element was being processed. This value is not available for
10686** all query elements - if it is unavailable the output variable is
10687** set to -1.</dd>
10688** </dl>
10689*/
10690#define SQLITE_SCANSTAT_NLOOP    0
10691#define SQLITE_SCANSTAT_NVISIT   1
10692#define SQLITE_SCANSTAT_EST      2
10693#define SQLITE_SCANSTAT_NAME     3
10694#define SQLITE_SCANSTAT_EXPLAIN  4
10695#define SQLITE_SCANSTAT_SELECTID 5
10696#define SQLITE_SCANSTAT_PARENTID 6
10697#define SQLITE_SCANSTAT_NCYCLE   7
10698
10699/*
10700** CAPI3REF: Prepared Statement Scan Status
10701** METHOD: sqlite3_stmt
10702**
10703** These interfaces return information about the predicted and measured
10704** performance for pStmt.  Advanced applications can use this
10705** interface to compare the predicted and the measured performance and
10706** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
10707**
10708** Since this interface is expected to be rarely used, it is only
10709** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
10710** compile-time option.
10711**
10712** The "iScanStatusOp" parameter determines which status information to return.
10713** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
10714** of this interface is undefined. ^The requested measurement is written into
10715** a variable pointed to by the "pOut" parameter.
10716**
10717** The "flags" parameter must be passed a mask of flags. At present only
10718** one flag is defined - [SQLITE_SCANSTAT_COMPLEX]. If SQLITE_SCANSTAT_COMPLEX
10719** is specified, then status information is available for all elements
10720** of a query plan that are reported by "[EXPLAIN QUERY PLAN]" output. If
10721** SQLITE_SCANSTAT_COMPLEX is not specified, then only query plan elements
10722** that correspond to query loops (the "SCAN..." and "SEARCH..." elements of
10723** the EXPLAIN QUERY PLAN output) are available. Invoking API
10724** sqlite3_stmt_scanstatus() is equivalent to calling
10725** sqlite3_stmt_scanstatus_v2() with a zeroed flags parameter.
10726**
10727** Parameter "idx" identifies the specific query element to retrieve statistics
10728** for. Query elements are numbered starting from zero. A value of -1 may
10729** retrieve statistics for the entire query. ^If idx is out of range
10730** - less than -1 or greater than or equal to the total number of query
10731** elements used to implement the statement - a non-zero value is returned and
10732** the variable that pOut points to is unchanged.
10733**
10734** See also: [sqlite3_stmt_scanstatus_reset()] and the
10735** [nexec and ncycle] columns of the [bytecode virtual table].
10736*/
10737SQLITE_API int sqlite3_stmt_scanstatus(
10738  sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
10739  int idx,                  /* Index of loop to report on */
10740  int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
10741  void *pOut                /* Result written here */
10742);
10743SQLITE_API int sqlite3_stmt_scanstatus_v2(
10744  sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
10745  int idx,                  /* Index of loop to report on */
10746  int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
10747  int flags,                /* Mask of flags defined below */
10748  void *pOut                /* Result written here */
10749);
10750
10751/*
10752** CAPI3REF: Prepared Statement Scan Status
10753** KEYWORDS: {scan status flags}
10754*/
10755#define SQLITE_SCANSTAT_COMPLEX 0x0001
10756
10757/*
10758** CAPI3REF: Zero Scan-Status Counters
10759** METHOD: sqlite3_stmt
10760**
10761** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
10762**
10763** This API is only available if the library is built with pre-processor
10764** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
10765*/
10766SQLITE_API void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
10767
10768/*
10769** CAPI3REF: Flush caches to disk mid-transaction
10770** METHOD: sqlite3
10771**
10772** ^If a write-transaction is open on [database connection] D when the
10773** [sqlite3_db_cacheflush(D)] interface is invoked, any dirty
10774** pages in the pager-cache that are not currently in use are written out
10775** to disk. A dirty page may be in use if a database cursor created by an
10776** active SQL statement is reading from it, or if it is page 1 of a database
10777** file (page 1 is always "in use").  ^The [sqlite3_db_cacheflush(D)]
10778** interface flushes caches for all schemas - "main", "temp", and
10779** any [attached] databases.
10780**
10781** ^If this function needs to obtain extra database locks before dirty pages
10782** can be flushed to disk, it does so. ^If those locks cannot be obtained
10783** immediately and there is a busy-handler callback configured, it is invoked
10784** in the usual manner. ^If the required lock still cannot be obtained, then
10785** the database is skipped and an attempt made to flush any dirty pages
10786** belonging to the next (if any) database. ^If any databases are skipped
10787** because locks cannot be obtained, but no other error occurs, this
10788** function returns SQLITE_BUSY.
10789**
10790** ^If any other error occurs while flushing dirty pages to disk (for
10791** example an IO error or out-of-memory condition), then processing is
10792** abandoned and an SQLite [error code] is returned to the caller immediately.
10793**
10794** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK.
10795**
10796** ^This function does not set the database handle error code or message
10797** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions.
10798*/
10799SQLITE_API int sqlite3_db_cacheflush(sqlite3*);
10800
10801/*
10802** CAPI3REF: The pre-update hook.
10803** METHOD: sqlite3
10804**
10805** ^These interfaces are only available if SQLite is compiled using the
10806** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option.
10807**
10808** ^The [sqlite3_preupdate_hook()] interface registers a callback function
10809** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation
10810** on a database table.
10811** ^At most one preupdate hook may be registered at a time on a single
10812** [database connection]; each call to [sqlite3_preupdate_hook()] overrides
10813** the previous setting.
10814** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()]
10815** with a NULL pointer as the second parameter.
10816** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as
10817** the first parameter to callbacks.
10818**
10819** ^The preupdate hook only fires for changes to real database tables; the
10820** preupdate hook is not invoked for changes to [virtual tables] or to
10821** system tables like sqlite_sequence or sqlite_stat1.
10822**
10823** ^The second parameter to the preupdate callback is a pointer to
10824** the [database connection] that registered the preupdate hook.
10825** ^The third parameter to the preupdate callback is one of the constants
10826** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the
10827** kind of update operation that is about to occur.
10828** ^(The fourth parameter to the preupdate callback is the name of the
10829** database within the database connection that is being modified.  This
10830** will be "main" for the main database or "temp" for TEMP tables or
10831** the name given after the AS keyword in the [ATTACH] statement for attached
10832** databases.)^
10833** ^The fifth parameter to the preupdate callback is the name of the
10834** table that is being modified.
10835**
10836** For an UPDATE or DELETE operation on a [rowid table], the sixth
10837** parameter passed to the preupdate callback is the initial [rowid] of the
10838** row being modified or deleted. For an INSERT operation on a rowid table,
10839** or any operation on a WITHOUT ROWID table, the value of the sixth
10840** parameter is undefined. For an INSERT or UPDATE on a rowid table the
10841** seventh parameter is the final rowid value of the row being inserted
10842** or updated. The value of the seventh parameter passed to the callback
10843** function is not defined for operations on WITHOUT ROWID tables, or for
10844** DELETE operations on rowid tables.
10845**
10846** ^The sqlite3_preupdate_hook(D,C,P) function returns the P argument from
10847** the previous call on the same [database connection] D, or NULL for
10848** the first call on D.
10849**
10850** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()],
10851** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces
10852** provide additional information about a preupdate event. These routines
10853** may only be called from within a preupdate callback.  Invoking any of
10854** these routines from outside of a preupdate callback or with a
10855** [database connection] pointer that is different from the one supplied
10856** to the preupdate callback results in undefined and probably undesirable
10857** behavior.
10858**
10859** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns
10860** in the row that is being inserted, updated, or deleted.
10861**
10862** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to
10863** a [protected sqlite3_value] that contains the value of the Nth column of
10864** the table row before it is updated.  The N parameter must be between 0
10865** and one less than the number of columns or the behavior will be
10866** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE
10867** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the
10868** behavior is undefined.  The [sqlite3_value] that P points to
10869** will be destroyed when the preupdate callback returns.
10870**
10871** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to
10872** a [protected sqlite3_value] that contains the value of the Nth column of
10873** the table row after it is updated.  The N parameter must be between 0
10874** and one less than the number of columns or the behavior will be
10875** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE
10876** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the
10877** behavior is undefined.  The [sqlite3_value] that P points to
10878** will be destroyed when the preupdate callback returns.
10879**
10880** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate
10881** callback was invoked as a result of a direct insert, update, or delete
10882** operation; or 1 for inserts, updates, or deletes invoked by top-level
10883** triggers; or 2 for changes resulting from triggers called by top-level
10884** triggers; and so forth.
10885**
10886** When the [sqlite3_blob_write()] API is used to update a blob column,
10887** the pre-update hook is invoked with SQLITE_DELETE, because
10888** the new values are not yet available. In this case, when a
10889** callback made with op==SQLITE_DELETE is actually a write using the
10890** sqlite3_blob_write() API, the [sqlite3_preupdate_blobwrite()] returns
10891** the index of the column being written. In other cases, where the
10892** pre-update hook is being invoked for some other reason, including a
10893** regular DELETE, sqlite3_preupdate_blobwrite() returns -1.
10894**
10895** See also:  [sqlite3_update_hook()]
10896*/
10897#if defined(SQLITE_ENABLE_PREUPDATE_HOOK)
10898SQLITE_API void *sqlite3_preupdate_hook(
10899  sqlite3 *db,
10900  void(*xPreUpdate)(
10901    void *pCtx,                   /* Copy of third arg to preupdate_hook() */
10902    sqlite3 *db,                  /* Database handle */
10903    int op,                       /* SQLITE_UPDATE, DELETE or INSERT */
10904    char const *zDb,              /* Database name */
10905    char const *zName,            /* Table name */
10906    sqlite3_int64 iKey1,          /* Rowid of row about to be deleted/updated */
10907    sqlite3_int64 iKey2           /* New rowid value (for a rowid UPDATE) */
10908  ),
10909  void*
10910);
10911SQLITE_API int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **);
10912SQLITE_API int sqlite3_preupdate_count(sqlite3 *);
10913SQLITE_API int sqlite3_preupdate_depth(sqlite3 *);
10914SQLITE_API int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **);
10915SQLITE_API int sqlite3_preupdate_blobwrite(sqlite3 *);
10916#endif
10917
10918/*
10919** CAPI3REF: Low-level system error code
10920** METHOD: sqlite3
10921**
10922** ^Attempt to return the underlying operating system error code or error
10923** number that caused the most recent I/O error or failure to open a file.
10924** The return value is OS-dependent.  For example, on unix systems, after
10925** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be
10926** called to get back the underlying "errno" that caused the problem, such
10927** as ENOSPC, EAUTH, EISDIR, and so forth.
10928*/
10929SQLITE_API int sqlite3_system_errno(sqlite3*);
10930
10931/*
10932** CAPI3REF: Database Snapshot
10933** KEYWORDS: {snapshot} {sqlite3_snapshot}
10934**
10935** An instance of the snapshot object records the state of a [WAL mode]
10936** database for some specific point in history.
10937**
10938** In [WAL mode], multiple [database connections] that are open on the
10939** same database file can each be reading a different historical version
10940** of the database file.  When a [database connection] begins a read
10941** transaction, that connection sees an unchanging copy of the database
10942** as it existed for the point in time when the transaction first started.
10943** Subsequent changes to the database from other connections are not seen
10944** by the reader until a new read transaction is started.
10945**
10946** The sqlite3_snapshot object records state information about an historical
10947** version of the database file so that it is possible to later open a new read
10948** transaction that sees that historical version of the database rather than
10949** the most recent version.
10950*/
10951typedef struct sqlite3_snapshot {
10952  unsigned char hidden[48];
10953} sqlite3_snapshot;
10954
10955/*
10956** CAPI3REF: Record A Database Snapshot
10957** CONSTRUCTOR: sqlite3_snapshot
10958**
10959** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a
10960** new [sqlite3_snapshot] object that records the current state of
10961** schema S in database connection D.  ^On success, the
10962** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly
10963** created [sqlite3_snapshot] object into *P and returns SQLITE_OK.
10964** If there is not already a read-transaction open on schema S when
10965** this function is called, one is opened automatically.
10966**
10967** If a read-transaction is opened by this function, then it is guaranteed
10968** that the returned snapshot object may not be invalidated by a database
10969** writer or checkpointer until after the read-transaction is closed. This
10970** is not guaranteed if a read-transaction is already open when this
10971** function is called. In that case, any subsequent write or checkpoint
10972** operation on the database may invalidate the returned snapshot handle,
10973** even while the read-transaction remains open.
10974**
10975** The following must be true for this function to succeed. If any of
10976** the following statements are false when sqlite3_snapshot_get() is
10977** called, SQLITE_ERROR is returned. The final value of *P is undefined
10978** in this case.
10979**
10980** <ul>
10981**   <li> The database handle must not be in [autocommit mode].
10982**
10983**   <li> Schema S of [database connection] D must be a [WAL mode] database.
10984**
10985**   <li> There must not be a write transaction open on schema S of database
10986**        connection D.
10987**
10988**   <li> One or more transactions must have been written to the current wal
10989**        file since it was created on disk (by any connection). This means
10990**        that a snapshot cannot be taken on a wal mode database with no wal
10991**        file immediately after it is first opened. At least one transaction
10992**        must be written to it first.
10993** </ul>
10994**
10995** This function may also return SQLITE_NOMEM.  If it is called with the
10996** database handle in autocommit mode but fails for some other reason,
10997** whether or not a read transaction is opened on schema S is undefined.
10998**
10999** The [sqlite3_snapshot] object returned from a successful call to
11000** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()]
11001** to avoid a memory leak.
11002**
11003** The [sqlite3_snapshot_get()] interface is only available when the
11004** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
11005*/
11006SQLITE_API int sqlite3_snapshot_get(
11007  sqlite3 *db,
11008  const char *zSchema,
11009  sqlite3_snapshot **ppSnapshot
11010);
11011
11012/*
11013** CAPI3REF: Start a read transaction on an historical snapshot
11014** METHOD: sqlite3_snapshot
11015**
11016** ^The [sqlite3_snapshot_open(D,S,P)] interface either starts a new read
11017** transaction or upgrades an existing one for schema S of
11018** [database connection] D such that the read transaction refers to
11019** historical [snapshot] P, rather than the most recent change to the
11020** database. ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK
11021** on success or an appropriate [error code] if it fails.
11022**
11023** ^In order to succeed, the database connection must not be in
11024** [autocommit mode] when [sqlite3_snapshot_open(D,S,P)] is called. If there
11025** is already a read transaction open on schema S, then the database handle
11026** must have no active statements (SELECT statements that have been passed
11027** to sqlite3_step() but not sqlite3_reset() or sqlite3_finalize()).
11028** SQLITE_ERROR is returned if either of these conditions is violated, or
11029** if schema S does not exist, or if the snapshot object is invalid.
11030**
11031** ^A call to sqlite3_snapshot_open() will fail to open if the specified
11032** snapshot has been overwritten by a [checkpoint]. In this case
11033** SQLITE_ERROR_SNAPSHOT is returned.
11034**
11035** If there is already a read transaction open when this function is
11036** invoked, then the same read transaction remains open (on the same
11037** database snapshot) if SQLITE_ERROR, SQLITE_BUSY or SQLITE_ERROR_SNAPSHOT
11038** is returned. If another error code - for example SQLITE_PROTOCOL or an
11039** SQLITE_IOERR error code - is returned, then the final state of the
11040** read transaction is undefined. If SQLITE_OK is returned, then the
11041** read transaction is now open on database snapshot P.
11042**
11043** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the
11044** database connection D does not know that the database file for
11045** schema S is in [WAL mode].  A database connection might not know
11046** that the database file is in [WAL mode] if there has been no prior
11047** I/O on that database connection, or if the database entered [WAL mode]
11048** after the most recent I/O on the database connection.)^
11049** (Hint: Run "[PRAGMA application_id]" against a newly opened
11050** database connection in order to make it ready to use snapshots.)
11051**
11052** The [sqlite3_snapshot_open()] interface is only available when the
11053** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
11054*/
11055SQLITE_API int sqlite3_snapshot_open(
11056  sqlite3 *db,
11057  const char *zSchema,
11058  sqlite3_snapshot *pSnapshot
11059);
11060
11061/*
11062** CAPI3REF: Destroy a snapshot
11063** DESTRUCTOR: sqlite3_snapshot
11064**
11065** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P.
11066** The application must eventually free every [sqlite3_snapshot] object
11067** using this routine to avoid a memory leak.
11068**
11069** The [sqlite3_snapshot_free()] interface is only available when the
11070** [SQLITE_ENABLE_SNAPSHOT] compile-time option is used.
11071*/
11072SQLITE_API void sqlite3_snapshot_free(sqlite3_snapshot*);
11073
11074/*
11075** CAPI3REF: Compare the ages of two snapshot handles.
11076** METHOD: sqlite3_snapshot
11077**
11078** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
11079** of two valid snapshot handles.
11080**
11081** If the two snapshot handles are not associated with the same database
11082** file, the result of the comparison is undefined.
11083**
11084** Additionally, the result of the comparison is only valid if both of the
11085** snapshot handles were obtained by calling sqlite3_snapshot_get() since the
11086** last time the wal file was deleted. The wal file is deleted when the
11087** database is changed back to rollback mode or when the number of database
11088** clients drops to zero. If either snapshot handle was obtained before the
11089** wal file was last deleted, the value returned by this function
11090** is undefined.
11091**
11092** Otherwise, this API returns a negative value if P1 refers to an older
11093** snapshot than P2, zero if the two handles refer to the same database
11094** snapshot, and a positive value if P1 is a newer snapshot than P2.
11095**
11096** This interface is only available if SQLite is compiled with the
11097** [SQLITE_ENABLE_SNAPSHOT] option.
11098*/
11099SQLITE_API int sqlite3_snapshot_cmp(
11100  sqlite3_snapshot *p1,
11101  sqlite3_snapshot *p2
11102);
11103
11104/*
11105** CAPI3REF: Recover snapshots from a wal file
11106** METHOD: sqlite3_snapshot
11107**
11108** If a [WAL file] remains on disk after all database connections close
11109** (either through the use of the [SQLITE_FCNTL_PERSIST_WAL] [file control]
11110** or because the last process to have the database opened exited without
11111** calling [sqlite3_close()]) and a new connection is subsequently opened
11112** on that database and [WAL file], the [sqlite3_snapshot_open()] interface
11113** will only be able to open the last transaction added to the WAL file
11114** even though the WAL file contains other valid transactions.
11115**
11116** This function attempts to scan the WAL file associated with database zDb
11117** of database handle db and make all valid snapshots available to
11118** sqlite3_snapshot_open(). It is an error if there is already a read
11119** transaction open on the database, or if the database is not a WAL mode
11120** database.
11121**
11122** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
11123**
11124** This interface is only available if SQLite is compiled with the
11125** [SQLITE_ENABLE_SNAPSHOT] option.
11126*/
11127SQLITE_API int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb);
11128
11129/*
11130** CAPI3REF: Serialize a database
11131**
11132** The sqlite3_serialize(D,S,P,F) interface returns a pointer to
11133** memory that is a serialization of the S database on
11134** [database connection] D.  If S is a NULL pointer, the main database is used.
11135** If P is not a NULL pointer, then the size of the database in bytes
11136** is written into *P.
11137**
11138** For an ordinary on-disk database file, the serialization is just a
11139** copy of the disk file.  For an in-memory database or a "TEMP" database,
11140** the serialization is the same sequence of bytes which would be written
11141** to disk if that database were backed up to disk.
11142**
11143** The usual case is that sqlite3_serialize() copies the serialization of
11144** the database into memory obtained from [sqlite3_malloc64()] and returns
11145** a pointer to that memory.  The caller is responsible for freeing the
11146** returned value to avoid a memory leak.  However, if the F argument
11147** contains the SQLITE_SERIALIZE_NOCOPY bit, then no memory allocations
11148** are made, and the sqlite3_serialize() function will return a pointer
11149** to the contiguous memory representation of the database that SQLite
11150** is currently using for that database, or NULL if no such contiguous
11151** memory representation of the database exists.  A contiguous memory
11152** representation of the database will usually only exist if there has
11153** been a prior call to [sqlite3_deserialize(D,S,...)] with the same
11154** values of D and S.
11155** The size of the database is written into *P even if the
11156** SQLITE_SERIALIZE_NOCOPY bit is set but no contiguous copy
11157** of the database exists.
11158**
11159** After the call, if the SQLITE_SERIALIZE_NOCOPY bit had been set,
11160** the returned buffer content will remain accessible and unchanged
11161** until either the next write operation on the connection or when
11162** the connection is closed, and applications must not modify the
11163** buffer. If the bit had been clear, the returned buffer will not
11164** be accessed by SQLite after the call.
11165**
11166** A call to sqlite3_serialize(D,S,P,F) might return NULL even if the
11167** SQLITE_SERIALIZE_NOCOPY bit is omitted from argument F if a memory
11168** allocation error occurs.
11169**
11170** This interface is omitted if SQLite is compiled with the
11171** [SQLITE_OMIT_DESERIALIZE] option.
11172*/
11173SQLITE_API unsigned char *sqlite3_serialize(
11174  sqlite3 *db,           /* The database connection */
11175  const char *zSchema,   /* Which DB to serialize. ex: "main", "temp", ... */
11176  sqlite3_int64 *piSize, /* Write size of the DB here, if not NULL */
11177  unsigned int mFlags    /* Zero or more SQLITE_SERIALIZE_* flags */
11178);
11179
11180/*
11181** CAPI3REF: Flags for sqlite3_serialize
11182**
11183** Zero or more of the following constants can be OR-ed together for
11184** the F argument to [sqlite3_serialize(D,S,P,F)].
11185**
11186** SQLITE_SERIALIZE_NOCOPY means that [sqlite3_serialize()] will return
11187** a pointer to contiguous in-memory database that it is currently using,
11188** without making a copy of the database.  If SQLite is not currently using
11189** a contiguous in-memory database, then this option causes
11190** [sqlite3_serialize()] to return a NULL pointer.  SQLite will only be
11191** using a contiguous in-memory database if it has been initialized by a
11192** prior call to [sqlite3_deserialize()].
11193*/
11194#define SQLITE_SERIALIZE_NOCOPY 0x001   /* Do no memory allocations */
11195
11196/*
11197** CAPI3REF: Deserialize a database
11198**
11199** The sqlite3_deserialize(D,S,P,N,M,F) interface causes the
11200** [database connection] D to disconnect from database S and then
11201** reopen S as an in-memory database based on the serialization
11202** contained in P.  If S is a NULL pointer, the main database is
11203** used. The serialized database P is N bytes in size.  M is the size
11204** of the buffer P, which might be larger than N.  If M is larger than
11205** N, and the SQLITE_DESERIALIZE_READONLY bit is not set in F, then
11206** SQLite is permitted to add content to the in-memory database as
11207** long as the total size does not exceed M bytes.
11208**
11209** If the SQLITE_DESERIALIZE_FREEONCLOSE bit is set in F, then SQLite will
11210** invoke sqlite3_free() on the serialization buffer when the database
11211** connection closes.  If the SQLITE_DESERIALIZE_RESIZEABLE bit is set, then
11212** SQLite will try to increase the buffer size using sqlite3_realloc64()
11213** if writes on the database cause it to grow larger than M bytes.
11214**
11215** Applications must not modify the buffer P or invalidate it before
11216** the database connection D is closed.
11217**
11218** The sqlite3_deserialize() interface will fail with SQLITE_BUSY if the
11219** database is currently in a read transaction or is involved in a backup
11220** operation.
11221**
11222** It is not possible to deserialize into the TEMP database.  If the
11223** S argument to sqlite3_deserialize(D,S,P,N,M,F) is "temp" then the
11224** function returns SQLITE_ERROR.
11225**
11226** The deserialized database should not be in [WAL mode].  If the database
11227** is in WAL mode, then any attempt to use the database file will result
11228** in an [SQLITE_CANTOPEN] error.  The application can set the
11229** [file format version numbers] (bytes 18 and 19) of the input database P
11230** to 0x01 prior to invoking sqlite3_deserialize(D,S,P,N,M,F) to force the
11231** database file into rollback mode and work around this limitation.
11232**
11233** If sqlite3_deserialize(D,S,P,N,M,F) fails for any reason and if the
11234** SQLITE_DESERIALIZE_FREEONCLOSE bit is set in argument F, then
11235** [sqlite3_free()] is invoked on argument P prior to returning.
11236**
11237** This interface is omitted if SQLite is compiled with the
11238** [SQLITE_OMIT_DESERIALIZE] option.
11239*/
11240SQLITE_API int sqlite3_deserialize(
11241  sqlite3 *db,            /* The database connection */
11242  const char *zSchema,    /* Which DB to reopen with the deserialization */
11243  unsigned char *pData,   /* The serialized database content */
11244  sqlite3_int64 szDb,     /* Number of bytes in the deserialization */
11245  sqlite3_int64 szBuf,    /* Total size of buffer pData[] */
11246  unsigned mFlags         /* Zero or more SQLITE_DESERIALIZE_* flags */
11247);
11248
11249/*
11250** CAPI3REF: Flags for sqlite3_deserialize()
11251**
11252** The following are allowed values for the 6th argument (the F argument) to
11253** the [sqlite3_deserialize(D,S,P,N,M,F)] interface.
11254**
11255** The SQLITE_DESERIALIZE_FREEONCLOSE means that the database serialization
11256** in the P argument is held in memory obtained from [sqlite3_malloc64()]
11257** and that SQLite should take ownership of this memory and automatically
11258** free it when it has finished using it.  Without this flag, the caller
11259** is responsible for freeing any dynamically allocated memory.
11260**
11261** The SQLITE_DESERIALIZE_RESIZEABLE flag means that SQLite is allowed to
11262** grow the size of the database using calls to [sqlite3_realloc64()].  This
11263** flag should only be used if SQLITE_DESERIALIZE_FREEONCLOSE is also used.
11264** Without this flag, the deserialized database cannot increase in size beyond
11265** the number of bytes specified by the M parameter.
11266**
11267** The SQLITE_DESERIALIZE_READONLY flag means that the deserialized database
11268** should be treated as read-only.
11269*/
11270#define SQLITE_DESERIALIZE_FREEONCLOSE 1 /* Call sqlite3_free() on close */
11271#define SQLITE_DESERIALIZE_RESIZEABLE  2 /* Resize using sqlite3_realloc64() */
11272#define SQLITE_DESERIALIZE_READONLY    4 /* Database is read-only */
11273
11274/*
11275** CAPI3REF: Bind array values to the CARRAY table-valued function
11276**
11277** The sqlite3_carray_bind_v2(S,I,P,N,F,X,D) interface binds an array value to
11278** parameter that is the first argument of the [carray() table-valued function].
11279** The S parameter is a pointer to the [prepared statement] that uses the
11280** carray() functions.  I is the parameter index to be bound.  I must be the
11281** index of the parameter that is the first argument to the carray()
11282** table-valued function. P is a pointer to the array to be bound, and N
11283** is the number of elements in the array.  The F argument is one of
11284** constants [SQLITE_CARRAY_INT32], [SQLITE_CARRAY_INT64],
11285** [SQLITE_CARRAY_DOUBLE], [SQLITE_CARRAY_TEXT],
11286** or [SQLITE_CARRAY_BLOB] to indicate the datatype of the array P.
11287**
11288** If the X argument is not a NULL pointer or one of the special
11289** values [SQLITE_STATIC] or [SQLITE_TRANSIENT], then SQLite will invoke
11290** the function X with argument D when it is finished using the data in P.
11291** The call to X(D) is a destructor for the array P. The destructor X(D)
11292** is invoked even if the call to sqlite3_carray_bind_v2() fails. If the X
11293** parameter is the special-case value [SQLITE_STATIC], then SQLite assumes
11294** that the data static and the destructor is never invoked.  If the X
11295** parameter is the special-case value [SQLITE_TRANSIENT], then
11296** sqlite3_carray_bind_v2() makes its own private copy of the data prior
11297** to returning and never invokes the destructor X.
11298**
11299** The sqlite3_carray_bind() function works the same as sqlite3_carray_bind_v2()
11300** with a D parameter set to P.  In other words,
11301** sqlite3_carray_bind(S,I,P,N,F,X) is same as
11302** sqlite3_carray_bind_v2(S,I,P,N,F,X,P).
11303*/
11304SQLITE_API int sqlite3_carray_bind_v2(
11305  sqlite3_stmt *pStmt,        /* Statement to be bound */
11306  int i,                      /* Parameter index */
11307  void *aData,                /* Pointer to array data */
11308  int nData,                  /* Number of data elements */
11309  int mFlags,                 /* CARRAY flags */
11310  void (*xDel)(void*),        /* Destructor for aData */
11311  void *pDel                  /* Optional argument to xDel() */
11312);
11313SQLITE_API int sqlite3_carray_bind(
11314  sqlite3_stmt *pStmt,        /* Statement to be bound */
11315  int i,                      /* Parameter index */
11316  void *aData,                /* Pointer to array data */
11317  int nData,                  /* Number of data elements */
11318  int mFlags,                 /* CARRAY flags */
11319  void (*xDel)(void*)         /* Destructor for aData */
11320);
11321
11322/*
11323** CAPI3REF: Datatypes for the CARRAY table-valued function
11324**
11325** The fifth argument to the [sqlite3_carray_bind()] interface musts be
11326** one of the following constants, to specify the datatype of the array
11327** that is being bound into the [carray table-valued function].
11328*/
11329#define SQLITE_CARRAY_INT32     0    /* Data is 32-bit signed integers */
11330#define SQLITE_CARRAY_INT64     1    /* Data is 64-bit signed integers */
11331#define SQLITE_CARRAY_DOUBLE    2    /* Data is doubles */
11332#define SQLITE_CARRAY_TEXT      3    /* Data is char* */
11333#define SQLITE_CARRAY_BLOB      4    /* Data is struct iovec */
11334
11335/*
11336** Versions of the above #defines that omit the initial SQLITE_, for
11337** legacy compatibility.
11338*/
11339#define CARRAY_INT32     0    /* Data is 32-bit signed integers */
11340#define CARRAY_INT64     1    /* Data is 64-bit signed integers */
11341#define CARRAY_DOUBLE    2    /* Data is doubles */
11342#define CARRAY_TEXT      3    /* Data is char* */
11343#define CARRAY_BLOB      4    /* Data is struct iovec */
11344
11345/*
11346** Undo the hack that converts floating point types to integer for
11347** builds on processors without floating point support.
11348*/
11349#ifdef SQLITE_OMIT_FLOATING_POINT
11350# undef double
11351#endif
11352
11353#if defined(__wasi__)
11354# undef SQLITE_WASI
11355# define SQLITE_WASI 1
11356# ifndef SQLITE_OMIT_LOAD_EXTENSION
11357#  define SQLITE_OMIT_LOAD_EXTENSION
11358# endif
11359# ifndef SQLITE_THREADSAFE
11360#  define SQLITE_THREADSAFE 0
11361# endif
11362#endif
11363
11364#ifdef __cplusplus
11365}  /* End of the 'extern "C"' block */
11366#endif
11367/* #endif for SQLITE3_H will be added by mksqlite3.tcl */
11368
11369/******** Begin file sqlite3rtree.h *********/
11370/*
11371** 2010 August 30
11372**
11373** The author disclaims copyright to this source code.  In place of
11374** a legal notice, here is a blessing:
11375**
11376**    May you do good and not evil.
11377**    May you find forgiveness for yourself and forgive others.
11378**    May you share freely, never taking more than you give.
11379**
11380*************************************************************************
11381*/
11382
11383#ifndef _SQLITE3RTREE_H_
11384#define _SQLITE3RTREE_H_
11385
11386
11387#ifdef __cplusplus
11388extern "C" {
11389#endif
11390
11391typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
11392typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
11393
11394/* The double-precision datatype used by RTree depends on the
11395** SQLITE_RTREE_INT_ONLY compile-time option.
11396*/
11397#ifdef SQLITE_RTREE_INT_ONLY
11398  typedef sqlite3_int64 sqlite3_rtree_dbl;
11399#else
11400  typedef double sqlite3_rtree_dbl;
11401#endif
11402
11403/*
11404** Register a geometry callback named zGeom that can be used as part of an
11405** R-Tree geometry query as follows:
11406**
11407**   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
11408*/
11409SQLITE_API int sqlite3_rtree_geometry_callback(
11410  sqlite3 *db,
11411  const char *zGeom,
11412  int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
11413  void *pContext
11414);
11415
11416
11417/*
11418** A pointer to a structure of the following type is passed as the first
11419** argument to callbacks registered using rtree_geometry_callback().
11420*/
11421struct sqlite3_rtree_geometry {
11422  void *pContext;                 /* Copy of pContext passed to s_r_g_c() */
11423  int nParam;                     /* Size of array aParam[] */
11424  sqlite3_rtree_dbl *aParam;      /* Parameters passed to SQL geom function */
11425  void *pUser;                    /* Callback implementation user data */
11426  void (*xDelUser)(void *);       /* Called by SQLite to clean up pUser */
11427};
11428
11429/*
11430** Register a 2nd-generation geometry callback named zScore that can be
11431** used as part of an R-Tree geometry query as follows:
11432**
11433**   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
11434*/
11435SQLITE_API int sqlite3_rtree_query_callback(
11436  sqlite3 *db,
11437  const char *zQueryFunc,
11438  int (*xQueryFunc)(sqlite3_rtree_query_info*),
11439  void *pContext,
11440  void (*xDestructor)(void*)
11441);
11442
11443
11444/*
11445** A pointer to a structure of the following type is passed as the
11446** argument to scored geometry callback registered using
11447** sqlite3_rtree_query_callback().
11448**
11449** Note that the first 5 fields of this structure are identical to
11450** sqlite3_rtree_geometry.  This structure is a subclass of
11451** sqlite3_rtree_geometry.
11452*/
11453struct sqlite3_rtree_query_info {
11454  void *pContext;                   /* pContext from when function registered */
11455  int nParam;                       /* Number of function parameters */
11456  sqlite3_rtree_dbl *aParam;        /* value of function parameters */
11457  void *pUser;                      /* callback can use this, if desired */
11458  void (*xDelUser)(void*);          /* function to free pUser */
11459  sqlite3_rtree_dbl *aCoord;        /* Coordinates of node or entry to check */
11460  unsigned int *anQueue;            /* Number of pending entries in the queue */
11461  int nCoord;                       /* Number of coordinates */
11462  int iLevel;                       /* Level of current node or entry */
11463  int mxLevel;                      /* The largest iLevel value in the tree */
11464  sqlite3_int64 iRowid;             /* Rowid for current entry */
11465  sqlite3_rtree_dbl rParentScore;   /* Score of parent node */
11466  int eParentWithin;                /* Visibility of parent node */
11467  int eWithin;                      /* OUT: Visibility */
11468  sqlite3_rtree_dbl rScore;         /* OUT: Write the score here */
11469  /* The following fields are only available in 3.8.11 and later */
11470  sqlite3_value **apSqlParam;       /* Original SQL values of parameters */
11471};
11472
11473/*
11474** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
11475*/
11476#define NOT_WITHIN       0   /* Object completely outside of query region */
11477#define PARTLY_WITHIN    1   /* Object partially overlaps query region */
11478#define FULLY_WITHIN     2   /* Object fully contained within query region */
11479
11480
11481#ifdef __cplusplus
11482}  /* end of the 'extern "C"' block */
11483#endif
11484
11485#endif  /* ifndef _SQLITE3RTREE_H_ */
11486
11487/******** End of sqlite3rtree.h *********/
11488/******** Begin file sqlite3session.h *********/
11489
11490#if !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION)
11491#define __SQLITESESSION_H_ 1
11492
11493/*
11494** Make sure we can call this stuff from C++.
11495*/
11496#ifdef __cplusplus
11497extern "C" {
11498#endif
11499
11500
11501/*
11502** CAPI3REF: Session Object Handle
11503**
11504** An instance of this object is a [session] that can be used to
11505** record changes to a database.
11506*/
11507typedef struct sqlite3_session sqlite3_session;
11508
11509/*
11510** CAPI3REF: Changeset Iterator Handle
11511**
11512** An instance of this object acts as a cursor for iterating
11513** over the elements of a [changeset] or [patchset].
11514*/
11515typedef struct sqlite3_changeset_iter sqlite3_changeset_iter;
11516
11517/*
11518** CAPI3REF: Create A New Session Object
11519** CONSTRUCTOR: sqlite3_session
11520**
11521** Create a new session object attached to database handle db. If successful,
11522** a pointer to the new object is written to *ppSession and SQLITE_OK is
11523** returned. If an error occurs, *ppSession is set to NULL and an SQLite
11524** error code (e.g. SQLITE_NOMEM) is returned.
11525**
11526** It is possible to create multiple session objects attached to a single
11527** database handle.
11528**
11529** Session objects created using this function should be deleted using the
11530** [sqlite3session_delete()] function before the database handle that they
11531** are attached to is itself closed. If the database handle is closed before
11532** the session object is deleted, then the results of calling any session
11533** module function, including [sqlite3session_delete()] on the session object
11534** are undefined.
11535**
11536** Because the session module uses the [sqlite3_preupdate_hook()] API, it
11537** is not possible for an application to register a pre-update hook on a
11538** database handle that has one or more session objects attached. Nor is
11539** it possible to create a session object attached to a database handle for
11540** which a pre-update hook is already defined. The results of attempting
11541** either of these things are undefined.
11542**
11543** The session object will be used to create changesets for tables in
11544** database zDb, where zDb is either "main", or "temp", or the name of an
11545** attached database. It is not an error if database zDb is not attached
11546** to the database when the session object is created.
11547*/
11548SQLITE_API int sqlite3session_create(
11549  sqlite3 *db,                    /* Database handle */
11550  const char *zDb,                /* Name of db (e.g. "main") */
11551  sqlite3_session **ppSession     /* OUT: New session object */
11552);
11553
11554/*
11555** CAPI3REF: Delete A Session Object
11556** DESTRUCTOR: sqlite3_session
11557**
11558** Delete a session object previously allocated using
11559** [sqlite3session_create()]. Once a session object has been deleted, the
11560** results of attempting to use pSession with any other session module
11561** function are undefined.
11562**
11563** Session objects must be deleted before the database handle to which they
11564** are attached is closed. Refer to the documentation for
11565** [sqlite3session_create()] for details.
11566*/
11567SQLITE_API void sqlite3session_delete(sqlite3_session *pSession);
11568
11569/*
11570** CAPI3REF: Configure a Session Object
11571** METHOD: sqlite3_session
11572**
11573** This method is used to configure a session object after it has been
11574** created. At present the only valid values for the second parameter are
11575** [SQLITE_SESSION_OBJCONFIG_SIZE] and [SQLITE_SESSION_OBJCONFIG_ROWID].
11576**
11577*/
11578SQLITE_API int sqlite3session_object_config(sqlite3_session*, int op, void *pArg);
11579
11580/*
11581** CAPI3REF: Options for sqlite3session_object_config
11582**
11583** The following values may passed as the the 2nd parameter to
11584** sqlite3session_object_config().
11585**
11586** <dt>SQLITE_SESSION_OBJCONFIG_SIZE <dd>
11587**   This option is used to set, clear or query the flag that enables
11588**   the [sqlite3session_changeset_size()] API. Because it imposes some
11589**   computational overhead, this API is disabled by default. Argument
11590**   pArg must point to a value of type (int). If the value is initially
11591**   0, then the sqlite3session_changeset_size() API is disabled. If it
11592**   is greater than 0, then the same API is enabled. Or, if the initial
11593**   value is less than zero, no change is made. In all cases the (int)
11594**   variable is set to 1 if the sqlite3session_changeset_size() API is
11595**   enabled following the current call, or 0 otherwise.
11596**
11597**   It is an error (SQLITE_MISUSE) to attempt to modify this setting after
11598**   the first table has been attached to the session object.
11599**
11600** <dt>SQLITE_SESSION_OBJCONFIG_ROWID <dd>
11601**   This option is used to set, clear or query the flag that enables
11602**   collection of data for tables with no explicit PRIMARY KEY.
11603**
11604**   Normally, tables with no explicit PRIMARY KEY are simply ignored
11605**   by the sessions module. However, if this flag is set, it behaves
11606**   as if such tables have a column "_rowid_ INTEGER PRIMARY KEY" inserted
11607**   as their leftmost columns.
11608**
11609**   It is an error (SQLITE_MISUSE) to attempt to modify this setting after
11610**   the first table has been attached to the session object.
11611*/
11612#define SQLITE_SESSION_OBJCONFIG_SIZE  1
11613#define SQLITE_SESSION_OBJCONFIG_ROWID 2
11614
11615/*
11616** CAPI3REF: Enable Or Disable A Session Object
11617** METHOD: sqlite3_session
11618**
11619** Enable or disable the recording of changes by a session object. When
11620** enabled, a session object records changes made to the database. When
11621** disabled - it does not. A newly created session object is enabled.
11622** Refer to the documentation for [sqlite3session_changeset()] for further
11623** details regarding how enabling and disabling a session object affects
11624** the eventual changesets.
11625**
11626** Passing zero to this function disables the session. Passing a value
11627** greater than zero enables it. Passing a value less than zero is a
11628** no-op, and may be used to query the current state of the session.
11629**
11630** The return value indicates the final state of the session object: 0 if
11631** the session is disabled, or 1 if it is enabled.
11632*/
11633SQLITE_API int sqlite3session_enable(sqlite3_session *pSession, int bEnable);
11634
11635/*
11636** CAPI3REF: Set Or Clear the Indirect Change Flag
11637** METHOD: sqlite3_session
11638**
11639** Each change recorded by a session object is marked as either direct or
11640** indirect. A change is marked as indirect if either:
11641**
11642** <ul>
11643**   <li> The session object "indirect" flag is set when the change is
11644**        made, or
11645**   <li> The change is made by an SQL trigger or foreign key action
11646**        instead of directly as a result of a users SQL statement.
11647** </ul>
11648**
11649** If a single row is affected by more than one operation within a session,
11650** then the change is considered indirect if all operations meet the criteria
11651** for an indirect change above, or direct otherwise.
11652**
11653** This function is used to set, clear or query the session object indirect
11654** flag.  If the second argument passed to this function is zero, then the
11655** indirect flag is cleared. If it is greater than zero, the indirect flag
11656** is set. Passing a value less than zero does not modify the current value
11657** of the indirect flag, and may be used to query the current state of the
11658** indirect flag for the specified session object.
11659**
11660** The return value indicates the final state of the indirect flag: 0 if
11661** it is clear, or 1 if it is set.
11662*/
11663SQLITE_API int sqlite3session_indirect(sqlite3_session *pSession, int bIndirect);
11664
11665/*
11666** CAPI3REF: Attach A Table To A Session Object
11667** METHOD: sqlite3_session
11668**
11669** If argument zTab is not NULL, then it is the name of a table to attach
11670** to the session object passed as the first argument. All subsequent changes
11671** made to the table while the session object is enabled will be recorded. See
11672** documentation for [sqlite3session_changeset()] for further details.
11673**
11674** Or, if argument zTab is NULL, then changes are recorded for all tables
11675** in the database. If additional tables are added to the database (by
11676** executing "CREATE TABLE" statements) after this call is made, changes for
11677** the new tables are also recorded.
11678**
11679** Changes can only be recorded for tables that have a PRIMARY KEY explicitly
11680** defined as part of their CREATE TABLE statement. It does not matter if the
11681** PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias) or not. The PRIMARY
11682** KEY may consist of a single column, or may be a composite key.
11683**
11684** It is not an error if the named table does not exist in the database. Nor
11685** is it an error if the named table does not have a PRIMARY KEY. However,
11686** no changes will be recorded in either of these scenarios.
11687**
11688** Changes are not recorded for individual rows that have NULL values stored
11689** in one or more of their PRIMARY KEY columns.
11690**
11691** SQLITE_OK is returned if the call completes without error. Or, if an error
11692** occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned.
11693**
11694** <h3>Special sqlite_stat1 Handling</h3>
11695**
11696** As of SQLite version 3.22.0, the "sqlite_stat1" table is an exception to
11697** some of the rules above. In SQLite, the schema of sqlite_stat1 is:
11698**  <pre>
11699**  &nbsp;     CREATE TABLE sqlite_stat1(tbl,idx,stat)
11700**  </pre>
11701**
11702** Even though sqlite_stat1 does not have a PRIMARY KEY, changes are
11703** recorded for it as if the PRIMARY KEY is (tbl,idx). Additionally, changes
11704** are recorded for rows for which (idx IS NULL) is true. However, for such
11705** rows a zero-length blob (SQL value X'') is stored in the changeset or
11706** patchset instead of a NULL value. This allows such changesets to be
11707** manipulated by legacy implementations of sqlite3changeset_invert(),
11708** concat() and similar.
11709**
11710** The sqlite3changeset_apply() function automatically converts the
11711** zero-length blob back to a NULL value when updating the sqlite_stat1
11712** table. However, if the application calls sqlite3changeset_new(),
11713** sqlite3changeset_old() or sqlite3changeset_conflict on a changeset
11714** iterator directly (including on a changeset iterator passed to a
11715** conflict-handler callback) then the X'' value is returned. The application
11716** must translate X'' to NULL itself if required.
11717**
11718** Legacy (older than 3.22.0) versions of the sessions module cannot capture
11719** changes made to the sqlite_stat1 table. Legacy versions of the
11720** sqlite3changeset_apply() function silently ignore any modifications to the
11721** sqlite_stat1 table that are part of a changeset or patchset.
11722*/
11723SQLITE_API int sqlite3session_attach(
11724  sqlite3_session *pSession,      /* Session object */
11725  const char *zTab                /* Table name */
11726);
11727
11728/*
11729** CAPI3REF: Set a table filter on a Session Object.
11730** METHOD: sqlite3_session
11731**
11732** The second argument (xFilter) is the "filter callback". For changes to rows
11733** in tables that are not attached to the Session object, the filter is called
11734** to determine whether changes to the table's rows should be tracked or not.
11735** If xFilter returns 0, changes are not tracked. Note that once a table is
11736** attached, xFilter will not be called again.
11737*/
11738SQLITE_API void sqlite3session_table_filter(
11739  sqlite3_session *pSession,      /* Session object */
11740  int(*xFilter)(
11741    void *pCtx,                   /* Copy of third arg to _filter_table() */
11742    const char *zTab              /* Table name */
11743  ),
11744  void *pCtx                      /* First argument passed to xFilter */
11745);
11746
11747/*
11748** CAPI3REF: Generate A Changeset From A Session Object
11749** METHOD: sqlite3_session
11750**
11751** Obtain a changeset containing changes to the tables attached to the
11752** session object passed as the first argument. If successful,
11753** set *ppChangeset to point to a buffer containing the changeset
11754** and *pnChangeset to the size of the changeset in bytes before returning
11755** SQLITE_OK. If an error occurs, set both *ppChangeset and *pnChangeset to
11756** zero and return an SQLite error code.
11757**
11758** A changeset consists of zero or more INSERT, UPDATE and/or DELETE changes,
11759** each representing a change to a single row of an attached table. An INSERT
11760** change contains the values of each field of a new database row. A DELETE
11761** contains the original values of each field of a deleted database row. An
11762** UPDATE change contains the original values of each field of an updated
11763** database row along with the updated values for each updated non-primary-key
11764** column. It is not possible for an UPDATE change to represent a change that
11765** modifies the values of primary key columns. If such a change is made, it
11766** is represented in a changeset as a DELETE followed by an INSERT.
11767**
11768** Changes are not recorded for rows that have NULL values stored in one or
11769** more of their PRIMARY KEY columns. If such a row is inserted or deleted,
11770** no corresponding change is present in the changesets returned by this
11771** function. If an existing row with one or more NULL values stored in
11772** PRIMARY KEY columns is updated so that all PRIMARY KEY columns are non-NULL,
11773** only an INSERT is appears in the changeset. Similarly, if an existing row
11774** with non-NULL PRIMARY KEY values is updated so that one or more of its
11775** PRIMARY KEY columns are set to NULL, the resulting changeset contains a
11776** DELETE change only.
11777**
11778** The contents of a changeset may be traversed using an iterator created
11779** using the [sqlite3changeset_start()] API. A changeset may be applied to
11780** a database with a compatible schema using the [sqlite3changeset_apply()]
11781** API.
11782**
11783** Within a changeset generated by this function, all changes related to a
11784** single table are grouped together. In other words, when iterating through
11785** a changeset or when applying a changeset to a database, all changes related
11786** to a single table are processed before moving on to the next table. Tables
11787** are sorted in the same order in which they were attached (or auto-attached)
11788** to the sqlite3_session object. The order in which the changes related to
11789** a single table are stored is undefined.
11790**
11791** Following a successful call to this function, it is the responsibility of
11792** the caller to eventually free the buffer that *ppChangeset points to using
11793** [sqlite3_free()].
11794**
11795** <h3>Changeset Generation</h3>
11796**
11797** Once a table has been attached to a session object, the session object
11798** records the primary key values of all new rows inserted into the table.
11799** It also records the original primary key and other column values of any
11800** deleted or updated rows. For each unique primary key value, data is only
11801** recorded once - the first time a row with said primary key is inserted,
11802** updated or deleted in the lifetime of the session.
11803**
11804** There is one exception to the previous paragraph: when a row is inserted,
11805** updated or deleted, if one or more of its primary key columns contain a
11806** NULL value, no record of the change is made.
11807**
11808** The session object therefore accumulates two types of records - those
11809** that consist of primary key values only (created when the user inserts
11810** a new record) and those that consist of the primary key values and the
11811** original values of other table columns (created when the users deletes
11812** or updates a record).
11813**
11814** When this function is called, the requested changeset is created using
11815** both the accumulated records and the current contents of the database
11816** file. Specifically:
11817**
11818** <ul>
11819**   <li> For each record generated by an insert, the database is queried
11820**        for a row with a matching primary key. If one is found, an INSERT
11821**        change is added to the changeset. If no such row is found, no change
11822**        is added to the changeset.
11823**
11824**   <li> For each record generated by an update or delete, the database is
11825**        queried for a row with a matching primary key. If such a row is
11826**        found and one or more of the non-primary key fields have been
11827**        modified from their original values, an UPDATE change is added to
11828**        the changeset. Or, if no such row is found in the table, a DELETE
11829**        change is added to the changeset. If there is a row with a matching
11830**        primary key in the database, but all fields contain their original
11831**        values, no change is added to the changeset.
11832** </ul>
11833**
11834** This means, amongst other things, that if a row is inserted and then later
11835** deleted while a session object is active, neither the insert nor the delete
11836** will be present in the changeset. Or if a row is deleted and then later a
11837** row with the same primary key values inserted while a session object is
11838** active, the resulting changeset will contain an UPDATE change instead of
11839** a DELETE and an INSERT.
11840**
11841** When a session object is disabled (see the [sqlite3session_enable()] API),
11842** it does not accumulate records when rows are inserted, updated or deleted.
11843** This may appear to have some counter-intuitive effects if a single row
11844** is written to more than once during a session. For example, if a row
11845** is inserted while a session object is enabled, then later deleted while
11846** the same session object is disabled, no INSERT record will appear in the
11847** changeset, even though the delete took place while the session was disabled.
11848** Or, if one field of a row is updated while a session is enabled, and
11849** then another field of the same row is updated while the session is disabled,
11850** the resulting changeset will contain an UPDATE change that updates both
11851** fields.
11852*/
11853SQLITE_API int sqlite3session_changeset(
11854  sqlite3_session *pSession,      /* Session object */
11855  int *pnChangeset,               /* OUT: Size of buffer at *ppChangeset */
11856  void **ppChangeset              /* OUT: Buffer containing changeset */
11857);
11858
11859/*
11860** CAPI3REF: Return An Upper-limit For The Size Of The Changeset
11861** METHOD: sqlite3_session
11862**
11863** By default, this function always returns 0. For it to return
11864** a useful result, the sqlite3_session object must have been configured
11865** to enable this API using sqlite3session_object_config() with the
11866** SQLITE_SESSION_OBJCONFIG_SIZE verb.
11867**
11868** When enabled, this function returns an upper limit, in bytes, for the size
11869** of the changeset that might be produced if sqlite3session_changeset() were
11870** called. The final changeset size might be equal to or smaller than the
11871** size in bytes returned by this function.
11872*/
11873SQLITE_API sqlite3_int64 sqlite3session_changeset_size(sqlite3_session *pSession);
11874
11875/*
11876** CAPI3REF: Load The Difference Between Tables Into A Session
11877** METHOD: sqlite3_session
11878**
11879** If it is not already attached to the session object passed as the first
11880** argument, this function attaches table zTbl in the same manner as the
11881** [sqlite3session_attach()] function. If zTbl does not exist, or if it
11882** does not have a primary key, this function is a no-op (but does not return
11883** an error).
11884**
11885** Argument zFromDb must be the name of a database ("main", "temp" etc.)
11886** attached to the same database handle as the session object that contains
11887** a table compatible with the table attached to the session by this function.
11888** A table is considered compatible if it:
11889**
11890** <ul>
11891**   <li> Has the same name,
11892**   <li> Has the same set of columns declared in the same order, and
11893**   <li> Has the same PRIMARY KEY definition.
11894** </ul>
11895**
11896** If the tables are not compatible, SQLITE_SCHEMA is returned. If the tables
11897** are compatible but do not have any PRIMARY KEY columns, it is not an error
11898** but no changes are added to the session object. As with other session
11899** APIs, tables without PRIMARY KEYs are simply ignored.
11900**
11901** This function adds a set of changes to the session object that could be
11902** used to update the table in database zFrom (call this the "from-table")
11903** so that its content is the same as the table attached to the session
11904** object (call this the "to-table"). Specifically:
11905**
11906** <ul>
11907**   <li> For each row (primary key) that exists in the to-table but not in
11908**     the from-table, an INSERT record is added to the session object.
11909**
11910**   <li> For each row (primary key) that exists in the to-table but not in
11911**     the from-table, a DELETE record is added to the session object.
11912**
11913**   <li> For each row (primary key) that exists in both tables, but features
11914**     different non-PK values in each, an UPDATE record is added to the
11915**     session.
11916** </ul>
11917**
11918** To clarify, if this function is called and then a changeset constructed
11919** using [sqlite3session_changeset()], then after applying that changeset to
11920** database zFrom the contents of the two compatible tables would be
11921** identical.
11922**
11923** Unless the call to this function is a no-op as described above, it is an
11924** error if database zFrom does not exist or does not contain the required
11925** compatible table.
11926**
11927** If the operation is successful, SQLITE_OK is returned. Otherwise, an SQLite
11928** error code. In this case, if argument pzErrMsg is not NULL, *pzErrMsg
11929** may be set to point to a buffer containing an English language error
11930** message. It is the responsibility of the caller to free this buffer using
11931** sqlite3_free().
11932*/
11933SQLITE_API int sqlite3session_diff(
11934  sqlite3_session *pSession,
11935  const char *zFromDb,
11936  const char *zTbl,
11937  char **pzErrMsg
11938);
11939
11940
11941/*
11942** CAPI3REF: Generate A Patchset From A Session Object
11943** METHOD: sqlite3_session
11944**
11945** The differences between a patchset and a changeset are that:
11946**
11947** <ul>
11948**   <li> DELETE records consist of the primary key fields only. The
11949**        original values of other fields are omitted.
11950**   <li> The original values of any modified fields are omitted from
11951**        UPDATE records.
11952** </ul>
11953**
11954** A patchset blob may be used with up to date versions of all
11955** sqlite3changeset_xxx API functions except for sqlite3changeset_invert(),
11956** which returns SQLITE_CORRUPT if it is passed a patchset. Similarly,
11957** attempting to use a patchset blob with old versions of the
11958** sqlite3changeset_xxx APIs also provokes an SQLITE_CORRUPT error.
11959**
11960** Because the non-primary key "old.*" fields are omitted, no
11961** SQLITE_CHANGESET_DATA conflicts can be detected or reported if a patchset
11962** is passed to the sqlite3changeset_apply() API. Other conflict types work
11963** in the same way as for changesets.
11964**
11965** Changes within a patchset are ordered in the same way as for changesets
11966** generated by the sqlite3session_changeset() function (i.e. all changes for
11967** a single table are grouped together, tables appear in the order in which
11968** they were attached to the session object).
11969*/
11970SQLITE_API int sqlite3session_patchset(
11971  sqlite3_session *pSession,      /* Session object */
11972  int *pnPatchset,                /* OUT: Size of buffer at *ppPatchset */
11973  void **ppPatchset               /* OUT: Buffer containing patchset */
11974);
11975
11976/*
11977** CAPI3REF: Test if a changeset has recorded any changes.
11978**
11979** Return non-zero if no changes to attached tables have been recorded by
11980** the session object passed as the first argument. Otherwise, if one or
11981** more changes have been recorded, return zero.
11982**
11983** Even if this function returns zero, it is possible that calling
11984** [sqlite3session_changeset()] on the session handle may still return a
11985** changeset that contains no changes. This can happen when a row in
11986** an attached table is modified and then later on the original values
11987** are restored. However, if this function returns non-zero, then it is
11988** guaranteed that a call to sqlite3session_changeset() will return a
11989** changeset containing zero changes.
11990*/
11991SQLITE_API int sqlite3session_isempty(sqlite3_session *pSession);
11992
11993/*
11994** CAPI3REF: Query for the amount of heap memory used by a session object.
11995**
11996** This API returns the total amount of heap memory in bytes currently
11997** used by the session object passed as the only argument.
11998*/
11999SQLITE_API sqlite3_int64 sqlite3session_memory_used(sqlite3_session *pSession);
12000
12001/*
12002** CAPI3REF: Create An Iterator To Traverse A Changeset
12003** CONSTRUCTOR: sqlite3_changeset_iter
12004**
12005** Create an iterator used to iterate through the contents of a changeset.
12006** If successful, *pp is set to point to the iterator handle and SQLITE_OK
12007** is returned. Otherwise, if an error occurs, *pp is set to zero and an
12008** SQLite error code is returned.
12009**
12010** The following functions can be used to advance and query a changeset
12011** iterator created by this function:
12012**
12013** <ul>
12014**   <li> [sqlite3changeset_next()]
12015**   <li> [sqlite3changeset_op()]
12016**   <li> [sqlite3changeset_new()]
12017**   <li> [sqlite3changeset_old()]
12018** </ul>
12019**
12020** It is the responsibility of the caller to eventually destroy the iterator
12021** by passing it to [sqlite3changeset_finalize()]. The buffer containing the
12022** changeset (pChangeset) must remain valid until after the iterator is
12023** destroyed.
12024**
12025** Assuming the changeset blob was created by one of the
12026** [sqlite3session_changeset()], [sqlite3changeset_concat()] or
12027** [sqlite3changeset_invert()] functions, all changes within the changeset
12028** that apply to a single table are grouped together. This means that when
12029** an application iterates through a changeset using an iterator created by
12030** this function, all changes that relate to a single table are visited
12031** consecutively. There is no chance that the iterator will visit a change
12032** the applies to table X, then one for table Y, and then later on visit
12033** another change for table X.
12034**
12035** The behavior of sqlite3changeset_start_v2() and its streaming equivalent
12036** may be modified by passing a combination of
12037** [SQLITE_CHANGESETSTART_INVERT | supported flags] as the 4th parameter.
12038**
12039** Note that the sqlite3changeset_start_v2() API is still <b>experimental</b>
12040** and therefore subject to change.
12041*/
12042SQLITE_API int sqlite3changeset_start(
12043  sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
12044  int nChangeset,                 /* Size of changeset blob in bytes */
12045  void *pChangeset                /* Pointer to blob containing changeset */
12046);
12047SQLITE_API int sqlite3changeset_start_v2(
12048  sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
12049  int nChangeset,                 /* Size of changeset blob in bytes */
12050  void *pChangeset,               /* Pointer to blob containing changeset */
12051  int flags                       /* SESSION_CHANGESETSTART_* flags */
12052);
12053
12054/*
12055** CAPI3REF: Flags for sqlite3changeset_start_v2
12056**
12057** The following flags may passed via the 4th parameter to
12058** [sqlite3changeset_start_v2] and [sqlite3changeset_start_v2_strm]:
12059**
12060** <dt>SQLITE_CHANGESETSTART_INVERT <dd>
12061**   Invert the changeset while iterating through it. This is equivalent to
12062**   inverting a changeset using sqlite3changeset_invert() before applying it.
12063**   It is an error to specify this flag with a patchset.
12064*/
12065#define SQLITE_CHANGESETSTART_INVERT        0x0002
12066
12067
12068/*
12069** CAPI3REF: Advance A Changeset Iterator
12070** METHOD: sqlite3_changeset_iter
12071**
12072** This function may only be used with iterators created by the function
12073** [sqlite3changeset_start()]. If it is called on an iterator passed to
12074** a conflict-handler callback by [sqlite3changeset_apply()], SQLITE_MISUSE
12075** is returned and the call has no effect.
12076**
12077** Immediately after an iterator is created by sqlite3changeset_start(), it
12078** does not point to any change in the changeset. Assuming the changeset
12079** is not empty, the first call to this function advances the iterator to
12080** point to the first change in the changeset. Each subsequent call advances
12081** the iterator to point to the next change in the changeset (if any). If
12082** no error occurs and the iterator points to a valid change after a call
12083** to sqlite3changeset_next() has advanced it, SQLITE_ROW is returned.
12084** Otherwise, if all changes in the changeset have already been visited,
12085** SQLITE_DONE is returned.
12086**
12087** If an error occurs, an SQLite error code is returned. Possible error
12088** codes include SQLITE_CORRUPT (if the changeset buffer is corrupt) or
12089** SQLITE_NOMEM.
12090*/
12091SQLITE_API int sqlite3changeset_next(sqlite3_changeset_iter *pIter);
12092
12093/*
12094** CAPI3REF: Obtain The Current Operation From A Changeset Iterator
12095** METHOD: sqlite3_changeset_iter
12096**
12097** The pIter argument passed to this function may either be an iterator
12098** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
12099** created by [sqlite3changeset_start()]. In the latter case, the most recent
12100** call to [sqlite3changeset_next()] must have returned [SQLITE_ROW]. If this
12101** is not the case, this function returns [SQLITE_MISUSE].
12102**
12103** Arguments pOp, pnCol and pzTab may not be NULL. Upon return, three
12104** outputs are set through these pointers:
12105**
12106** *pOp is set to one of [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE],
12107** depending on the type of change that the iterator currently points to;
12108**
12109** *pnCol is set to the number of columns in the table affected by the change; and
12110**
12111** *pzTab is set to point to a nul-terminated utf-8 encoded string containing
12112** the name of the table affected by the current change. The buffer remains
12113** valid until either sqlite3changeset_next() is called on the iterator
12114** or until the conflict-handler function returns.
12115**
12116** If pbIndirect is not NULL, then *pbIndirect is set to true (1) if the change
12117** is an indirect change, or false (0) otherwise. See the documentation for
12118** [sqlite3session_indirect()] for a description of direct and indirect
12119** changes.
12120**
12121** If no error occurs, SQLITE_OK is returned. If an error does occur, an
12122** SQLite error code is returned. The values of the output variables may not
12123** be trusted in this case.
12124*/
12125SQLITE_API int sqlite3changeset_op(
12126  sqlite3_changeset_iter *pIter,  /* Iterator object */
12127  const char **pzTab,             /* OUT: Pointer to table name */
12128  int *pnCol,                     /* OUT: Number of columns in table */
12129  int *pOp,                       /* OUT: SQLITE_INSERT, DELETE or UPDATE */
12130  int *pbIndirect                 /* OUT: True for an 'indirect' change */
12131);
12132
12133/*
12134** CAPI3REF: Obtain The Primary Key Definition Of A Table
12135** METHOD: sqlite3_changeset_iter
12136**
12137** For each modified table, a changeset includes the following:
12138**
12139** <ul>
12140**   <li> The number of columns in the table, and
12141**   <li> Which of those columns make up the tables PRIMARY KEY.
12142** </ul>
12143**
12144** This function is used to find which columns comprise the PRIMARY KEY of
12145** the table modified by the change that iterator pIter currently points to.
12146** If successful, *pabPK is set to point to an array of nCol entries, where
12147** nCol is the number of columns in the table. Elements of *pabPK are set to
12148** 0x01 if the corresponding column is part of the tables primary key, or
12149** 0x00 if it is not.
12150**
12151** If argument pnCol is not NULL, then *pnCol is set to the number of columns
12152** in the table.
12153**
12154** If this function is called when the iterator does not point to a valid
12155** entry, SQLITE_MISUSE is returned and the output variables zeroed. Otherwise,
12156** SQLITE_OK is returned and the output variables populated as described
12157** above.
12158*/
12159SQLITE_API int sqlite3changeset_pk(
12160  sqlite3_changeset_iter *pIter,  /* Iterator object */
12161  unsigned char **pabPK,          /* OUT: Array of boolean - true for PK cols */
12162  int *pnCol                      /* OUT: Number of entries in output array */
12163);
12164
12165/*
12166** CAPI3REF: Obtain old.* Values From A Changeset Iterator
12167** METHOD: sqlite3_changeset_iter
12168**
12169** The pIter argument passed to this function may either be an iterator
12170** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
12171** created by [sqlite3changeset_start()]. In the latter case, the most recent
12172** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
12173** Furthermore, it may only be called if the type of change that the iterator
12174** currently points to is either [SQLITE_DELETE] or [SQLITE_UPDATE]. Otherwise,
12175** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
12176**
12177** Argument iVal must be greater than or equal to 0, and less than the number
12178** of columns in the table affected by the current change. Otherwise,
12179** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
12180**
12181** If successful, this function sets *ppValue to point to a protected
12182** sqlite3_value object containing the iVal'th value from the vector of
12183** original row values stored as part of the UPDATE or DELETE change and
12184** returns SQLITE_OK. The name of the function comes from the fact that this
12185** is similar to the "old.*" columns available to update or delete triggers.
12186**
12187** If some other error occurs (e.g. an OOM condition), an SQLite error code
12188** is returned and *ppValue is set to NULL.
12189*/
12190SQLITE_API int sqlite3changeset_old(
12191  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
12192  int iVal,                       /* Column number */
12193  sqlite3_value **ppValue         /* OUT: Old value (or NULL pointer) */
12194);
12195
12196/*
12197** CAPI3REF: Obtain new.* Values From A Changeset Iterator
12198** METHOD: sqlite3_changeset_iter
12199**
12200** The pIter argument passed to this function may either be an iterator
12201** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
12202** created by [sqlite3changeset_start()]. In the latter case, the most recent
12203** call to [sqlite3changeset_next()] must have returned SQLITE_ROW.
12204** Furthermore, it may only be called if the type of change that the iterator
12205** currently points to is either [SQLITE_UPDATE] or [SQLITE_INSERT]. Otherwise,
12206** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
12207**
12208** Argument iVal must be greater than or equal to 0, and less than the number
12209** of columns in the table affected by the current change. Otherwise,
12210** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
12211**
12212** If successful, this function sets *ppValue to point to a protected
12213** sqlite3_value object containing the iVal'th value from the vector of
12214** new row values stored as part of the UPDATE or INSERT change and
12215** returns SQLITE_OK. If the change is an UPDATE and does not include
12216** a new value for the requested column, *ppValue is set to NULL and
12217** SQLITE_OK returned. The name of the function comes from the fact that
12218** this is similar to the "new.*" columns available to update or delete
12219** triggers.
12220**
12221** If some other error occurs (e.g. an OOM condition), an SQLite error code
12222** is returned and *ppValue is set to NULL.
12223*/
12224SQLITE_API int sqlite3changeset_new(
12225  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
12226  int iVal,                       /* Column number */
12227  sqlite3_value **ppValue         /* OUT: New value (or NULL pointer) */
12228);
12229
12230/*
12231** CAPI3REF: Obtain Conflicting Row Values From A Changeset Iterator
12232** METHOD: sqlite3_changeset_iter
12233**
12234** This function should only be used with iterator objects passed to a
12235** conflict-handler callback by [sqlite3changeset_apply()] with either
12236** [SQLITE_CHANGESET_DATA] or [SQLITE_CHANGESET_CONFLICT]. If this function
12237** is called on any other iterator, [SQLITE_MISUSE] is returned and *ppValue
12238** is set to NULL.
12239**
12240** Argument iVal must be greater than or equal to 0, and less than the number
12241** of columns in the table affected by the current change. Otherwise,
12242** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
12243**
12244** If successful, this function sets *ppValue to point to a protected
12245** sqlite3_value object containing the iVal'th value from the
12246** "conflicting row" associated with the current conflict-handler callback
12247** and returns SQLITE_OK.
12248**
12249** If some other error occurs (e.g. an OOM condition), an SQLite error code
12250** is returned and *ppValue is set to NULL.
12251*/
12252SQLITE_API int sqlite3changeset_conflict(
12253  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
12254  int iVal,                       /* Column number */
12255  sqlite3_value **ppValue         /* OUT: Value from conflicting row */
12256);
12257
12258/*
12259** CAPI3REF: Determine The Number Of Foreign Key Constraint Violations
12260** METHOD: sqlite3_changeset_iter
12261**
12262** This function may only be called with an iterator passed to an
12263** SQLITE_CHANGESET_FOREIGN_KEY conflict handler callback. In this case
12264** it sets the output variable to the total number of known foreign key
12265** violations in the destination database and returns SQLITE_OK.
12266**
12267** In all other cases this function returns SQLITE_MISUSE.
12268*/
12269SQLITE_API int sqlite3changeset_fk_conflicts(
12270  sqlite3_changeset_iter *pIter,  /* Changeset iterator */
12271  int *pnOut                      /* OUT: Number of FK violations */
12272);
12273
12274
12275/*
12276** CAPI3REF: Finalize A Changeset Iterator
12277** METHOD: sqlite3_changeset_iter
12278**
12279** This function is used to finalize an iterator allocated with
12280** [sqlite3changeset_start()].
12281**
12282** This function should only be called on iterators created using the
12283** [sqlite3changeset_start()] function. If an application calls this
12284** function with an iterator passed to a conflict-handler by
12285** [sqlite3changeset_apply()], [SQLITE_MISUSE] is immediately returned and the
12286** call has no effect.
12287**
12288** If an error was encountered within a call to an sqlite3changeset_xxx()
12289** function (for example an [SQLITE_CORRUPT] in [sqlite3changeset_next()] or an
12290** [SQLITE_NOMEM] in [sqlite3changeset_new()]) then an error code corresponding
12291** to that error is returned by this function. Otherwise, SQLITE_OK is
12292** returned. This is to allow the following pattern (pseudo-code):
12293**
12294** <pre>
12295**   sqlite3changeset_start();
12296**   while( SQLITE_ROW==sqlite3changeset_next() ){
12297**     // Do something with change.
12298**   }
12299**   rc = sqlite3changeset_finalize();
12300**   if( rc!=SQLITE_OK ){
12301**     // An error has occurred
12302**   }
12303** </pre>
12304*/
12305SQLITE_API int sqlite3changeset_finalize(sqlite3_changeset_iter *pIter);
12306
12307/*
12308** CAPI3REF: Invert A Changeset
12309**
12310** This function is used to "invert" a changeset object. Applying an inverted
12311** changeset to a database reverses the effects of applying the uninverted
12312** changeset. Specifically:
12313**
12314** <ul>
12315**   <li> Each DELETE change is changed to an INSERT, and
12316**   <li> Each INSERT change is changed to a DELETE, and
12317**   <li> For each UPDATE change, the old.* and new.* values are exchanged.
12318** </ul>
12319**
12320** This function does not change the order in which changes appear within
12321** the changeset. It merely reverses the sense of each individual change.
12322**
12323** If successful, a pointer to a buffer containing the inverted changeset
12324** is stored in *ppOut, the size of the same buffer is stored in *pnOut, and
12325** SQLITE_OK is returned. If an error occurs, both *pnOut and *ppOut are
12326** zeroed and an SQLite error code returned.
12327**
12328** It is the responsibility of the caller to eventually call sqlite3_free()
12329** on the *ppOut pointer to free the buffer allocation following a successful
12330** call to this function.
12331**
12332** WARNING/TODO: This function currently assumes that the input is a valid
12333** changeset. If it is not, the results are undefined.
12334*/
12335SQLITE_API int sqlite3changeset_invert(
12336  int nIn, const void *pIn,       /* Input changeset */
12337  int *pnOut, void **ppOut        /* OUT: Inverse of input */
12338);
12339
12340/*
12341** CAPI3REF: Concatenate Two Changeset Objects
12342**
12343** This function is used to concatenate two changesets, A and B, into a
12344** single changeset. The result is a changeset equivalent to applying
12345** changeset A followed by changeset B.
12346**
12347** This function combines the two input changesets using an
12348** sqlite3_changegroup object. Calling it produces similar results as the
12349** following code fragment:
12350**
12351** <pre>
12352**   sqlite3_changegroup *pGrp;
12353**   rc = sqlite3_changegroup_new(&pGrp);
12354**   if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nA, pA);
12355**   if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nB, pB);
12356**   if( rc==SQLITE_OK ){
12357**     rc = sqlite3changegroup_output(pGrp, pnOut, ppOut);
12358**   }else{
12359**     *ppOut = 0;
12360**     *pnOut = 0;
12361**   }
12362** </pre>
12363**
12364** Refer to the sqlite3_changegroup documentation below for details.
12365*/
12366SQLITE_API int sqlite3changeset_concat(
12367  int nA,                         /* Number of bytes in buffer pA */
12368  void *pA,                       /* Pointer to buffer containing changeset A */
12369  int nB,                         /* Number of bytes in buffer pB */
12370  void *pB,                       /* Pointer to buffer containing changeset B */
12371  int *pnOut,                     /* OUT: Number of bytes in output changeset */
12372  void **ppOut                    /* OUT: Buffer containing output changeset */
12373);
12374
12375/*
12376** CAPI3REF: Changegroup Handle
12377**
12378** A changegroup is an object used to combine two or more
12379** [changesets] or [patchsets]
12380*/
12381typedef struct sqlite3_changegroup sqlite3_changegroup;
12382
12383/*
12384** CAPI3REF: Create A New Changegroup Object
12385** CONSTRUCTOR: sqlite3_changegroup
12386**
12387** An sqlite3_changegroup object is used to combine two or more changesets
12388** (or patchsets) into a single changeset (or patchset). A single changegroup
12389** object may combine changesets or patchsets, but not both. The output is
12390** always in the same format as the input.
12391**
12392** If successful, this function returns SQLITE_OK and populates (*pp) with
12393** a pointer to a new sqlite3_changegroup object before returning. The caller
12394** should eventually free the returned object using a call to
12395** sqlite3changegroup_delete(). If an error occurs, an SQLite error code
12396** (i.e. SQLITE_NOMEM) is returned and *pp is set to NULL.
12397**
12398** The usual usage pattern for an sqlite3_changegroup object is as follows:
12399**
12400** <ul>
12401**   <li> It is created using a call to sqlite3changegroup_new().
12402**
12403**   <li> Zero or more changesets (or patchsets) are added to the object
12404**        by calling sqlite3changegroup_add().
12405**
12406**   <li> The result of combining all input changesets together is obtained
12407**        by the application via a call to sqlite3changegroup_output().
12408**
12409**   <li> The object is deleted using a call to sqlite3changegroup_delete().
12410** </ul>
12411**
12412** Any number of calls to add() and output() may be made between the calls to
12413** new() and delete(), and in any order.
12414**
12415** As well as the regular sqlite3changegroup_add() and
12416** sqlite3changegroup_output() functions, also available are the streaming
12417** versions sqlite3changegroup_add_strm() and sqlite3changegroup_output_strm().
12418*/
12419SQLITE_API int sqlite3changegroup_new(sqlite3_changegroup **pp);
12420
12421/*
12422** CAPI3REF: Add a Schema to a Changegroup
12423** METHOD: sqlite3_changegroup_schema
12424**
12425** This method may be used to optionally enforce the rule that the changesets
12426** added to the changegroup handle must match the schema of database zDb
12427** ("main", "temp", or the name of an attached database). If
12428** sqlite3changegroup_add() is called to add a changeset that is not compatible
12429** with the configured schema, SQLITE_SCHEMA is returned and the changegroup
12430** object is left in an undefined state.
12431**
12432** A changeset schema is considered compatible with the database schema in
12433** the same way as for sqlite3changeset_apply(). Specifically, for each
12434** table in the changeset, there exists a database table with:
12435**
12436** <ul>
12437**   <li> The name identified by the changeset, and
12438**   <li> at least as many columns as recorded in the changeset, and
12439**   <li> the primary key columns in the same position as recorded in
12440**        the changeset.
12441** </ul>
12442**
12443** The output of the changegroup object always has the same schema as the
12444** database nominated using this function. In cases where changesets passed
12445** to sqlite3changegroup_add() have fewer columns than the corresponding table
12446** in the database schema, these are filled in using the default column
12447** values from the database schema. This makes it possible to combined
12448** changesets that have different numbers of columns for a single table
12449** within a changegroup, provided that they are otherwise compatible.
12450*/
12451SQLITE_API int sqlite3changegroup_schema(sqlite3_changegroup*, sqlite3*, const char *zDb);
12452
12453/*
12454** CAPI3REF: Add A Changeset To A Changegroup
12455** METHOD: sqlite3_changegroup
12456**
12457** Add all changes within the changeset (or patchset) in buffer pData (size
12458** nData bytes) to the changegroup.
12459**
12460** If the buffer contains a patchset, then all prior calls to this function
12461** on the same changegroup object must also have specified patchsets. Or, if
12462** the buffer contains a changeset, so must have the earlier calls to this
12463** function. Otherwise, SQLITE_ERROR is returned and no changes are added
12464** to the changegroup.
12465**
12466** Rows within the changeset and changegroup are identified by the values in
12467** their PRIMARY KEY columns. A change in the changeset is considered to
12468** apply to the same row as a change already present in the changegroup if
12469** the two rows have the same primary key.
12470**
12471** Changes to rows that do not already appear in the changegroup are
12472** simply copied into it. Or, if both the new changeset and the changegroup
12473** contain changes that apply to a single row, the final contents of the
12474** changegroup depends on the type of each change, as follows:
12475**
12476** <table border=1 style="margin-left:8ex;margin-right:8ex">
12477**   <tr><th style="white-space:pre">Existing Change  </th>
12478**       <th style="white-space:pre">New Change       </th>
12479**       <th>Output Change
12480**   <tr><td>INSERT <td>INSERT <td>
12481**       The new change is ignored. This case does not occur if the new
12482**       changeset was recorded immediately after the changesets already
12483**       added to the changegroup.
12484**   <tr><td>INSERT <td>UPDATE <td>
12485**       The INSERT change remains in the changegroup. The values in the
12486**       INSERT change are modified as if the row was inserted by the
12487**       existing change and then updated according to the new change.
12488**   <tr><td>INSERT <td>DELETE <td>
12489**       The existing INSERT is removed from the changegroup. The DELETE is
12490**       not added.
12491**   <tr><td>UPDATE <td>INSERT <td>
12492**       The new change is ignored. This case does not occur if the new
12493**       changeset was recorded immediately after the changesets already
12494**       added to the changegroup.
12495**   <tr><td>UPDATE <td>UPDATE <td>
12496**       The existing UPDATE remains within the changegroup. It is amended
12497**       so that the accompanying values are as if the row was updated once
12498**       by the existing change and then again by the new change.
12499**   <tr><td>UPDATE <td>DELETE <td>
12500**       The existing UPDATE is replaced by the new DELETE within the
12501**       changegroup.
12502**   <tr><td>DELETE <td>INSERT <td>
12503**       If one or more of the column values in the row inserted by the
12504**       new change differ from those in the row deleted by the existing
12505**       change, the existing DELETE is replaced by an UPDATE within the
12506**       changegroup. Otherwise, if the inserted row is exactly the same
12507**       as the deleted row, the existing DELETE is simply discarded.
12508**   <tr><td>DELETE <td>UPDATE <td>
12509**       The new change is ignored. This case does not occur if the new
12510**       changeset was recorded immediately after the changesets already
12511**       added to the changegroup.
12512**   <tr><td>DELETE <td>DELETE <td>
12513**       The new change is ignored. This case does not occur if the new
12514**       changeset was recorded immediately after the changesets already
12515**       added to the changegroup.
12516** </table>
12517**
12518** If the new changeset contains changes to a table that is already present
12519** in the changegroup, then the number of columns and the position of the
12520** primary key columns for the table must be consistent. If this is not the
12521** case, this function fails with SQLITE_SCHEMA. Except, if the changegroup
12522** object has been configured with a database schema using the
12523** sqlite3changegroup_schema() API, then it is possible to combine changesets
12524** with different numbers of columns for a single table, provided that
12525** they are otherwise compatible.
12526**
12527** If the input changeset appears to be corrupt and the corruption is
12528** detected, SQLITE_CORRUPT is returned. Or, if an out-of-memory condition
12529** occurs during processing, this function returns SQLITE_NOMEM.
12530**
12531** In all cases, if an error occurs the state of the final contents of the
12532** changegroup is undefined. If no error occurs, SQLITE_OK is returned.
12533*/
12534SQLITE_API int sqlite3changegroup_add(sqlite3_changegroup*, int nData, void *pData);
12535
12536/*
12537** CAPI3REF: Add A Single Change To A Changegroup
12538** METHOD: sqlite3_changegroup
12539**
12540** This function adds the single change currently indicated by the iterator
12541** passed as the second argument to the changegroup object. The rules for
12542** adding the change are just as described for [sqlite3changegroup_add()].
12543**
12544** If the change is successfully added to the changegroup, SQLITE_OK is
12545** returned. Otherwise, an SQLite error code is returned.
12546**
12547** The iterator must point to a valid entry when this function is called.
12548** If it does not, SQLITE_ERROR is returned and no change is added to the
12549** changegroup. Additionally, the iterator must not have been opened with
12550** the SQLITE_CHANGESETAPPLY_INVERT flag. In this case SQLITE_ERROR is also
12551** returned.
12552*/
12553SQLITE_API int sqlite3changegroup_add_change(
12554  sqlite3_changegroup*,
12555  sqlite3_changeset_iter*
12556);
12557
12558
12559
12560/*
12561** CAPI3REF: Obtain A Composite Changeset From A Changegroup
12562** METHOD: sqlite3_changegroup
12563**
12564** Obtain a buffer containing a changeset (or patchset) representing the
12565** current contents of the changegroup. If the inputs to the changegroup
12566** were themselves changesets, the output is a changeset. Or, if the
12567** inputs were patchsets, the output is also a patchset.
12568**
12569** As with the output of the sqlite3session_changeset() and
12570** sqlite3session_patchset() functions, all changes related to a single
12571** table are grouped together in the output of this function. Tables appear
12572** in the same order as for the very first changeset added to the changegroup.
12573** If the second or subsequent changesets added to the changegroup contain
12574** changes for tables that do not appear in the first changeset, they are
12575** appended onto the end of the output changeset, again in the order in
12576** which they are first encountered.
12577**
12578** If an error occurs, an SQLite error code is returned and the output
12579** variables (*pnData) and (*ppData) are set to 0. Otherwise, SQLITE_OK
12580** is returned and the output variables are set to the size of and a
12581** pointer to the output buffer, respectively. In this case it is the
12582** responsibility of the caller to eventually free the buffer using a
12583** call to sqlite3_free().
12584*/
12585SQLITE_API int sqlite3changegroup_output(
12586  sqlite3_changegroup*,
12587  int *pnData,                    /* OUT: Size of output buffer in bytes */
12588  void **ppData                   /* OUT: Pointer to output buffer */
12589);
12590
12591/*
12592** CAPI3REF: Delete A Changegroup Object
12593** DESTRUCTOR: sqlite3_changegroup
12594*/
12595SQLITE_API void sqlite3changegroup_delete(sqlite3_changegroup*);
12596
12597/*
12598** CAPI3REF: Apply A Changeset To A Database
12599**
12600** Apply a changeset or patchset to a database. These functions attempt to
12601** update the "main" database attached to handle db with the changes found in
12602** the changeset passed via the second and third arguments.
12603**
12604** All changes made by these functions are enclosed in a savepoint transaction.
12605** If any other error (aside from a constraint failure when attempting to
12606** write to the target database) occurs, then the savepoint transaction is
12607** rolled back, restoring the target database to its original state, and an
12608** SQLite error code returned. Additionally, starting with version 3.51.0,
12609** an error code and error message that may be accessed using the
12610** [sqlite3_errcode()] and [sqlite3_errmsg()] APIs are left in the database
12611** handle.
12612**
12613** The fourth argument (xFilter) passed to these functions is the "filter
12614** callback". This may be passed NULL, in which case all changes in the
12615** changeset are applied to the database. For sqlite3changeset_apply() and
12616** sqlite3_changeset_apply_v2(), if it is not NULL, then it is invoked once
12617** for each table affected by at least one change in the changeset. In this
12618** case the table name is passed as the second argument, and a copy of
12619** the context pointer passed as the sixth argument to apply() or apply_v2()
12620** as the first. If the "filter callback" returns zero, then no attempt is
12621** made to apply any changes to the table. Otherwise, if the return value is
12622** non-zero, all changes related to the table are attempted.
12623**
12624** For sqlite3_changeset_apply_v3(), the xFilter callback is invoked once
12625** per change. The second argument in this case is an sqlite3_changeset_iter
12626** that may be queried using the usual APIs for the details of the current
12627** change. If the "filter callback" returns zero in this case, then no attempt
12628** is made to apply the current change. If it returns non-zero, the change
12629** is applied.
12630**
12631** For each table that is not excluded by the filter callback, this function
12632** tests that the target database contains a compatible table. A table is
12633** considered compatible if all of the following are true:
12634**
12635** <ul>
12636**   <li> The table has the same name as the name recorded in the
12637**        changeset, and
12638**   <li> The table has at least as many columns as recorded in the
12639**        changeset, and
12640**   <li> The table has primary key columns in the same position as
12641**        recorded in the changeset.
12642** </ul>
12643**
12644** If there is no compatible table, it is not an error, but none of the
12645** changes associated with the table are applied. A warning message is issued
12646** via the sqlite3_log() mechanism with the error code SQLITE_SCHEMA. At most
12647** one such warning is issued for each table in the changeset.
12648**
12649** For each change for which there is a compatible table, an attempt is made
12650** to modify the table contents according to each UPDATE, INSERT or DELETE
12651** change that is not excluded by a filter callback. If a change cannot be
12652** applied cleanly, the conflict handler function passed as the fifth argument
12653** to sqlite3changeset_apply() may be invoked. A description of exactly when
12654** the conflict handler is invoked for each type of change is below.
12655**
12656** Unlike the xFilter argument, xConflict may not be passed NULL. The results
12657** of passing anything other than a valid function pointer as the xConflict
12658** argument are undefined.
12659**
12660** Each time the conflict handler function is invoked, it must return one
12661** of [SQLITE_CHANGESET_OMIT], [SQLITE_CHANGESET_ABORT] or
12662** [SQLITE_CHANGESET_REPLACE]. SQLITE_CHANGESET_REPLACE may only be returned
12663** if the second argument passed to the conflict handler is either
12664** SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If the conflict-handler
12665** returns an illegal value, any changes already made are rolled back and
12666** the call to sqlite3changeset_apply() returns SQLITE_MISUSE. Different
12667** actions are taken by sqlite3changeset_apply() depending on the value
12668** returned by each invocation of the conflict-handler function. Refer to
12669** the documentation for the three
12670** [SQLITE_CHANGESET_OMIT|available return values] for details.
12671**
12672** <dl>
12673** <dt>DELETE Changes<dd>
12674**   For each DELETE change, the function checks if the target database
12675**   contains a row with the same primary key value (or values) as the
12676**   original row values stored in the changeset. If it does, and the values
12677**   stored in all non-primary key columns also match the values stored in
12678**   the changeset the row is deleted from the target database.
12679**
12680**   If a row with matching primary key values is found, but one or more of
12681**   the non-primary key fields contains a value different from the original
12682**   row value stored in the changeset, the conflict-handler function is
12683**   invoked with [SQLITE_CHANGESET_DATA] as the second argument. If the
12684**   database table has more columns than are recorded in the changeset,
12685**   only the values of those non-primary key fields are compared against
12686**   the current database contents - any trailing database table columns
12687**   are ignored.
12688**
12689**   If no row with matching primary key values is found in the database,
12690**   the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
12691**   passed as the second argument.
12692**
12693**   If the DELETE operation is attempted, but SQLite returns SQLITE_CONSTRAINT
12694**   (which can only happen if a foreign key constraint is violated), the
12695**   conflict-handler function is invoked with [SQLITE_CHANGESET_CONSTRAINT]
12696**   passed as the second argument. This includes the case where the DELETE
12697**   operation is attempted because an earlier call to the conflict handler
12698**   function returned [SQLITE_CHANGESET_REPLACE].
12699**
12700** <dt>INSERT Changes<dd>
12701**   For each INSERT change, an attempt is made to insert the new row into
12702**   the database. If the changeset row contains fewer fields than the
12703**   database table, the trailing fields are populated with their default
12704**   values.
12705**
12706**   If the attempt to insert the row fails because the database already
12707**   contains a row with the same primary key values, the conflict handler
12708**   function is invoked with the second argument set to
12709**   [SQLITE_CHANGESET_CONFLICT].
12710**
12711**   If the attempt to insert the row fails because of some other constraint
12712**   violation (e.g. NOT NULL or UNIQUE), the conflict handler function is
12713**   invoked with the second argument set to [SQLITE_CHANGESET_CONSTRAINT].
12714**   This includes the case where the INSERT operation is re-attempted because
12715**   an earlier call to the conflict handler function returned
12716**   [SQLITE_CHANGESET_REPLACE].
12717**
12718** <dt>UPDATE Changes<dd>
12719**   For each UPDATE change, the function checks if the target database
12720**   contains a row with the same primary key value (or values) as the
12721**   original row values stored in the changeset. If it does, and the values
12722**   stored in all modified non-primary key columns also match the values
12723**   stored in the changeset the row is updated within the target database.
12724**
12725**   If a row with matching primary key values is found, but one or more of
12726**   the modified non-primary key fields contains a value different from an
12727**   original row value stored in the changeset, the conflict-handler function
12728**   is invoked with [SQLITE_CHANGESET_DATA] as the second argument. Since
12729**   UPDATE changes only contain values for non-primary key fields that are
12730**   to be modified, only those fields need to match the original values to
12731**   avoid the SQLITE_CHANGESET_DATA conflict-handler callback.
12732**
12733**   If no row with matching primary key values is found in the database,
12734**   the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
12735**   passed as the second argument.
12736**
12737**   If the UPDATE operation is attempted, but SQLite returns
12738**   SQLITE_CONSTRAINT, the conflict-handler function is invoked with
12739**   [SQLITE_CHANGESET_CONSTRAINT] passed as the second argument.
12740**   This includes the case where the UPDATE operation is attempted after
12741**   an earlier call to the conflict handler function returned
12742**   [SQLITE_CHANGESET_REPLACE].
12743** </dl>
12744**
12745** It is safe to execute SQL statements, including those that write to the
12746** table that the callback related to, from within the xConflict callback.
12747** This can be used to further customize the application's conflict
12748** resolution strategy.
12749**
12750** If the output parameters (ppRebase) and (pnRebase) are non-NULL and
12751** the input is a changeset (not a patchset), then sqlite3changeset_apply_v2()
12752** may set (*ppRebase) to point to a "rebase" that may be used with the
12753** sqlite3_rebaser APIs buffer before returning. In this case (*pnRebase)
12754** is set to the size of the buffer in bytes. It is the responsibility of the
12755** caller to eventually free any such buffer using sqlite3_free(). The buffer
12756** is only allocated and populated if one or more conflicts were encountered
12757** while applying the patchset. See comments surrounding the sqlite3_rebaser
12758** APIs for further details.
12759**
12760** The behavior of sqlite3changeset_apply_v2() and its streaming equivalent
12761** may be modified by passing a combination of
12762** [SQLITE_CHANGESETAPPLY_NOSAVEPOINT | supported flags] as the 9th parameter.
12763**
12764** Note that the sqlite3changeset_apply_v2() API is still <b>experimental</b>
12765** and therefore subject to change.
12766*/
12767SQLITE_API int sqlite3changeset_apply(
12768  sqlite3 *db,                    /* Apply change to "main" db of this handle */
12769  int nChangeset,                 /* Size of changeset in bytes */
12770  void *pChangeset,               /* Changeset blob */
12771  int(*xFilter)(
12772    void *pCtx,                   /* Copy of sixth arg to _apply() */
12773    const char *zTab              /* Table name */
12774  ),
12775  int(*xConflict)(
12776    void *pCtx,                   /* Copy of sixth arg to _apply() */
12777    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
12778    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
12779  ),
12780  void *pCtx                      /* First argument passed to xConflict */
12781);
12782SQLITE_API int sqlite3changeset_apply_v2(
12783  sqlite3 *db,                    /* Apply change to "main" db of this handle */
12784  int nChangeset,                 /* Size of changeset in bytes */
12785  void *pChangeset,               /* Changeset blob */
12786  int(*xFilter)(
12787    void *pCtx,                   /* Copy of sixth arg to _apply() */
12788    const char *zTab              /* Table name */
12789  ),
12790  int(*xConflict)(
12791    void *pCtx,                   /* Copy of sixth arg to _apply() */
12792    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
12793    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
12794  ),
12795  void *pCtx,                     /* First argument passed to xConflict */
12796  void **ppRebase, int *pnRebase, /* OUT: Rebase data */
12797  int flags                       /* SESSION_CHANGESETAPPLY_* flags */
12798);
12799SQLITE_API int sqlite3changeset_apply_v3(
12800  sqlite3 *db,                    /* Apply change to "main" db of this handle */
12801  int nChangeset,                 /* Size of changeset in bytes */
12802  void *pChangeset,               /* Changeset blob */
12803  int(*xFilter)(
12804    void *pCtx,                   /* Copy of sixth arg to _apply() */
12805    sqlite3_changeset_iter *p     /* Handle describing change */
12806  ),
12807  int(*xConflict)(
12808    void *pCtx,                   /* Copy of sixth arg to _apply() */
12809    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
12810    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
12811  ),
12812  void *pCtx,                     /* First argument passed to xConflict */
12813  void **ppRebase, int *pnRebase, /* OUT: Rebase data */
12814  int flags                       /* SESSION_CHANGESETAPPLY_* flags */
12815);
12816
12817/*
12818** CAPI3REF: Flags for sqlite3changeset_apply_v2
12819**
12820** The following flags may passed via the 9th parameter to
12821** [sqlite3changeset_apply_v2] and [sqlite3changeset_apply_v2_strm]:
12822**
12823** <dl>
12824** <dt>SQLITE_CHANGESETAPPLY_NOSAVEPOINT <dd>
12825**   Usually, the sessions module encloses all operations performed by
12826**   a single call to apply_v2() or apply_v2_strm() in a [SAVEPOINT]. The
12827**   SAVEPOINT is committed if the changeset or patchset is successfully
12828**   applied, or rolled back if an error occurs. Specifying this flag
12829**   causes the sessions module to omit this savepoint. In this case, if the
12830**   caller has an open transaction or savepoint when apply_v2() is called,
12831**   it may revert the partially applied changeset by rolling it back.
12832**
12833** <dt>SQLITE_CHANGESETAPPLY_INVERT <dd>
12834**   Invert the changeset before applying it. This is equivalent to inverting
12835**   a changeset using sqlite3changeset_invert() before applying it. It is
12836**   an error to specify this flag with a patchset.
12837**
12838** <dt>SQLITE_CHANGESETAPPLY_IGNORENOOP <dd>
12839**   Do not invoke the conflict handler callback for any changes that
12840**   would not actually modify the database even if they were applied.
12841**   Specifically, this means that the conflict handler is not invoked
12842**   for:
12843**    <ul>
12844**    <li>a delete change if the row being deleted cannot be found,
12845**    <li>an update change if the modified fields are already set to
12846**        their new values in the conflicting row, or
12847**    <li>an insert change if all fields of the conflicting row match
12848**        the row being inserted.
12849**    </ul>
12850**
12851** <dt>SQLITE_CHANGESETAPPLY_FKNOACTION <dd>
12852**   If this flag it set, then all foreign key constraints in the target
12853**   database behave as if they were declared with "ON UPDATE NO ACTION ON
12854**   DELETE NO ACTION", even if they are actually CASCADE, RESTRICT, SET NULL
12855**   or SET DEFAULT.
12856*/
12857#define SQLITE_CHANGESETAPPLY_NOSAVEPOINT   0x0001
12858#define SQLITE_CHANGESETAPPLY_INVERT        0x0002
12859#define SQLITE_CHANGESETAPPLY_IGNORENOOP    0x0004
12860#define SQLITE_CHANGESETAPPLY_FKNOACTION    0x0008
12861
12862/*
12863** CAPI3REF: Constants Passed To The Conflict Handler
12864**
12865** Values that may be passed as the second argument to a conflict-handler.
12866**
12867** <dl>
12868** <dt>SQLITE_CHANGESET_DATA<dd>
12869**   The conflict handler is invoked with CHANGESET_DATA as the second argument
12870**   when processing a DELETE or UPDATE change if a row with the required
12871**   PRIMARY KEY fields is present in the database, but one or more other
12872**   (non primary-key) fields modified by the update do not contain the
12873**   expected "before" values.
12874**
12875**   The conflicting row, in this case, is the database row with the matching
12876**   primary key.
12877**
12878** <dt>SQLITE_CHANGESET_NOTFOUND<dd>
12879**   The conflict handler is invoked with CHANGESET_NOTFOUND as the second
12880**   argument when processing a DELETE or UPDATE change if a row with the
12881**   required PRIMARY KEY fields is not present in the database.
12882**
12883**   There is no conflicting row in this case. The results of invoking the
12884**   sqlite3changeset_conflict() API are undefined.
12885**
12886** <dt>SQLITE_CHANGESET_CONFLICT<dd>
12887**   CHANGESET_CONFLICT is passed as the second argument to the conflict
12888**   handler while processing an INSERT change if the operation would result
12889**   in duplicate primary key values.
12890**
12891**   The conflicting row in this case is the database row with the matching
12892**   primary key.
12893**
12894** <dt>SQLITE_CHANGESET_FOREIGN_KEY<dd>
12895**   If foreign key handling is enabled, and applying a changeset leaves the
12896**   database in a state containing foreign key violations, the conflict
12897**   handler is invoked with CHANGESET_FOREIGN_KEY as the second argument
12898**   exactly once before the changeset is committed. If the conflict handler
12899**   returns CHANGESET_OMIT, the changes, including those that caused the
12900**   foreign key constraint violation, are committed. Or, if it returns
12901**   CHANGESET_ABORT, the changeset is rolled back.
12902**
12903**   No current or conflicting row information is provided. The only function
12904**   it is possible to call on the supplied sqlite3_changeset_iter handle
12905**   is sqlite3changeset_fk_conflicts().
12906**
12907** <dt>SQLITE_CHANGESET_CONSTRAINT<dd>
12908**   If any other constraint violation occurs while applying a change (i.e.
12909**   a UNIQUE, CHECK or NOT NULL constraint), the conflict handler is
12910**   invoked with CHANGESET_CONSTRAINT as the second argument.
12911**
12912**   There is no conflicting row in this case. The results of invoking the
12913**   sqlite3changeset_conflict() API are undefined.
12914**
12915** </dl>
12916*/
12917#define SQLITE_CHANGESET_DATA        1
12918#define SQLITE_CHANGESET_NOTFOUND    2
12919#define SQLITE_CHANGESET_CONFLICT    3
12920#define SQLITE_CHANGESET_CONSTRAINT  4
12921#define SQLITE_CHANGESET_FOREIGN_KEY 5
12922
12923/*
12924** CAPI3REF: Constants Returned By The Conflict Handler
12925**
12926** A conflict handler callback must return one of the following three values.
12927**
12928** <dl>
12929** <dt>SQLITE_CHANGESET_OMIT<dd>
12930**   If a conflict handler returns this value no special action is taken. The
12931**   change that caused the conflict is not applied. The session module
12932**   continues to the next change in the changeset.
12933**
12934** <dt>SQLITE_CHANGESET_REPLACE<dd>
12935**   This value may only be returned if the second argument to the conflict
12936**   handler was SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If this
12937**   is not the case, any changes applied so far are rolled back and the
12938**   call to sqlite3changeset_apply() returns SQLITE_MISUSE.
12939**
12940**   If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_DATA conflict
12941**   handler, then the conflicting row is either updated or deleted, depending
12942**   on the type of change.
12943**
12944**   If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_CONFLICT conflict
12945**   handler, then the conflicting row is removed from the database and a
12946**   second attempt to apply the change is made. If this second attempt fails,
12947**   the original row is restored to the database before continuing.
12948**
12949** <dt>SQLITE_CHANGESET_ABORT<dd>
12950**   If this value is returned, any changes applied so far are rolled back
12951**   and the call to sqlite3changeset_apply() returns SQLITE_ABORT.
12952** </dl>
12953*/
12954#define SQLITE_CHANGESET_OMIT       0
12955#define SQLITE_CHANGESET_REPLACE    1
12956#define SQLITE_CHANGESET_ABORT      2
12957
12958/*
12959** CAPI3REF: Rebasing changesets
12960** EXPERIMENTAL
12961**
12962** Suppose there is a site hosting a database in state S0. And that
12963** modifications are made that move that database to state S1 and a
12964** changeset recorded (the "local" changeset). Then, a changeset based
12965** on S0 is received from another site (the "remote" changeset) and
12966** applied to the database. The database is then in state
12967** (S1+"remote"), where the exact state depends on any conflict
12968** resolution decisions (OMIT or REPLACE) made while applying "remote".
12969** Rebasing a changeset is to update it to take those conflict
12970** resolution decisions into account, so that the same conflicts
12971** do not have to be resolved elsewhere in the network.
12972**
12973** For example, if both the local and remote changesets contain an
12974** INSERT of the same key on "CREATE TABLE t1(a PRIMARY KEY, b)":
12975**
12976**   local:  INSERT INTO t1 VALUES(1, 'v1');
12977**   remote: INSERT INTO t1 VALUES(1, 'v2');
12978**
12979** and the conflict resolution is REPLACE, then the INSERT change is
12980** removed from the local changeset (it was overridden). Or, if the
12981** conflict resolution was "OMIT", then the local changeset is modified
12982** to instead contain:
12983**
12984**           UPDATE t1 SET b = 'v2' WHERE a=1;
12985**
12986** Changes within the local changeset are rebased as follows:
12987**
12988** <dl>
12989** <dt>Local INSERT<dd>
12990**   This may only conflict with a remote INSERT. If the conflict
12991**   resolution was OMIT, then add an UPDATE change to the rebased
12992**   changeset. Or, if the conflict resolution was REPLACE, add
12993**   nothing to the rebased changeset.
12994**
12995** <dt>Local DELETE<dd>
12996**   This may conflict with a remote UPDATE or DELETE. In both cases the
12997**   only possible resolution is OMIT. If the remote operation was a
12998**   DELETE, then add no change to the rebased changeset. If the remote
12999**   operation was an UPDATE, then the old.* fields of change are updated
13000**   to reflect the new.* values in the UPDATE.
13001**
13002** <dt>Local UPDATE<dd>
13003**   This may conflict with a remote UPDATE or DELETE. If it conflicts
13004**   with a DELETE, and the conflict resolution was OMIT, then the update
13005**   is changed into an INSERT. Any undefined values in the new.* record
13006**   from the update change are filled in using the old.* values from
13007**   the conflicting DELETE. Or, if the conflict resolution was REPLACE,
13008**   the UPDATE change is simply omitted from the rebased changeset.
13009**
13010**   If conflict is with a remote UPDATE and the resolution is OMIT, then
13011**   the old.* values are rebased using the new.* values in the remote
13012**   change. Or, if the resolution is REPLACE, then the change is copied
13013**   into the rebased changeset with updates to columns also updated by
13014**   the conflicting remote UPDATE removed. If this means no columns would
13015**   be updated, the change is omitted.
13016** </dl>
13017**
13018** A local change may be rebased against multiple remote changes
13019** simultaneously. If a single key is modified by multiple remote
13020** changesets, they are combined as follows before the local changeset
13021** is rebased:
13022**
13023** <ul>
13024**    <li> If there has been one or more REPLACE resolutions on a
13025**         key, it is rebased according to a REPLACE.
13026**
13027**    <li> If there have been no REPLACE resolutions on a key, then
13028**         the local changeset is rebased according to the most recent
13029**         of the OMIT resolutions.
13030** </ul>
13031**
13032** Note that conflict resolutions from multiple remote changesets are
13033** combined on a per-field basis, not per-row. This means that in the
13034** case of multiple remote UPDATE operations, some fields of a single
13035** local change may be rebased for REPLACE while others are rebased for
13036** OMIT.
13037**
13038** In order to rebase a local changeset, the remote changeset must first
13039** be applied to the local database using sqlite3changeset_apply_v2() and
13040** the buffer of rebase information captured. Then:
13041**
13042** <ol>
13043**   <li> An sqlite3_rebaser object is created by calling
13044**        sqlite3rebaser_create().
13045**   <li> The new object is configured with the rebase buffer obtained from
13046**        sqlite3changeset_apply_v2() by calling sqlite3rebaser_configure().
13047**        If the local changeset is to be rebased against multiple remote
13048**        changesets, then sqlite3rebaser_configure() should be called
13049**        multiple times, in the same order that the multiple
13050**        sqlite3changeset_apply_v2() calls were made.
13051**   <li> Each local changeset is rebased by calling sqlite3rebaser_rebase().
13052**   <li> The sqlite3_rebaser object is deleted by calling
13053**        sqlite3rebaser_delete().
13054** </ol>
13055*/
13056typedef struct sqlite3_rebaser sqlite3_rebaser;
13057
13058/*
13059** CAPI3REF: Create a changeset rebaser object.
13060** EXPERIMENTAL
13061**
13062** Allocate a new changeset rebaser object. If successful, set (*ppNew) to
13063** point to the new object and return SQLITE_OK. Otherwise, if an error
13064** occurs, return an SQLite error code (e.g. SQLITE_NOMEM) and set (*ppNew)
13065** to NULL.
13066*/
13067SQLITE_API int sqlite3rebaser_create(sqlite3_rebaser **ppNew);
13068
13069/*
13070** CAPI3REF: Configure a changeset rebaser object.
13071** EXPERIMENTAL
13072**
13073** Configure the changeset rebaser object to rebase changesets according
13074** to the conflict resolutions described by buffer pRebase (size nRebase
13075** bytes), which must have been obtained from a previous call to
13076** sqlite3changeset_apply_v2().
13077*/
13078SQLITE_API int sqlite3rebaser_configure(
13079  sqlite3_rebaser*,
13080  int nRebase, const void *pRebase
13081);
13082
13083/*
13084** CAPI3REF: Rebase a changeset
13085** EXPERIMENTAL
13086**
13087** Argument pIn must point to a buffer containing a changeset nIn bytes
13088** in size. This function allocates and populates a buffer with a copy
13089** of the changeset rebased according to the configuration of the
13090** rebaser object passed as the first argument. If successful, (*ppOut)
13091** is set to point to the new buffer containing the rebased changeset and
13092** (*pnOut) to its size in bytes and SQLITE_OK returned. It is the
13093** responsibility of the caller to eventually free the new buffer using
13094** sqlite3_free(). Otherwise, if an error occurs, (*ppOut) and (*pnOut)
13095** are set to zero and an SQLite error code returned.
13096*/
13097SQLITE_API int sqlite3rebaser_rebase(
13098  sqlite3_rebaser*,
13099  int nIn, const void *pIn,
13100  int *pnOut, void **ppOut
13101);
13102
13103/*
13104** CAPI3REF: Delete a changeset rebaser object.
13105** EXPERIMENTAL
13106**
13107** Delete the changeset rebaser object and all associated resources. There
13108** should be one call to this function for each successful invocation
13109** of sqlite3rebaser_create().
13110*/
13111SQLITE_API void sqlite3rebaser_delete(sqlite3_rebaser *p);
13112
13113/*
13114** CAPI3REF: Streaming Versions of API functions.
13115**
13116** The six streaming API xxx_strm() functions serve similar purposes to the
13117** corresponding non-streaming API functions:
13118**
13119** <table border=1 style="margin-left:8ex;margin-right:8ex">
13120**   <tr><th>Streaming function<th>Non-streaming equivalent</th>
13121**   <tr><td>sqlite3changeset_apply_strm<td>[sqlite3changeset_apply]
13122**   <tr><td>sqlite3changeset_apply_strm_v2<td>[sqlite3changeset_apply_v2]
13123**   <tr><td>sqlite3changeset_concat_strm<td>[sqlite3changeset_concat]
13124**   <tr><td>sqlite3changeset_invert_strm<td>[sqlite3changeset_invert]
13125**   <tr><td>sqlite3changeset_start_strm<td>[sqlite3changeset_start]
13126**   <tr><td>sqlite3session_changeset_strm<td>[sqlite3session_changeset]
13127**   <tr><td>sqlite3session_patchset_strm<td>[sqlite3session_patchset]
13128** </table>
13129**
13130** Non-streaming functions that accept changesets (or patchsets) as input
13131** require that the entire changeset be stored in a single buffer in memory.
13132** Similarly, those that return a changeset or patchset do so by returning
13133** a pointer to a single large buffer allocated using sqlite3_malloc().
13134** Normally this is convenient. However, if an application running in a
13135** low-memory environment is required to handle very large changesets, the
13136** large contiguous memory allocations required can become onerous.
13137**
13138** In order to avoid this problem, instead of a single large buffer, input
13139** is passed to a streaming API functions by way of a callback function that
13140** the sessions module invokes to incrementally request input data as it is
13141** required. In all cases, a pair of API function parameters such as
13142**
13143**  <pre>
13144**  &nbsp;     int nChangeset,
13145**  &nbsp;     void *pChangeset,
13146**  </pre>
13147**
13148** Is replaced by:
13149**
13150**  <pre>
13151**  &nbsp;     int (*xInput)(void *pIn, void *pData, int *pnData),
13152**  &nbsp;     void *pIn,
13153**  </pre>
13154**
13155** Each time the xInput callback is invoked by the sessions module, the first
13156** argument passed is a copy of the supplied pIn context pointer. The second
13157** argument, pData, points to a buffer (*pnData) bytes in size. Assuming no
13158** error occurs the xInput method should copy up to (*pnData) bytes of data
13159** into the buffer and set (*pnData) to the actual number of bytes copied
13160** before returning SQLITE_OK. If the input is completely exhausted, (*pnData)
13161** should be set to zero to indicate this. Or, if an error occurs, an SQLite
13162** error code should be returned. In all cases, if an xInput callback returns
13163** an error, all processing is abandoned and the streaming API function
13164** returns a copy of the error code to the caller.
13165**
13166** In the case of sqlite3changeset_start_strm(), the xInput callback may be
13167** invoked by the sessions module at any point during the lifetime of the
13168** iterator. If such an xInput callback returns an error, the iterator enters
13169** an error state, whereby all subsequent calls to iterator functions
13170** immediately fail with the same error code as returned by xInput.
13171**
13172** Similarly, streaming API functions that return changesets (or patchsets)
13173** return them in chunks by way of a callback function instead of via a
13174** pointer to a single large buffer. In this case, a pair of parameters such
13175** as:
13176**
13177**  <pre>
13178**  &nbsp;     int *pnChangeset,
13179**  &nbsp;     void **ppChangeset,
13180**  </pre>
13181**
13182** Is replaced by:
13183**
13184**  <pre>
13185**  &nbsp;     int (*xOutput)(void *pOut, const void *pData, int nData),
13186**  &nbsp;     void *pOut
13187**  </pre>
13188**
13189** The xOutput callback is invoked zero or more times to return data to
13190** the application. The first parameter passed to each call is a copy of the
13191** pOut pointer supplied by the application. The second parameter, pData,
13192** points to a buffer nData bytes in size containing the chunk of output
13193** data being returned. If the xOutput callback successfully processes the
13194** supplied data, it should return SQLITE_OK to indicate success. Otherwise,
13195** it should return some other SQLite error code. In this case processing
13196** is immediately abandoned and the streaming API function returns a copy
13197** of the xOutput error code to the application.
13198**
13199** The sessions module never invokes an xOutput callback with the third
13200** parameter set to a value less than or equal to zero. Other than this,
13201** no guarantees are made as to the size of the chunks of data returned.
13202*/
13203SQLITE_API int sqlite3changeset_apply_strm(
13204  sqlite3 *db,                    /* Apply change to "main" db of this handle */
13205  int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
13206  void *pIn,                                          /* First arg for xInput */
13207  int(*xFilter)(
13208    void *pCtx,                   /* Copy of sixth arg to _apply() */
13209    const char *zTab              /* Table name */
13210  ),
13211  int(*xConflict)(
13212    void *pCtx,                   /* Copy of sixth arg to _apply() */
13213    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
13214    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
13215  ),
13216  void *pCtx                      /* First argument passed to xConflict */
13217);
13218SQLITE_API int sqlite3changeset_apply_v2_strm(
13219  sqlite3 *db,                    /* Apply change to "main" db of this handle */
13220  int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
13221  void *pIn,                                          /* First arg for xInput */
13222  int(*xFilter)(
13223    void *pCtx,                   /* Copy of sixth arg to _apply() */
13224    const char *zTab              /* Table name */
13225  ),
13226  int(*xConflict)(
13227    void *pCtx,                   /* Copy of sixth arg to _apply() */
13228    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
13229    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
13230  ),
13231  void *pCtx,                     /* First argument passed to xConflict */
13232  void **ppRebase, int *pnRebase,
13233  int flags
13234);
13235SQLITE_API int sqlite3changeset_apply_v3_strm(
13236  sqlite3 *db,                    /* Apply change to "main" db of this handle */
13237  int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
13238  void *pIn,                                          /* First arg for xInput */
13239  int(*xFilter)(
13240    void *pCtx,                   /* Copy of sixth arg to _apply() */
13241    sqlite3_changeset_iter *p
13242  ),
13243  int(*xConflict)(
13244    void *pCtx,                   /* Copy of sixth arg to _apply() */
13245    int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
13246    sqlite3_changeset_iter *p     /* Handle describing change and conflict */
13247  ),
13248  void *pCtx,                     /* First argument passed to xConflict */
13249  void **ppRebase, int *pnRebase,
13250  int flags
13251);
13252SQLITE_API int sqlite3changeset_concat_strm(
13253  int (*xInputA)(void *pIn, void *pData, int *pnData),
13254  void *pInA,
13255  int (*xInputB)(void *pIn, void *pData, int *pnData),
13256  void *pInB,
13257  int (*xOutput)(void *pOut, const void *pData, int nData),
13258  void *pOut
13259);
13260SQLITE_API int sqlite3changeset_invert_strm(
13261  int (*xInput)(void *pIn, void *pData, int *pnData),
13262  void *pIn,
13263  int (*xOutput)(void *pOut, const void *pData, int nData),
13264  void *pOut
13265);
13266SQLITE_API int sqlite3changeset_start_strm(
13267  sqlite3_changeset_iter **pp,
13268  int (*xInput)(void *pIn, void *pData, int *pnData),
13269  void *pIn
13270);
13271SQLITE_API int sqlite3changeset_start_v2_strm(
13272  sqlite3_changeset_iter **pp,
13273  int (*xInput)(void *pIn, void *pData, int *pnData),
13274  void *pIn,
13275  int flags
13276);
13277SQLITE_API int sqlite3session_changeset_strm(
13278  sqlite3_session *pSession,
13279  int (*xOutput)(void *pOut, const void *pData, int nData),
13280  void *pOut
13281);
13282SQLITE_API int sqlite3session_patchset_strm(
13283  sqlite3_session *pSession,
13284  int (*xOutput)(void *pOut, const void *pData, int nData),
13285  void *pOut
13286);
13287SQLITE_API int sqlite3changegroup_add_strm(sqlite3_changegroup*,
13288    int (*xInput)(void *pIn, void *pData, int *pnData),
13289    void *pIn
13290);
13291SQLITE_API int sqlite3changegroup_output_strm(sqlite3_changegroup*,
13292    int (*xOutput)(void *pOut, const void *pData, int nData),
13293    void *pOut
13294);
13295SQLITE_API int sqlite3rebaser_rebase_strm(
13296  sqlite3_rebaser *pRebaser,
13297  int (*xInput)(void *pIn, void *pData, int *pnData),
13298  void *pIn,
13299  int (*xOutput)(void *pOut, const void *pData, int nData),
13300  void *pOut
13301);
13302
13303/*
13304** CAPI3REF: Configure global parameters
13305**
13306** The sqlite3session_config() interface is used to make global configuration
13307** changes to the sessions module in order to tune it to the specific needs
13308** of the application.
13309**
13310** The sqlite3session_config() interface is not threadsafe. If it is invoked
13311** while any other thread is inside any other sessions method then the
13312** results are undefined. Furthermore, if it is invoked after any sessions
13313** related objects have been created, the results are also undefined.
13314**
13315** The first argument to the sqlite3session_config() function must be one
13316** of the SQLITE_SESSION_CONFIG_XXX constants defined below. The
13317** interpretation of the (void*) value passed as the second parameter and
13318** the effect of calling this function depends on the value of the first
13319** parameter.
13320**
13321** <dl>
13322** <dt>SQLITE_SESSION_CONFIG_STRMSIZE<dd>
13323**    By default, the sessions module streaming interfaces attempt to input
13324**    and output data in approximately 1 KiB chunks. This operand may be used
13325**    to set and query the value of this configuration setting. The pointer
13326**    passed as the second argument must point to a value of type (int).
13327**    If this value is greater than 0, it is used as the new streaming data
13328**    chunk size for both input and output. Before returning, the (int) value
13329**    pointed to by pArg is set to the final value of the streaming interface
13330**    chunk size.
13331** </dl>
13332**
13333** This function returns SQLITE_OK if successful, or an SQLite error code
13334** otherwise.
13335*/
13336SQLITE_API int sqlite3session_config(int op, void *pArg);
13337
13338/*
13339** CAPI3REF: Values for sqlite3session_config().
13340*/
13341#define SQLITE_SESSION_CONFIG_STRMSIZE 1
13342
13343/*
13344** CAPI3REF: Configure a changegroup object
13345**
13346** Configure the changegroup object passed as the first argument.
13347** At present the only valid value for the second parameter is
13348** [SQLITE_CHANGEGROUP_CONFIG_PATCHSET].
13349*/
13350SQLITE_API int sqlite3changegroup_config(sqlite3_changegroup*, int, void *pArg);
13351
13352/*
13353** CAPI3REF: Options for sqlite3changegroup_config().
13354**
13355** The following values may be passed as the 2nd parameter to
13356** sqlite3changegroup_config().
13357**
13358** <dt>SQLITE_CHANGEGROUP_CONFIG_PATCHSET <dd>
13359**   A changegroup object generates either a changeset or patchset. Usually,
13360**   this is determined by whether the first call to sqlite3changegroup_add()
13361**   is passed a changeset or a patchset. Or, if the first changes are added
13362**   to the changegroup object using the sqlite3changegroup_change_xxx()
13363**   APIs, then this option may be used to configure whether the changegroup
13364**   object generates a changeset or patchset.
13365**
13366**   When this option is invoked, parameter pArg must point to a value of
13367**   type int. If the changegroup currently contains zero changes, and the
13368**   value of the int variable is zero or greater than zero, then the
13369**   changegroup is configured to generate a changeset or patchset,
13370**   respectively. It is a no-op, not an error, if the changegroup is not
13371**   configured because it has already started accumulating changes.
13372**
13373**   Before returning, the int variable is set to 0 if the changegroup is
13374**   configured to generate a changeset, or 1 if it is configured to generate
13375**   a patchset.
13376*/
13377#define SQLITE_CHANGEGROUP_CONFIG_PATCHSET 1
13378
13379
13380/*
13381** CAPI3REF: Begin adding a change to a changegroup
13382**
13383** This API is used, in concert with other sqlite3changegroup_change_xxx()
13384** APIs, to add changes to a changegroup object one at a time. To add a
13385** single change, the caller must:
13386**
13387**   1. Invoke sqlite3changegroup_change_begin() to indicate the type of
13388**      change (INSERT, UPDATE or DELETE), the affected table and whether
13389**      or not the change should be marked as indirect.
13390**
13391**   2. Invoke sqlite3changegroup_change_int64() or one of the other four
13392**      value functions - _null(), _double(), _text() or _blob() - one or
13393**      more times to specify old.* and new.* values for the change being
13394**      constructed.
13395**
13396**   3. Invoke sqlite3changegroup_change_finish() to either finish adding
13397**      the change to the group, or to discard the change altogether.
13398**
13399** The first argument to this function must be a pointer to the existing
13400** changegroup object that the change will be added to. The second argument
13401** must be SQLITE_INSERT, SQLITE_UPDATE or SQLITE_DELETE. The third is the
13402** name of the table that the change affects, and the fourth is a boolean
13403** flag specifying whether the change should be marked as "indirect" (if
13404** bIndirect is non-zero) or not indirect (if bIndirect is zero).
13405**
13406** Following a successful call to this function, this function may not be
13407** called again on the same changegroup object until after
13408** sqlite3changegroup_change_finish() has been called. Doing so is an
13409** SQLITE_MISUSE error.
13410**
13411** The changegroup object passed as the first argument must be already
13412** configured with schema data for the specified table. It may be configured
13413** either by calling sqlite3changegroup_schema() with a database that contains
13414** the table, or sqlite3changegroup_add() with a changeset that contains the
13415** table. If the changegroup object has not been configured with a schema for
13416** the specified table when this function is called, SQLITE_ERROR is returned.
13417**
13418** If successful, SQLITE_OK is returned. Otherwise, if an error occurs, an
13419** SQLite error code is returned. In this case, if argument pzErr is non-NULL,
13420** then (*pzErr) may be set to point to a buffer containing a utf-8 formated,
13421** nul-terminated, English language error message. It is the responsibility
13422** of the caller to eventually free this buffer using sqlite3_free().
13423*/
13424SQLITE_API int sqlite3changegroup_change_begin(
13425  sqlite3_changegroup*,
13426  int eOp,
13427  const char *zTab,
13428  int bIndirect,
13429  char **pzErr
13430);
13431
13432/*
13433** CAPI3REF: Add a 64-bit integer to a changegroup
13434**
13435** This function may only be called between a successful call to
13436** sqlite3changegroup_change_begin() and its matching
13437** sqlite3changegroup_change_finish() call. If it is called at any
13438** other time, it is an SQLITE_MISUSE error. Calling this function
13439** specifies a 64-bit integer value to be used in the change currently being
13440** added to the changegroup object passed as the first argument.
13441**
13442** The second parameter, bNew, specifies whether the value is to be part of
13443** the new.* (if bNew is non-zero) or old.* (if bNew is zero) record of
13444** the change under construction. If this does not match the type of change
13445** specified by the preceding call to sqlite3changegroup_change_begin() (i.e.
13446** an old.* value for an SQLITE_INSERT change, or a new.* value for an
13447** SQLITE_DELETE), then SQLITE_ERROR is returned.
13448**
13449** The third parameter specifies the column of the old.* or new.* record that
13450** the value will be a part of. If the specified table has an explicit primary
13451** key, then this is the index of the table column, numbered from 0 in the order
13452** specified within the CREATE TABLE statement. Or, if the table uses an
13453** implicit rowid key, then the column 0 is the rowid and the explicit columns
13454** are numbered starting from 1. If the iCol parameter is less than 0 or greater
13455** than the index of the last column in the table, SQLITE_RANGE is returned.
13456**
13457** The fourth parameter is the integer value to use as part of the old.* or
13458** new.* record.
13459**
13460** If this call is successful, SQLITE_OK is returned. Otherwise, if an
13461** error occurs, an SQLite error code is returned.
13462*/
13463SQLITE_API int sqlite3changegroup_change_int64(
13464  sqlite3_changegroup*,
13465  int bNew,
13466  int iCol,
13467  sqlite3_int64 iVal
13468);
13469
13470/*
13471** CAPI3REF: Add a NULL to a changegroup
13472**
13473** This function is similar to sqlite3changegroup_change_int64(). Except that
13474** it configures the change currently under construction with a NULL value
13475** instead of a 64-bit integer.
13476*/
13477SQLITE_API int sqlite3changegroup_change_null(sqlite3_changegroup*, int, int);
13478
13479/*
13480** CAPI3REF: Add an double to a changegroup
13481**
13482** This function is similar to sqlite3changegroup_change_int64(). Except that
13483** it configures the change currently being constructed with a real value
13484** instead of a 64-bit integer.
13485*/
13486SQLITE_API int sqlite3changegroup_change_double(sqlite3_changegroup*, int, int, double);
13487
13488/*
13489** CAPI3REF: Add a text value to a changegroup
13490**
13491** This function is similar to sqlite3changegroup_change_int64(). It configures
13492** the currently accumulated change with a text value instead of a 64-bit
13493** integer. Parameter pVal points to a buffer containing the text encoded using
13494** utf-8. Parameter nVal may either be the size of the text value in bytes, or
13495** else a negative value, in which case the buffer pVal points to is assumed to
13496** be nul-terminated.
13497*/
13498SQLITE_API int sqlite3changegroup_change_text(
13499  sqlite3_changegroup*, int, int, const char *pVal, int nVal
13500);
13501
13502/*
13503** CAPI3REF: Add a blob to a changegroup
13504**
13505** This function is similar to sqlite3changegroup_change_int64(). It configures
13506** the currently accumulated change with a blob value instead of a 64-bit
13507** integer. Parameter pVal points to a buffer containing the blob. Parameter
13508** nVal is the size of the blob in bytes.
13509*/
13510SQLITE_API int sqlite3changegroup_change_blob(
13511    sqlite3_changegroup*, int, int, const void *pVal, int nVal
13512);
13513
13514/*
13515** CAPI3REF: Finish adding one-at-at-time changes to a changegroup
13516**
13517** This function may only be called following a successful call to
13518** sqlite3changegroup_change_begin(). Otherwise, it is an SQLITE_MISUSE error.
13519**
13520** If parameter bDiscard is non-zero, then the current change is simply
13521** discarded. In this case this function is always successful and SQLITE_OK
13522** returned.
13523**
13524** If parameter bDiscard is zero, then an attempt is made to add the current
13525** change to the changegroup. Assuming the changegroup is configured to
13526** produce a changeset (not a patchset), this requires that:
13527**
13528**   *  If the change is an INSERT or DELETE, then a value must be specified
13529**      for all columns of the new.* or old.* record, respectively.
13530**
13531**   *  If the change is an UPDATE record, then values must be provided for
13532**      the PRIMARY KEY columns of the old.* record, but must not be provided
13533**      for PRIMARY KEY columns of the new.* record.
13534**
13535**   *  If the change is an UPDATE record, then for each non-PRIMARY KEY
13536**      column in the old.* record for which a value has been provided, a
13537**      value must also be provided for the same column in the new.* record.
13538**      Similarly, for each non-PK column in the old.* record for which
13539**      a value is not provided, a value must not be provided for the same
13540**      column in the new.* record.
13541**
13542**   *  All values specified for PRIMARY KEY columns must be non-NULL.
13543**
13544** Otherwise, it is an error.
13545**
13546** If the changegroup already contains a change for the same row (identified
13547** by PRIMARY KEY columns), then the current change is combined with the
13548** existing change in the same way as for sqlite3changegroup_add().
13549**
13550** For a patchset, all of the above rules apply except that it doesn't matter
13551** whether or not values are provided for the non-PK old.* record columns
13552** for an UPDATE or DELETE change. This means that code used to produce
13553** a changeset using the sqlite3changegroup_change_xxx() APIs may also
13554** be used to produce patchsets.
13555**
13556** If the call is successful, SQLITE_OK is returned. Otherwise, if an error
13557** occurs, an SQLite error code is returned. If an error is returned and
13558** parameter pzErr is not NULL, then (*pzErr) may be set to point to a buffer
13559** containing a nul-terminated, utf-8 encoded, English language error message.
13560** It is the responsibility of the caller to eventually free any such error
13561** message buffer using sqlite3_free().
13562*/
13563SQLITE_API int sqlite3changegroup_change_finish(
13564  sqlite3_changegroup*,
13565  int bDiscard,
13566  char **pzErr
13567);
13568
13569/*
13570** Make sure we can call this stuff from C++.
13571*/
13572#ifdef __cplusplus
13573}
13574#endif
13575
13576#endif  /* !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) */
13577
13578/******** End of sqlite3session.h *********/
13579/******** Begin file fts5.h *********/
13580/*
13581** 2014 May 31
13582**
13583** The author disclaims copyright to this source code.  In place of
13584** a legal notice, here is a blessing:
13585**
13586**    May you do good and not evil.
13587**    May you find forgiveness for yourself and forgive others.
13588**    May you share freely, never taking more than you give.
13589**
13590******************************************************************************
13591**
13592** Interfaces to extend FTS5. Using the interfaces defined in this file,
13593** FTS5 may be extended with:
13594**
13595**     * custom tokenizers, and
13596**     * custom auxiliary functions.
13597*/
13598
13599
13600#ifndef _FTS5_H
13601#define _FTS5_H
13602
13603
13604#ifdef __cplusplus
13605extern "C" {
13606#endif
13607
13608/*************************************************************************
13609** CUSTOM AUXILIARY FUNCTIONS
13610**
13611** Virtual table implementations may overload SQL functions by implementing
13612** the sqlite3_module.xFindFunction() method.
13613*/
13614
13615typedef struct Fts5ExtensionApi Fts5ExtensionApi;
13616typedef struct Fts5Context Fts5Context;
13617typedef struct Fts5PhraseIter Fts5PhraseIter;
13618
13619typedef void (*fts5_extension_function)(
13620  const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
13621  Fts5Context *pFts,              /* First arg to pass to pApi functions */
13622  sqlite3_context *pCtx,          /* Context for returning result/error */
13623  int nVal,                       /* Number of values in apVal[] array */
13624  sqlite3_value **apVal           /* Array of trailing arguments */
13625);
13626
13627struct Fts5PhraseIter {
13628  const unsigned char *a;
13629  const unsigned char *b;
13630};
13631
13632/*
13633** EXTENSION API FUNCTIONS
13634**
13635** xUserData(pFts):
13636**   Return a copy of the pUserData pointer passed to the xCreateFunction()
13637**   API when the extension function was registered.
13638**
13639** xColumnTotalSize(pFts, iCol, pnToken):
13640**   If parameter iCol is less than zero, set output variable *pnToken
13641**   to the total number of tokens in the FTS5 table. Or, if iCol is
13642**   non-negative but less than the number of columns in the table, return
13643**   the total number of tokens in column iCol, considering all rows in
13644**   the FTS5 table.
13645**
13646**   If parameter iCol is greater than or equal to the number of columns
13647**   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
13648**   an OOM condition or IO error), an appropriate SQLite error code is
13649**   returned.
13650**
13651** xColumnCount(pFts):
13652**   Return the number of columns in the table.
13653**
13654** xColumnSize(pFts, iCol, pnToken):
13655**   If parameter iCol is less than zero, set output variable *pnToken
13656**   to the total number of tokens in the current row. Or, if iCol is
13657**   non-negative but less than the number of columns in the table, set
13658**   *pnToken to the number of tokens in column iCol of the current row.
13659**
13660**   If parameter iCol is greater than or equal to the number of columns
13661**   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
13662**   an OOM condition or IO error), an appropriate SQLite error code is
13663**   returned.
13664**
13665**   This function may be quite inefficient if used with an FTS5 table
13666**   created with the "columnsize=0" option.
13667**
13668** xColumnText:
13669**   If parameter iCol is less than zero, or greater than or equal to the
13670**   number of columns in the table, SQLITE_RANGE is returned.
13671**
13672**   Otherwise, this function attempts to retrieve the text of column iCol of
13673**   the current document. If successful, (*pz) is set to point to a buffer
13674**   containing the text in utf-8 encoding, (*pn) is set to the size in bytes
13675**   (not characters) of the buffer and SQLITE_OK is returned. Otherwise,
13676**   if an error occurs, an SQLite error code is returned and the final values
13677**   of (*pz) and (*pn) are undefined.
13678**
13679** xPhraseCount:
13680**   Returns the number of phrases in the current query expression.
13681**
13682** xPhraseSize:
13683**   If parameter iCol is less than zero, or greater than or equal to the
13684**   number of phrases in the current query, as returned by xPhraseCount,
13685**   0 is returned. Otherwise, this function returns the number of tokens in
13686**   phrase iPhrase of the query. Phrases are numbered starting from zero.
13687**
13688** xInstCount:
13689**   Set *pnInst to the total number of occurrences of all phrases within
13690**   the query within the current row. Return SQLITE_OK if successful, or
13691**   an error code (i.e. SQLITE_NOMEM) if an error occurs.
13692**
13693**   This API can be quite slow if used with an FTS5 table created with the
13694**   "detail=none" or "detail=column" option. If the FTS5 table is created
13695**   with either "detail=none" or "detail=column" and "content=" option
13696**   (i.e. if it is a contentless table), then this API always returns 0.
13697**
13698** xInst:
13699**   Query for the details of phrase match iIdx within the current row.
13700**   Phrase matches are numbered starting from zero, so the iIdx argument
13701**   should be greater than or equal to zero and smaller than the value
13702**   output by xInstCount(). If iIdx is less than zero or greater than
13703**   or equal to the value returned by xInstCount(), SQLITE_RANGE is returned.
13704**
13705**   Otherwise, output parameter *piPhrase is set to the phrase number, *piCol
13706**   to the column in which it occurs and *piOff the token offset of the
13707**   first token of the phrase. SQLITE_OK is returned if successful, or an
13708**   error code (i.e. SQLITE_NOMEM) if an error occurs.
13709**
13710**   This API can be quite slow if used with an FTS5 table created with the
13711**   "detail=none" or "detail=column" option.
13712**
13713** xRowid:
13714**   Returns the rowid of the current row.
13715**
13716** xTokenize:
13717**   Tokenize text using the tokenizer belonging to the FTS5 table.
13718**
13719** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback):
13720**   This API function is used to query the FTS table for phrase iPhrase
13721**   of the current query. Specifically, a query equivalent to:
13722**
13723**       ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid
13724**
13725**   with $p set to a phrase equivalent to the phrase iPhrase of the
13726**   current query is executed. Any column filter that applies to
13727**   phrase iPhrase of the current query is included in $p. For each
13728**   row visited, the callback function passed as the fourth argument
13729**   is invoked. The context and API objects passed to the callback
13730**   function may be used to access the properties of each matched row.
13731**   Invoking Api.xUserData() returns a copy of the pointer passed as
13732**   the third argument to pUserData.
13733**
13734**   If parameter iPhrase is less than zero, or greater than or equal to
13735**   the number of phrases in the query, as returned by xPhraseCount(),
13736**   this function returns SQLITE_RANGE.
13737**
13738**   If the callback function returns any value other than SQLITE_OK, the
13739**   query is abandoned and the xQueryPhrase function returns immediately.
13740**   If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK.
13741**   Otherwise, the error code is propagated upwards.
13742**
13743**   If the query runs to completion without incident, SQLITE_OK is returned.
13744**   Or, if some error occurs before the query completes or is aborted by
13745**   the callback, an SQLite error code is returned.
13746**
13747**
13748** xSetAuxdata(pFts5, pAux, xDelete)
13749**
13750**   Save the pointer passed as the second argument as the extension function's
13751**   "auxiliary data". The pointer may then be retrieved by the current or any
13752**   future invocation of the same fts5 extension function made as part of
13753**   the same MATCH query using the xGetAuxdata() API.
13754**
13755**   Each extension function is allocated a single auxiliary data slot for
13756**   each FTS query (MATCH expression). If the extension function is invoked
13757**   more than once for a single FTS query, then all invocations share a
13758**   single auxiliary data context.
13759**
13760**   If there is already an auxiliary data pointer when this function is
13761**   invoked, then it is replaced by the new pointer. If an xDelete callback
13762**   was specified along with the original pointer, it is invoked at this
13763**   point.
13764**
13765**   The xDelete callback, if one is specified, is also invoked on the
13766**   auxiliary data pointer after the FTS5 query has finished.
13767**
13768**   If an error (e.g. an OOM condition) occurs within this function,
13769**   the auxiliary data is set to NULL and an error code returned. If the
13770**   xDelete parameter was not NULL, it is invoked on the auxiliary data
13771**   pointer before returning.
13772**
13773**
13774** xGetAuxdata(pFts5, bClear)
13775**
13776**   Returns the current auxiliary data pointer for the fts5 extension
13777**   function. See the xSetAuxdata() method for details.
13778**
13779**   If the bClear argument is non-zero, then the auxiliary data is cleared
13780**   (set to NULL) before this function returns. In this case the xDelete,
13781**   if any, is not invoked.
13782**
13783**
13784** xRowCount(pFts5, pnRow)
13785**
13786**   This function is used to retrieve the total number of rows in the table.
13787**   In other words, the same value that would be returned by:
13788**
13789**        SELECT count(*) FROM ftstable;
13790**
13791** xPhraseFirst()
13792**   This function is used, along with type Fts5PhraseIter and the xPhraseNext
13793**   method, to iterate through all instances of a single query phrase within
13794**   the current row. This is the same information as is accessible via the
13795**   xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient
13796**   to use, this API may be faster under some circumstances. To iterate
13797**   through instances of phrase iPhrase, use the following code:
13798**
13799**       Fts5PhraseIter iter;
13800**       int iCol, iOff;
13801**       for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff);
13802**           iCol>=0;
13803**           pApi->xPhraseNext(pFts, &iter, &iCol, &iOff)
13804**       ){
13805**         // An instance of phrase iPhrase at offset iOff of column iCol
13806**       }
13807**
13808**   The Fts5PhraseIter structure is defined above. Applications should not
13809**   modify this structure directly - it should only be used as shown above
13810**   with the xPhraseFirst() and xPhraseNext() API methods (and by
13811**   xPhraseFirstColumn() and xPhraseNextColumn() as illustrated below).
13812**
13813**   This API can be quite slow if used with an FTS5 table created with the
13814**   "detail=none" or "detail=column" option. If the FTS5 table is created
13815**   with either "detail=none" or "detail=column" and "content=" option
13816**   (i.e. if it is a contentless table), then this API always iterates
13817**   through an empty set (all calls to xPhraseFirst() set iCol to -1).
13818**
13819**   In all cases, matches are visited in (column ASC, offset ASC) order.
13820**   i.e. all those in column 0, sorted by offset, followed by those in
13821**   column 1, etc.
13822**
13823** xPhraseNext()
13824**   See xPhraseFirst above.
13825**
13826** xPhraseFirstColumn()
13827**   This function and xPhraseNextColumn() are similar to the xPhraseFirst()
13828**   and xPhraseNext() APIs described above. The difference is that instead
13829**   of iterating through all instances of a phrase in the current row, these
13830**   APIs are used to iterate through the set of columns in the current row
13831**   that contain one or more instances of a specified phrase. For example:
13832**
13833**       Fts5PhraseIter iter;
13834**       int iCol;
13835**       for(pApi->xPhraseFirstColumn(pFts, iPhrase, &iter, &iCol);
13836**           iCol>=0;
13837**           pApi->xPhraseNextColumn(pFts, &iter, &iCol)
13838**       ){
13839**         // Column iCol contains at least one instance of phrase iPhrase
13840**       }
13841**
13842**   This API can be quite slow if used with an FTS5 table created with the
13843**   "detail=none" option. If the FTS5 table is created with either
13844**   "detail=none" "content=" option (i.e. if it is a contentless table),
13845**   then this API always iterates through an empty set (all calls to
13846**   xPhraseFirstColumn() set iCol to -1).
13847**
13848**   The information accessed using this API and its companion
13849**   xPhraseFirstColumn() may also be obtained using xPhraseFirst/xPhraseNext
13850**   (or xInst/xInstCount). The chief advantage of this API is that it is
13851**   significantly more efficient than those alternatives when used with
13852**   "detail=column" tables.
13853**
13854** xPhraseNextColumn()
13855**   See xPhraseFirstColumn above.
13856**
13857** xQueryToken(pFts5, iPhrase, iToken, ppToken, pnToken)
13858**   This is used to access token iToken of phrase iPhrase of the current
13859**   query. Before returning, output parameter *ppToken is set to point
13860**   to a buffer containing the requested token, and *pnToken to the
13861**   size of this buffer in bytes.
13862**
13863**   If iPhrase or iToken are less than zero, or if iPhrase is greater than
13864**   or equal to the number of phrases in the query as reported by
13865**   xPhraseCount(), or if iToken is equal to or greater than the number of
13866**   tokens in the phrase, SQLITE_RANGE is returned and *ppToken and *pnToken
13867     are both zeroed.
13868**
13869**   The output text is not a copy of the query text that specified the
13870**   token. It is the output of the tokenizer module. For tokendata=1
13871**   tables, this includes any embedded 0x00 and trailing data.
13872**
13873** xInstToken(pFts5, iIdx, iToken, ppToken, pnToken)
13874**   This is used to access token iToken of phrase hit iIdx within the
13875**   current row. If iIdx is less than zero or greater than or equal to the
13876**   value returned by xInstCount(), SQLITE_RANGE is returned.  Otherwise,
13877**   output variable (*ppToken) is set to point to a buffer containing the
13878**   matching document token, and (*pnToken) to the size of that buffer in
13879**   bytes.
13880**
13881**   The output text is not a copy of the document text that was tokenized.
13882**   It is the output of the tokenizer module. For tokendata=1 tables, this
13883**   includes any embedded 0x00 and trailing data.
13884**
13885**   This API may be slow in some cases if the token identified by parameters
13886**   iIdx and iToken matched a prefix token in the query. In most cases, the
13887**   first call to this API for each prefix token in the query is forced
13888**   to scan the portion of the full-text index that matches the prefix
13889**   token to collect the extra data required by this API. If the prefix
13890**   token matches a large number of token instances in the document set,
13891**   this may be a performance problem.
13892**
13893**   If the user knows in advance that a query may use this API for a
13894**   prefix token, FTS5 may be configured to collect all required data as part
13895**   of the initial querying of the full-text index, avoiding the second scan
13896**   entirely. This also causes prefix queries that do not use this API to
13897**   run more slowly and use more memory. FTS5 may be configured in this way
13898**   either on a per-table basis using the [FTS5 insttoken | 'insttoken']
13899**   option, or on a per-query basis using the
13900**   [fts5_insttoken | fts5_insttoken()] user function.
13901**
13902**   This API can be quite slow if used with an FTS5 table created with the
13903**   "detail=none" or "detail=column" option.
13904**
13905** xColumnLocale(pFts5, iIdx, pzLocale, pnLocale)
13906**   If parameter iCol is less than zero, or greater than or equal to the
13907**   number of columns in the table, SQLITE_RANGE is returned.
13908**
13909**   Otherwise, this function attempts to retrieve the locale associated
13910**   with column iCol of the current row. Usually, there is no associated
13911**   locale, and output parameters (*pzLocale) and (*pnLocale) are set
13912**   to NULL and 0, respectively. However, if the fts5_locale() function
13913**   was used to associate a locale with the value when it was inserted
13914**   into the fts5 table, then (*pzLocale) is set to point to a nul-terminated
13915**   buffer containing the name of the locale in utf-8 encoding. (*pnLocale)
13916**   is set to the size in bytes of the buffer, not including the
13917**   nul-terminator.
13918**
13919**   If successful, SQLITE_OK is returned. Or, if an error occurs, an
13920**   SQLite error code is returned. The final value of the output parameters
13921**   is undefined in this case.
13922**
13923** xTokenize_v2:
13924**   Tokenize text using the tokenizer belonging to the FTS5 table. This
13925**   API is the same as the xTokenize() API, except that it allows a tokenizer
13926**   locale to be specified.
13927*/
13928struct Fts5ExtensionApi {
13929  int iVersion;                   /* Currently always set to 4 */
13930
13931  void *(*xUserData)(Fts5Context*);
13932
13933  int (*xColumnCount)(Fts5Context*);
13934  int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
13935  int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);
13936
13937  int (*xTokenize)(Fts5Context*,
13938    const char *pText, int nText, /* Text to tokenize */
13939    void *pCtx,                   /* Context passed to xToken() */
13940    int (*xToken)(void*, int, const char*, int, int, int)       /* Callback */
13941  );
13942
13943  int (*xPhraseCount)(Fts5Context*);
13944  int (*xPhraseSize)(Fts5Context*, int iPhrase);
13945
13946  int (*xInstCount)(Fts5Context*, int *pnInst);
13947  int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff);
13948
13949  sqlite3_int64 (*xRowid)(Fts5Context*);
13950  int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn);
13951  int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken);
13952
13953  int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData,
13954    int(*)(const Fts5ExtensionApi*,Fts5Context*,void*)
13955  );
13956  int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*));
13957  void *(*xGetAuxdata)(Fts5Context*, int bClear);
13958
13959  int (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*);
13960  void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff);
13961
13962  int (*xPhraseFirstColumn)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*);
13963  void (*xPhraseNextColumn)(Fts5Context*, Fts5PhraseIter*, int *piCol);
13964
13965  /* Below this point are iVersion>=3 only */
13966  int (*xQueryToken)(Fts5Context*,
13967      int iPhrase, int iToken,
13968      const char **ppToken, int *pnToken
13969  );
13970  int (*xInstToken)(Fts5Context*, int iIdx, int iToken, const char**, int*);
13971
13972  /* Below this point are iVersion>=4 only */
13973  int (*xColumnLocale)(Fts5Context*, int iCol, const char **pz, int *pn);
13974  int (*xTokenize_v2)(Fts5Context*,
13975    const char *pText, int nText,      /* Text to tokenize */
13976    const char *pLocale, int nLocale,  /* Locale to pass to tokenizer */
13977    void *pCtx,                        /* Context passed to xToken() */
13978    int (*xToken)(void*, int, const char*, int, int, int)       /* Callback */
13979  );
13980};
13981
13982/*
13983** CUSTOM AUXILIARY FUNCTIONS
13984*************************************************************************/
13985
13986/*************************************************************************
13987** CUSTOM TOKENIZERS
13988**
13989** Applications may also register custom tokenizer types. A tokenizer
13990** is registered by providing fts5 with a populated instance of the
13991** following structure. All structure methods must be defined, setting
13992** any member of the fts5_tokenizer struct to NULL leads to undefined
13993** behaviour. The structure methods are expected to function as follows:
13994**
13995** xCreate:
13996**   This function is used to allocate and initialize a tokenizer instance.
13997**   A tokenizer instance is required to actually tokenize text.
13998**
13999**   The first argument passed to this function is a copy of the (void*)
14000**   pointer provided by the application when the fts5_tokenizer_v2 object
14001**   was registered with FTS5 (the third argument to xCreateTokenizer()).
14002**   The second and third arguments are an array of nul-terminated strings
14003**   containing the tokenizer arguments, if any, specified following the
14004**   tokenizer name as part of the CREATE VIRTUAL TABLE statement used
14005**   to create the FTS5 table.
14006**
14007**   The final argument is an output variable. If successful, (*ppOut)
14008**   should be set to point to the new tokenizer handle and SQLITE_OK
14009**   returned. If an error occurs, some value other than SQLITE_OK should
14010**   be returned. In this case, fts5 assumes that the final value of *ppOut
14011**   is undefined.
14012**
14013** xDelete:
14014**   This function is invoked to delete a tokenizer handle previously
14015**   allocated using xCreate(). Fts5 guarantees that this function will
14016**   be invoked exactly once for each successful call to xCreate().
14017**
14018** xTokenize:
14019**   This function is expected to tokenize the nText byte string indicated
14020**   by argument pText. pText may or may not be nul-terminated. The first
14021**   argument passed to this function is a pointer to an Fts5Tokenizer object
14022**   returned by an earlier call to xCreate().
14023**
14024**   The third argument indicates the reason that FTS5 is requesting
14025**   tokenization of the supplied text. This is always one of the following
14026**   four values:
14027**
14028**   <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into
14029**            or removed from the FTS table. The tokenizer is being invoked to
14030**            determine the set of tokens to add to (or delete from) the
14031**            FTS index.
14032**
14033**       <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed
14034**            against the FTS index. The tokenizer is being called to tokenize
14035**            a bareword or quoted string specified as part of the query.
14036**
14037**       <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as
14038**            FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is
14039**            followed by a "*" character, indicating that the last token
14040**            returned by the tokenizer will be treated as a token prefix.
14041**
14042**       <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to
14043**            satisfy an fts5_api.xTokenize() request made by an auxiliary
14044**            function. Or an fts5_api.xColumnSize() request made by the same
14045**            on a columnsize=0 database.
14046**   </ul>
14047**
14048**   The sixth and seventh arguments passed to xTokenize() - pLocale and
14049**   nLocale - are a pointer to a buffer containing the locale to use for
14050**   tokenization (e.g. "en_US") and its size in bytes, respectively. The
14051**   pLocale buffer is not nul-terminated. pLocale may be passed NULL (in
14052**   which case nLocale is always 0) to indicate that the tokenizer should
14053**   use its default locale.
14054**
14055**   For each token in the input string, the supplied callback xToken() must
14056**   be invoked. The first argument to it should be a copy of the pointer
14057**   passed as the second argument to xTokenize(). The third and fourth
14058**   arguments are a pointer to a buffer containing the token text, and the
14059**   size of the token in bytes. The 4th and 5th arguments are the byte offsets
14060**   of the first byte of and first byte immediately following the text from
14061**   which the token is derived within the input.
14062**
14063**   The second argument passed to the xToken() callback ("tflags") should
14064**   normally be set to 0. The exception is if the tokenizer supports
14065**   synonyms. In this case see the discussion below for details.
14066**
14067**   FTS5 assumes the xToken() callback is invoked for each token in the
14068**   order that they occur within the input text.
14069**
14070**   If an xToken() callback returns any value other than SQLITE_OK, then
14071**   the tokenization should be abandoned and the xTokenize() method should
14072**   immediately return a copy of the xToken() return value. Or, if the
14073**   input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally,
14074**   if an error occurs with the xTokenize() implementation itself, it
14075**   may abandon the tokenization and return any error code other than
14076**   SQLITE_OK or SQLITE_DONE.
14077**
14078**   If the tokenizer is registered using an fts5_tokenizer_v2 object,
14079**   then the xTokenize() method has two additional arguments - pLocale
14080**   and nLocale. These specify the locale that the tokenizer should use
14081**   for the current request. If pLocale and nLocale are both 0, then the
14082**   tokenizer should use its default locale. Otherwise, pLocale points to
14083**   an nLocale byte buffer containing the name of the locale to use as utf-8
14084**   text. pLocale is not nul-terminated.
14085**
14086** FTS5_TOKENIZER
14087**
14088** There is also an fts5_tokenizer object. This is an older, deprecated,
14089** version of fts5_tokenizer_v2. It is similar except that:
14090**
14091**  <ul>
14092**    <li> There is no "iVersion" field, and
14093**    <li> The xTokenize() method does not take a locale argument.
14094**  </ul>
14095**
14096** Legacy fts5_tokenizer tokenizers must be registered using the
14097** legacy xCreateTokenizer() function, instead of xCreateTokenizer_v2().
14098**
14099** Tokenizer implementations registered using either API may be retrieved
14100** using both xFindTokenizer() and xFindTokenizer_v2().
14101**
14102** SYNONYM SUPPORT
14103**
14104**   Custom tokenizers may also support synonyms. Consider a case in which a
14105**   user wishes to query for a phrase such as "first place". Using the
14106**   built-in tokenizers, the FTS5 query 'first + place' will match instances
14107**   of "first place" within the document set, but not alternative forms
14108**   such as "1st place". In some applications, it would be better to match
14109**   all instances of "first place" or "1st place" regardless of which form
14110**   the user specified in the MATCH query text.
14111**
14112**   There are several ways to approach this in FTS5:
14113**
14114**   <ol><li> By mapping all synonyms to a single token. In this case, using
14115**            the above example, this means that the tokenizer returns the
14116**            same token for inputs "first" and "1st". Say that token is in
14117**            fact "first", so that when the user inserts the document "I won
14118**            1st place" entries are added to the index for tokens "i", "won",
14119**            "first" and "place". If the user then queries for '1st + place',
14120**            the tokenizer substitutes "first" for "1st" and the query works
14121**            as expected.
14122**
14123**       <li> By querying the index for all synonyms of each query term
14124**            separately. In this case, when tokenizing query text, the
14125**            tokenizer may provide multiple synonyms for a single term
14126**            within the document. FTS5 then queries the index for each
14127**            synonym individually. For example, faced with the query:
14128**
14129**   <codeblock>
14130**     ... MATCH 'first place'</codeblock>
14131**
14132**            the tokenizer offers both "1st" and "first" as synonyms for the
14133**            first token in the MATCH query and FTS5 effectively runs a query
14134**            similar to:
14135**
14136**   <codeblock>
14137**     ... MATCH '(first OR 1st) place'</codeblock>
14138**
14139**            except that, for the purposes of auxiliary functions, the query
14140**            still appears to contain just two phrases - "(first OR 1st)"
14141**            being treated as a single phrase.
14142**
14143**       <li> By adding multiple synonyms for a single term to the FTS index.
14144**            Using this method, when tokenizing document text, the tokenizer
14145**            provides multiple synonyms for each token. So that when a
14146**            document such as "I won first place" is tokenized, entries are
14147**            added to the FTS index for "i", "won", "first", "1st" and
14148**            "place".
14149**
14150**            This way, even if the tokenizer does not provide synonyms
14151**            when tokenizing query text (it should not - to do so would be
14152**            inefficient), it doesn't matter if the user queries for
14153**            'first + place' or '1st + place', as there are entries in the
14154**            FTS index corresponding to both forms of the first token.
14155**   </ol>
14156**
14157**   Whether it is parsing document or query text, any call to xToken that
14158**   specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit
14159**   is considered to supply a synonym for the previous token. For example,
14160**   when parsing the document "I won first place", a tokenizer that supports
14161**   synonyms would call xToken() 5 times, as follows:
14162**
14163**   <codeblock>
14164**       xToken(pCtx, 0, "i",                      1,  0,  1);
14165**       xToken(pCtx, 0, "won",                    3,  2,  5);
14166**       xToken(pCtx, 0, "first",                  5,  6, 11);
14167**       xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3,  6, 11);
14168**       xToken(pCtx, 0, "place",                  5, 12, 17);
14169**</codeblock>
14170**
14171**   It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time
14172**   xToken() is called. Multiple synonyms may be specified for a single token
14173**   by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence.
14174**   There is no limit to the number of synonyms that may be provided for a
14175**   single token.
14176**
14177**   In many cases, method (1) above is the best approach. It does not add
14178**   extra data to the FTS index or require FTS5 to query for multiple terms,
14179**   so it is efficient in terms of disk space and query speed. However, it
14180**   does not support prefix queries very well. If, as suggested above, the
14181**   token "first" is substituted for "1st" by the tokenizer, then the query:
14182**
14183**   <codeblock>
14184**     ... MATCH '1s*'</codeblock>
14185**
14186**   will not match documents that contain the token "1st" (as the tokenizer
14187**   will probably not map "1s" to any prefix of "first").
14188**
14189**   For full prefix support, method (3) may be preferred. In this case,
14190**   because the index contains entries for both "first" and "1st", prefix
14191**   queries such as 'fi*' or '1s*' will match correctly. However, because
14192**   extra entries are added to the FTS index, this method uses more space
14193**   within the database.
14194**
14195**   Method (2) offers a midpoint between (1) and (3). Using this method,
14196**   a query such as '1s*' will match documents that contain the literal
14197**   token "1st", but not "first" (assuming the tokenizer is not able to
14198**   provide synonyms for prefixes). However, a non-prefix query like '1st'
14199**   will match against "1st" and "first". This method does not require
14200**   extra disk space, as no extra entries are added to the FTS index.
14201**   On the other hand, it may require more CPU cycles to run MATCH queries,
14202**   as separate queries of the FTS index are required for each synonym.
14203**
14204**   When using methods (2) or (3), it is important that the tokenizer only
14205**   provide synonyms when tokenizing document text (method (3)) or query
14206**   text (method (2)), not both. Doing so will not cause any errors, but is
14207**   inefficient.
14208*/
14209typedef struct Fts5Tokenizer Fts5Tokenizer;
14210typedef struct fts5_tokenizer_v2 fts5_tokenizer_v2;
14211struct fts5_tokenizer_v2 {
14212  int iVersion;             /* Currently always 2 */
14213
14214  int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
14215  void (*xDelete)(Fts5Tokenizer*);
14216  int (*xTokenize)(Fts5Tokenizer*,
14217      void *pCtx,
14218      int flags,            /* Mask of FTS5_TOKENIZE_* flags */
14219      const char *pText, int nText,
14220      const char *pLocale, int nLocale,
14221      int (*xToken)(
14222        void *pCtx,         /* Copy of 2nd argument to xTokenize() */
14223        int tflags,         /* Mask of FTS5_TOKEN_* flags */
14224        const char *pToken, /* Pointer to buffer containing token */
14225        int nToken,         /* Size of token in bytes */
14226        int iStart,         /* Byte offset of token within input text */
14227        int iEnd            /* Byte offset of end of token within input text */
14228      )
14229  );
14230};
14231
14232/*
14233** New code should use the fts5_tokenizer_v2 type to define tokenizer
14234** implementations. The following type is included for legacy applications
14235** that still use it.
14236*/
14237typedef struct fts5_tokenizer fts5_tokenizer;
14238struct fts5_tokenizer {
14239  int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
14240  void (*xDelete)(Fts5Tokenizer*);
14241  int (*xTokenize)(Fts5Tokenizer*,
14242      void *pCtx,
14243      int flags,            /* Mask of FTS5_TOKENIZE_* flags */
14244      const char *pText, int nText,
14245      int (*xToken)(
14246        void *pCtx,         /* Copy of 2nd argument to xTokenize() */
14247        int tflags,         /* Mask of FTS5_TOKEN_* flags */
14248        const char *pToken, /* Pointer to buffer containing token */
14249        int nToken,         /* Size of token in bytes */
14250        int iStart,         /* Byte offset of token within input text */
14251        int iEnd            /* Byte offset of end of token within input text */
14252      )
14253  );
14254};
14255
14256
14257/* Flags that may be passed as the third argument to xTokenize() */
14258#define FTS5_TOKENIZE_QUERY     0x0001
14259#define FTS5_TOKENIZE_PREFIX    0x0002
14260#define FTS5_TOKENIZE_DOCUMENT  0x0004
14261#define FTS5_TOKENIZE_AUX       0x0008
14262
14263/* Flags that may be passed by the tokenizer implementation back to FTS5
14264** as the third argument to the supplied xToken callback. */
14265#define FTS5_TOKEN_COLOCATED    0x0001      /* Same position as prev. token */
14266
14267/*
14268** END OF CUSTOM TOKENIZERS
14269*************************************************************************/
14270
14271/*************************************************************************
14272** FTS5 EXTENSION REGISTRATION API
14273*/
14274typedef struct fts5_api fts5_api;
14275struct fts5_api {
14276  int iVersion;                   /* Currently always set to 3 */
14277
14278  /* Create a new tokenizer */
14279  int (*xCreateTokenizer)(
14280    fts5_api *pApi,
14281    const char *zName,
14282    void *pUserData,
14283    fts5_tokenizer *pTokenizer,
14284    void (*xDestroy)(void*)
14285  );
14286
14287  /* Find an existing tokenizer */
14288  int (*xFindTokenizer)(
14289    fts5_api *pApi,
14290    const char *zName,
14291    void **ppUserData,
14292    fts5_tokenizer *pTokenizer
14293  );
14294
14295  /* Create a new auxiliary function */
14296  int (*xCreateFunction)(
14297    fts5_api *pApi,
14298    const char *zName,
14299    void *pUserData,
14300    fts5_extension_function xFunction,
14301    void (*xDestroy)(void*)
14302  );
14303
14304  /* APIs below this point are only available if iVersion>=3 */
14305
14306  /* Create a new tokenizer */
14307  int (*xCreateTokenizer_v2)(
14308    fts5_api *pApi,
14309    const char *zName,
14310    void *pUserData,
14311    fts5_tokenizer_v2 *pTokenizer,
14312    void (*xDestroy)(void*)
14313  );
14314
14315  /* Find an existing tokenizer */
14316  int (*xFindTokenizer_v2)(
14317    fts5_api *pApi,
14318    const char *zName,
14319    void **ppUserData,
14320    fts5_tokenizer_v2 **ppTokenizer
14321  );
14322};
14323
14324/*
14325** END OF REGISTRATION API
14326*************************************************************************/
14327
14328#ifdef __cplusplus
14329}  /* end of the 'extern "C"' block */
14330#endif
14331
14332#endif /* _FTS5_H */
14333
14334/******** End of fts5.h *********/
14335#endif /* SQLITE3_H */