Extend Lua with custom C functions using Clang

note, May 23, 2023 on Mitja Felicijan's blog

Here is a boilerplate for extending Lua with custom C functions. This requires -Clang and Lua 5.1 to be installed. GCC can be used instead of Clang, but the -Makefile will need to be modified.

  • nativefunc.c

    #include <lua.h>
-#include <lauxlib.h>
-
-static int l_mult50(lua_State *L) {
-  double number = luaL_checknumber(L, 1);
-  lua_pushnumber(L, number * 50);
-  return 1;
-}
-
-int luaopen_nativefunc(lua_State *L) {
-  static const struct luaL_Reg nativeFuncLib[] = {{"mult50", l_mult50}, {NULL, NULL}};
-
-  luaL_register(L, "nativelib", nativeFuncLib);
-  return 1;
-}
-

  • main.lua

    require "nativefunc"
-print(nativelib.mult50(50))
-

  • Makefile

    CC       = clang
-CFLAGS   =
-INCLUDES = `pkg-config lua5.1 --cflags-only-I`
-
-all:
-  $(CC) -shared -o nativefunc.so -fPIC nativefunc.c $(CFLAGS) $(INCLUDES)
-
-clean:
-  rm *.so
-