Notes: Embedding resources into binary with C

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+---
+title: "Embedding resources into binary with C"
+url: embedding-resources-into-binary-with-c.html
+date: 2024-06-19T16:13:13+02:00
+type: note
+draft: false
+tags: [c]
+---
+
+[Binary resource inclusion](https://en.cppreference.com/w/c/preprocessor/embed)
+preprocessor has been put into the C23 standard but has not yet been
+implemented by the compilers. 
+
+Until then a workaround with
+[`xxd`](https://en.cppreference.com/w/c/preprocessor/embed) is possible without
+spending time on rolling out your own.
+
+`xxd` has an option to export to C header file which makes this much easier.
+This works for all files be that text files or binary ones such as images, etc.
+
+Convert `text.txt` into a C header file with `xxd -i test.txt > test.h`. This
+creates the following file and uses the filename for variable names.
+
+```c
+// test.h
+unsigned char test_txt[] = {
+  0x54, 0x68, 0x65, 0x20, 0x66, 0x69, 0x72, 0x73, 0x74, 0x20, 0x72, 0x75,
+  0x6c, 0x65, 0x20, 0x69, 0x73, 0x20, 0x74, 0x79, 0x70, 0x69, 0x63, 0x61,
+  0x6c, 0x20, 0x6f, 0x66, 0x20, 0x71, 0x75, 0x61, 0x6e, 0x74, 0x75, 0x6d,
+  ...
+  };
+unsigned int test_txt_len = 547;
+```
+
+Then use it in C in this manner.
+
+```c
+// main.c
+#include <stdio.h>
+#include "test.h"
+
+int main(void) {
+  printf("Testing embedding of files into binary.\n");
+
+  for (unsigned int i = 0; i < test_txt_len; i++) {
+    printf("%02x ", test_txt[i]);
+  }
+  printf("\n\n");
+
+  for (unsigned int i = 0; i < test_txt_len; i++) {
+    printf("%c", test_txt[i]);
+  }
+  printf("\n\n");
+
+  return 0;
+}
+```