Embedding in C (x07 build)

x07 build compiles a project to a single C file. You can use the output either as:

• a runner executable (generated main() with framed stdin/stdout), or
• an embeddable library entry point (x07_solve_v2) in freestanding mode.

For end-user distribution (a normal CLI binary that runs without the X07 toolchain installed), use x07 bundle.

Generate C

x07 build --project x07.json --out build/program.c

Optional: emit a C header:

x07 build --project x07.json --emit-c-header build/x07.h

Freestanding mode (library embedding)

Freestanding mode generates a C file that exports x07_solve_v2:

x07 build --project x07.json --out build/program.c --emit-c-header build/x07.h --freestanding

The header declares:

bytes_t x07_solve_v2(
    uint8_t* arena_mem,
    uint32_t arena_cap,
    const uint8_t* input_ptr,
    uint32_t input_len
);

Usage model:

• You provide an arena buffer (arena_mem, arena_cap).
• x07_solve_v2 runs solve(input_bytes) -> bytes.
• The returned bytes_t points into the arena buffer.

Example test_embed.c:

#include "x07.h"

#include <stdint.h>
#include <stdio.h>

int main(void) {
  static uint8_t arena[64 * 1024 * 1024];
  const uint8_t input[] = {'h', 'i', '\n'};
  bytes_t out = x07_solve_v2(
      arena,
      (uint32_t)sizeof(arena),
      input,
      (uint32_t)sizeof(input)
  );
  (void)fwrite(out.ptr, 1, out.len, stdout);
  return 0;
}

Build and run:

clang -O2 -Ibuild -o test_embed test_embed.c build/program.c
./test_embed

Runner executable mode (framed I/O)

The default (non-freestanding) output includes a main() that uses the standard X07 executable framing:

• stdin: u32_le(len) then len bytes
• stdout: u32_le(len) then len bytes

If you pipe raw text into the executable, it will interpret the first 4 bytes as the length prefix (which can look like an “out of memory” failure).

See: Running programs.