CToon C API

CToon is a high-performance, zero-dependency C99 library for reading and writing the TOON serialization format, with built-in JSON interop. This reference documents the plain C API declared in ctoon.h.

Installation

# CMakeLists.txt
include(FetchContent)
FetchContent_Declare(
  ctoon
  GIT_REPOSITORY https://github.com/MohammadRaziei/ctoon.git
  GIT_TAG        v0.9.0
)
FetchContent_MakeAvailable(ctoon)
 
# Link the C target
target_link_libraries(my_app PRIVATE ctoon::ctoon)

Requires CMake 3.19+ and a C99-compatible compiler.

Quick example

#include "ctoon.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
 
int main(void) {
    const char *src = "name: Alice\nage: 30";
    ctoon_doc *doc  = ctoon_read(src, strlen(src), 0);
    ctoon_val *root = ctoon_doc_get_root(doc);
 
    /* Access fields */
    ctoon_val *name = ctoon_obj_get(root, "name");
    printf("%s\n", ctoon_get_str(name));   /* Alice */
 
    /* Serialise back to TOON */
    size_t len;
    char *toon = ctoon_write(doc, &len);
    free(toon);
 
    /* Export as JSON (on by default; define CTOON_DISABLE_JSON to turn off) */
    char *json = ctoon_doc_to_json(doc, 2,
                     CTOON_WRITE_NOFLAG, NULL, &len, NULL);
    printf("%s\n", json);
    free(json);
 
    ctoon_doc_free(doc);
    return 0;
}

TOON spec version

The toon-format/spec release the library targets (written by CMake into ctoon.h, same time as supported_spec.conf):

CTOON_SPEC_VERSION_STRING   // "4.1"
CTOON_SPEC_TAG_STRING       // "v4.1.2"  (CTOON_SPEC_TAG_MAJOR / _MINOR / _PATCH, CTOON_SPEC_TAG_HEX)
CTOON_SPEC_DATE_STRING      // "2026-07-26"

The same values are available at runtime through ctoon_spec_version_string(), ctoon_spec_tag_hex() and ctoon_spec_date_string().

See ctoon.h for the full function reference - document I/O (ctoon_read, ctoon_write), the object/array accessors (ctoon_obj_get, ctoon_arr_get, ...), and JSON interop (ctoon_doc_to_json).