#define MAX_FN 32

static void(*atexit_fn[MAX_FN])(void);
static int atexit_fn_count = 0;

int atexit(void(*fn)(void))
{
    if (atexit_fn_count == MAX_FN) {
        return -1;
    }

    atexit_fn[atexit_fn_count++] = fn;
    return 0;
}

void __crt_run_atexit()
{
    for (int i = 0; i < atexit_fn_count; i++) {
        atexit_fn[i]();
    }
}