#include "pthread_impl.h"
#include <threads.h>

int __pthread_mutex_trylock(pthread_mutex_t *restrict m);

int mtx_trylock(mtx_t *restrict m) {
	if (m->_m_type == PTHREAD_MUTEX_NORMAL)
		return (a_cas(&m->_m_lock, 0, EBUSY) & EBUSY) ? thrd_busy : thrd_success;

	int ret = __pthread_mutex_trylock(m);
	switch (ret) {
	/* In case of UB may also return EINVAL or EAGAIN. EAGAIN is
	   specially tricky since C11 doesn't define how many recursive
	   calls can be done. (this *isn't* the maximum amount of nested
	   calls!) This implementation here deals this with a counter and
	   detects overflow, so this is definitively UB. */
	default:    return thrd_error;
	case 0:     return thrd_success;
	case EBUSY: return thrd_busy;
	}
}