#ifndef __STDC_NO_THREADS__
# include <threads.h>
#endif
void call_once(once_flag *flag, void (*func)(void));
int cnd_broadcast(cnd_t *cond);
void cnd_destroy(cnd_t *cond);
int cnd_init(cnd_t *cond);
int cnd_signal(cnd_t *cond);
int cnd_timedwait(cnd_t *restrict cond, mtx_t *restrict mtx, const struct timespec *restrict ts);
int cnd_wait(cnd_t *cond, mtx_t *mtx);
void mtx_destroy(mtx_t *mtx);
int mtx_init(mtx_t *mtx, int type);
int mtx_lock(mtx_t *mtx);
int mtx_timedlock(mtx_t *restrict mtx, const struct timespec *restrict ts);
int mtx_trylock(mtx_t *mtx);
int mtx_unlock(mtx_t *mtx);
int thrd_create(thrd_t *thr, thrd_start_t func, void *arg);
thrd_t thrd_current(void);
int thrd_detach(thrd_t thr);
int thrd_equal(thrd_t thr0, thrd_t thr1);
_Noreturn void thrd_exit(int res);
int thrd_join(thrd_t thr, int *res);
int thrd_sleep(const struct timespec *duration, struct timespec* remaining);
void thrd_yield(void);
int tss_create(tss_t *key, tss_dtor_t dtor);
void tss_delete(tss_t key);
void *tss_get(tss_t key);
int tss_set(tss_t key, void *val);
C11 threads are an optional feature. Their absence can be tested with __STDC__NO_THREAD__
. Currently (Jul 2016) this feature is not yet implemented by all C libraries that otherwise support C11.