Function pthread_cond_broadcast

numexpr3/win32/pthread.c:189–216

* DOUBLY IMPORTANT: This implementation requires that pthread_cond_broadcast * is called while the mutex is held that is used in the corresponding * pthread_cond_wait calls! */

 * pthread_cond_wait calls!
 */
int pthread_cond_broadcast(pthread_cond_t *cond)
{
    EnterCriticalSection(&cond->waiters_lock);

    if ((cond->was_broadcast = cond->waiters > 0)) {
        /* wake up all waiters */
        ReleaseSemaphore(cond->sema, cond->waiters, NULL);
        LeaveCriticalSection(&cond->waiters_lock);
        /*
         * At this point all waiters continue. Each one takes its
         * slice of the semaphor. Now it's our turn to wait: Since
         * the external mutex is held, no thread can leave cond_wait,
         * yet. For this reason, we can be sure that no thread gets
         * a chance to eat *more* than one slice. OTOH, it means
         * that the last waiter must send us a wake-up.
         */
        WaitForSingleObject(cond->continue_broadcast, INFINITE);
        /*
         * Since the external mutex is held, no thread can enter
         * cond_wait, and, hence, it is safe to reset this flag
         * without cond->waiters_lock held.
         */
        cond->was_broadcast = 0;
    } else {
        LeaveCriticalSection(&cond->waiters_lock);
    }
    return 0;
}