pthread_cond_broadcast

Synopsis

#include <pthread.h>

int pthread_cond_broadcast(pthread_cond_t *cond);

int pthread_cond_signal(pthread_cond_t *cond);

Status

Implemented

Conformance

IEEE Std 1003.1-2017

Description

These functions shall unblock threads blocked on a condition variable.

The pthread_cond_broadcast() function shall unblock all threads currently blocked on the specified condition variable cond.

The pthread_cond_signal() function shall unblock at least one of the threads that are blocked on the specified condition variable cond (if any threads are blocked on cond).

If more than one thread is blocked on a condition variable, the scheduling policy shall determine the order in which threads are unblocked. When each thread unblocked as a result of a pthread_cond_broadcast() or pthread_cond_signal() returns from its call to pthread_cond_wait() or pthread_cond_timedwait(), the thread shall own the mutex with which it called pthread_cond_wait() or pthread_cond_timedwait(). The thread(s) that are unblocked shall contend for the mutex according to the scheduling policy (if applicable), and as if each had called pthread_mutex_lock().

The pthread_cond_broadcast() or pthread_cond_signal() functions may be called by a thread whether it currently owns the mutex that threads calling pthread_cond_wait() or pthread_cond_timedwait() have associated with the condition variable during their waits; however, if predictable scheduling behavior is required, then that mutex shall be locked by the thread calling pthread_cond_broadcast() or pthread_cond_signal().

The pthread_cond_broadcast() and pthread_cond_signal() functions shall have no effect if there are no threads currently blocked on cond.

The behavior is undefined if the value specified by the cond argument to pthread_cond_broadcast() or pthread_cond_signal() does not refer to an initialized condition variable.

Return value

If successful, the pthread_cond_broadcast() and pthread_cond_signal() functions shall return zero; otherwise, an error number shall be returned to indicate the error.

Errors

These functions shall not return an error code of EINTR.

POSIX deviations

No POSIX deviations discovered.