pthread_cond_signal(PTHREAD)

pthread_cond_signal, pthread_cond_broadcast -- wake up threads waiting on a condition variable

Synopsis

cc [options] -Kthread file

#include <pthread.h>

int pthread_cond_signal(pthread_cond_t *cond);
int pthread_cond_broadcast(pthread_cond_t *cond);

Description

pthread_cond_signal wakes up a single thread, if one exists, waiting on the condition cond. pthread_cond_broadcast wakes up all threads waiting on the condition cond. If more than one thread is waiting, the choice of which to release from the blocked group is scheduling policy-specific: Bound threads have priority over multiplexed threads; then within each category the choice of thread is scheduling-policy-specific.

pthread_cond_signal and pthread_cond_broadcast have no effect if there are no threads waiting on cond.

A pthread_cond_signal or pthread_cond_broadcast will be more reliable if the associated mutex used by waiters is held across the call.

The condition variable denoted by cond must previously have been initialized (see pthread_cond_init(PTHREAD)).

See the description of how to use condition variables on Intro(PTHREAD).

Return values

pthread_cond_signal aand pthread_cond_broadcast return zero for success and an error number for failure.

Diagnostics

If the following condition is detected, pthread_cond_signal or pthread_cond_broadcast return the corresponding value:

EINVAL: invalid argument specified

References

Intro(PTHREAD) pthread_cond_init(PTHREAD), pthread_cond_timedwait(PTHREAD), pthread(F)

Standards compliance

The Single UNIX Specification, Version 2; The Open Group.