pthread_barrier_wait(3P)pthread_barrier_wait(3P)NAME
pthread_barrier_init, pthread_barrier_wait, pthread_barrier_destroy -
pthread barriers
C SYNOPSIS
#include <pthread.h>
int pthread_barrier_init(pthread_barrier_t *barrier,
const pthread_barrierattr_t *attr, unsigned count);
int pthread_barrier_wait(pthread_barrier_t *barrier);
int pthread_barrier_destroy(pthread_barrier_t *barrier);
DESCRIPTION
Barriers are a method of synchronizing multiple threads. Threads
blocking on a barrier will not proceed past the barrier until all the
threads using the barrier have arrived and blocked on it.
pthread_barrier_init() initializes the barrier object referenced by
barrier using the attributes referenced by attr. If attr is NULL then
default attributes will be used. The results are undefined if called on
an already initialized barrier.
pthread_barrier_wait() will synchronize participating threads at the
barrier referenced by barrier until the required number have called the
function specifying barrier. At that time PTHREAD_BARRIER_SERIAL_THREAD
will be returned to a single thread and zero to the remaining threads.
If a thread blocked on a barrier receives a signal it will return to
blocking on the barrier at the end of the signal handler.
pthread_barrier_destroy() destroys the barrier object referenced by
barrier and frees any resources associated with it. The results are
undefined if it is called when any threads are blocked on the barrier.
DIAGNOSTICS
On success these functions return zero; otherwise an error number is
returned. pthread_barrier_wait() will return
PTHREAD_BARRIER_SERIAL_THREAD to a single thread.
pthread_barrier_init() can return the following errors:
[EINVAL] The value specified by count is zero.
pthread_barrier_wait() can return the following errors:
[EINVAL] The object specified by barrier in invalid.
pthread_barrier_destroy() can return the following errors:
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pthread_barrier_wait(3P)pthread_barrier_wait(3P)
[EINVAL] The object specified by barrier in invalid.
SEE ALSOpthread_barrierattr_init(3P)
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