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PTHREAD_BARRIER(3) Library Functions Manual PTHREAD_BARRIER(3)

pthread_barrier_destroy, pthread_barrier_init, pthread_barrier_waitdestroy, initialize or wait on a barrier object

library “libpthread”

#include <pthread.h>

int
pthread_barrier_destroy(pthread_barrier_t *barrier);

int
pthread_barrier_init(pthread_barrier_t * restrict barrier, const pthread_barrierattr_t * restrict attr, unsigned count);

int
pthread_barrier_wait(pthread_barrier_t *barrier);

The () function will initialize barrier with attributes specified in attr, or if it is NULL, with default attributes. The number of threads that must call pthread_barrier_wait() before any of the waiting threads can be released is specified by count. The () function will destroy barrier and release any resources that may have been allocated on its behalf.

The () function will synchronize calling threads at barrier. The threads will be blocked from making further progress until a sufficient number of threads calls this function. The number of threads that must call it before any of them will be released is determined by the count argument to pthread_barrier_init(). Once the threads have been released the barrier will be reset.

The PTHREAD_BARRIER_SERIAL_THREAD return value will always be returned by the last thread to reach the barrier.

If successful, both pthread_barrier_destroy() and pthread_barrier_init() will return zero. Otherwise, an error number will be returned to indicate the error. If the call to pthread_barrier_wait() is successful, all but one of the threads will return zero. That one thread will return PTHREAD_BARRIER_SERIAL_THREAD. Otherwise, an error number will be returned to indicate the error.

None of these functions will return EINTR.

The pthread_barrier_destroy() function will fail if:

[]
An attempt was made to destroy barrier while it was in use.

The pthread_barrier_destroy() and pthread_barrier_wait() functions may fail if:

[]
The value specified by barrier is invalid.

The pthread_barrier_init() function will fail if:

[]
The system lacks resources, other than memory, to initialize barrier.
[]
The count argument is less than 1.
[]
Insufficient memory to initialize barrier.

pthread_barrierattr(3)

February 22, 2018 DragonFly-5.6.1