FreeBSD manual
download PDF document: pthread_barrier_destroy.3.pdf
PTHREAD_BARRIER(3) FreeBSD Library Functions Manual PTHREAD_BARRIER(3)
NAME
pthread_barrier_destroy, pthread_barrier_init, pthread_barrier_wait -
destroy, initialize or wait on a barrier object
LIBRARY
POSIX Threads Library (libpthread, -lpthread)
SYNOPSIS
#include <pthread.h>
int
pthread_barrier_destroy(pthread_barrier_t *barrier);
int
pthread_barrier_init(pthread_barrier_t *restrict barrier,
const pthread_barrierattr_t *attr, unsigned count);
int
pthread_barrier_wait(pthread_barrier_t *barrier);
DESCRIPTION
The pthread_barrier_init() 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
pthread_barrier_destroy() function will destroy barrier and release any
resources that may have been allocated on its behalf.
The pthread_barrier_wait() 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.
IMPLEMENTATION NOTES
In 1:1 Threading Library (libthr, -lthr) the
PTHREAD_BARRIER_SERIAL_THREAD return value will always be returned by the
last thread to reach the barrier.
RETURN VALUES
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.
ERRORS
The pthread_barrier_destroy() function will fail if:
[EBUSY] An attempt was made to destroy barrier while it was in
use.
The pthread_barrier_destroy() and pthread_barrier_wait() functions may
initialize barrier.
[EINVAL] The count argument is less than 1.
[ENOMEM] Insufficient memory to initialize barrier.
SEE ALSO
pthread_barrierattr(3)
HISTORY
The pthread_barrier_destroy(), pthread_barrier_init() and
pthread_barrier_wait() functions first appeared in N:M Threading Library
(libkse, -lkse) in FreeBSD 5.2, and in 1:1 Threading Library (libthr,
-lthr) in FreeBSD 5.3.
FreeBSD 14.0-RELEASE-p11 August 17, 2018 FreeBSD 14.0-RELEASE-p11