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$FreeBSD: head/share/man/man3/pthread_barrier_destroy.3 152772 2005-11-24 15:10:38Z ru $
.Dd February 19, 2004 .Dt PTHREAD_BARRIER 3 .Os .Sh NAME .Nm pthread_barrier_destroy , pthread_barrier_init , pthread_barrier_wait .Nd "destroy, initialize or wait on a barrier object" .Sh LIBRARY .Lb libpthread .Lb libthr .Sh SYNOPSIS n pthread.h .Ft int .Fn pthread_barrier_destroy "pthread_barrier_t *barrier" .Ft int .Fn pthread_barrier_init "pthread_barrier_t *barrier" "const pthread_barrierattr_t *attr" "unsigned count" .Ft int .Fn pthread_barrier_wait "pthread_barrier_t *barrier" .Sh DESCRIPTION The .Fn pthread_barrier_init function will initialize .Fa barrier with attributes specified in .Fa attr , or if it is .Dv NULL , with default attributes. The number of threads that must call .Fn pthread_barrier_wait before any of the waiting threads can be released is specified by .Fa count . The .Fn pthread_barrier_destroy function will destroy .Fa barrier and release any resources that may have been allocated on its behalf.
p The .Fn pthread_barrier_wait function will synchronize calling threads at .Fa 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 .Fa count argument to .Fn pthread_barrier_init . Once the threads have been released the barrier will be reset. .Sh IMPLEMENTATION NOTES In both .Lb libpthread and .Lb libthr the .Dv PTHREAD_BARRIER_SERIAL_THREAD return value will always be returned by the last thread to reach the barrier. .Sh RETURN VALUES If successful, both .Fn pthread_barrier_destroy and .Fn pthread_barrier_init will return zero. Otherwise, an error number will be returned to indicate the error. If the call to .Fn pthread_barrier_wait is successful, all but one of the threads will return zero. That one thread will return .Dv PTHREAD_BARRIER_SERIAL_THREAD . Otherwise, an error number will be returned to indicate the error.
p None of these functions will return .Er EINTR . .Sh ERRORS The .Fn pthread_barrier_destroy function will fail if: l -tag -width Er t Bq Er EBUSY An attempt was made to destroy .Fa barrier while it was in use. .El
p The .Fn pthread_barrier_destroy and .Fn pthread_barrier_wait functions may fail if: l -tag -width Er t Bq Er EINVAL The value specified by .Fa barrier is invalid. .El
p The .Fn pthread_barrier_init function will fail if: l -tag -width Er t Bq Er EAGAIN The system lacks resources, other than memory, to initialize .Fa barrier . t Bq Er EINVAL The .Fa count argument is less than 1. t Bq Er ENOMEM Insufficient memory to initialize .Fa barrier . .El .Sh SEE ALSO .Xr pthread_barrierattr 3 .Sh HISTORY The .Fn pthread_barrier_destroy , .Fn pthread_barrier_init and .Fn pthread_barrier_wait functions first appeared in .Lb libpthread in .Fx 5.2 , and in .Lb libthr in .Fx 5.3 .