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/*
* barrier_init.c
*
* Description:
* This translation unit implements barrier primitives.
*
* --------------------------------------------------------------------------
*
* Pthreads-win32 - POSIX Threads Library for Win32
* Copyright(C) 1998 John E. Bossom
* Copyright(C) 1999,2002 Pthreads-win32 contributors
*
* Contact Email: rpj@ise.canberra.edu.au
*
* The current list of contributors is contained
* in the file CONTRIBUTORS included with the source
* code distribution. The list can also be seen at the
* following World Wide Web location:
* http://sources.redhat.com/pthreads-win32/contributors.html
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library in the file COPYING.LIB;
* if not, write to the Free Software Foundation, Inc.,
* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#include "pthread.h"
#include "implement.h"
int
pthread_barrier_init(pthread_barrier_t * barrier,
const pthread_barrierattr_t * attr,
unsigned int count)
{
pthread_barrier_t b;
if (barrier == NULL || count == 0)
{
return EINVAL;
}
if (NULL != (b = (pthread_barrier_t) calloc(1, sizeof(*b))))
{
b->pshared = (attr != NULL && *attr != NULL
? (*attr)->pshared
: PTHREAD_PROCESS_PRIVATE);
b->nCurrentBarrierHeight = b->nInitialBarrierHeight = count;
b->iStep = 0;
/*
* Two semaphores are used in the same way as two stepping
* stones might be used in crossing a stream. Once all
* threads are safely on one stone, the other stone can
* be moved ahead, and the threads can start moving to it.
* If some threads decide to eat their lunch before moving
* then the other threads have to wait.
*/
if (0 == sem_init(&(b->semBarrierBreeched[0]), b->pshared, 0))
{
if (0 == sem_init(&(b->semBarrierBreeched[1]), b->pshared, 0))
{
*barrier = b;
return 0;
}
(void) sem_destroy(&(b->semBarrierBreeched[0]));
}
(void) free(b);
}
return ENOMEM;
}
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