| /* |
| * pthread_barrier_wait.c |
| * |
| * Description: |
| * This translation unit implements barrier primitives. |
| * |
| * -------------------------------------------------------------------------- |
| * |
| * Pthreads-win32 - POSIX Threads Library for Win32 |
| * Copyright(C) 1998 John E. Bossom |
| * Copyright(C) 1999,2005 Pthreads-win32 contributors |
| * |
| * Contact Email: rpj@callisto.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_wait (pthread_barrier_t * barrier) |
| { |
| int result; |
| pthread_barrier_t b; |
| |
| ptw32_mcs_local_node_t node; |
| |
| if (barrier == NULL || *barrier == (pthread_barrier_t) PTW32_OBJECT_INVALID) |
| { |
| return EINVAL; |
| } |
| |
| ptw32_mcs_lock_acquire(&(*barrier)->lock, &node); |
| |
| b = *barrier; |
| if (--b->nCurrentBarrierHeight == 0) |
| { |
| /* |
| * We are the last thread to arrive at the barrier before it releases us. |
| * Move our MCS local node to the global scope barrier handle so that the |
| * last thread out (not necessarily us) can release the lock. |
| */ |
| ptw32_mcs_node_transfer(&b->proxynode, &node); |
| |
| /* |
| * Any threads that have not quite entered sem_wait below when the |
| * multiple_post has completed will nevertheless continue through |
| * the semaphore (barrier). |
| */ |
| result = (b->nInitialBarrierHeight > 1 |
| ? sem_post_multiple (&(b->semBarrierBreeched), |
| b->nInitialBarrierHeight - 1) : 0); |
| } |
| else |
| { |
| ptw32_mcs_lock_release(&node); |
| /* |
| * Use the non-cancelable version of sem_wait(). |
| * |
| * It is possible that all nInitialBarrierHeight-1 threads are |
| * at this point when the last thread enters the barrier, resets |
| * nCurrentBarrierHeight = nInitialBarrierHeight and leaves. |
| * If pthread_barrier_destroy is called at that moment then the |
| * barrier will be destroyed along with the semas. |
| */ |
| result = ptw32_semwait (&(b->semBarrierBreeched)); |
| } |
| |
| if ((PTW32_INTERLOCKED_LONG)PTW32_INTERLOCKED_INCREMENT_LONG((PTW32_INTERLOCKED_LONGPTR)&b->nCurrentBarrierHeight) |
| == (PTW32_INTERLOCKED_LONG)b->nInitialBarrierHeight) |
| { |
| /* |
| * We are the last thread to cross this barrier |
| */ |
| ptw32_mcs_lock_release(&b->proxynode); |
| if (0 == result) |
| { |
| result = PTHREAD_BARRIER_SERIAL_THREAD; |
| } |
| } |
| |
| return (result); |
| } |