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+/*
+ * 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);
+}