diff options
Diffstat (limited to 'pthreads/pthread_rwlock_tryrdlock.c')
| -rw-r--r-- | pthreads/pthread_rwlock_tryrdlock.c | 205 |
1 files changed, 102 insertions, 103 deletions
diff --git a/pthreads/pthread_rwlock_tryrdlock.c b/pthreads/pthread_rwlock_tryrdlock.c index 308900d14..95dcca507 100644 --- a/pthreads/pthread_rwlock_tryrdlock.c +++ b/pthreads/pthread_rwlock_tryrdlock.c @@ -1,103 +1,102 @@ -/* - * pthread_rwlock_tryrdlock.c - * - * Description: - * This translation unit implements read/write lock 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 <errno.h> -#include <limits.h> - -#include "pthread.h" -#include "implement.h" - -int -pthread_rwlock_tryrdlock (pthread_rwlock_t * rwlock) -{ - int result; - pthread_rwlock_t rwl; - - if (rwlock == NULL || *rwlock == NULL) - { - return EINVAL; - } - - /* - * We do a quick check to see if we need to do more work - * to initialise a static rwlock. We check - * again inside the guarded section of ptw32_rwlock_check_need_init() - * to avoid race conditions. - */ - if (*rwlock == PTHREAD_RWLOCK_INITIALIZER) - { - result = ptw32_rwlock_check_need_init (rwlock); - - if (result != 0 && result != EBUSY) - { - return result; - } - } - - rwl = *rwlock; - - if (rwl->nMagic != PTW32_RWLOCK_MAGIC) - { - return EINVAL; - } - - if ((result = pthread_mutex_trylock (&(rwl->mtxExclusiveAccess))) != 0) - { - return result; - } - - if (++rwl->nSharedAccessCount == INT_MAX) - { - if ((result = - pthread_mutex_lock (&(rwl->mtxSharedAccessCompleted))) != 0) - { - (void) pthread_mutex_unlock (&(rwl->mtxExclusiveAccess)); - return result; - } - - rwl->nSharedAccessCount -= rwl->nCompletedSharedAccessCount; - rwl->nCompletedSharedAccessCount = 0; - - if ((result = - pthread_mutex_unlock (&(rwl->mtxSharedAccessCompleted))) != 0) - { - (void) pthread_mutex_unlock (&(rwl->mtxExclusiveAccess)); - return result; - } - } - - return (pthread_mutex_unlock (&rwl->mtxExclusiveAccess)); -} +/*
+ * pthread_rwlock_tryrdlock.c
+ *
+ * Description:
+ * This translation unit implements read/write lock 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 <limits.h>
+
+#include "pthread.h"
+#include "implement.h"
+
+int
+pthread_rwlock_tryrdlock (pthread_rwlock_t * rwlock)
+{
+ int result;
+ pthread_rwlock_t rwl;
+
+ if (rwlock == NULL || *rwlock == NULL)
+ {
+ return EINVAL;
+ }
+
+ /*
+ * We do a quick check to see if we need to do more work
+ * to initialise a static rwlock. We check
+ * again inside the guarded section of ptw32_rwlock_check_need_init()
+ * to avoid race conditions.
+ */
+ if (*rwlock == PTHREAD_RWLOCK_INITIALIZER)
+ {
+ result = ptw32_rwlock_check_need_init (rwlock);
+
+ if (result != 0 && result != EBUSY)
+ {
+ return result;
+ }
+ }
+
+ rwl = *rwlock;
+
+ if (rwl->nMagic != PTW32_RWLOCK_MAGIC)
+ {
+ return EINVAL;
+ }
+
+ if ((result = pthread_mutex_trylock (&(rwl->mtxExclusiveAccess))) != 0)
+ {
+ return result;
+ }
+
+ if (++rwl->nSharedAccessCount == INT_MAX)
+ {
+ if ((result =
+ pthread_mutex_lock (&(rwl->mtxSharedAccessCompleted))) != 0)
+ {
+ (void) pthread_mutex_unlock (&(rwl->mtxExclusiveAccess));
+ return result;
+ }
+
+ rwl->nSharedAccessCount -= rwl->nCompletedSharedAccessCount;
+ rwl->nCompletedSharedAccessCount = 0;
+
+ if ((result =
+ pthread_mutex_unlock (&(rwl->mtxSharedAccessCompleted))) != 0)
+ {
+ (void) pthread_mutex_unlock (&(rwl->mtxExclusiveAccess));
+ return result;
+ }
+ }
+
+ return (pthread_mutex_unlock (&rwl->mtxExclusiveAccess));
+}
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