diff options
Diffstat (limited to 'pthreads/pthread_rwlock_tryrdlock.c')
| -rw-r--r-- | pthreads/pthread_rwlock_tryrdlock.c | 209 |
1 files changed, 107 insertions, 102 deletions
diff --git a/pthreads/pthread_rwlock_tryrdlock.c b/pthreads/pthread_rwlock_tryrdlock.c index 95dcca507..5660b5ad5 100644 --- a/pthreads/pthread_rwlock_tryrdlock.c +++ b/pthreads/pthread_rwlock_tryrdlock.c @@ -1,102 +1,107 @@ -/*
- * 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));
-}
+/* + * 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) 1999,2012 Pthreads-win32 contributors + * + * Homepage1: http://sourceware.org/pthreads-win32/ + * Homepage2: http://sourceforge.net/projects/pthreads4w/ + * + * 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 + */ + +#ifdef HAVE_CONFIG_H +# include <config.h> +#endif + +#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)); +} |