diff options
Diffstat (limited to 'pthread_rwlock_destroy.c')
| -rw-r--r-- | pthread_rwlock_destroy.c | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/pthread_rwlock_destroy.c b/pthread_rwlock_destroy.c new file mode 100644 index 0000000..96feb0f --- /dev/null +++ b/pthread_rwlock_destroy.c @@ -0,0 +1,140 @@ +/* + * pthread_rwlock_destroy.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) 1999,2002 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 <errno.h> +#include <limits.h> + +#include "pthread.h" +#include "implement.h" + +int +pthread_rwlock_destroy(pthread_rwlock_t *rwlock) +{ + pthread_rwlock_t rwl; + int result = 0, result1 = 0, result2 = 0; + + if (rwlock == NULL || *rwlock == NULL) + { + return EINVAL; + } + + if (*rwlock != PTHREAD_RWLOCK_INITIALIZER) + { + rwl = *rwlock; + + if (rwl->nMagic != PTW32_RWLOCK_MAGIC) + { + return EINVAL; + } + + if ((result = pthread_mutex_lock(&(rwl->mtxExclusiveAccess))) != 0) + { + return result; + } + + if ((result = pthread_mutex_lock(&(rwl->mtxSharedAccessCompleted))) != 0) + { + (void) pthread_mutex_unlock(&(rwl->mtxExclusiveAccess)); + return result; + } + + /* + * Check whether any threads own/wait for the lock (wait for ex.access); + * report "BUSY" if so. + */ + if (rwl->nExclusiveAccessCount > 0 + || rwl->nSharedAccessCount > rwl->nCompletedSharedAccessCount) + { + result = pthread_mutex_unlock(&(rwl->mtxSharedAccessCompleted)); + result1 = pthread_mutex_unlock(&(rwl->mtxExclusiveAccess)); + result2 = EBUSY; + } + else + { + rwl->nMagic = 0; + + if ((result = pthread_mutex_unlock(&(rwl->mtxSharedAccessCompleted))) != 0) + { + pthread_mutex_unlock(&rwl->mtxExclusiveAccess); + return result; + } + + if ((result = pthread_mutex_unlock(&(rwl->mtxExclusiveAccess))) != 0) + { + return result; + } + + *rwlock = NULL; /* Invalidate rwlock before anything else */ + result = pthread_cond_destroy(&(rwl->cndSharedAccessCompleted)); + result1 = pthread_mutex_destroy(&(rwl->mtxSharedAccessCompleted)); + result2 = pthread_mutex_destroy(&(rwl->mtxExclusiveAccess)); + (void) free(rwl); + } + } + else + { + /* + * See notes in ptw32_rwlock_check_need_init() above also. + */ + EnterCriticalSection(&ptw32_rwlock_test_init_lock); + + /* + * Check again. + */ + if (*rwlock == PTHREAD_RWLOCK_INITIALIZER) + { + /* + * This is all we need to do to destroy a statically + * initialised rwlock that has not yet been used (initialised). + * If we get to here, another thread + * waiting to initialise this rwlock will get an EINVAL. + */ + *rwlock = NULL; + } + else + { + /* + * The rwlock has been initialised while we were waiting + * so assume it's in use. + */ + result = EBUSY; + } + + LeaveCriticalSection(&ptw32_rwlock_test_init_lock); + } + + return ((result != 0) ? result : ((result1 != 0) ? result1 : result2)); +} |