/* * 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) 1999,2005 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_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 { ptw32_mcs_local_node_t node; /* * See notes in ptw32_rwlock_check_need_init() above also. */ ptw32_mcs_lock_acquire(&ptw32_rwlock_test_init_lock, &node); /* * 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; } ptw32_mcs_lock_release(&node); } return ((result != 0) ? result : ((result1 != 0) ? result1 : result2)); }