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Diffstat (limited to 'condvar_destroy.c')
| -rw-r--r-- | condvar_destroy.c | 222 |
1 files changed, 0 insertions, 222 deletions
diff --git a/condvar_destroy.c b/condvar_destroy.c deleted file mode 100644 index d0af374..0000000 --- a/condvar_destroy.c +++ /dev/null @@ -1,222 +0,0 @@ -/* - * condvar_destroy.c - * - * Description: - * This translation unit implements condition variables and their 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 "pthread.h" -#include "implement.h" - - -int -pthread_cond_destroy (pthread_cond_t * cond) - /* - * ------------------------------------------------------ - * DOCPUBLIC - * This function destroys a condition variable - * - * - * PARAMETERS - * cond - * pointer to an instance of pthread_cond_t - * - * - * DESCRIPTION - * This function destroys a condition variable. - * - * NOTES: - * 1) A condition variable can be destroyed - * immediately after all the threads that - * are blocked on it are awakened. e.g. - * - * struct list { - * pthread_mutex_t lm; - * ... - * } - * - * struct elt { - * key k; - * int busy; - * pthread_cond_t notbusy; - * ... - * } - * - * - * struct elt * - * list_find(struct list *lp, key k) - * { - * struct elt *ep; - * - * pthread_mutex_lock(&lp->lm); - * while ((ep = find_elt(l,k) != NULL) && ep->busy) - * pthread_cond_wait(&ep->notbusy, &lp->lm); - * if (ep != NULL) - * ep->busy = 1; - * pthread_mutex_unlock(&lp->lm); - * return(ep); - * } - * - * delete_elt(struct list *lp, struct elt *ep) - * { - * pthread_mutex_lock(&lp->lm); - * assert(ep->busy); - * ... remove ep from list ... - * ep->busy = 0; - * (A) pthread_cond_broadcast(&ep->notbusy); - * pthread_mutex_unlock(&lp->lm); - * (B) pthread_cond_destroy(&rp->notbusy); - * free(ep); - * } - * - * In this example, the condition variable - * and its list element may be freed (line B) - * immediately after all threads waiting for - * it are awakened (line A), since the mutex - * and the code ensure that no other thread - * can touch the element to be deleted. - * - * RESULTS - * 0 successfully released condition variable, - * EINVAL 'cond' is invalid, - * EBUSY 'cond' is in use, - * - * ------------------------------------------------------ - */ -{ - pthread_cond_t cv; - int result = 0, result1 = 0, result2 = 0; - - /* - * Assuming any race condition here is harmless. - */ - if (cond == NULL - || *cond == NULL) - { - return EINVAL; - } - - if (*cond != PTHREAD_COND_INITIALIZER) - { - cv = *cond; - - /* - * Close the gate; this will synchronize this thread with - * all already signaled waiters to let them retract their - * waiter status - SEE NOTE 1 ABOVE!!! - */ - if (sem_wait(&(cv->semBlockLock)) != 0) - { - return errno; - } - - /* - * !TRY! lock mtxUnblockLock; try will detect busy condition - * and will not course a deadlock with respect to concurrent - * signal/broadcast. - */ - if ((result = pthread_mutex_trylock(&(cv->mtxUnblockLock))) != 0) - { - (void) sem_post(&(cv->semBlockLock)); - return result; - } - - /* - * Check whether cv is still busy (still has waiters) - */ - if (cv->nWaitersBlocked > cv->nWaitersGone) - { - if (sem_post(&(cv->semBlockLock)) != 0) - { - result = errno; - } - result1 = pthread_mutex_unlock(&(cv->mtxUnblockLock)); - result2 = EBUSY; - } - else - { - /* - * Now it is safe to destroy - */ - *cond = NULL; - if (sem_destroy(&(cv->semBlockLock)) != 0) - { - result = errno; - } - if (sem_destroy(&(cv->semBlockQueue)) != 0) - { - result1 = errno; - } - if ((result2 = pthread_mutex_unlock(&(cv->mtxUnblockLock))) == 0) - { - result2 = pthread_mutex_destroy(&(cv->mtxUnblockLock)); - } - - (void) free(cv); - } - } - else - { - /* - * See notes in ptw32_cond_check_need_init() above also. - */ - EnterCriticalSection(&ptw32_cond_test_init_lock); - - /* - * Check again. - */ - if (*cond == PTHREAD_COND_INITIALIZER) - { - /* - * This is all we need to do to destroy a statically - * initialised cond that has not yet been used (initialised). - * If we get to here, another thread waiting to initialise - * this cond will get an EINVAL. That's OK. - */ - *cond = NULL; - } - else - { - /* - * The cv has been initialised while we were waiting - * so assume it's in use. - */ - result = EBUSY; - } - - LeaveCriticalSection(&ptw32_cond_test_init_lock); - } - - return ((result != 0) ? result : ((result1 != 0) ? result1 : result2)); - -} |