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/* Copyright (C) 2002, 2003, 2004, 2007 Free Software Foundation, Inc. This file is part of the GNU C Library. Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. The GNU C 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 2.1 of the License, or (at your option) any later version. The GNU C 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 the GNU C Library; if not, see <http://www.gnu.org/licenses/>. */ #include <errno.h> #include "pthreadP.h" int attribute_protected __pthread_cond_destroy ( pthread_cond_t *cond) { int pshared = (cond->__data.__mutex == (void *) ~0l) ? LLL_SHARED : LLL_PRIVATE; /* Make sure we are alone. */ lll_lock (cond->__data.__lock, pshared); if (cond->__data.__total_seq > cond->__data.__wakeup_seq) { /* If there are still some waiters which have not been woken up, this is an application bug. */ lll_unlock (cond->__data.__lock, pshared); return EBUSY; } /* Tell pthread_cond_*wait that this condvar is being destroyed. */ cond->__data.__total_seq = -1ULL; /* If there are waiters which have been already signalled or broadcasted, but still are using the pthread_cond_t structure, pthread_cond_destroy needs to wait for them. */ unsigned int nwaiters = cond->__data.__nwaiters; if (nwaiters >= (1 << COND_NWAITERS_SHIFT)) { /* Wake everybody on the associated mutex in case there are threads that have been requeued to it. Without this, pthread_cond_destroy could block potentially for a long time or forever, as it would depend on other thread's using the mutex. When all threads waiting on the mutex are woken up, pthread_cond_wait only waits for threads to acquire and release the internal condvar lock. */ if (cond->__data.__mutex != NULL && cond->__data.__mutex != (void *) ~0l) { pthread_mutex_t *mut = (pthread_mutex_t *) cond->__data.__mutex; lll_futex_wake (&mut->__data.__lock, INT_MAX, PTHREAD_MUTEX_PSHARED (mut)); } do { lll_unlock (cond->__data.__lock, pshared); lll_futex_wait (&cond->__data.__nwaiters, nwaiters, pshared); lll_lock (cond->__data.__lock, pshared); nwaiters = cond->__data.__nwaiters; } while (nwaiters >= (1 << COND_NWAITERS_SHIFT)); } return 0; } weak_alias(__pthread_cond_destroy, pthread_cond_destroy) |