diff options
Diffstat (limited to 'libpthread/nptl/pthread_cond_destroy.c')
-rw-r--r-- | libpthread/nptl/pthread_cond_destroy.c | 83 |
1 files changed, 83 insertions, 0 deletions
diff --git a/libpthread/nptl/pthread_cond_destroy.c b/libpthread/nptl/pthread_cond_destroy.c new file mode 100644 index 000000000..b67b53506 --- /dev/null +++ b/libpthread/nptl/pthread_cond_destroy.c @@ -0,0 +1,83 @@ +/* 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, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <errno.h> +#include "pthreadP.h" + + +int +__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) |