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/* Copyright (C) 2002-2016 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 <shlib-compat.h>
#include "pthreadP.h"
#include <stap-probe.h>
int
__pthread_cond_destroy (pthread_cond_t *cond)
{
int pshared = (cond->__data.__mutex == (void *) ~0l)
? LLL_SHARED : LLL_PRIVATE;
LIBC_PROBE (cond_destroy, 1, cond);
/* 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;
}
versioned_symbol (libpthread, __pthread_cond_destroy,
pthread_cond_destroy, GLIBC_2_3_2);
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