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[glibc/history.git] / nptl / pthread_cond_destroy.c
blob35135a68bc699b874ce5e6a1a2f65fc107ea4480
1 /* Copyright (C) 2002, 2003, 2004, 2007 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, write to the Free
17 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
18 02111-1307 USA. */
20 #include <errno.h>
21 #include <shlib-compat.h>
22 #include "pthreadP.h"
25 int
26 __pthread_cond_destroy (cond)
27 pthread_cond_t *cond;
29 int pshared = (cond->__data.__mutex == (void *) ~0l)
30 ? LLL_SHARED : LLL_PRIVATE;
32 /* Make sure we are alone. */
33 lll_lock (cond->__data.__lock, pshared);
35 if (cond->__data.__total_seq > cond->__data.__wakeup_seq)
37 /* If there are still some waiters which have not been
38 woken up, this is an application bug. */
39 lll_unlock (cond->__data.__lock, pshared);
40 return EBUSY;
43 /* Tell pthread_cond_*wait that this condvar is being destroyed. */
44 cond->__data.__total_seq = -1ULL;
46 /* If there are waiters which have been already signalled or
47 broadcasted, but still are using the pthread_cond_t structure,
48 pthread_cond_destroy needs to wait for them. */
49 unsigned int nwaiters = cond->__data.__nwaiters;
51 if (nwaiters >= (1 << COND_NWAITERS_SHIFT))
53 /* Wake everybody on the associated mutex in case there are
54 threads that have been requeued to it.
55 Without this, pthread_cond_destroy could block potentially
56 for a long time or forever, as it would depend on other
57 thread's using the mutex.
58 When all threads waiting on the mutex are woken up, pthread_cond_wait
59 only waits for threads to acquire and release the internal
60 condvar lock. */
61 if (cond->__data.__mutex != NULL
62 && cond->__data.__mutex != (void *) ~0l)
64 pthread_mutex_t *mut = (pthread_mutex_t *) cond->__data.__mutex;
65 lll_futex_wake (&mut->__data.__lock, INT_MAX,
66 PTHREAD_MUTEX_PSHARED (mut));
71 lll_unlock (cond->__data.__lock, pshared);
73 lll_futex_wait (&cond->__data.__nwaiters, nwaiters, pshared);
75 lll_lock (cond->__data.__lock, pshared);
77 nwaiters = cond->__data.__nwaiters;
79 while (nwaiters >= (1 << COND_NWAITERS_SHIFT));
82 return 0;
84 versioned_symbol (libpthread, __pthread_cond_destroy,
85 pthread_cond_destroy, GLIBC_2_3_2);