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/*
* pthread_mutex_destroy.c
*
* Description:
* This translation unit implements mutual exclusion (mutex) primitives.
*
* --------------------------------------------------------------------------
*
* Pthreads-win32 - POSIX Threads Library for Win32
* Copyright(C) 1998 John E. Bossom
* Copyright(C) 1999,2003 Pthreads-win32 contributors
*
* Contact Email: rpj@callisto.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_mutex_destroy (pthread_mutex_t * mutex)
{
int result = 0;
pthread_mutex_t mx;
if (mutex == NULL || *mutex == NULL)
{
return EINVAL;
}
/*
* Check to see if we have something to delete.
*/
if (*mutex != PTHREAD_MUTEX_INITIALIZER)
{
mx = *mutex;
result = pthread_mutex_trylock (&mx);
/*
* If trylock succeeded and the mutex is not recursively locked it
* can be destroyed.
*/
if (result == 0)
{
if (1 == mx->recursive_count)
{
/*
* FIXME!!!
* The mutex isn't held by another thread but we could still
* be too late invalidating the mutex below since another thread
* may already have entered mutex_lock and the check for a valid
* *mutex != NULL.
*
* Note that this would be an unusual situation because it is not
* common that mutexes are destroyed while they are still in
* use by other threads.
*/
*mutex = NULL;
result = pthread_mutex_unlock (&mx);
if (result == 0)
{
(void) sem_destroy (&mx->wait_sema);
DeleteCriticalSection (&mx->wait_cs);
free (mx);
}
else
{
/*
* Restore the mutex before we return the error.
*/
*mutex = mx;
}
}
else /* mx->recursive_count > 1 */
{
/*
* The mutex must be recursive and already locked by us (this thread).
*/
mx->recursive_count--; /* Undo effect of pthread_mutex_trylock() above */
result = EBUSY;
}
}
}
else
{
/*
* See notes in ptw32_mutex_check_need_init() above also.
*/
EnterCriticalSection (&ptw32_mutex_test_init_lock);
/*
* Check again.
*/
if (*mutex == PTHREAD_MUTEX_INITIALIZER)
{
/*
* This is all we need to do to destroy a statically
* initialised mutex that has not yet been used (initialised).
* If we get to here, another thread
* waiting to initialise this mutex will get an EINVAL.
*/
*mutex = NULL;
}
else
{
/*
* The mutex has been initialised while we were waiting
* so assume it's in use.
*/
result = EBUSY;
}
LeaveCriticalSection (&ptw32_mutex_test_init_lock);
}
return (result);
}
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