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/*
* pthread_mutex_trylock.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) 1999,2002 Pthreads-win32 contributors
*
* Contact Email: rpj@ise.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_trylock(pthread_mutex_t *mutex)
{
int result = 0;
pthread_mutex_t mx;
if (mutex == NULL || *mutex == NULL)
{
return EINVAL;
}
/*
* We do a quick check to see if we need to do more work
* to initialise a static mutex. We check
* again inside the guarded section of ptw32_mutex_check_need_init()
* to avoid race conditions.
*/
if (*mutex == PTHREAD_MUTEX_INITIALIZER)
{
result = ptw32_mutex_check_need_init(mutex);
}
mx = *mutex;
if (result == 0)
{
if ( (PTW32_INTERLOCKED_LONG) PTW32_MUTEX_LOCK_IDX_INIT ==
ptw32_interlocked_compare_exchange((PTW32_INTERLOCKED_LPLONG) &mx->lock_idx,
(PTW32_INTERLOCKED_LONG) 0,
(PTW32_INTERLOCKED_LONG) PTW32_MUTEX_LOCK_IDX_INIT))
{
mx->recursive_count = 1;
mx->ownerThread = (mx->kind != PTHREAD_MUTEX_FAST_NP
? pthread_self()
: (pthread_t) PTW32_MUTEX_OWNER_ANONYMOUS);
}
else
{
if( mx->kind != PTHREAD_MUTEX_FAST_NP &&
pthread_equal( mx->ownerThread, pthread_self() ) )
{
if( mx->kind == PTHREAD_MUTEX_RECURSIVE_NP )
{
mx->recursive_count++;
}
else
{
result = EDEADLK;
}
}
else
{
result = EBUSY;
}
}
}
return(result);
}
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