/* * 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) 1999,2005 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"intpthread_mutex_trylock (pthread_mutex_t * mutex){  int result = 0;  pthread_mutex_t mx;  /*   * Let the system deal with invalid pointers.   */  /*   * 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_ERRORCHECK_MUTEX_INITIALIZER)    {      if ((result = ptw32_mutex_check_need_init (mutex)) != 0)	{	  return (result);	}    }  mx = *mutex;  if (0 == (LONG) PTW32_INTERLOCKED_COMPARE_EXCHANGE (		     (PTW32_INTERLOCKED_LPLONG) &mx->lock_idx,		     (PTW32_INTERLOCKED_LONG) 1,		     (PTW32_INTERLOCKED_LONG) 0))    {      if (mx->kind != PTHREAD_MUTEX_NORMAL)	{	  mx->recursive_count = 1;	  mx->ownerThread = pthread_self ();	}    }  else    {      if (mx->kind == PTHREAD_MUTEX_RECURSIVE &&	  pthread_equal (mx->ownerThread, pthread_self ()))	{	  mx->recursive_count++;	}      else	{	  result = EBUSY;	}    }  return (result);}