78 lines
2.6 KiB
C
78 lines
2.6 KiB
C
|
/*
|
||
|
|
* pthread_rwlock_check_need_init.c
|
||
|
|
*
|
||
|
|
* Description:
|
||
|
|
* This translation unit implements read/write lock 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.,
|
||
|
|
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
|
||
|
|
*/
|
||
|
|
|
||
|
|
#include "pthread.h"
|
||
|
|
#include "implement.h"
|
||
|
|
|
||
|
|
INLINE int
|
||
|
|
ptw32_rwlock_check_need_init (pthread_rwlock_t * rwlock)
|
||
|
|
{
|
||
|
|
int result = 0;
|
||
|
|
ptw32_mcs_local_node_t node;
|
||
|
|
|
||
|
|
/*
|
||
|
|
* The following guarded test is specifically for statically
|
||
|
|
* initialised rwlocks (via PTHREAD_RWLOCK_INITIALIZER).
|
||
|
|
*/
|
||
|
|
ptw32_mcs_lock_acquire(&ptw32_rwlock_test_init_lock, &node);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* We got here possibly under race
|
||
|
|
* conditions. Check again inside the critical section
|
||
|
|
* and only initialise if the rwlock is valid (not been destroyed).
|
||
|
|
* If a static rwlock has been destroyed, the application can
|
||
|
|
* re-initialise it only by calling pthread_rwlock_init()
|
||
|
|
* explicitly.
|
||
|
|
*/
|
||
|
|
if (*rwlock == PTHREAD_RWLOCK_INITIALIZER)
|
||
|
|
{
|
||
|
|
result = pthread_rwlock_init (rwlock, NULL);
|
||
|
|
}
|
||
|
|
else if (*rwlock == NULL)
|
||
|
|
{
|
||
|
|
/*
|
||
|
|
* The rwlock has been destroyed while we were waiting to
|
||
|
|
* initialise it, so the operation that caused the
|
||
|
|
* auto-initialisation should fail.
|
||
|
|
*/
|
||
|
|
result = EINVAL;
|
||
|
|
}
|
||
|
|
|
||
|
|
ptw32_mcs_lock_release(&node);
|
||
|
|
|
||
|
|
return result;
|
||
|
|
}
|