obs-studio/deps/w32-pthreads/ptw32_spinlock_check_need_i...

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2013-09-30 19:37:13 -07:00
/*
* ptw32_spinlock_check_need_init.c
*
* Description:
* This translation unit implements spin 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
2013-09-30 19:37:13 -07:00
*/
#include "pthread.h"
#include "implement.h"
INLINE int
ptw32_spinlock_check_need_init (pthread_spinlock_t * lock)
{
int result = 0;
ptw32_mcs_local_node_t node;
/*
* The following guarded test is specifically for statically
* initialised spinlocks (via PTHREAD_SPINLOCK_INITIALIZER).
*/
ptw32_mcs_lock_acquire(&ptw32_spinlock_test_init_lock, &node);
/*
* We got here possibly under race
* conditions. Check again inside the critical section
* and only initialise if the spinlock is valid (not been destroyed).
* If a static spinlock has been destroyed, the application can
* re-initialise it only by calling pthread_spin_init()
* explicitly.
*/
if (*lock == PTHREAD_SPINLOCK_INITIALIZER)
{
result = pthread_spin_init (lock, PTHREAD_PROCESS_PRIVATE);
}
else if (*lock == NULL)
{
/*
* The spinlock 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);
}