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/*
* pthread_spin_destroy.c
*
* Description:
* This translation unit implements spin lock primitives.
*
* --------------------------------------------------------------------------
*
* Pthreads-win32 - POSIX Threads Library for Win32
* Copyright(C) 1998 John E. Bossom
* Copyright(C) 1999,2002 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_spin_destroy(pthread_spinlock_t *lock)
{
register pthread_spinlock_t s;
if (lock == NULL || *lock == NULL)
{
return EINVAL;
}
if ((s = *lock) != PTHREAD_SPINLOCK_INITIALIZER)
{
if (s->interlock == PTW32_SPIN_USE_MUTEX)
{
return pthread_mutex_destroy(&(s->u.mutex));
}
if ( (PTW32_INTERLOCKED_LONG) PTW32_SPIN_UNLOCKED ==
ptw32_interlocked_compare_exchange((PTW32_INTERLOCKED_LPLONG) &(s->interlock),
(PTW32_INTERLOCKED_LONG) PTW32_OBJECT_INVALID,
(PTW32_INTERLOCKED_LONG) PTW32_SPIN_UNLOCKED))
{
/*
* The spinlock isn't held by another thread so other threads that have
* just entered another spin_* routine will get PTW32_OBJECT_INVALID
* and so return EINVAL. This will not be so if the memory freed below is
* re-allocated and initialised before that happens.
*
* We are relying on the application to be responsible for ensuring that
* all other threads have finished with the spinlock before destroying it.
*/
*lock = NULL;
(void) free(s);
return 0;
}
return EINVAL;
}
else
{
int result = 0;
/*
* See notes in ptw32_spinlock_check_need_init() above also.
*/
EnterCriticalSection(&ptw32_spinlock_test_init_lock);
/*
* Check again.
*/
if (*lock == PTHREAD_SPINLOCK_INITIALIZER)
{
/*
* This is all we need to do to destroy a statically
* initialised spinlock that has not yet been used (initialised).
* If we get to here, another thread
* waiting to initialise this mutex will get an EINVAL.
*/
*lock = NULL;
}
else
{
/*
* The spinlock has been initialised while we were waiting
* so assume it's in use.
*/
result = EBUSY;
}
LeaveCriticalSection(&ptw32_spinlock_test_init_lock);
return(result);
}
}
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