78 lines
2.3 KiB
C
78 lines
2.3 KiB
C
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/*
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* pthread_spin_trylock.c
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*
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* Description:
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* This translation unit implements spin lock primitives.
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*
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* --------------------------------------------------------------------------
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*
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* Pthreads-win32 - POSIX Threads Library for Win32
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* Copyright(C) 1998 John E. Bossom
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* Copyright(C) 1999,2005 Pthreads-win32 contributors
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*
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* Contact Email: rpj@callisto.canberra.edu.au
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*
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* The current list of contributors is contained
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* in the file CONTRIBUTORS included with the source
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* code distribution. The list can also be seen at the
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* following World Wide Web location:
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* http://sources.redhat.com/pthreads-win32/contributors.html
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library in the file COPYING.LIB;
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* if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
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*/
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#include "pthread.h"
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#include "implement.h"
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int
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pthread_spin_trylock (pthread_spinlock_t * lock)
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{
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register pthread_spinlock_t s;
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if (NULL == lock || NULL == *lock)
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{
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return (EINVAL);
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}
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if (*lock == PTHREAD_SPINLOCK_INITIALIZER)
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{
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int result;
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if ((result = ptw32_spinlock_check_need_init (lock)) != 0)
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{
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return (result);
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}
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}
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s = *lock;
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switch ((long)
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PTW32_INTERLOCKED_COMPARE_EXCHANGE_LONG ((PTW32_INTERLOCKED_LONGPTR) &s->interlock,
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(PTW32_INTERLOCKED_LONG) PTW32_SPIN_LOCKED,
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(PTW32_INTERLOCKED_LONG) PTW32_SPIN_UNLOCKED))
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{
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case PTW32_SPIN_UNLOCKED:
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return 0;
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case PTW32_SPIN_LOCKED:
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return EBUSY;
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case PTW32_SPIN_USE_MUTEX:
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return pthread_mutex_trylock (&(s->u.mutex));
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}
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return EINVAL;
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}
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