71 lines
2.0 KiB
C
71 lines
2.0 KiB
C
/* Spin locks (native Windows implementation).
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Copyright (C) 2019-2026 Free Software Foundation, Inc.
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This file is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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This file 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
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* Written by Bruno Haible <bruno@clisp.org>, 2019. */
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#include <config.h>
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/* Specification. */
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#include "windows-spin.h"
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#include <errno.h>
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void
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glwthread_spin_init (glwthread_spinlock_t *lock)
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{
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lock->word = 0;
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MemoryBarrier ();
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}
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int
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glwthread_spin_lock (glwthread_spinlock_t *lock)
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{
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/* Wait until lock->word becomes 0, then replace it with 1. */
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/* InterlockedCompareExchange
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<https://docs.microsoft.com/en-us/windows/win32/api/winnt/nf-winnt-interlockedcompareexchange> */
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while (InterlockedCompareExchange (&lock->word, 1, 0))
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;
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return 0;
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}
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int
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glwthread_spin_trylock (glwthread_spinlock_t *lock)
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{
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/* If lock->word is 0, then replace it with 1. */
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/* InterlockedCompareExchange
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<https://docs.microsoft.com/en-us/windows/win32/api/winnt/nf-winnt-interlockedcompareexchange> */
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if (InterlockedCompareExchange (&lock->word, 1, 0))
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return EBUSY;
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return 0;
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}
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int
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glwthread_spin_unlock (glwthread_spinlock_t *lock)
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{
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/* If lock->word is 1, then replace it with 0. */
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/* InterlockedCompareExchange
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<https://docs.microsoft.com/en-us/windows/win32/api/winnt/nf-winnt-interlockedcompareexchange> */
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if (!InterlockedCompareExchange (&lock->word, 0, 1))
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return EINVAL;
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return 0;
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}
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int
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glwthread_spin_destroy (glwthread_spinlock_t *lock)
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{
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return 0;
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}
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