| /* Spin locks (native Windows implementation). |
| Copyright (C) 2019-2020 Free Software Foundation, Inc. |
| |
| This program is free software; you can redistribute it and/or modify |
| it under the terms of the GNU General Public License as published by |
| the Free Software Foundation; either version 2, or (at your option) |
| any later version. |
| |
| This program 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 General Public License for more details. |
| |
| You should have received a copy of the GNU General Public License |
| along with this program; if not, see <https://www.gnu.org/licenses/>. */ |
| |
| /* Written by Bruno Haible <bruno@clisp.org>, 2019. */ |
| |
| #include <config.h> |
| |
| /* Specification. */ |
| #include "windows-spin.h" |
| |
| #include <errno.h> |
| |
| void |
| glwthread_spin_init (glwthread_spinlock_t *lock) |
| { |
| lock->word = 0; |
| } |
| |
| int |
| glwthread_spin_lock (glwthread_spinlock_t *lock) |
| { |
| /* Wait until lock->word becomes 0, then replace it with 1. */ |
| /* InterlockedCompareExchange |
| <https://docs.microsoft.com/en-us/windows/win32/api/winnt/nf-winnt-interlockedcompareexchange> */ |
| while (InterlockedCompareExchange (&lock->word, 1, 0)) |
| ; |
| return 0; |
| } |
| |
| int |
| glwthread_spin_trylock (glwthread_spinlock_t *lock) |
| { |
| /* If lock->word is 0, then replace it with 1. */ |
| /* InterlockedCompareExchange |
| <https://docs.microsoft.com/en-us/windows/win32/api/winnt/nf-winnt-interlockedcompareexchange> */ |
| if (InterlockedCompareExchange (&lock->word, 1, 0)) |
| return EBUSY; |
| return 0; |
| } |
| |
| int |
| glwthread_spin_unlock (glwthread_spinlock_t *lock) |
| { |
| /* If lock->word is 1, then replace it with 0. */ |
| /* InterlockedCompareExchange |
| <https://docs.microsoft.com/en-us/windows/win32/api/winnt/nf-winnt-interlockedcompareexchange> */ |
| if (!InterlockedCompareExchange (&lock->word, 0, 1)) |
| return EINVAL; |
| return 0; |
| } |
| |
| int |
| glwthread_spin_destroy (glwthread_spinlock_t *lock) |
| { |
| return 0; |
| } |