/* Plain mutexes (native Windows implementation). Copyright (C) 2005-2020 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 3, 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>, 2005. Based on GCC's gthr-win32.h. */ #include <config.h> /* Specification. */ #include "windows-mutex.h" #include <errno.h> void glwthread_mutex_init (glwthread_mutex_t *mutex) { InitializeCriticalSection (&mutex->lock); mutex->guard.done = 1; } int glwthread_mutex_lock (glwthread_mutex_t *mutex) { if (!mutex->guard.done) { if (InterlockedIncrement (&mutex->guard.started) == 0) /* This thread is the first one to need this mutex. Initialize it. */ glwthread_mutex_init (mutex); else { /* Don't let mutex->guard.started grow and wrap around. */ InterlockedDecrement (&mutex->guard.started); /* Yield the CPU while waiting for another thread to finish initializing this mutex. */ while (!mutex->guard.done) Sleep (0); } } EnterCriticalSection (&mutex->lock); return 0; } int glwthread_mutex_trylock (glwthread_mutex_t *mutex) { if (!mutex->guard.done) { if (InterlockedIncrement (&mutex->guard.started) == 0) /* This thread is the first one to need this mutex. Initialize it. */ glwthread_mutex_init (mutex); else { /* Don't let mutex->guard.started grow and wrap around. */ InterlockedDecrement (&mutex->guard.started); /* Let another thread finish initializing this mutex, and let it also lock this mutex. */ return EBUSY; } } if (!TryEnterCriticalSection (&mutex->lock)) return EBUSY; return 0; } int glwthread_mutex_unlock (glwthread_mutex_t *mutex) { if (!mutex->guard.done) return EINVAL; LeaveCriticalSection (&mutex->lock); return 0; } int glwthread_mutex_destroy (glwthread_mutex_t *mutex) { if (!mutex->guard.done) return EINVAL; DeleteCriticalSection (&mutex->lock); mutex->guard.done = 0; return 0; } |