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Diffstat (limited to '3rdparty/plibsys/src/pmutex.h')
-rw-r--r-- | 3rdparty/plibsys/src/pmutex.h | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/3rdparty/plibsys/src/pmutex.h b/3rdparty/plibsys/src/pmutex.h new file mode 100644 index 0000000..449a652 --- /dev/null +++ b/3rdparty/plibsys/src/pmutex.h @@ -0,0 +1,136 @@ +/* + * The MIT License + * + * Copyright (C) 2010-2017 Alexander Saprykin <saprykin.spb@gmail.com> + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files (the + * 'Software'), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. + * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY + * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, + * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE + * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + */ + +/** + * @file pmutex.h + * @brief Mutex routines + * @author Alexander Saprykin + * + * A mutex is a mutual exclusive (hence mutex) synchronization primitive which + * allows access to a critical section only to one of the concurrently running + * threads. It is used to protected shared data structures from concurrent + * modifications which could lead to unpredictable behavior. + * + * When entering a critical section a thread must call p_mutex_lock() to get a + * lock. If another thread is already holding the lock all other threads will + * be suspended until the lock is released with p_mutex_unlock(). After + * releasing the lock one of the waiting threads is resumed to continue + * execution. On most systems it is not specified whether a mutex waiting queue + * is fair (FIFO) or not. + * + * The typical mutex usage: + * @code + * p_mutex_lock (mutex); + * + * ... code in critical section ... + * + * p_mutex_unlock (mutex); + * @endcode + * You can also think of the mutex as a binary semaphore. + * + * It is implementation dependent whether recursive locking or non-locked mutex + * unlocking is allowed, but such actions can lead to unpredictable behavior. + * Do not rely on such behavior in cross-platform applications. + * + * This is the thread scoped mutex implementation. You could not share this + * mutex outside the process adress space, but you can share it between the + * threads of the same process. + */ + +#if !defined (PLIBSYS_H_INSIDE) && !defined (PLIBSYS_COMPILATION) +# error "Header files shouldn't be included directly, consider using <plibsys.h> instead." +#endif + +#ifndef PLIBSYS_HEADER_PMUTEX_H +#define PLIBSYS_HEADER_PMUTEX_H + +#include <pmacros.h> +#include <ptypes.h> + +P_BEGIN_DECLS + +/** Mutex opaque data structure. */ +typedef struct PMutex_ PMutex; + +/** + * @brief Creates a new #PMutex object. + * @return Pointer to a newly created #PMutex object. + * @since 0.0.1 + */ +P_LIB_API PMutex * p_mutex_new (void); + +/** + * @brief Locks a mutex. + * @param mutex #PMutex to lock. + * @return TRUE in case of success, FALSE otherwise. + * @since 0.0.1 + * @warning Do not lock the mutex recursively - it may lead to an application + * deadlock (implementation dependent). + * + * Forces the calling thread to sleep until @a mutex becomes available for + * locking. + */ +P_LIB_API pboolean p_mutex_lock (PMutex *mutex); + +/** + * @brief Tries to lock a mutex immediately. + * @param mutex #PMutex to lock. + * @return TRUE in case of success, FALSE otherwise. + * @since 0.0.1 + * @warning Do not lock the mutex recursively - it may lead to an application + * deadlock (implementation dependent). + * + * Tries to lock @a mutex and returns immediately if it is not available for + * locking. + */ +P_LIB_API pboolean p_mutex_trylock (PMutex *mutex); + +/** + * @brief Releases a locked mutex. + * @param mutex #PMutex to release. + * @return TRUE in case of success, FALSE otherwise. + * @since 0.0.1 + * @warning Do not use this function on non-locked mutexes - behavior may be + * unpredictable. + * + * If @a mutex was previously locked then it becomes unlocked. + * + * It's implementation dependent whether only the same thread can lock and + * unlock the same mutex. + */ +P_LIB_API pboolean p_mutex_unlock (PMutex *mutex); + +/** + * @brief Frees #PMutex object. + * @param mutex #PMutex to free. + * @since 0.0.1 + * @warning It doesn't unlock @a mutex before freeing memory, so you should do + * it manually. + */ +P_LIB_API void p_mutex_free (PMutex *mutex); + +P_END_DECLS + +#endif /* PLIBSYS_HEADER_PMUTEX_H */ |