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81e293422c
- Move `@defgroup core_sync` group definition to doc.txt - Adapt usage of `@ingroup core_sync` accordingly
136 lines
3.1 KiB
C
136 lines
3.1 KiB
C
/*
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* Copyright (C) 2015 Kaspar Schleiser <kaspar@schleiser.de>
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* 2013, 2014 Freie Universität Berlin
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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/**
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* @defgroup core_sync_mutex Mutex
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* @ingroup core_sync
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* @brief Mutex for thread synchronization
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* @{
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*
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* @file
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* @brief Mutex for thread synchronization
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*
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* @author Kaspar Schleiser <kaspar@schleiser.de>
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*/
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#ifndef MUTEX_H
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#define MUTEX_H
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#include <stddef.h>
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#include "list.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* @brief Mutex structure. Must never be modified by the user.
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*/
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typedef struct {
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/**
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* @brief The process waiting queue of the mutex. **Must never be changed
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* by the user.**
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* @internal
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*/
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list_node_t queue;
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} mutex_t;
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/**
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* @brief Static initializer for mutex_t.
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* @details This initializer is preferable to mutex_init().
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*/
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#define MUTEX_INIT { { NULL } }
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/**
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* @brief Static initializer for mutex_t with a locked mutex
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*/
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#define MUTEX_INIT_LOCKED { { MUTEX_LOCKED } }
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/**
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* @cond INTERNAL
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* @brief This is the value of the mutex when locked and no threads are waiting
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* for it
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*/
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#define MUTEX_LOCKED ((list_node_t *)-1)
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/**
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* @endcond
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*/
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/**
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* @brief Initializes a mutex object.
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* @details For initialization of variables use MUTEX_INIT instead.
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* Only use the function call for dynamically allocated mutexes.
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* @param[out] mutex pre-allocated mutex structure, must not be NULL.
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*/
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static inline void mutex_init(mutex_t *mutex)
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{
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mutex->queue.next = NULL;
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}
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/**
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* @brief Lock a mutex, blocking or non-blocking.
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*
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* @details For commit purposes you should probably use mutex_trylock() and
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* mutex_lock() instead.
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*
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* @param[in] mutex Mutex object to lock. Has to be initialized first.
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* Must not be NULL.
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* @param[in] blocking if true, block until mutex is available.
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*
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* @return 1 if mutex was unlocked, now it is locked.
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* @return 0 if the mutex was locked.
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*/
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int _mutex_lock(mutex_t *mutex, int blocking);
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/**
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* @brief Tries to get a mutex, non-blocking.
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*
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* @param[in] mutex Mutex object to lock. Has to be initialized first. Must not
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* be NULL.
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*
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* @return 1 if mutex was unlocked, now it is locked.
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* @return 0 if the mutex was locked.
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*/
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static inline int mutex_trylock(mutex_t *mutex)
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{
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return _mutex_lock(mutex, 0);
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}
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/**
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* @brief Locks a mutex, blocking.
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*
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* @param[in] mutex Mutex object to lock. Has to be initialized first. Must not be NULL.
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*/
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static inline void mutex_lock(mutex_t *mutex)
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{
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_mutex_lock(mutex, 1);
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}
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/**
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* @brief Unlocks the mutex.
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*
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* @param[in] mutex Mutex object to unlock, must not be NULL.
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*/
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void mutex_unlock(mutex_t *mutex);
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/**
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* @brief Unlocks the mutex and sends the current thread to sleep
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*
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* @param[in] mutex Mutex object to unlock, must not be NULL.
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*/
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void mutex_unlock_and_sleep(mutex_t *mutex);
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#ifdef __cplusplus
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}
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#endif
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#endif /* MUTEX_H */
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/** @} */
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