Mutex.h

00001 /* mbed Microcontroller Library
00002  * Copyright (c) 2006-2012 ARM Limited
00003  *
00004  * Permission is hereby granted, free of charge, to any person obtaining a copy
00005  * of this software and associated documentation files (the "Software"), to deal
00006  * in the Software without restriction, including without limitation the rights
00007  * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
00008  * copies of the Software, and to permit persons to whom the Software is
00009  * furnished to do so, subject to the following conditions:
00010  *
00011  * The above copyright notice and this permission notice shall be included in
00012  * all copies or substantial portions of the Software.
00013  *
00014  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00015  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00016  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
00017  * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00018  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00019  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
00020  * SOFTWARE.
00021  */
00022 #ifndef MUTEX_H
00023 #define MUTEX_H
00024 
00025 #include <stdint.h>
00026 #include "cmsis_os.h"
00027 
00028 namespace rtos {
00029 
00030 /** The Mutex class is used to synchronise the execution of threads.
00031  This is for example used to protect access to a shared resource.
00032 */
00033 class Mutex {
00034 public:
00035     /** Create and Initialize a Mutex object */
00036     Mutex();
00037 
00038     /** Wait until a Mutex becomes available.
00039       @param   millisec  timeout value or 0 in case of no time-out. (default: osWaitForever)
00040       @return  status code that indicates the execution status of the function.
00041      */
00042     osStatus lock(uint32_t millisec=osWaitForever);
00043 
00044     /** Try to lock the mutex, and return immediately
00045       @return  true if the mutex was acquired, false otherwise.
00046      */
00047     bool trylock();
00048 
00049     /** Unlock the mutex that has previously been locked by the same thread
00050       @return  status code that indicates the execution status of the function.
00051      */
00052     osStatus unlock();
00053 
00054     ~Mutex();
00055 
00056 private:
00057     osMutexId _osMutexId;
00058     osMutexDef_t _osMutexDef;
00059 #ifdef CMSIS_OS_RTX
00060 #ifdef __MBED_CMSIS_RTOS_CA9
00061     int32_t _mutex_data[4];
00062 #else
00063     int32_t _mutex_data[3];
00064 #endif
00065 #endif
00066 };
00067 
00068 }
00069 #endif