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_os2.h"
00027 #include "mbed_rtos1_types.h"
00028 #include "mbed_rtos_storage.h"
00029 
00030 #include "platform/NonCopyable.h"
00031 
00032 namespace rtos {
00033 /** \addtogroup rtos */
00034 /** @{*/
00035 
00036 /** The Mutex class is used to synchronize the execution of threads.
00037  This is for example used to protect access to a shared resource.
00038 
00039  @note
00040  Memory considerations: The mutex control structures will be created on current thread's stack, both for the mbed OS
00041  and underlying RTOS objects (static or dynamic RTOS memory pools are not being used).
00042 */
00043 class Mutex : private mbed::NonCopyable<Mutex> {
00044 public:
00045     /** Create and Initialize a Mutex object */
00046     Mutex();
00047 
00048     /** Create and Initialize a Mutex object
00049 
00050      @param name name to be used for this mutex. It has to stay allocated for the lifetime of the thread.
00051     */
00052     Mutex(const char *name);
00053 
00054     /** Wait until a Mutex becomes available.
00055       @param   millisec  timeout value or 0 in case of no time-out. (default: osWaitForever)
00056       @return  status code that indicates the execution status of the function:
00057                @a osOK the mutex has been obtained.
00058                @a osErrorTimeout the mutex could not be obtained in the given time.
00059                @a osErrorParameter internal error.
00060                @a osErrorResource the mutex could not be obtained when no timeout was specified.
00061                @a osErrorISR this function cannot be called from the interrupt service routine.
00062      */
00063     osStatus lock(uint32_t millisec=osWaitForever);
00064 
00065     /** Try to lock the mutex, and return immediately
00066       @return true if the mutex was acquired, false otherwise.
00067      */
00068     bool trylock();
00069 
00070     /** Unlock the mutex that has previously been locked by the same thread
00071       @return status code that indicates the execution status of the function:
00072               @a osOK the mutex has been released.
00073               @a osErrorParameter internal error.
00074               @a osErrorResource the mutex was not locked or the current thread wasn't the owner.
00075               @a osErrorISR this function cannot be called from the interrupt service routine.
00076      */
00077     osStatus unlock();
00078 
00079     ~Mutex();
00080 
00081 private:
00082     void constructor(const char *name = NULL);
00083 
00084     osMutexId_t               _id;
00085     osMutexAttr_t             _attr;
00086     mbed_rtos_storage_mutex_t _obj_mem;
00087 };
00088 
00089 }
00090 #endif
00091 
00092 /** @}*/