Semaphore.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 SEMAPHORE_H
00023 #define SEMAPHORE_H
00024 
00025 #include <stdint.h>
00026 #include "cmsis_os.h"
00027 
00028 namespace rtos {
00029 /** \addtogroup rtos */
00030 /** @{*/
00031 
00032 /** The Semaphore class is used to manage and protect access to a set of shared resources. */
00033 class Semaphore {
00034 public:
00035     /** Create and Initialize a Semaphore object used for managing resources.
00036       @param number of available resources; maximum index value is (count-1). (default: 0).
00037     */
00038     Semaphore(int32_t count=0);
00039 
00040     /** Wait until a Semaphore resource becomes available.
00041       @param   millisec  timeout value or 0 in case of no time-out. (default: osWaitForever).
00042       @return  number of available tokens, or -1 in case of incorrect parameters
00043     */
00044     int32_t wait(uint32_t millisec=osWaitForever);
00045 
00046     /** Release a Semaphore resource that was obtain with Semaphore::wait.
00047       @return  status code that indicates the execution status of the function.
00048     */
00049     osStatus release(void);
00050 
00051     ~Semaphore();
00052 
00053 private:
00054     osSemaphoreId _osSemaphoreId;
00055     osSemaphoreDef_t _osSemaphoreDef;
00056 #ifdef CMSIS_OS_RTX
00057     uint32_t _semaphore_data[2];
00058 #endif
00059 };
00060 
00061 }
00062 #endif
00063 
00064 /** @}*/