00001 /* +---------------------------------------------------------------------------+ 00002 | The Mobile Robot Programming Toolkit (MRPT) C++ library | 00003 | | 00004 | http://mrpt.sourceforge.net/ | 00005 | | 00006 | Copyright (C) 2005-2011 University of Malaga | 00007 | | 00008 | This software was written by the Machine Perception and Intelligent | 00009 | Robotics Lab, University of Malaga (Spain). | 00010 | Contact: Jose-Luis Blanco <jlblanco@ctima.uma.es> | 00011 | | 00012 | This file is part of the MRPT project. | 00013 | | 00014 | MRPT is free software: you can redistribute it and/or modify | 00015 | it under the terms of the GNU General Public License as published by | 00016 | the Free Software Foundation, either version 3 of the License, or | 00017 | (at your option) any later version. | 00018 | | 00019 | MRPT is distributed in the hope that it will be useful, | 00020 | but WITHOUT ANY WARRANTY; without even the implied warranty of | 00021 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | 00022 | GNU General Public License for more details. | 00023 | | 00024 | You should have received a copy of the GNU General Public License | 00025 | along with MRPT. If not, see <http://www.gnu.org/licenses/>. | 00026 | | 00027 +---------------------------------------------------------------------------+ */ 00028 #ifndef mrpt_synch_semaphore_H 00029 #define mrpt_synch_semaphore_H 00030 00031 #include <mrpt/utils/utils_defs.h> 00032 #include <mrpt/utils/CStream.h> 00033 #include <mrpt/utils/CReferencedMemBlock.h> 00034 00035 /*--------------------------------------------------------------- 00036 Class 00037 ---------------------------------------------------------------*/ 00038 namespace mrpt 00039 { 00040 /** This namespace provides multitask, synchronization utilities. 00041 */ 00042 namespace synch 00043 { 00044 /** A semaphore for inter-thread synchronization. 00045 * The state of a semaphore object is signaled when its count is greater than zero, 00046 * and nonsignaled when its count is equal to zero. The initialCount parameter specifies 00047 * the initial count. Each time a waiting thread is released because of the semaphore's 00048 * signaled state, the count of the semaphore is decreased by one. Use the release function 00049 * to increment a semaphore's count by a specified amount. The count can never be less 00050 * than zero or greater than the value specified in the maxCount parameter. 00051 */ 00052 class BASE_IMPEXP CSemaphore 00053 { 00054 protected: 00055 utils::CReferencedMemBlock m_data; 00056 00057 public: 00058 /** Creates a semaphore. 00059 */ 00060 CSemaphore( 00061 unsigned int initialCount, 00062 unsigned int maxCount, 00063 const std::string &name=std::string("") ); 00064 00065 /** Destructor 00066 */ 00067 virtual ~CSemaphore(); 00068 00069 /** Blocks until the count of the semaphore to be non-zero. 00070 * \param timeout_ms The timeout in milliseconds, or set to zero to wait indefinidely. 00071 * \return true if the semaphore has been signaled, false on timeout or any other error. 00072 */ 00073 bool waitForSignal( unsigned int timeout_ms = 0 ); 00074 00075 /** Increments the count of the semaphore by a given amount. 00076 */ 00077 void release(unsigned int increaseCount = 1); 00078 00079 }; 00080 00081 } // End of namespace 00082 00083 } // End of namespace 00084 00085 #endif
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