本文概要：

        敏捷开发大家想必知道并且评价甚高，缩短开发周期，提高开发质量。将大project独立为不同的小app开发，整个开发过程，程序可用可測，所以提高了总体的质量。基于这样的开发模式和开发理念，进程间通信必定是童鞋们必掌握技能之中的一个了，而boost库是众多库中平台支持性非常好，效果非常高之中的一个。做嵌入式或者server等应用的人肯定有所涉及。本文以手冊方式讲述boost共享内存，信号，以及消息队列的编程方式。非常easy，列出最经常使用使用方法，供大家拷贝直接使用。本文出自CSDN-固本培元。转载注明出处-leoluopy@gmail.com。

应用思路注意事项：

         信号是进程内通信，非常类似于Qt的信号槽，配合消息队列以及boost多线程使用效果非常好。

共享内存：

#include 
     
        #include 
      
         #include 
       
          #include 
        
           #include 
         
               int main(int argc, char *argv[])  {     using namespace boost::interprocess;        if(argc == 1){  //Parent process        //Remove shared memory on construction and destruction        struct shm_remove        {           shm_remove() { shared_memory_object::remove("MySharedMemory"); }           ~shm_remove(){ shared_memory_object::remove("MySharedMemory"); }        } remover;           //Create a shared memory object.        shared_memory_object shm (create_only, "MySharedMemory", read_write);           //Set size        shm.truncate(1000);           //Map the whole shared memory in this process        mapped_region region(shm, read_write);           //Write all the memory to 1        std::memset(region.get_address(), 1, region.get_size());           //Launch child process        std::string s(argv[0]); s += " child ";        if(0 != std::system(s.c_str()))           return 1;     }     else{        //Open already created shared memory object.        shared_memory_object shm (open_only, "MySharedMemory", read_only);           //Map the whole shared memory in this process        mapped_region region(shm, read_only);           //Check that memory was initialized to 1        char *mem = static_cast
          
           (region.get_address()); for(std::size_t i = 0; i < region.get_size(); ++i) if(*mem++ != 1) return 1; //Error checking memory } return 0; }
          
         
        
       
      
     

信号通信：

贴出一个经常使用带參数的写法，具体的其它使用方法能够參考文章末的參考文章：

#include 
     
      #include 
      
       #include 
       
        #include 
        
          using namespace std;using namespace boost; float print_sum(float x, float y){  std::cout << "The sum is " << x+y << std::endl;  return x+y;} float print_product(float x, float y){  std::cout << "The product is " << x*y << std::endl;  return x*y;} float print_difference(float x, float y){  std::cout << "The difference is " << x-y << std::endl;  return x-y;} float print_quotient(float x, float y){  std::cout << "The quotient is " << x/y << std::endl;  return x/y;} int main(){  boost::signal
         
           sig;  sig.connect(0, &print_sum);  sig.connect(1, &print_product);  sig.connect(2, &print_difference);  sig.connect(3, &print_quotient);  // Output 1.6667 because return by the last slot called.  cout << sig(5, 3) << endl;     return 0;}
         
        
       
      
     

信号槽删除及堵塞：

Seg 1: Disconnecting slots.        boost::signals::connection c = sig.connect(HelloWorld());        if (c.connected()) {        // c is still connected to the signal        sig(); // Prints "Hello, World!"        }        c.disconnect(); // Disconnect the HelloWorld object        assert(!c.connected()); //c isn't connected any more        sig(); // Does nothing: there are no connected slotsSeg 2:        boost::signals::connection c = sig.connect(HelloWorld());        sig(); // Prints "Hello, World!"         c.block(); // block the slot        assert(c.blocked());        sig(); // No output: the slot is blocked         c.unblock(); // unblock the slot        sig(); // Prints "Hello, World!"

消息队列：

消息队列发送：

#include 
     
      #include 
      
       #include 
       
        using namespace boost::interprocess;int main (){   try{      //Erase previous message queue      message_queue::remove("message_queue");      //Create a message_queue.      message_queue mq         (create_only               //only create         ,"message_queue"           //name         ,100                       //max message number         ,sizeof(int)               //max message size         );      //Send 100 numbers      for(int i = 0; i < 100; ++i){         mq.send(&i, sizeof(i), 0);      }   }   catch(interprocess_exception &ex){      std::cout << ex.what() << std::endl;      return 1;   }   return 0;}
       
      
     

消息队列接收：

#include 
     
      #include 
      
       #include 
       
        using namespace boost::interprocess;int main (){   try{      //Open a message queue.      message_queue mq         (open_only        //only create         ,"message_queue"  //name         );      unsigned int priority;      message_queue::size_type recvd_size;      //Receive 100 numbers      for(int i = 0; i < 100; ++i)	  {         int number;         mq.receive(&number, sizeof(number), recvd_size, priority);		 printf("I:%d Rec:%d\n",i,number);         if(number != i || recvd_size != sizeof(number))            return 1;      }   }   catch(interprocess_exception &ex){      message_queue::remove("message_queue");      std::cout << ex.what() << std::endl;      return 1;   }   message_queue::remove("message_queue");   return 0;}
       
      
     

编译命令：

[root@localhost tmp]# g++ boost_queue_send.cpp -o queue_send -lboost_thread -lboost_system[root@localhost tmp]# g++ boost_queue_rec.cpp -o queue_rec -lboost_thread -lboost_system

将消息队列整理了一下，能够直接方便使用例如以下：

注（BoostMsg.h）用于将函数外部化，无其它用处。

#include 
     
      #include 
      
         #include 
       
          #include 
        
           using namespace boost::interprocess;  int BoostMsg_CreateMsg(const char* MsgQueName,int MaxQueLen,int MaxMsgLen){	message_queue::remove(MsgQueName);  	//Create a message_queue.  	message_queue mq  		(create_only               //only create  		,MsgQueName						//name  		,MaxQueLen                       //max message number  		,MaxMsgLen              //max message size  		);  	printf("Boost Msg Created Name:%s QueLen:%d MsgMaxLen:%d \n",MsgQueName,MaxQueLen,MaxMsgLen);	return 0;}int BoostMsg_OpenMsgToSend(char* BufMsg,const char* MsgQueName,int MsgLen){  	try{  		//Erase previous message queue  		//message_queue::remove("message_queue");  		//Create a message_queue.  		message_queue mq  			(open_only               //only create  			,MsgQueName						//name  			);  		mq.send(BufMsg, MsgLen, 0);  	}  	catch(interprocess_exception &ex){  		std::cout << ex.what() << std::endl;  		return 1;  	}  	return 0;  } int BoostMsg_OpenMsgToRec(char* RecivedMsg,const char* MsgQueName,int MaxReceivedLen){  	try{  		//Open a message queue.  		message_queue mq  			(open_only        //only create  			,MsgQueName  //name  			);  		unsigned int priority;  		message_queue::size_type recvd_size;  		memset(RecivedMsg,0,MaxReceivedLen);		mq.receive(RecivedMsg, MaxReceivedLen, recvd_size, priority);  		return recvd_size;	}  	catch(interprocess_exception &ex){  		message_queue::remove("message_queue");  		std::cout << ex.what() << std::endl;  		return 1;  	}  	message_queue::remove("message_queue");  	return 0;  }
        
       
      
     

用法非常easy，就是Create 然后Send 和Rec，进程之间通信 非常方便。

參考文章：