管道读写报错121：信号灯超时时间已到

Posted 2023-02-06 水澹澹兮生烟.

记录error:在进行一个项目的时候利用管道传输数据，当一端异常退出后重新启动时报错，如下代码：

客户端：

//打开可用的命名管道，并与服务器端进行进程间通信
	hPipe = CreateFileA(
		EXAMP_PIPE,
		GENERIC_READ | GENERIC_WRITE,
		FILE_SHARE_READ | FILE_SHARE_WRITE,
		NULL, OPEN_EXISTING,
		FILE_FLAG_WRITE_THROUGH,
		NULL);
	if (hPipe == INVALID_HANDLE_VALUE) 
		cout << "open read pipe error" << GetLastError() << endl;

		return 0;
	
	else 
		while(1)
			//向服务端发送数据
			cout << "please input the path：" << endl;
			char szBuffer[BUF_SIZE] =  0 ;
			//getline(szBuffer,BUF_SIZE);
			cin >> szBuffer;
			ast = WriteFile(hPipe, szBuffer, BUF_SIZE, &cb_write, NULL);
			if (!ast) 
				cout << "write Failed !!error number:" << GetLastError() << endl;
				break;
			
			else 
				cout << "write success" << endl;
			
			
		
	

服务端：

hPipe = CreateNamedPipeA(
		EXAMP_PIPE,
		PIPE_ACCESS_DUPLEX | FILE_FLAG_OVERLAPPED,
		PIPE_TYPE_MESSAGE | PIPE_READMODE_MESSAGE | PIPE_WAIT,
		PIPE_UNLIMITED_INSTANCES,
		BUF_SIZE,
		BUF_SIZE,
		0,
		&sa);

	//检查是否创建成功
	if (hPipe == INVALID_HANDLE_VALUE)
	
		WriteToLog("Create named Pipe Error:" + to_string(GetLastError()));
		return;
	
	WriteToLog("Create named Pipe success:");
	等待一个客户端进行连接时，事件变成有信号状态
	if (!ConnectNamedPipe(hPipe, NULL))
	
		CloseHandle(hPipe);
		WriteToLog("wait connect Failed:" + to_string(GetLastError()));
		return;
	
	else
	
		WriteToLog("connect success!");
	

	while (ServiceStatus.dwCurrentState == SERVICE_RUNNING) //服务的工作线程循环
		//连接成功，进行通信，读写
		char szBuffer[BUF_SIZE];
		::ZeroMemory(szBuffer, BUF_SIZE);
		DWORD cbRead = 0;
		BOOL hRead = ReadFile(hPipe, szBuffer, BUF_SIZE, &cbRead, NULL);
		if (!hRead) 
			//读取失败,
			int t_error = GetLastError();
			WriteToLog("read failed!" + to_string(t_error));
		
	    else //读取成功后，将读取内容写入日志
		WriteToLog("read success!");
     	
	//将读入的数据遍历到map中
	int num = 0;
	SearchFile(szBuffer, &num, &_path);
	WriteToLog("end_of_reverse");
    

可以看出，客户端在退出后再重新连接是是一个动态的创建新的实例的过程，而服务端的管道是一个静态的实例，因此客户端只能通信一次，在之后进行通信的话就会报错121：信号灯超时时间已到 ；

解决的方法：我的代码中当客户端异常退出时会出现两种错误，一部分是会出现再连接时候报错error：535，error：536（目前为止遇到了这两种）；另一种错误是读数据时报错109：管道结束，因此在这两部分异常终止之后重新创建新的管道实例即可，如下代码：

只用更改服务端：

	//检查是否创建成功
	if (hPipe == INVALID_HANDLE_VALUE)
	
		WriteToLog("Create named Pipe Error:" + to_string(GetLastError()));
		return;
	
	WriteToLog("Create named Pipe success:");
	while (ServiceStatus.dwCurrentState == SERVICE_RUNNING) //服务的工作线程循环
		//等待一个客户端进行连接时，事件变成有信号状态
		if (!ConnectNamedPipe(hPipe, NULL))
		
			CloseHandle(hPipe);//关闭管道
			int the_error = GetLastError();
			WriteToLog("wait connect Failed:" + to_string(the_error));
				hPipe = CreateNamedPipeA(
					EXAMP_PIPE,
					PIPE_ACCESS_DUPLEX | FILE_FLAG_OVERLAPPED,
					PIPE_TYPE_MESSAGE | PIPE_READMODE_MESSAGE | PIPE_WAIT,
					PIPE_UNLIMITED_INSTANCES,
					BUF_SIZE,
					BUF_SIZE,
					0,
					&sa);
				//检查是否创建成功
				if (hPipe == INVALID_HANDLE_VALUE)
				
					WriteToLog("Create named Pipe Error:" + to_string(GetLastError()));
					return;
				
				WriteToLog("Create named Pipe success:");
				continue;
		
		else
		
			WriteToLog("connect success!");
		
		//连接成功，进行通信，读写
		char szBuffer[BUF_SIZE];
		::ZeroMemory(szBuffer, BUF_SIZE);
		DWORD cbRead = 0;
		BOOL hRead = ReadFile(hPipe, szBuffer, BUF_SIZE, &cbRead, NULL);
		if (!hRead) 
			//读取失败,
			int t_error = GetLastError();
			WriteToLog("read failed!" + to_string(t_error));
			if (t_error == 109) 
				CloseHandle(hPipe);//关闭管道
				hPipe = CreateNamedPipeA(
					EXAMP_PIPE,
					PIPE_ACCESS_DUPLEX | FILE_FLAG_OVERLAPPED,
					PIPE_TYPE_MESSAGE | PIPE_READMODE_MESSAGE | PIPE_WAIT,
					PIPE_UNLIMITED_INSTANCES,
					BUF_SIZE,
					BUF_SIZE,
					0,
					&sa);
				//检查是否创建成功
				if (hPipe == INVALID_HANDLE_VALUE)
				
					WriteToLog("Create named Pipe Error:" + to_string(GetLastError()));
					return;
				
				WriteToLog("Create named Pipe success:");
				continue;
			
		
	    else //读取成功后，将读取内容写入日志
		WriteToLog("read success!");
     	
	//将读入的数据遍历到map中
	int num = 0;
	SearchFile(szBuffer, &num, &_path);
	WriteToLog("end_of_reverse");
    

 这个问题的解决参考另一篇博客，在这里我贴上链接：信号灯超时