C++ 使用 Windows 命名管道

C++ Using windows named pipes

提问by Fire Lancer

For some reason both the mast and slave fail, however I could find any good examples on how their meant to work, so im not sure where I went wrong.

由于某种原因，桅杆和奴隶都失败了，但是我可以找到任何关于它们如何工作的好例子，所以我不确定我哪里出错了。

The master never exits the WaitForSingleObject after ConnectNamedPipe, and the slave throws an exception in the first boost::asio::read call, "Waiting for a process to open the other end of the pipe", which I though the WaitNamedPipe was meant to wait for along with the ConnectNamedPipe in the master?

在 ConnectNamedPipe 之后，master 永远不会退出 WaitForSingleObject，而 slave 在第一个 boost::asio::read 调用中抛出异常，“等待进程打开管道的另一端”，我认为 WaitNamedPipe 是为了等待与主中的 ConnectNamedPipe 一起？

master.cpp

主程序

asio::io_service ioservice; 
asio::windows::stream_handle in(ioservice); 
int main()
{
    HANDLE pipe = INVALID_HANDLE_VALUE;
    try
    {
        //create pipe
        pipe = CreateNamedPipe("\\.\pipe\FLTest",
            PIPE_ACCESS_DUPLEX | FILE_FLAG_FIRST_PIPE_INSTANCE | FILE_FLAG_OVERLAPPED,
            PIPE_TYPE_BYTE | PIPE_READMODE_BYTE,
            255, 50000,50000, 0, 0);
        if(pipe == INVALID_HANDLE_VALUE)
        {
            printWinError();
            return -1;
        }
        in.assign(pipe); 
        std::cout << "Created pipe" << std::endl;
        //spawn child
        STARTUPINFO         startInfo;
        ZeroMemory(&startInfo, sizeof(STARTUPINFO));
        startInfo.cb = sizeof(STARTUPINFO);
        PROCESS_INFORMATION procInfo;
        ZeroMemory(&procInfo, sizeof(PROCESS_INFORMATION));
        if(CreateProcess(0, "slave.exe", 0,0, FALSE, CREATE_NEW_CONSOLE,
            0, 0, &startInfo, &procInfo))
        {
            std::cout << "Slave process created" << std::endl;
        }
        else
        {
            printWinError();
            DisconnectNamedPipe(pipe);
            return -1;
        }

        OVERLAPPED overlapped = {0};
        overlapped.hEvent = CreateEvent(0,TRUE,FALSE,0);
        if(ConnectNamedPipe(pipe, &overlapped) == FALSE)
        {
            unsigned error = GetLastError();
            if(error != ERROR_PIPE_CONNECTED &&
                error != ERROR_IO_PENDING)
            {
                printWinError();
                DisconnectNamedPipe(pipe);
                return -1;
            }
        }
        WaitForSingleObject(overlapped.hEvent, INFINITE);
        CloseHandle(overlapped.hEvent);
        std::cout << "Pipe connected" << std::endl;

        for(int i = 0; i < 100; ++i)
        {
            boost::system::error_code error;
            unsigned n = i * 5;
            asio::write(in,asio::buffer((char*)&n, sizeof(unsigned)),
                asio::transfer_all(), error);
            if(error)throw boost::system::system_error(error);
        }
        std::cout << "Sent data" << std::endl;

        FlushFileBuffers(pipe);
        DisconnectNamedPipe(pipe);
        system("pause");
        return 0;
    }
    catch(const std::exception &e)
    {
        std::cout << e.what() << std::endl;
        if(pipe != INVALID_HANDLE_VALUE)
            DisconnectNamedPipe(pipe);
        system("pause");
        return -1;
    }
}

slave.cpp

奴隶.cpp

asio::io_service ioservice; 
asio::windows::stream_handle in(ioservice); 
int main()
{
    try
    {
        WaitNamedPipe("\\.\pipe\FLTest", NMPWAIT_WAIT_FOREVER);

        std::cout << "Pipe avaible" << std::endl;
        HANDLE pipe = CreateNamedPipe("\\.\pipe\FLTest",
            PIPE_ACCESS_DUPLEX | FILE_FLAG_OVERLAPPED,
            PIPE_TYPE_BYTE | PIPE_READMODE_BYTE,
            255, 50000,50000,0,0);
        if(pipe == INVALID_HANDLE_VALUE)
        {
            printWinError();
            return -1;
        }

        in.assign(pipe); 
        std::cout << "Pipe connected" << std::endl;

        for(int i = 0; i < 100; ++i)
        {
            std::cout << "i: " << i << std::endl;
            boost::system::error_code error;
            unsigned n;
            asio::read(in,asio::buffer((char*)&n,sizeof(unsigned)),
                asio::transfer_all(), error);
            if(error)throw boost::system::system_error(error);
        }
        system("pause");
        return 0;
    }
    catch(const std::exception &e)
    {
        std::cout << e.what() << std::endl;
        system("pause");
        return -1;
    }
}

Obviously ive got something completely wrong, however I couldn't find anything on the net to compare my code with.

显然我完全错了，但是我在网上找不到任何东西来比较我的代码。

回答by sylvanaar

In your slave you need to call CreateFile() to open the pipe, not CreateNamedPipe.

在您的从属设备中，您需要调用 CreateFile() 来打开管道，而不是 CreateNamedPipe。

   HANDLE pipe = CreateFile("\\.\pipe\FLTest",                 
      GENERIC_READ | GENERIC_WRITE,            
      0,                                          
      NULL,                                       
      OPEN_EXISTING,                              
      FILE_FLAG_OVERLAPPED,                     
      NULL
      );    

回答by steve

You need to specify the mode of the pipe in the server part as PIPE_WAIT

您需要在服务器部分指定管道的模式为 PIPE_WAIT