C++ Named Pipes over network invalid name error

Question

I am trying to send messages via named pipes between two Windows pc´s. When calling CreateNamedPipe locally everything works fine. If I change the hostname from "\\\\.\\pipe\\testpipename" to "\\\\myHostname\\pipe\\testpipename" I get an ERROR_INVALID_NAME(123) from getLastError().

This is my code:

    BOOL   fConnected = FALSE;
    DWORD  dwThreadId = 0;
    HANDLE hPipe = INVALID_HANDLE_VALUE, hThread = NULL;
    LPTSTR pipeName = /*nullptr*/ TEXT("\\\\myHostname\\pipe\\testpipename");

    SECURITY_ATTRIBUTES sa = { 0 };
    SECURITY_DESCRIPTOR sd = { 0 };

    InitializeSecurityDescriptor(&sd, SECURITY_DESCRIPTOR_REVISION);

    SetSecurityDescriptorDacl(&sd, TRUE, NULL, FALSE);

    sa.bInheritHandle = false;
    sa.lpSecurityDescriptor = &sd;
    sa.nLength = sizeof(sa);

    hPipe = CreateNamedPipe(
    pipeName,                 // pipe name  
    PIPE_ACCESS_DUPLEX,       // read/write access 
    PIPE_TYPE_MESSAGE |       // message type pipe 
    PIPE_READMODE_MESSAGE |   // message-read mode 
    PIPE_WAIT,                // blocking mode 
    PIPE_UNLIMITED_INSTANCES, // max. instances  
    255,                      // output buffer size 
    255,                      // input buffer size 
    0,                        // client time-out 
    &sa);                     // default security attribute 

    if (hPipe == INVALID_HANDLE_VALUE)
    {
        cout << GetLastError();
        return -2;
    }

    cout << "Waiting for client to connect!" << endl;

    //waiting for client to connect
    fConnected = ConnectNamedPipe(hPipe, NULL) ?
        TRUE : (GetLastError() == ERROR_PIPE_CONNECTED);

    cout << "Client connected! YEAH" << endl;

My guess is that the pipename is invalid but I don´t know why. Any Ideas?

Answer 1

Problem solved! Pipenames for Server and Client are:

Server: "\\\\.\\pipe\\testpipe"
Client: "\\\\serverHostName\\pipe\\testpipe"

Some minor changes at the client were also made. Full code can be found at my Github repo.