C# - System.Net Socket.Listen Backlog

Question

Ok, I have connected to an IP address using the following code:

        IPAddress myIpAddress = IPAddress.Parse("10.10.15.200");

        IPEndPoint ip = new IPEndPoint(myIpAddress, 5001);
        Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
        socket.Connect(ip);

I now want to listen to the socket. When I type socket.Listen, intellisense says I need to enter a backlog number, what does this mean?

Also, once I am listening to the socket, how do I capture the content of what I am 'listening' to.

Thanks

John

Answer 1

you can use BeginAccept to read what arrived to your socket/endpoint.

there is a full example on MSDN, here: Socket.BeginAccept Method

// This server waits for a connection and then uses asynchronous operations to
    // accept the connection with initial data sent from the client.


    // Establish the local endpoint for the socket.

    IPHostEntry ipHostInfo = Dns.GetHostEntry(Dns.GetHostName());
    IPAddress ipAddress = ipHostInfo.AddressList[0];
    IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 11000);

    // Create a TCP/IP socket.
    Socket listener = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp );

    // Bind the socket to the local endpoint, and listen for incoming connections.
    listener.Bind(localEndPoint);
    listener.Listen(100);

    while (true) 
    {
        // Set the event to nonsignaled state.
        allDone.Reset();

        // Start an asynchronous socket to listen for connections and receive data from the client.
        Console.WriteLine("Waiting for a connection...");

        // Accept the connection and receive the first 10 bytes of data.
        int receivedDataSize = 10;
        listener.BeginAccept(receivedDataSize, new AsyncCallback(AcceptReceiveCallback), listener);

        // Wait until a connection is made and processed before continuing.
        allDone.WaitOne();
    }

}


public static void AcceptReceiveCallback(IAsyncResult ar) 
{
    // Get the socket that handles the client request.
    Socket listener = (Socket) ar.AsyncState;

    // End the operation and display the received data on the console.
    byte[] Buffer;
    int bytesTransferred;
    Socket handler = listener.EndAccept(out Buffer, out bytesTransferred, ar);
    string stringTransferred = Encoding.ASCII.GetString(Buffer, 0, bytesTransferred);

    Console.WriteLine(stringTransferred);
    Console.WriteLine("Size of data transferred is {0}", bytesTransferred);

    // Create the state object for the asynchronous receive.
    StateObject state = new StateObject();
    state.workSocket = handler;
    handler.BeginReceive( state.buffer, 0, StateObject.BufferSize, 0,
    new AsyncCallback(ReadCallback), state);
}