CODEWITHSUNDEEP
cwindowssocketsasynchronousudp
Ayse
Ayse

Reputation: 2754

Making udp socket non-blocking

I had been working on non-blocking udp socket. The code that I had developed generates a Window Message whenever there is any data to be read over the socket. Below is the code snippet:

void createSocket(HWND hwnd)
{
   ///Socket Binding///
   WSADATA wsa; 
   ///Initialise winsock///
   if (WSAStartup(MAKEWORD(2,2),&wsa) != 0)
      {
         exit(EXIT_FAILURE);
      }

   ///Create a socket///
   if((socketIdentifier = socket(AF_INET , SOCK_DGRAM , 0 )) == INVALID_SOCKET)
      {                 
         //Socket Creation Failed
      }
   ///Socket Created///

   ///Prepare the sockaddr_in structure///
   serverSocket.sin_family = AF_INET;
   serverSocket.sin_addr.s_addr = INADDR_ANY;
   serverSocket.sin_port = htons( PORT );

   ///Bind///
   if( bind(socketIdentifier ,(struct sockaddr *)&serverSocket , sizeof(serverSocket)) == SOCKET_ERROR)
      {     
         //Bind Failed      
      }

    WSAAsyncSelect (socketIdentifier, hwnd, MY_MESSAGE_NOTIFICATION, FD_READ | FD_CONNECT | FD_CLOSE | FD_ACCEPT); //Set
   ///Bind Done///

}

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam);    
int WINAPI WinMain(  HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd 
{
   //Window Created
   createSocket() //Socket Created
   while(GetMessage(&Msg, NULL, 0, 0) > 0)  //Check on Window Messages
      {         
         TranslateMessage(&Msg);
         DispatchMessage(&Msg);
      }
   return Msg.wParam;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
   switch(msg)
   {
    case MY_MESSAGE_NOTIFICATION: //Is a message being sent?
        {
      switch (lParam) //If so, which one is it?
            {
            case FD_ACCEPT:
                //Connection request was made
                break;

            case FD_CONNECT:
                //Connection was made successfully
                break;

            case FD_READ:
               receiveAtSocket();
            break;

            case FD_CLOSE:
                //Lost the connection
             break;
            }
        }
        break;
   }
}

This code is working fine, and socket does not have to wait in call to snedto() or recvfrom(). Instead, A window Message is generated whenever data is ready to be read or written on the socket.

Now, I want to find out some other way of informing that data data is ready rather than a window message. i.e. I don't want any window message to be generated whenever there is data to be read or written on the socket.

Is there any other way of implementing the above mentioned functionality without using Window Messages> Please help me.

Waiting for help :(

Upvotes: 0

Views: 3440

Answers (1)

John Zwinck
John Zwinck

Reputation: 249133

Another way would be to use WaitForSingleObject or WaitForMultipleObjects or their brethren. You can see some code doing that here: Asynchronous winsock server wrapper, CPU lagging - C++

Upvotes: 1

Related Questions