How to know if there are data?

[Patrice Neff]

I just tried to write my first tiny example using CC++ sockets.

Setting up the server and accepting new connections works fine.

But I have problems getting the data of clients, because I don't know how to detect if there are new data.

This is my current code:

_tcpstream is an object of type tcpstream.

  string input;
 
  while(_tcpstream.isPending( SOCKET_PENDING_INPUT, 20 ))
    {
      if(_tcpstream.eof()) {
    cout << "End of file detected" << endl << flush;
    break;
      } else {
    _tcpstream >> input;
    _tcpstream << "user entered " << input << endl;
    cout << "user entered " << input << endl;
      }
    }

The isPending() call always returns true after the client first sent some data. eof() is false. So the code goes to the call of

    _tcpstream >> input;

Which blocks until there is new data.

Can you help me? How do I detect there is really new data?