Problem using Connect(), send(), recv, with UDP sockets

Question

For my Uni assignment I have to create a fast action paced networked game and so have chosen to use UDP as opposed to TCP. I am aware of a lot of the differences in programming both UDP and TCP and have read through most of the relevant parts of MSDN's documentation on winsock. On MSDN it states that creating a UDP socket via the connect() function should bind the socket to the address and port specified and as a result be able use the send() and recv() functions with the created socket.

For my application I create a client and use connect() using the loopback address which sends a number of packets via the send() function. The client, after calling select(), then receives the packets it sent out. However the result I get from the recv() function is SOCKET_ERROR and the error description using WSAGetLastError() is "An existing connection was forcibly closed by the remote host".

If i use the bind() function and use sendto() to send data over the loopback address, I recv() packets without any errors... Does anyone know why the connect() function is not doing what it is supposed to do, and has anyone been able to use UDP sockets with the connect() function?

Answer 1

You will need to call bind() if you want your program to receive UDP packets. connect() only sets the address that the socket will send packets to if you call send(); it does not associate the socket with a local UDP port to receive on; for that you must call bind().