C / C++ / MFC

Todd Smith

// ----------------------------------------------------------------------------
// udp_recv_setup()
//
// This function sets the server socket.  It lets the system determine the port 
// number.  The function returns the server socket number.
// ----------------------------------------------------------------------------
//
int udp_recv_setup()
{
	struct sockaddr_in local;			// socket address for local side 
	int nLocalAddrLen = sizeof(local);	// length of local address
	int nServerSocket = 0;

	//
	// Create the socket.
	//
	nServerSocket = socket(AF_INET, SOCK_DGRAM, 0);

	if ( nServerSocket < 0)
    {
		cout << "%error opening datagram socket \n" ;
		exit(1);
    }

	//
	// Bind the socket to a port, let the system decide the number.
	//
	local.sin_family		= AF_INET;		// Internet family
	local.sin_addr.s_addr	= INADDR_ANY;	// Wild card machine address  (defaults to local)
	local.sin_port			= 0;			// Let system choose the port 

	bind(nServerSocket, (struct sockaddr *) &local,sizeof(local));	//bind the name (address) to a port

	//
	// Get the port name and print it out.
	//
	getsockname( nServerSocket, (struct sockaddr *) &local, &nLocalAddrLen);		
	cout << "socket has port " << local.sin_port << endl;

	return  nServerSocket;
}

-Masaaki Onishi-