UDP_Multicast.cpp

This is a simple example on how to do UDP multicast.

Output if any non-local network is available:

Your.local.ip.addr:47776 Welcome to our multicast group!
We got another message.

#include <UDPSocket.h>

#include <iostream>

static const char send_msg[] = "Welcome to our multicast group!";
static char recv_msg[sizeof(send_msg)];
static size_t len = sizeof(send_msg);

int main()
{
    try {

    NET::UDPSocket recv_socket;
    // listen on the given port and any address
    recv_socket.bind(47777);
    // receive data from our multicast group
    recv_socket.joinGroup("224.40.0.1");

    NET::UDPSocket send_socket;
    // don't route our packets
    send_socket.setMulticastTTL(0);
    // optional, the OS would select a sender port
    send_socket.bind(47776);


    int bytes;
    std::string source;
    unsigned short port = 0;

    // send data to a specific destination
    send_socket.sendTo( send_msg, len, "224.40.0.1", 47777);

    // receive data from with sender information
    bytes = recv_socket.receiveFrom( recv_msg, len, source, port);

    if(bytes > 0)
        std::cout << source << ":" << port << " " << recv_msg << std::endl;


    // set default address for sending
    send_socket.connect( "224.40.0.1", 47777);

    send_socket.send( send_msg, len);
    bytes = recv_socket.receive( recv_msg, len);

    if(bytes > 0)
        std::cout << "We got another message." << std::endl;

    // this is optional and just for demonstration
    recv_socket.leaveGroup("224.40.0.1");


    // if something fails, we get here
    } catch( const NET::SocketException& e)
    {
        std::cerr << e.what() << std::endl;
        return 1;
    }

    return 0;
}