How to send a packet via a UDP CFSocket?

Question

I am a complete newbie to networking, however I am a c/c++ programmer, and am working in objective-c (This is for OSX/iPhone).

I am trying to learn how to send a mag

Answer 1

This is my first working bit of code for two whole nights! Hopefully will help someone else! Thought I should share it, might save someone a bit of hassle.

I disabled the listen call, as I only wanted to send data.

+ (void)broadCast
{
    int socketSD = socket(PF_INET, SOCK_DGRAM, IPPROTO_UDP);
    if (socketSD <= 0) {
        NSLog(@"Error: Could not open socket.");
        return;
    }

    // set socket options enable broadcast
    int broadcastEnable = 1;
    int ret = setsockopt(socketSD, SOL_SOCKET, SO_BROADCAST, &broadcastEnable, sizeof(broadcastEnable));
    if (ret) {
        NSLog(@"Error: Could not open set socket to broadcast mode");
        close(socketSD);
        return;
    }

    // Configure the port and ip we want to send to
    struct sockaddr_in broadcastAddr;
    memset(&broadcastAddr, 0, sizeof(broadcastAddr));
    broadcastAddr.sin_family = AF_INET;
    inet_pton(AF_INET, "255.255.255.255", &broadcastAddr.sin_addr);
    broadcastAddr.sin_port = htons(33333);

    char *request = "message from ios by c";
    ret = sendto(socketSD, request, strlen(request), 0, (struct sockaddr*)&broadcastAddr, sizeof(broadcastAddr));
    if (ret < 0) {
        NSLog(@"Error: Could not open send broadcast.");
        close(socketSD);
        return;
    }

    close(socketSD);

    dispatch_async(dispatch_get_global_queue(0, 0), ^{
        //[self listenForPackets];
    });

}