MAVLink UDP C example

[Ryan Edmonds]

Hello all, I have a question about the MAVLink UDP C Example. I have been following the instructions from the official mavlink documentation. There seems to be some sort of conflict over udp ports between the mavlink_udp executable and the QGroundControl. When I launch the mavlink_udp first and then QGroundControl I get this error:



When I try the opposite launch order I get this error from the mavlink_udp example:

Any help or suggestion would be greatly appreciated! Thanks so much!

[Ryan Edmonds]

Update: I configured the UDP connection in QGroundControl and I think they are atleast communicating now.

In the mavlink help docs it says the following for step 6.)


Inspecting the example C code, this does not exist in the C code. It only prints:

void handle_heartbeat(const mavlink_message_t* message)
{
    mavlink_heartbeat_t heartbeat;
    mavlink_msg_heartbeat_decode(message, &heartbeat);

    printf("Got heartbeat from ");
    switch (heartbeat.autopilot) {
        case MAV_AUTOPILOT_GENERIC:
            printf("generic");
            break;
        case MAV_AUTOPILOT_ARDUPILOTMEGA:
            printf("ArduPilot");
            break;
        case MAV_AUTOPILOT_PX4:
            printf("PX4");
            break;
        default:
            printf("other");
            break;
    }
    printf(" autopilot\n");
}

from the terminal where the c example is running, I only see this:


Am I missing something, or is this a newer example than what is in the help docs?

[Hamish Willee]

The example doesn't even build for me. I've made some modifications but I don't know if they are OK

The fact that you got a heartbeat is a good sign. I did not know the reason for the errors, but have created an issue for tracking:   https://github.com/mavlink/mavlink/issues/2332

[Hamish Willee]

OK, the example is fixed up, and so is the documentation - you can see how to run it now in https://github.com/mavlink/mavlink-devguide/pull/623 - that should go live soon.

This now builds properly via cmake, which is a bit easier. 

The connection works. I was having problems because I was trying to connect to QGC. This connects to an autopilot - if you connect to QGC you end up being in conflict for the port, because both QGC and the example bind to the port to listen to it.