Threading Acts Differently on the Debugger

  • I'm new to threading and perhaps I didn't do it correctly but I'm seeing one kind of behavior on my desktop, and another kind of behavior on the embedded device (BeagleBone Black).

    My application has a singleton object called a Messenger, which communicates to a server through a tcp/ip pipe. I wanted to run this messenger in a separate thread so I did the following:
    (I typedef the Messenger singleton to Communicator and invoke it with an Instance method)

    typedef Singleton<Messenger> Communicator;

    In the interface,

    class MainWindow : public QMainWindow
        QThread messengerThread;
    ... more code

    and then in the constructor,


    In the main window, I present a progress bar for feedback while the app sets up the main window buttons, labels, etc. I want that progress bar to be shown while the Messenger sends and receives messages from the server.

        dss = new DialogStartupScreen(this);
        dss->incrementProgressBar("Please wait, connecting...");

    The call to processEvents() is meant to make sure the progress bar is displayed.
    This works fine on the debugger running on my desktop, however when I run on the embedded device, I still see all the items getting populated, watching the names getting assigned to buttons, etc. and I don't see the progress bar screen.

    On the debugger as soon as I execute processEvents, I see the proper startup screen.
    While I'm running on the debugger, I have the connection to the same server. The only difference is that I'm running on the desktop instead of the embedded device.

    There is something I don't understand about why it behaves differently on the BeagleBone.

    Any thoughts that might point me in the right direction? Many Thanks!

  • Moderators

    @mstoth said in Threading Acts Differently on the Debugger:

    dss = new DialogStartupScreen(this);

    I guess you do this after ui->setupUI(this)?
    Create and show this dialog as an independent window before calling ui->setupUI(this).

  • Thanks! That caused the screen to display, but then it goes away again and I get to see my buttons and labels constructed even though it initially shows up. I must be doing something that puts the main window on top again. I will continue to investigate but it looks like you got me headed on the right track!

Log in to reply

Looks like your connection to Qt Forum was lost, please wait while we try to reconnect.