Re: UI hangs while updating

[Jason Calhoun <jason thecolossal com>]

Hi,

Actually, the application is not multithreaded, at least not 
intentionally.  I've got the RFID code in a separate object, but that 
object is instantiated in the MainWindow thread.  However, when running 
the application through gdb, I noticed that it did spawn multiple 
threads.  Does gtkmm using multithreading under the hood?

I wasn't able to get much more information out of gdb.  With a 
breakpoint on g_log, the backtrace shows three steps through the gtk 
libraries and then gives the "corrupt stack?" message.

Thanks,
Jason

On 12/03/2015 12:43 AM, Andrew E. Makeev wrote:
> I suppose your application is multithreaded.
>
> RFID reader and GTK main loop should be runned in same thread. Otherwise
> you should use Glib::Dispatcher to deliver events (signals) from thread
> that read RFID tag to GTK thread (that update graphics).
>
> В Срд, 02/12/2015 в 14:52 -0700, Jason Calhoun пишет:
> > Hi,
> >
> > I'm developing an application using gtkmm-3.0, and running into a bug
> > with the UI I haven't been able to track down.  I've never used GTK or
> > gtkmm before, and haven't done any real development on linux either.
> >
> > The application uses a Phidgets RFID reader to read an RFID tag, and
> > display some information on a simple UI.  The problem is that the UI
> > seems to freeze at some point while handling events.  Once the UI is
> > hung, I can close the window, at which point I get the error at the
> > console "GLib-CRITICAL **: Source ID XXX was not found when attempting
> > to remove it".  This warning or error occurs only in cases when the UI
> > has hung.  However, even with the UI apparently hung, the application
> > continues to run, it can still read tags and output to the console, for
> > instance.  Also, I've noticed this problem only on the target platform,
> > which is a Raspberry Pi running the Ubuntu MATE distribution available
> > on raspberrypi.org.  I haven't been able to duplicate it on my desktop
> > machine, which is running slightly older versions of the glibmm and
> > gtkmm libraries.
> >
> > I use the event handlers defined by the Phidgets library to emit sigc
> > signals so I can handle those events in the application's main window.
> > In the signal handlers, there are a few simple calls to update the UI,
> > such as using the set_text method to update the text in a label, and
> > display or clear an image.  I use the built in timeout signal to display
> > a clock, and reset the display after a certain period of time.
> >
> > I'm not sure if the UI freeze is due to some error in my code, or due to
> > an error in the gtk/glib libraries somewhere.  I would appreciate any
> > help anyone can offer.  I can provide code samples and/or more details
> > as needed.
> >
> > Can anyone help?
> >
> >
> > Thanks,
> > Jason
> >
> >
> >
> >
> >
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