Re: ***[Possible UCE]*** Re: GUI doesn't appear when using ./run-octave

[Daniel J Sebald]

On 09/16/2012 04:07 AM, Philip Nienhuis wrote:
> marco atzeri-2 wrote
> > On 9/16/2012 1:05 AM, Philip Nienhuis wrote:
> > > The last days . /run-octave (with or without --force-gui) doesn't start
> > > the
> > > GUI but simply returns to the prompt..
> > > octave --no-gui   starts up the good old CLI.
> > > Just to be sure I wiped all source and build dirs and started anew with a
> > > fresh clone, with the same result.
> > >
> > > Where can I start searching for the cause?
> > >
> > > Linux Mageia 2, gcc 4.6.3, Pentium-M
> > >
> > > Philip
> >
> > eventually, same root cause of
> > https://savannah.gnu.org/bugs/?37359
> >
> > Now the error message at start is:
> >
> > QCoreApplication::sendPostedEvents: Cannot send posted events for
> > objects in another thread
> >
> > and the GUI frozes and is not anymore usable.
> > Kill -9 is needed to close the program.
>
> At least you do get error messages.
>
> On my (linux) box simply nothing happens (apart from a little spike in the
> CPU applet on some desktop panel) and nothing seems broken. It just won't
> work - kill -9 isn't even needed.
>
> The error message in your case seems related to one I posted a while ago
> "QObject::startTimer: timers cannot be started from another thread" (2X)
> here:
>
> https://mailman.cae.wisc.edu/pipermail/octave-maintainers/2012-August/029811.html
> (which in my case didn't hang the GUI - I just had to click in the terminal
> to get focus there, and then hit<Enter>)
>
> Maybe a red herring, but do you have  win32/moc-QWinTerminalImpl.cc   or
> unix/moc-QUnixTerminalImpl.cc
> in<BUILDDIR>/libgui/ libqterminal ?

I don't think it is a red herring.  I've been searching around for a bug 
in which the GUIDE+O won't appear when the editor tab files are present 
in the configuration file, i.e., "savedSessionTabs=/home/sebald...". 
But I've isolated the problem to the QTerminal.  That is, I put some 
fprintf's around the instruction that is failing:

  // Octave Terminal subwindow.
fprintf(stderr,"construct: before QTerminal\n");
  _terminal = new QTerminal (this);
fprintf(stderr,"construct: after QTerminal\n");

All along I've noticed that the terminal doesn't work properly either. 
Text will appear but if switching between Qt windows, the text will 
stop, unless I move the position bar up and down back to the command 
line.  Then text will appear.

That's where I am right now, and I will resume searching for the bug 
tomorrow.

Dan