Re: Once more: Qt Terminal (no output)

[Philipp K. J. <ja...@ie...>]

On Sun, 15 Jun 2014 20:41:22 -0700
sfeam <sf...@us...> wrote:

I wanted to re-raise this issue: when using the
Qt terminal, I simply don't get a plot window, 
using my preferred window mgr.

set t qt
plot sin(x)

does "nothing" - control returns to the gnuplot
command, but no window appears.

I finally got around to trying it out with a
different window manager (Mate - which is the
default for my distro, which is Mint), and now
everything works just fine.

So, the problem is apparently somewhere between
gnuplot, qt, and iceWM (and possibly my iceWM 
configurations!).

How does one make progress on something like this? ;-)


> On Sunday, 15 June 2014 06:36:18 PM you wrote:
> > On Sun, 15 Jun 2014 18:22:17 -0700
> > sfeam <sf...@us...> wrote:
> > 
> > > On Sunday, 15 June 2014 06:18:50 PM Philipp K. Janert wrote:
> > > > On Sun, 15 Jun 2014 16:55:26 -0700
> > > > Ethan Merritt <merritt@u.washington.edu> wrote:
> > > > 
> > > > > On Sunday, 15 June 2014 04:47:14 PM Philipp K. Janert wrote:
> > > > > > 
> > > > > > I can now build and run gnuplot5 rc1 with Qt,
> > > > > > but when I try to use the qt terminal, I do
> > > > > > not get an output window. I also do not seem
> > > > > > to get an error message - just nothing happens.
> > > > > > 
> > > > > > I have no problem using either wxt or x11.
> > > > > > 
> > > > > > Is this known behavior?
> > > > > 
> > > > > Nope.
> > > > > 
> > > > > If you run "top" or "ps" in another terminal do you see
> > > > > gnuplot_qt? Do you see any evidence of font-config or some
> > > > > other system utility eating up time?
> > > > 
> > > > Both gnuplot and gnuplot_qt are running
> > > > (according to ps), but neither is consuming
> > > > significant resources (according to top).
> > > > 
> > > > My window manager is iceWM (for what it's
> > > > worth).
> > > > 
> > > > The gnuplot "output" is sent to "STDOUT".
> > > > 
> > > > "show terminal" says:
> > > > 	terminal type is qt 0 font "Sans,9"
> > > > 
> > > > Anything I should try to get more info?
> > > 
> > > 
> > > use ps to gid the pid of gnuplot_qt.
> > > Let's say it's 12345.
> > > 
> > > gdb -p 12345
> > > gdb> where
> > > 
> > 
> > gdb required me to be root to attach to process.
> 
> Really?  That is very strange.
> When you see the gnuplot_qt process in ps or top, 
> does it belong to you or does it belong to root?
> (the process itself, not the file).
> If it belongs to root then I think that might
> actually be the problem, although I don't know
> how it would get into that state.
> 
> Conversely, I suppose you could try running the program
> as root to see if the same problem occurs.
> 
> > The output is below:
> > 
> > (skipping many lines)
> > 
> > Reading symbols
> > from /usr/lib/x86_64-linux-gnu/qt5/plugins/imageformats/libqsvg.so...(no
> > debugging symbols found)...done. Loaded symbols
> > for /usr/lib/x86_64-linux-gnu/qt5/plugins/imageformats/libqsvg.so
> > 0x00007faf6f701f7d in poll () from /lib/x86_64-linux-gnu/libc.so.6
> > 
> > (gdb) where #0  0x00007faf6f701f7d in poll ()
> > from /lib/x86_64-linux-gnu/libc.so.6 #1  0x00007faf6ecd46a4 in ?? ()
> > from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #2  0x00007faf6ecd47ac
> > in g_main_context_iteration ()
> > from /lib/x86_64-linux-gnu/libglib-2.0.so.0 #3  0x00007faf70443b0c
> > in
> > QEventDispatcherGlib::processEvents(QFlags<QEventLoop::ProcessEventsFlag>)
> > () from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #4
> > 0x00007faf703fdb6b in
> > QEventLoop::exec(QFlags<QEventLoop::ProcessEventsFlag>) ()
> > from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #5
> > 0x00007faf70403301 in QCoreApplication::exec() ()
> > from /usr/lib/x86_64-linux-gnu/libQt5Core.so.5 #6
> > 0x000000000040d4be in main (argc=1, argv=<optimized out>) at
> > qtterminal/gnuplot_qt.cpp:78
> 
> Bah. That tells me nothing useful.
> It got stuck too deep in the qt library code for me to pin it down to
> anything particular that gnuplot did.
> 
> I don't think I'm going to be able to help much.
> I've never seen anything like this when using Qt with gnuplot
> or any other program for that matter.  Is there a Mint help forum
> you could ask in?
> 
> 	Ethan
>