Re: gnuplot and DISPLAY

[Ethan A M. <merritt@u.washington.edu>]

On Thursday 08 March 2007 19:51, Daniel J Sebald wrote:
> Ethan A Merritt wrote:
> > On Thursday 08 March 2007 19:32, Daniel J Sebald wrote:
> > 
> >>Recall there was a bit of a discussion about the x11 terminal 
> >>looking for the location of gnuplot_x11 at start up, i.e., 
> >>part of x11's initialization but since x11 is the default terminal
> > 
> > Yes, but this patch was supposed to fix it:
> > 
> > 2006-11-05 
> 
> That rings a bell...  That was only a few months ago?

Right. It wasn't found/reported/whatever until Nov 06 in the
main cvs branch.  We had already frozen the code for 4.2
at that point.  I don't specifically recall making a decision,
but I guess my feeling was that something that went unnoticed
or at least un-complained-about during 3 years of development
was not a release-critical bug.  Especially since there are
obvious work-arounds if needed.  

Plus, it's the sort of "fix" that could easily break as many
corner cases as it fixes. Even now that the fix has been in 
CVS for 3 months, I wouldn't bet a large amount that it hasn't
broken some corner case that nobody has noticed/reported yet.

The thing is, I still don't quite understand why Allin is
seeing this problem.  The original bug report was due
to incomplete installation;  gnuplot was built to default to
X11, but the X11 driver (gnuplot_x11) had not actually been
installed.  The problem arose because gnulot tried to open a
pipe to gnuplot_x11, but gnuplot_x11 wasn't there. This
is a different case entirely.

Allin:  I don't understand why you see this failure mode.
The strace output you posted showed that it *did* find gnuplot_x11,
but gnuplot_x11 couldn't open DISPLAY.
That's annoyng, but it shouldn't be a fatal error for gnuplot
proper. If I test it deliberately, I get this:

bash-3.1$ DISPLAY=junk:0
bash-3.1$ gnuplot_4.2

        G N U P L O T
        Version 4.2 patchlevel 0
        last modified March 2007
        System: Linux 2.6.12-24mdksmp

        Copyright (C) 1986 - 1993, 1998, 2004, 2007
        Thomas Williams, Colin Kelley and many others

        Type `help` to access the on-line reference manual.
        The gnuplot FAQ is available from
                http://www.gnuplot.info/faq/

        Send comments and help requests to  <gnu...@li...>
        Send bug reports and suggestions to <gnu...@li...>


Terminal type set to 'wxt'
gnuplot> set term x11
Terminal type set to 'x11'
Options are '0'
gnuplot> _X11TransSocketINETConnect() can't get address for junk:6000: Name or service not known

gnuplot: unable to open display 'junk:0'
gnuplot: X11 aborted.

gnuplot> set term png
Terminal type set to 'png'
Options are 'nocrop font verdana 12 '
     

So yes, a bad DISPLAY setting causes gnuplot_x11 to exit.
But the gnuplot session proper is still active and responsive.
So I still can't reproduce Allin's exact problem. 

-- 
Ethan A Merritt
Biomolecular Structure Center
University of Washington, Seattle 98195-7742