Re: Print plot error

[Ben Abbott]

On Aug 23, 2009, at 1:40 PM, Rob Mahurin wrote:

> On Aug 22, 2009, at 6:29 PM, Dmitri A. Sergatskov wrote:
> > On Sat, Aug 22, 2009 at 4:32 PM, Ben Abbott<address@hidden> wrote:
> > > I'm not sure I see the same thing ...
> > >
> > > plot(1:10)
> > > for n = 1:25
> > > > print -dpdf test.pdf
> > > > system ('ps axu | grep gnuplot | wc -l');
> > > > end
> > > 6
> > > 5
> > > 6
> > > 6
> > > 6
> >
> >
> > I think ps tranketes long output lines.
> > Try
> >
> > system ('ps axwww | grep gnuplot | wc -l');
>
> I can confirm this on both Linux and OS X 10.4.  Every Octave  
> command like
>
>         octave> print /tmp/out.pdf
>
> adds one more defunct process to
>
>         shell$ ps x -o pid,ppid,stat,command |
>                 awk '$3 ~ /Z/ {print}'
>
> I think the solution is an occasional waitpid(-1,0,WNOHANG), but I'm  
> not sure where in the code this goes.
>
> Rob

I'm running Mac OSX 10.5.8, and when I try ...

contour (peaks)
print test.pdf
contour (peaks)
print test.pdf
contour (peaks)
print test.pdf
contour (peaks)
print test.pdf
...

... and try Rob's command after each print, I see

$ ps x -o pid,ppid,stat,command | awk '$3 ~ /Z/ {print}'
 1660  1657 Z+   (gnuplot_x11)
 1661  1657 Z+   (gnuplot_x11)
 1890  1437 Z+   (sh)
$ ps x -o pid,ppid,stat,command | awk '$3 ~ /Z/ {print}'
 1969    57 Z    (SFLSharedPrefsTo)
 1660  1657 Z+   (gnuplot_x11)
 1661  1657 Z+   (gnuplot_x11)
 1890  1437 Z+   (sh)
 1967  1437 Z+   (sh)
$ ps x -o pid,ppid,stat,command | awk '$3 ~ /Z/ {print}'
 1660  1657 Z+   (gnuplot_x11)
 1661  1657 Z+   (gnuplot_x11)
 1890  1437 Z+   (sh)
 1967  1437 Z+   (sh)
 1974  1437 Z+   (sh)
$ ps x -o pid,ppid,stat,command | awk '$3 ~ /Z/ {print}'
 1660  1657 Z+   (gnuplot_x11)
 1661  1657 Z+   (gnuplot_x11)
 1890  1437 Z+   (sh)
 1967  1437 Z+   (sh)
 1974  1437 Z+   (sh)
 1980  1437 Z+   (sh)
$ ps x -o pid,ppid,stat,command | awk '$3 ~ /Z/ {print}'
 1660  1657 Z+   (gnuplot_x11)
 1661  1657 Z+   (gnuplot_x11)
 1890  1437 Z+   (sh)
 1967  1437 Z+   (sh)
 1974  1437 Z+   (sh)
 1980  1437 Z+   (sh)
 1987  1437 Z+   (sh)
$ ps x -o pid,ppid,stat,command | awk '$3 ~ /Z/ {print}'
 1660  1657 Z+   (gnuplot_x11)
 1661  1657 Z+   (gnuplot_x11)
 1890  1437 Z+   (sh)
 1967  1437 Z+   (sh)
 1974  1437 Z+   (sh)
 1980  1437 Z+   (sh)
 1987  1437 Z+   (sh)
 1994  1437 Z+   (sh)

The growing list of shells each have octave as their parent.

$ ps x -o pid,ppid,stat,command

 1437  1436 S+   /Users/bpabbott/Development/mercurial/octave-3.2/src/ 
octave --no-init-path --path=
 1656  1437 S+   /bin/sh /sw/bin/gnuplot
 1657  1656 S+   /sw/bin/gnuplotx
 1660  1657 Z+   (gnuplot_x11)
 1661  1657 Z+   (gnuplot_x11)
 1883  1657 S+   gnuplot_x11
 1890  1437 Z+   (sh)
 1967  1437 Z+   (sh)
 1974  1437 Z+   (sh)
 1980  1437 Z+   (sh)
 1987  1437 Z+   (sh)
 1994  1437 Z+   (sh)

So Mac OSX 10.5.8 does have the same problem.

It appears that when a bidirectional pipe is opened (via popen2()),  
pclose() is not doing all that is needed to close the pipes.

Ben