From help-octave-request at bevo dot che dot wisc dot edu  Wed Jan 27 02:36:05 1999
Subject: Re: tmp file problem +gnuplot
From: "John W. Eaton" <jwe at bevo dot che dot wisc dot edu>
To: Daniel Heiserer <Daniel dot Heiserer at bmw dot de>
Cc: "help-octave at bevo dot che dot wisc dot edu" <help-octave@bevo.che.wisc.edu>
Date: Wed, 27 Jan 1999 02:35:41 -0600 (CST)

On 27-Jan-1999, Daniel Heiserer <Daniel dot Heiserer at bmw dot de> wrote:

| John W. Eaton wrote:
| > 
| > On 26-Jan-1999, David Nicholson <David dot Nicholson at src dot bae dot co dot uk> wrote:
| > 
| > The reason Octave can't delete the files automatically is that it
| > cannot know when gnuplot is finished with them.
| 
| Well octave doesn't know, but gnuplot should know. Using gnuplots '!'
| they could be deleted or?

If you mean gnuplot's shell escape feature, I'm not sure how that
helps.  The problem is that if you type

  plot (x, y)
  purge_tmp_files
  replot

The replot fails because Octave doesn't recreate the data files on a
replot command, it just sends a replot command to gnuplot, which then
tries to access the data files again.  Since gnuplot closes and then
tries to reopen the files, it fails.

The fix for this problem is to use gnuplot's ability to handle data
and commands in the same input stream.  It just hasn't been done yet.
The reason Octave did not use this feature from the beginning is that
it did not exist in gnuplot until some 3.6beta release.

| What will be the new gnuplot's benefit for octave?

I'd guess that gnuplot 3.7 is a lot like the recent 3.6beta releases.

jwe