Re: '__gnuplot_has_feature__' undefined

[John W. Eaton]

On 09/01/2016 06:28 PM, Dmitri A. Sergatskov wrote:
>  HG ID for this build is "e5ae26e50374"
>
> octave> gnuplot_binary("/usr/bin/gnuplot")
> error: '__gnuplot_has_feature__' undefined near line 49 column 5
> error: called from
>     gnuplot_binary at line 49 column 5

Are you running Octave in the build tree with the run-octave script? 
And is your build tree separate from your source tree?

This problem happens after

  changeset:   22682:08aa03dfb00e
  user:        Rik <address@hidden>
  date:        Thu Sep 01 13:22:03 2016 -0700
  summary:     Allow switching gnuplot_binary value during a session.

because the gnuplot_binary.m file is generated and so is stored in the 
build tree.  But the private functions like __gnuplot_has_feature__ are 
in the source tree.  Since the private directory where 
__gnuplot_has_feature__ is located is not a subdirectory of the 
directory where gnuplot_binary is located, Octave doesn't find it.

I also noticed another problem due to this changeset.  The test executes

  gnuplot_binary ("X")

and that now ends up calling __gnuplot_version__ which attempts to 
execute the command "X --version".  On many systems, "X" is the X11 
server.  So then I see errors about the X server failing to start 
properly and Octave hangs.

It also seems bad that "gnuplot_binary (new_prog)" will now call 
gnuplot_binary recursively.  It currently works because the persistent 
value that stores the program name is set before calling 
__gnuplot_version__, but that seems a bit fragile.

For now I've backed out this changeset.

I'm also wondering how important it is to be able to change the gnuplot 
binary during a single Octave session.  Is this something that comes up 
frequently?

jwe