Re: MSVC/Win32: building the documentation

[Michael Goffioul]

John W. Eaton a écrit :
> | - run-octave failed to recreate the figures because it couldn't
> | start the gnuplot process, while pgnuplot was actually in my
> | PATH. I identified the cause as the way how gnuplot is invoked
> | when use_title_options is true. For some (still unidentified)
> | reasons, this does not work. But I could workaround it easily
> | by undefining DISPLAY, as in \"DISPLAY= make\". However, and that's
> | the funny part, you cannot set COMSPEC to an empty value to
> | build the images, as in the second point, otherwise octave is
> | unable to start pgnuplot as sub-process. So either you run a
> | suite of \"COMSPEC= make\" and \"DISPLAY= make\" up to the next error.
> | Or you can use the texi2dvi from the MiKTeX package, which does
> | not require COMSPEC set to empty. As a 3rd solution, you can
> | simply forget about the COMSPEC setting and just type \"../conf.texi\"
> | when texi2dvi/pdf fails to find it.
>
> How about just unsetting COMSPEC when running texinfo and texi2dvi, as
> in the patch below?  Does that work for you?
>   

I'll test it tomorrow. In the meantime, I could identify the problem 
with DISPLAY and
COMSPEC and it relates to popen implementation under Win32. The "popen" 
function
requires the program to have a console open and use COMSPEC variable to 
run the
program; hence COMSPEC needs to be defined.

OTOH, when DISPLAY is set, gnuplot is started as: "pgnuplot" -title 
"Figure 1". Again
the problem is due to the somewhat broken implementation of popen. When 
such a
command is used in popen, it will strips the leading and ending 
double-quote of the string
and send the result to cmd.exe (this is partially explained in "cmd 
/?"). This resuls in:
pgnuplot" -title "Figure1, which is plain wrong; hence the subprocess 
cannot be started.

One solution would be to prepend any popen command with "call". With the 
gnuplot
command above, it would lead to: call "pgnuplot" -title "Figure 1". This 
would fix the
popen problem, but it does not work for pgnuplot as the Win32 gnuplot 
version does
not know about the "-title" command flag and just fails. So, for the 
documentation building,
unsetting DISPLAY seems the easiest solution.

Michael.