Re: Octave on Windows

[Jaroslav Hajek]

On Wed, Jan 27, 2010 at 6:46 AM, LUK ShunTim <address@hidden> wrote:
> Benjamin Lindner wrote:
>> Ying-Foon Chow wrote:
>>> Sorry for the "typo" in my previous message, and the attached gif file
>>> actually shows the output of gnuplot_binary() after I started Octave is:
>>>
>>> ans = C:\Octave\3.2.3_gcc-4.4.0\bin\gnuplot.exe
>>>
>>> Then, I am not getting anything by typing:
>>>
>>> gnuplot_binary('C:\Octave\3.2.3_gcc-4.4.0\bin\gnuplot.exe')
>>>
>>> Is this expected? Again, any pointers on the error message shown in the
>>> previously attached screen shot is much appreciated.
>>>
>>
>> Hmm, line 33 in __gnuplot_version__ reads
>> [status, output] = system (sprintf ("\"%s\" --version", gnuplot_binary ()));
>>
>> and the error indicates that the call to system() does not return a
>> defined value (if I interpret this correctly).
>> I don't really have a good idea, so I am staring guessing around.
>>
>> What does
>>    system("exit 2")
>> return?
>>
>> And
>>    system("gnuplot --version")
>> ?
>>
>> And what does
>>    [foo,bar] = system("echo bla & exit 2")
>> return?
>
> I also encounter this problem on a Win XP SP2 running as a virtual
> machine under virtualbox. Tried all 3.2.x installers on sourceforge.
>
> This is what I got:
>
> octave:1:C:\> system (sprintf ("\"%s\" --version", gnuplot_binary ()))
> gnuplot 4.3.0-2009-07-08 CVS patchlevel 0 octave-mingw32
> ans = 0
> octave:2:C:\> [status, output] = system (sprintf ("\"%s\" --version",
> gnuplot_binary ()))
> error: value on right hand side of assignment is undefined
>
> I do *not* have such problems on my laptop with win XP SP2 running on
> real hardware. Very strange!
>

This is a bug in system (), it should have given an "unable to start
subprocess" error.
I checked in a fix:
http://hg.savannah.gnu.org/hgweb/octave/rev/56f7734f5448

Still, I don't understand why the second version is unable to run for
you; both calls work for me (on GNU/Linux).
I suppose the difference somehow lies with the fact that on Windows,
the first version is handled using CreateProcess, whereas the second
boils down to _popen. I have too little Windows knowledge to be of any
further help.

regards

-- 
RNDr. Jaroslav Hajek, PhD
computing expert & GNU Octave developer
Aeronautical Research and Test Institute (VZLU)
Prague, Czech Republic
url: www.highegg.matfyz.cz