[Gambas-user] Conflicting and bewildering help for pipes

[Tobias Boege]

On Fri, 25 Oct 2013, Beno?t Minisini wrote:
> Le 24/10/2013 15:08, Tobias Boege a ?crit :
> > My workaround always was like this:
> >
> >    ' Create the read pipe special file
> >    hGPstdout = Pipe "/tmp/gnuplotFIFO2" For Write
> >    Close #hGPstdout
> >    ' Create write end
> >    hGPpipe = Pipe "/tmp/gnuplotFIFO1" For Write
> >    ' Start writer
> >    hGPproc = Shell "gnuplot </tmp/gnuplotFIFO1 >/tmp/gnuplotFIFO2"
> >    ' Really create read end
> >    hGPstdout = Pipe "/tmp/gnuplotFIFO2" For Read Watch
> >
> > Note that since the shell which starts hGPproc already opened
> > /tmp/gnuplotFIFO2, you won't have any deadlock problems when opening
> > hGPstdout For Read afterwards.
> >
> > Anyway, if I
> >
> >    Print #hGPpipe, "plot x^2"
> >
> > only garbage (not non-sense but the string is always scrambled) seems to
> > arrive at gnuplot. Also, I seem to get output from gnuplot irregularly. So
> > I'm out of options for now. I remember that raising Read events for streams
> > has been subject to issues from time to time...
> >
> > Regards,
> > Tobi
> >
> 
> Please give details. I tried what you said (but "plot x*x" because" 
> "plot x^2" seems to not be the good syntax), and I always got the plot 
> as expected.
> 

Oookay! I wrote "plot x*x" and it went flawlessly. However, since "plot x^2"
was bad input, gnuplot sent an error message to me before. This just didn't
come through to me correctly - which means: the output was only partly there
or scrambled. Maybe buffering (although pipes are not buffered)? Maybe
something else? I will try again when I've time.

Regards,
Tobi