[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.
> 

OK. The attached project gives the following output after I pressed
"Button1" four or five times:

---
Read             line 0: non-integer passed to boolean operator


Read    
gnuplot> lot x^1
         ^
         line 0: invalid command


Read    
gnuplot> pot x^1
         ^
         line 0: 
Read    invalid command


Read    
gnuplot> lotx^1
         ^
         line 0: invalid command


Read    
gnuplot> plp plot x^1
         ^
         
Read    line 0: invalid command



---

You can see that in each message, one character is missing so that "plot" is
"lot" or "pot" or "lot" again. The missing characters "plp" appear in the
last message, totally mis-placed.

Am I maybe reading incorrectly from the pipe?

Regards,
Tobi
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