[Gambas-user] Conflicting and bewildering help for pipes

[Benoît Minisini]

Le 29/10/2013 23:12, Tobias Boege a écrit :
> 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
>

Spoke too fast. Now I have the same output as you (more or less)...

-- 
Benoît Minisini