Re: bidirectional communication

[Hans-Bernhard B. <br...@ph...>]

On Wed, 18 Feb 2004, Petr Mikulik wrote:

> And a demo for Java?

I have the (very crude) beginnings of a gpjava GUI interface.  
Interfacing the gnuplot process via a pair of pipes works, but that's
about all it does.

> ***
> 
> Well, ad to the above problem with fifo in Octave -- why the following in
> bash does not work?
> 
> bash$ mkfifo cau
> bash$ tail -f cau
> 
> and in another xterm:
> 
> gnuplot> set print "cau"
> gnuplot> print "hello"
> 
> Only sometimes the text appears in the "tail", but always it gets flushed
> after "set print" (closing print file) or quitting gnuplot -- and why it
> works in the C demo without closing "set print"?

This may well be a problem of buffering.  FIFOs are fully buffered by
default, I think, whereas stderr, the default 'set print' output channel,
is always completely unbuffered by C standard requirements.  I.e. it
should help to explicitly setbuf() the channel 'set print' opened to
unbuffered.


-- 
Hans-Bernhard Broeker (br...@ph...)
Even if all the snow were burnt, ashes would remain.