octave > FIFO

[Ted Harding]

Hi Folks,

I want to write from octave to a FIFO (named pipe). What is the best way
to do this? It doesn't seem to be straightforward.

Non-octave example:
-------------------
    mkfifo temp

Now go to another window (but the same directory) and execute

    cat < temp

Back in to first window, execute

    cat > temp
    line 1
    line 2
    ^D

(terminating with Ctrl-D). The lines typed in on screen 1 will be
displayed on screen 2 after their newlines are entered.

Having closed the stream with ^D, you can start a new stream in the same
way, from the same or a different wndow (the FIFO remains in place).

Otave example:
--------------

In the directory octave is running in, do

    mkfifo temp

Now fprintf("temp",FORMAT, args) looks tempting, but octave says

    error: fprintf: invalid file type

However, the line

    system("echo STUFF > temp")

works just fine. The only thing is, you don't want to send anything
complicated this way. It would be nice to have the formatting flexibility
of fprintf.

Any good suggestions?

The real reason I'm looking into this is not to do anything so naive as
the above examples.

Once some FIFOs have been created, other programs can read from them at
will, moving from one to another if need be. Octave can similarly write
different streams of output, line by line, to them. This offers a very
flexible interface between octave and a suite of external programs.

Who knows? It may even have something to do with recent discussions.

Bes wishes to all,
Ted.                                    (address@hidden)