🚀 go-pugleaf

jvp@doc.ic.ac.uk (Jeremy Pitt) writes:

>I've got this Quintus prolog program and this C program and, quite
>unreasonably really, I want them to `talk' to each other.

>However, the Quintus library predicate popen only allows me to get
>hold of one end of the pipe: I can either read from it or write
>to it, but not both.

>Does anybody either (a) know of an easy way of doing both or (b) have
>a library package which exports predicates to do this.

>Oh, and on top of that the C program writes its output to standard
>error (don't ask). So what I want is to be able to send stuff from
>my Quintus program through the pipe to the C program, and pick up 
>its output off standard error when its finished munging about with
>it.

>Don't want much, do I? However, any help with this would be greatly
>appreciated. Thanks,

>Jeremy
>--
>Jeremy Pitt, Department of Computing, Imperial College of Science, Technology
>& Medicine, Huxley Building, 180, Queen's Gate, London, England, SW7 2BZ.
>jvp@doc.ic.ac.uk    +44 71 589 5111 ext 4983

	I think it would be worth trying to create two named pipe files
(if you're using System V) in the /tmp directory, one for Quintus -> C
and the other for C -> Quintus.  You can redirect stderr and stdin of the
C program to these pipes.  Try using open/3 to open these pipe files in
Quintus (not quite sure whether this works).  If this does not work, try
redirecting Quintus' input and output streams to these files.  (tell/1,
told/0, etc).  If all these fails, write a small C program for opening
pipe files and link it to Quintus.

	Some time ago, I tried these techniques, but now I have already
forgotten how I let Quintus and C talk to each other exactly.  Of course,
the solution depends on the particular situation.  If this is not detailed
enough, you may send a email to me so that I will try these things out
myself to give you a more complete answer.
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Tong Bo-Ming                              email: bmtong@cs.cuhk.hk