Communicating with a background process

[Steve Scot Roy]

I was thinking of writing a front end for a particular program and there
is something that I haven't been able to figure out.  The program reads
from stdin and writes to stdout and it is not feasable to modify it.
What I want to do is run it in the background with pipes to my program
which will interpret mouse clicks and keystrikes and translate them into
text lines.

My problem is that I cannot find how to open a *two way* communication
line to a program.  popen(...) claims to set up a one way pipe to
another program, but I need two way communication.

This seems like a fairly natural thing to do.  I cannot believe that it
can't be done.

Steve Roy
Program of Applied Mathematics
Princeton University
ssr at courant.princeton.edu