Turning off buffering over pipes

[paul e nielsen]

I'm using pipes to create a routine which will execute and monitor a
series of programs that were designed to be interactive.  The problem
is that when writing to a pipe, rather than a terminal, they buffer
their output and cease to be interactive.  Is there a way to set the
properties of a pipe or program, prior to doing an exec, to turn off
buffering?  For many of these programs I do not have access to the
source.

I'm using SunOS on Sun 3's and 4's, but would like a reasonably
portable solution.

--
Paul Nielsen
GE Research
nielsen at crd.ge.com