Path: utzoo!attcan!uunet!midway!ncar!elroy.jpl.nasa.gov!jpl-devvax!lwall
From: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Newsgroups: comp.lang.perl
Subject: Re: Wait for an output pipe?
Message-ID: <9717@jpl-devvax.JPL.NASA.GOV>
Date: 27 Sep 90 20:52:38 GMT
References: <1990Sep27.195032.25135@uvaarpa.Virginia.EDU>
Reply-To: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 17

In article <1990Sep27.195032.25135@uvaarpa.Virginia.EDU> worley@compass.com writes:
: 
:    X-Name: Stephen Schaefer
: 
:    OK, I could collect the process ID from pipe open, but then how do I
:    wait for that process?
: 
: $pid = open(RDIST,"|rdist -f -");
: ... write stuff to RDIST ...
: close RDIST;
: # Wait until process $pid is done
: until (wait == $pid) {}

Er, you've just written an infinite loop, since close will harvest the
pid in question, and wait will return -1 eternally.

Larry