Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!samsung!think!eplunix!das
From: das@eplunix.UUCP (David Steffens)
Newsgroups: comp.unix.wizards
Subject: tcsh and process groups
Message-ID: <829@eplunix.UUCP>
Date: 10 Jan 90 21:47:38 GMT
Organization: Eaton-Peabody Lab, Boston, MA
Lines: 22

Late last summer (August?) there was a discussion in this group
about how csh/tcsh handles process groups.  The problem as I remember
was that under SunOS on a SUN4, you don't want to use vfork().
But vfork() enforces a certain processing order which is absent otherwise.
So if you don't use vfork(), you end up with the following annoyance:
	% egrep foo bar.c | less
	Stopped (tty output)
	%

The discussion seemed to revolve around how process groups are set up
for pipelines.  Chris Torek (I think) said that there was a race.
I don't remember whether it was ever explained why this problem
doesn't occur with the SunOS4.0 version of csh.

At this point I lost track of the discussion -- too much work to keep up
with the volume in this group! -- so I never did hear if there ever
was a fix posted or suggested.  Anyone know what I'm talking about?
Can you fill me in?  Tell me where I can get a fix?  advTHANKSance
-- 
{harvard,mit-eddie,think}!eplunix!das	David Allan Steffens
243 Charles St., Boston, MA 02114	Eaton-Peabody Laboratory
(617) 573-3748				Mass. Eye & Ear Infirmary