Path: utzoo!attcan!utgpu!jarvis.csri.toronto.edu!mailrus!iuvax!purdue!haven!adm!smoke!gwyn
From: gwyn@smoke.BRL.MIL (Doug Gwyn)
Newsgroups: comp.unix.wizards
Subject: Re: Looking for tcsh binary which uses vfork
Keywords: tcsh, vfork, SunOS 4.0
Message-ID: <10941@smoke.BRL.MIL>
Date: 5 Sep 89 17:34:33 GMT
References: <243@paralogics.UUCP>
Reply-To: gwyn@brl.arpa (Doug Gwyn)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 10

In article <243@paralogics.UUCP> shaw@paralogics.UUCP (Guy Shaw) writes:
>>   Stopped (tty output)
>> Presumably using vfork() forces things to happen in the right order.
>The idea that using vfork() would cure this problem sounds reasonable to me.

NO!  All that using vfork() instead of fork() does in this case is to
change the multiprocess timing so that the real problem, a race condition
involving process groups, is less evident.  Chris Torek recently posted
the explanation and suggested fix (set the process group N+1 times in
an N-process pipeline).