Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP
Path: utzoo!watmath!clyde!rutgers!brl-adm!brl-smoke!gwyn
From: gwyn@brl-smoke.UUCP
Newsgroups: comp.os.minix
Subject: Re: No SIGCLD?
Message-ID: <5617@brl-smoke.ARPA>
Date: Wed, 11-Feb-87 02:44:32 EST
Article-I.D.: brl-smok.5617
Posted: Wed Feb 11 02:44:32 1987
Date-Received: Thu, 12-Feb-87 04:30:54 EST
References: <14675@amdcad.UUCP>
Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 15
Keywords: wait(), shell background jobs

In article <14675@amdcad.UUCP> tim@amdcad.UUCP (Tim Olson) writes:
-Without SIGCLD, there may be problems in implementing background jobs in
-shells.  If we type
-
-	cc -o foo foo.c &
-
-we don't want the shell to wait() for the compilation to complete.  However,
-when the compile completes, it sits in the zombie state (HANGING) forever,
-using a process slot (and memory resources, too!).

This is a non-problem.  7th Edition UNIX didn't have SIGCLD,
and indeed many of the Bourne shells even on systems with SIGCLD
don't use the signal.  What saves the situation is that the
first wait() performed after a child process terminates will pick
it up.  So the next time one does a non-& command, all is well.