From owner-freebsd-hackers Sun Sep 7 00:24:07 1997 Return-Path: Received: (from root@localhost) by hub.freebsd.org (8.8.7/8.8.7) id AAA03583 for hackers-outgoing; Sun, 7 Sep 1997 00:24:07 -0700 (PDT) Received: from sax.sax.de (sax.sax.de [193.175.26.33]) by hub.freebsd.org (8.8.7/8.8.7) with SMTP id AAA03578 for ; Sun, 7 Sep 1997 00:24:01 -0700 (PDT) Received: (from uucp@localhost) by sax.sax.de (8.6.12/8.6.12-s1) with UUCP id JAA14541; Sun, 7 Sep 1997 09:24:00 +0200 Received: (from j@localhost) by uriah.heep.sax.de (8.8.7/8.8.5) id JAA05532; Sun, 7 Sep 1997 09:17:58 +0200 (MET DST) Message-ID: <19970907091757.ST01979@uriah.heep.sax.de> Date: Sun, 7 Sep 1997 09:17:57 +0200 From: j@uriah.heep.sax.de (J Wunsch) To: freebsd-hackers@FreeBSD.ORG Cc: jamil@counterintelligence.ml.org (Jamil J. Weatherbee) Subject: Re: SIGCLD References: <199709020249.TAA16490@implode.root.com> X-Mailer: Mutt 0.60_p2-3,5,8-9 Mime-Version: 1.0 X-Phone: +49-351-2012 669 X-PGP-Fingerprint: DC 47 E6 E4 FF A6 E9 8F 93 21 E0 7D F9 12 D6 4E Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch) In-Reply-To: <199709020249.TAA16490@implode.root.com>; from David Greenman on Sep 1, 1997 19:49:17 -0700 Sender: owner-freebsd-hackers@FreeBSD.ORG X-Loop: FreeBSD.org Precedence: bulk As David Greenman wrote: > Uh, I think you are misunderstanding this. Under FreeBSD, you *must* > call wait to reap child processes. Ignoring SIGCHLD doesn't let you off > the hook. The behavior is different under System V, but that isn't > relavent. The behaviour is different on SysV in that for SysV, SIG_DFL != SIG_IGN for SIGCLD. That is, while their default behaviour effectively ignores this signal, it isn't called SIG_IGN. By explicitly setting the signal handler to SIG_IGN, you tell the system that you aren't interested in the death of your child, and you won't get zombies. This of course is a terrible crock, but was the only way to express this in SVR3. SVR4 and Posix use the option SA_NOCLDWAIT in sigaction(2) to express this wish. FreeBSD doesn't implement this option (yet). -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)