Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!esosun!net1!sdcsvax!hp-sdd!hplabs!hpcea!hpda!hppcgo!hpisoa2!hpisod1!hpisoa1!davel From: davel@hpisoa1.HP.COM (Dave Lennert) Newsgroups: comp.unix.wizards Subject: Re: HELP! - why does this process die? Message-ID: <2200005@hpisoa1.HP.COM> Date: Mon, 24-Nov-86 20:01:11 EST Article-I.D.: hpisoa1.2200005 Posted: Mon Nov 24 20:01:11 1986 Date-Received: Wed, 3-Dec-86 21:55:44 EST References: <9@houligan.UUCP> Lines: 18 > The problem is that because shell C exits, it leaves D in the background > without a parent. Any process without a parent that receives the signal > SIGTSTP (which is what a -Z sends), or the signal SIGTTIN or SIGTTOU, > is silently killed by the kernel with a SIGKILL, which is why you can't trap > it. Technically, any process without a parent (orphaned to init) that *stops* as a result of receiving SIGTSTP, SIGTTIN, or SIGTTOU is sent SIGKILL. (SIGSTOP does not have this side effect.) An application can become immune to this side effect (the SIGKILL) by catching, ignoring, or masking SIGTSTP, SIGTTIN, and SIGTTOU. This will also prevent the application from being stopped by these signals. Dave Lennert ucbvax!hpda!davel [UUCP] Hewlett-Packard - 47UX ihnp4!hplabs!hpda!davel [UUCP] 19447 Pruneridge Ave. hpda!davel@Berkeley.edu [ARPA] Cupertino, CA 95014 (408) 447-6325 [AT&T]