Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: notesfiles Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!ihnp4!zehntel!tektronix!hplabs!hp-pcd!hpfcls!rml From: rml@hpfcls.UUCP (rml) Newsgroups: net.unix-wizards Subject: Re: signal 0 Message-ID: <132000008@hpfcls.UUCP> Date: Sat, 15-Dec-84 18:11:00 EST Article-I.D.: hpfcls.132000008 Posted: Sat Dec 15 18:11:00 1984 Date-Received: Sun, 16-Dec-84 06:37:18 EST References: <6192@brl-tgr.UUCP> Organization: Hewlett-Packard - Fort Collins, CO Lines: 17 Nf-ID: #R:brl-tgr:-619200:hpfcls:132000008:000:682 Nf-From: hpfcls!rml Dec 10 15:11:00 1984 > I couldn't find the original message about using signal 0 to determine > whether a child process has terminated without doing a wait for it. > Since then, friends have researched the issue, with the following result: > > signal 0 NOT SUPPORTED on 6th Edition UNIX, 7th Edition UNIX, > nor 4.1BSD > > signal 0 SUPPORTED on UNIX System III, UNIX System V, Research > Version 8, and 4.2BSD Using signal 0 to determine whether a child process has terminated assumes that, when sending a signal to a zombie process, kill(2) returns an error. This is true in 4.2BSD, but not in System III or V (I have no idea about Research Version 8). Bob Lenk {hplabs, ihnp4}!hpfcla!rml