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From: eli@panda.uucp (Eli Taub/100000)
Newsgroups: comp.unix.ultrix,comp.unix.wizards
Subject: Re: How to clear zombie children while parent still alive.
Summary: signal(SIGCLD, handler); handler(){wait(for child);}
Keywords: process termination. zombies
Message-ID: <3167@d75.UUCP>
Date: 27 Mar 90 22:13:43 GMT
References: <1642@jimi.cs.unlv.edu> <10333@cbmvax.commodore.com> <1657@jimi.cs.unlv.edu> <1990Mar27.164632.18462@ux1.cso.uiuc.edu>
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Reply-To: eli@reed.UUCP (Eli Taub/100000)
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Organization: IBM AWD, Austin, TX
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> Is that possible to clear all zombie children while the parent
> is still in execution under SunOS? I had the parent process to call
> signal(SIGCHLD, SIG_IGN). This should let init to clear the
> terminated child automaitically, when the parent got a SIGCHLD.

Under System V signal(SIGCLD, SIG_IGN) tells the kernel not to create
Zombies. This is special because the default for SIGCLD (or SIGCHLD) is
to ignore the signal.

> But SunOS still kept all the zombies until the parent exited. 
> Is SunOS different from other Unix systems in this regard? 
> Is it possible to clear zombies in a SunOS environment? And how?

In SUN and other BSDs you Must catch the signal and issue a wait 
so that the Zombie is cleared up.

Eli Taub	
Contractor at IBM (till Sep. `90)
(512) 838-4810