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From: jik@pit-manager.mit.edu (Jonathan I. Kamens)
Newsgroups: comp.unix.questions
Subject: Re: Some questions
Message-ID: <1990Jul1.213022.26393@athena.mit.edu>
Date: 2 Jul 90 00:29:39 GMT
References: <1716@jura.tcom.stc.co.uk> <1990Jun28.235729.26823@athena.mit.edu>
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In-Reply-To: jik@athena.mit.edu's message of Thu, 28 Jun 90 23:57:29 GMT


  One final note about SIGCHLD signal handlers.... Don Libes has
informed me in E-mail that SunOS 4 is one of the operating systems
under which signal(SIGCHLD, SIG_IGN) will cause dying child processes
to be cleaned up automatically.

  The people with whom I've discussed this in the past have implied
that this feature is a "SysV-derived" feature, but since SunOS is
BSD-derived (or, at least, I *thought* it was), perhaps it's no longer
safe to make that generalization.  I guess the only way to generalize
is to say that vendors which have decided to put this feature in have
done so, and those which haven't, haven't -- check your manual for
more information, or write a program to test it :-).

  However, it's probably still not a good idea to rely on this if
you're trying to write portable code -- you should install a signal
handler of your own, using wait3 if it's available, or wait if it
isn't (or wait4, I guess :-).

Jonathan Kamens			              USnail:
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