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From: jik@athena.mit.edu (Jonathan I. Kamens)
Newsgroups: comp.unix.questions
Subject: Re: Need help spawning a child
Message-ID: <12131@bloom-beacon.MIT.EDU>
Date: 21 Jun 89 23:48:46 GMT
References: <1661@apt.UUCP> <873@cbnewsl.ATT.COM>
Sender: daemon@bloom-beacon.MIT.EDU
Reply-To: jik@athena.mit.edu (Jonathan I. Kamens)
Distribution: usa
Organization: Massachusetts Institute of Technology
Lines: 37

In article <873@cbnewsl.ATT.COM> dune@cbnewsl.ATT.COM (Greg
Pasquariello) writes:

>Simply use signal() to ingnore the death of a child.  In SVR3.2 this will
>have the desired effect of letting the child die without creating
>zombies.

I can't speak for SVR3.2, but I can tell you for sure that this will
not work under BSD (in fact, I just checked with a five line program).
The method I use under BSD to accomplish this is a bit more
convoluted, but it just *might* be a bit more portable (I'm not sure,
because I've done very little work under anything other than BSD and
the SysV machine I have an account on is down right now :-).

Under BSD, you set up a signal handler which responds to SIGCHLD by
calling wait(0).  The return value of the wait() call is irrelevant --
it serves only to tell the kernel that it can free up the resources
reserved for the zombie child.

#include <signal.h>

main()
{
   ...
   signal(SIGCHLD, handler);
   ...
}

handler()
{
   wait(0);
}

Jonathan Kamens			              USnail:
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