Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!rutgers!njin!princeton!phoenix!bernsten
From: bernsten@phoenix.Princeton.EDU (Dan Bernstein)
Newsgroups: comp.unix.questions
Subject: Re: Avoiding <exiting> processes on Ultrix
Message-ID: <7693@phoenix.Princeton.EDU>
Date: 11 Apr 89 22:01:46 GMT
References: <520@pan.UUCP>
Reply-To: bernsten@phoenix.Princeton.EDU (Dan Bernstein)
Distribution: usa
Organization: Hmph.
Lines: 20

In article <520@pan.UUCP> jw@pan.UUCP (Jamie Watson) writes:
> Is there any way under Ultrix (2.0 or later) to write a C program
> such that any child processes created by that program will exit,
> without hanging in an <exiting> status until the parent does a wait()
> for the child?  Under SysV this is done with signal(SIGCLD, SIG_IGN);
> I have tried that under Ultrix, to no avail.

I'm surprised nobody's mentioned setting up a SIGCLD/SIGCHLD handler
that does a wait().

  sigchld() { wait(0); }

  signal(SIGCHLD,sigchld);

This is faster (on some machines, much much faster) than an extra
fork(). It is certainly more general than ignoring the signal, and
it's the basis for the shell job control (with a more intelligent
sigchld()).

---Dan Bernstein, bernsten@phoenix.princeton.edu