Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!usc!elroy.jpl.nasa.gov!jpl-devvax!lwall
From: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Newsgroups: comp.lang.perl
Subject: Re: fork() and wait()
Message-ID: <7104@jpl-devvax.JPL.NASA.GOV>
Date: 18 Feb 90 00:31:27 GMT
References: <2641@uvaarpa.virginia.edu>
Reply-To: lwall@jpl-devvax.JPL.NASA.GOV (Larry Wall)
Organization: Jet Propulsion Laboratory, Pasadena, CA
Lines: 28

In article <2641@uvaarpa.virginia.edu> kayvan@mrspoc.transact.com writes:
: Looking at eval.c, it seems that the perl's wait() ignores certain
: signals. I don't think this is correct behavior.

You're probably right.

: I have an application where I want to spawn a subprocess (which
: setpgrp()'s and goes about its merry way) and at the same time I want
: the parent to wait() for the child to finish. Now, if I want to
: interrupt the parent, I should be able to (without killing the child,
: so system() will not do).

It would probably be possible even now by calling wait thru syscall().

: Is there anything wrong with commenting out the signal(SIGINT, SIG_IGN) 
: and the other SIG_IGN line in the O_WAIT case in eval.c??

I'll do that in patch 9 and see if anyone screams.

: Why are they there in the first place?

Because the code was copied in from the mypopen routine.  But that's
a higher level routine, and most system()ish routines behave like that.
But wait should be a low level operator.  You can always ignore the
signals yourself around a wait if you like, but if the wait ignores
them then you can't unignore them.  >>patch9

Larry