rc-list - mailing list for the rc(1) shell
 help / color / mirror / Atom feed
From: malte@techfak.uni-bielefeld.de
To: rc@hawkwind.utcs.toronto.edu
Subject: Re: rc and signal handlers
Date: Fri, 6 Nov 1992 07:03:35 -0500	[thread overview]
Message-ID: <9211061203.AA01626@dahlie.techfak.uni-bielefeld.de> (raw)
In-Reply-To: Mail from 'Chris Siebenmann <cks@hawkwind.utcs.toronto.edu>' dated: 	Thu, 5 Nov 1992 18:16:05 -0500

	
	| Also, the man-page is not too clear about signals:
	|  "Only signals that are being ignored are passed on to programs run by rc"
	| The should read "signals that are being caught", I guess.
	
	 The manpage is correct as written; caught signals are not passed on to
	children, and revert to default behavior. Only ignored signals are passed
	on to children.
	
	 If one thinks about how catching signals works, it becomes obvious that
	this has to be that way.
	
		- cks

This is perfectly true! But also ugly ! This way, one has to redefine signal
handlers for each backquote substitution. On BSD and System V children
inherit signal handlers when forking and one has to change them explicitly.
Could someone explain to me why rc does it automatically ? I'd rather prefer
a simple way to reset signal handlers, something like

	fn sigreset {
		for( sig in `{ whatis -s | cut -f2 '-d ' } )
			eval fn $sig
	}

About "return"ing from a signal handler: One really doesn't want to do that.
I just mentioned it to make it clear to beginners. What bothers me most is
that rc doesn't complain about a return when defining the function and that
everything is fine when invoking the function interactively. But, when the
signal is caught, you'll get "return outside of function".

Malte



  parent reply	other threads:[~1992-11-06 12:03 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <cks@hawkwind.utcs.toronto.edu>
1992-11-04 12:45 ` set subtract malte
1992-11-06 12:03 ` malte [this message]
1992-11-05 20:45 rc and signal handlers malte
1992-11-05 23:16 ` Chris Siebenmann
1992-11-05 22:00 Byron Rakitzis

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=9211061203.AA01626@dahlie.techfak.uni-bielefeld.de \
    --to=malte@techfak.uni-bielefeld.de \
    --cc=rc@hawkwind.utcs.toronto.edu \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).