From: Lloyd Zusman <ljz@...>
Date: 2001-04-30T00:10:09+09:00
Subject: [ruby-talk:14406] Re: [REPOST] Retrieving current signal handler without altering it

"David S." <dgjs@acm.org> writes:

> On Sun, Apr 29, 2001 at 01:40:04PM +0900, Phil Tomson wrote:
> > >
> > >I'd like to retrieve the current handler for a given signal without
> > >changing it.  I know that I can do this:
> > >
> > How about: 
> > 
> >   currentHandler = trap('HUP','DEFAULT')
> > 
> > I think that's what you're looking for.
> 
> That command will set the handler to the default.  If that's not what you
> want, you have to restore it with
> 
> 	trap('HUP', currentHandler)
> 
> which introduces a race condition.  Without an interface to 'sigaction', 
> I don't think you can safely retrieve a signal handler.

Well, in Perl, you can do this ...

  $currentHandler = $SIG{'HUP'};

The Perl interpreter ensures that the %SIG hash always contains
references to the current handler routine for a given signal, if there
is one.  Could such a thing be added to Ruby?


> David S.


-- 
 Lloyd Zusman
 ljz@asfast.com