From: Bertram Scharpf <lists@...>
Date: 2007-10-04T21:01:47+09:00
Subject: Re: Signal handling strangeness (Linux)

Hi,

Am Donnerstag, 04. Okt 2007, 19:14:51 +0900 schrieb Han Holl:
> On 10/4/07, Bertram Scharpf <lists@bertram-scharpf.de> wrote:
> 
> > The wait is part of popen. So, `tail' runs until
> > Process.pid(==$$) terminates and $$ waits for the `tail' to
> > finish. It's a deadlock but it's the correct behaviour. You
> > should state a clear definition which task is to be stopped.
> > You can offer a pid or a kill command by another feature of
> > your Ruby application.
> >
> Yes, but the deadlock isn't there without the trap('TERM').

I didn't examine it thoroughly but "exit" seems to raise an
exception "SystemExit". This exception will probably not be
raised before the wait statement finishes. The default
signal handler for 'TERM' will not raise anything but rather
try to stop the whole Ruby process.

You can catch the SystemExit exception by putting a
begin-rescue-end frame around your popen call.

Bertram


-- 
Bertram Scharpf
Stuttgart, Deutschland/Germany
http://www.bertram-scharpf.de