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Date:      21 Aug 2002 09:48:34 -0400
From:      Lowell Gilbert <freebsd-stable-local@be-well.no-ip.com>
To:        stable@freebsd.org
Subject:   Re: minor annoyances
Message-ID:  <44k7mktj9p.fsf@be-well.ilk.org>
In-Reply-To: <E17hSKW-00008v-00@mailhost.firstcallgroup.co.uk>
References:  <E17hSKW-00008v-00@mailhost.firstcallgroup.co.uk>

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Pete French <pfrench@firstcallgroup.co.uk> writes:

> > If it works, '(aaa &) && bb' can't mean anything other than 'aaa & bb'.  
> > The "bb" always executes, regardless of the result of "aaa".
> 
> It does ? I would have thought that this would only execute "bb" if the
> fork succeeds on the right hand side.

That would be a useful feature, but it's never been an intentional
one, so it's hard to fault the changes that "broke" it.  The standard
specifically allows (but does not require) the parent shell to exit if
the fork fails, so there's definitely not agreement on the expected
behaviour.  [This has long been the behaviour that sh follows, by the
way.]  Some shells explicitly set the return code to 0 after an '&'
operator.

>                                       How else do you test for fork failing ?

Hmm.  That never worked anyway, but it's a good idea.  I don't know
that anyone intended to provide a way to do that.  If you were going
to make a mechanism from scratch, I'd be inclined toward raising a
signal, but this really isn't my area of standards expertise.

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