Date: Tue, 12 Jul 2005 14:01:36 -0700
From: David Fetter <david@fetter.org>
To: Andrew Dunstan <andrew@dunslane.net>
Cc: Alvaro Herrera <alvherre@alvh.no-ip.org>,
	Michael Fuhr <mike@fuhr.org>, pgsql-hackers@postgresql.org
Subject: Re: PL/Perl list value return causes segfault
Message-ID: <20050712210136.GA22301@fetter.org>
References: <20050712130452.GA84564@winnie.fuhr.org>
	<42D41319.70107@dunslane.net>
	<20050712193303.GA14060@alvh.no-ip.org>
	<42D41DF3.6050702@dunslane.net>
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On Tue, Jul 12, 2005 at 03:45:55PM -0400, Andrew Dunstan wrote:
> 
> 
> Alvaro Herrera wrote:
> 
> >On Tue, Jul 12, 2005 at 02:59:37PM -0400, Andrew Dunstan wrote:
> >
> > 
> >
> >>Note that all plperl functions are called in scalar context, and
> >>it is always wrong to return a list (as opposed to a listref). In
> >>fact, the value received might surprise you even if it worked (it
> >>would be the value of the last member of the list).
> >
> >Hmm, I don't know if it's feasible to do in Perl, but maybe check
> >whether the function wants to return something in list context and
> >throw an appropiate error message?
> 
> In perl, if there is any ambiguity it is the called function that is
> responsible for checking, not the caller. See "perldoc -f
> wantarray".  PLPerl explicitly passed G_SCALAR as a flag on all
> calls to plperl routines. So returning a list is a case of pilot
> error.

Is this a kind of pilot error that documents could help avert in some
useful way?

Cheers,
D
-- 
David Fetter david@fetter.org http://fetter.org/
phone: +1 510 893 6100   mobile: +1 415 235 3778

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