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Postings from February 2003
On Mon, Feb 17, 2003 at 02:14:59AM +0200, Enache Adrian wrote:
> I expected from it to:
>
> 1. print '(1) (1) (1)' ...
> 2. go in some crazy loop.
Before proceeding, mg_get() saves, then turns off, any magic associated
with the SV - I guess to avoid recursive crazy loops like you mention.
This is why 'untie $a', and '$a' have no magical effect within
FETCH().
The cause of the original coredump was that *a = \1 was immediately
freeing the tied scalar, since things pushed onto the stack aren't
refcounted. You can (almost) achieve similar effects with code like
$a = 1; f($a);
sub f { *a = \1; do_something_with($_[0]) }
except that av_fetch() has explicit code it in such that when it
tries to retrieve element n from @_, it checks that its a freed scalar,
and if so, returns undef instead. This is pure hackery since sometimes the
sv may have since been reassigned.
--
But Pity stayed his hand. "It's a pity I've run out of bullets",
he thought. - "Bored of the Rings"
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