weaken is normally found in Scalar::Util, so that's the only one that needs to be installed. A long time ago, at least on one version of RedHat, the system Scalar::Util package did not include weaken (the XS part of Scalar::Util, which provides weaken had been ommitted). I don't suppose that is the case here,

You can check by running this (replace ' by " on windows) :

perl -e'use Scalar::Util qw/weaken isweak/; use Test::More tests => 2; use strict; use warnings; my $foo; my $ref= \$foo; ok( ! isweak($ref), q{not weak}) ; weaken( $ref); ok( isweak($ref), q{weakened});'

In reply to Re^2: Warning from XML/Twig.pm : Use of uninitialized value in numeric eq (==) by mirod
in thread Warning from XML/Twig.pm : Use of uninitialized value in numeric eq (==) by jthomas

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