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Tie::RefHash(3pm)      Perl Programmers Reference Guide      Tie::RefHash(3pm)
NAME
       Tie::RefHash - use references as hash keys
SYNOPSIS
           require 5.004;
           use Tie::RefHash;
           tie HASHVARIABLE, 'Tie::RefHash', LIST;
           tie HASHVARIABLE, 'Tie::RefHash::Nestable', LIST;
           untie HASHVARIABLE;
DESCRIPTION
       This module provides the ability to use references as hash keys if you
       first "tie" the hash variable to this module.  Normally, only the keys
       of the tied hash itself are preserved as references; to use references
       as keys in hashes-of-hashes, use Tie::RefHash::Nestable, included as
       part of Tie::RefHash.
       It is implemented using the standard perl TIEHASH interface.  Please
       see the "tie" entry in perlfunc(1) and perltie(1) for more information.
       The Nestable version works by looking for hash references being stored
       and converting them to tied hashes so that they too can have references
       as keys.  This will happen without warning whenever you store a
       reference to one of your own hashes in the tied hash.
EXAMPLE
           use Tie::RefHash;
           tie %h, 'Tie::RefHash';
           $a = [];
           $b = {};
           $c = \*main;
           $d = \"gunk";
           $e = sub { 'foo' };
           %h = ($a => 1, $b => 2, $c => 3, $d => 4, $e => 5);
           $a->[0] = 'foo';
           $b->{foo} = 'bar';
           for (keys %h) {
              print ref($_), "\n";
           }
           tie %h, 'Tie::RefHash::Nestable';
           $h{$a}->{$b} = 1;
           for (keys %h, keys %{$h{$a}}) {
              print ref($_), "\n";
           }
THREAD SUPPORT
       Tie::RefHash fully supports threading using the "CLONE" method.
STORABLE SUPPORT
       Storable hooks are provided for semantically correct serialization and
       cloning of tied refhashes.
RELIC SUPPORT
       This version of Tie::RefHash seems to no longer work with 5.004. This
       has not been throughly investigated. Patches welcome ;-)
LICENSE
       This program is free software; you can redistribute it and/or modify it
       under the same terms as Perl itself
MAINTAINER
       Yuval Kogman <nothingmuch AT woobling.org>
AUTHOR
       Gurusamy Sarathy        gsar AT activestate.com
       'Nestable' by Ed Avis   ed AT membled.com
SEE ALSO
       perl(1), perlfunc(1), perltie(1)
perl v5.26.3                      2018-03-01                 Tie::RefHash(3pm)