# Tie::RefHash - phpMan

## NAME
    [Tie::RefHash] - Use references as hash keys

## VERSION
    version 1.40

## 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.

## SEE ALSO
    [perl(1)], [perlfunc(1)], [perltie(1)]

## SUPPORT
    Bugs may be submitted through the RT bug tracker
    <<https://rt.cpan.org/Public/Dist/Display.html?Name=Tie-RefHash>> (or
    <bug-Tie-RefHash@rt.cpan.org> <mailto:<bug-Tie-RefHash@rt.cpan.org>>).

## AUTHORS
    Gurusamy Sarathy <<gsar@activestate.com>>

    [Tie::RefHash::Nestable] by Ed Avis <<ed@membled.com>>

## CONTRIBUTORS
    *   Yuval Kogman <<nothingmuch@woobling.org>>

    *   Karen Etheridge <<ether@cpan.org>>

    *   Florian Ragwitz <<rafl@debian.org>>

    *   Jerry D. Hedden <<jdhedden@cpan.org>>

## COPYRIGHT AND LICENCE
    This software is copyright (c) 2006 by יובל קוג'מן (Yuval Kogman)
    <<nothingmuch@woobling.org>>.

    This is free software; you can redistribute it and/or modify it under
    the same terms as the Perl 5 programming language system itself.