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NAME
Scalar::Readonly - functions for controlling whether any scalar variable
is read-only
SYNOPSIS
use Scalar::Readonly ':all';
my $foo = "foo";
readonly_on($foo);
$foo = "bar"; #ERROR!
if (readonly($foo)) {
readonly_off($foo);
}
readonly_off($]);
$] = "6.0";
print "This is Perl v$]";
DESCRIPTION
This simple module can make scalars read-only. Useful to protect
configuration variables, for example.
This module can also be used to subvert Perl's many read-only variables
to potential evil trickery.
readonly
Ths function takes a scalar variable and tells you whether it is
read-only. It returns 0 if the scalar isn't read-only, and a positive
number if it is.
readonly_on
Makes the passed scalar variable read-only. If you try and modify a
read-only scalar, your code will die with the following error message:
Modification of a read-only value attempted at
readonly_off
Makes the passed scalar variable read-write. You can even do this to
read-only special variables, though you almost certainly don't want to
do that.
EXPORT
':all' => readonly, readonly_on, readonly_off
SEE ALSO
Scalar::Util, Attribute::Constant, Const::Fast.
AUTHOR
Philippe M. Chiasson, <gozer@cpan.org>
COPYRIGHT AND LICENSE
Copyright (C) 2004 by Philippe M. Chiasson
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself, either Perl version 5.8.3 or, at
your option, any later version of Perl 5 you may have available.
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