Tie::Scalar(3) Perl Programmers Reference Guide Tie::Scalar(3)NAME
Tie::Scalar, Tie::StdScalar - base class definitions for
tied scalars
SYNOPSIS
package NewScalar;
require Tie::Scalar;
@ISA = (Tie::Scalar);
sub FETCH { ... } # Provide a needed method
sub TIESCALAR { ... } # Overrides inherited method
package NewStdScalar;
require Tie::Scalar;
@ISA = (Tie::StdScalar);
# All methods provided by default, so define only what needs be overridden
sub FETCH { ... }
package main;
tie $new_scalar, 'NewScalar';
tie $new_std_scalar, 'NewStdScalar';
DESCRIPTION
This module provides some skeletal methods for scalar-
tying classes. See the perltie manpage for a list of the
functions required in tying a scalar to a package. The
basic Tie::Scalar package provides a "new" method, as well
as methods "TIESCALAR", "FETCH" and "STORE". The Tie::Std
Scalar package provides all the methods specified in the
perltie manpage. It inherits from Tie::Scalar and causes
scalars tied to it to behave exactly like the built-in
scalars, allowing for selective overloading of methods.
The "new" method is provided as a means of grandfathering,
for classes that forget to provide their own "TIESCALAR"
method.
For developers wishing to write their own tied-scalar
classes, the methods are summarized below. The the perltie
manpage section not only documents these, but has sample
code as well:
TIESCALAR classname, LIST
The method invoked by the command "tie $scalar, class
name". Associates a new scalar instance with the spec
ified class. "LIST" would represent additional argu
ments (along the lines of the AnyDBM_File manpage and
compatriots) needed to complete the association.
FETCH this
Retrieve the value of the tied scalar referenced by
this.
STORE this, value
Store data value in the tied scalar referenced by
this.
DESTROY this
Free the storage associated with the tied scalar ref
erenced by this. This is rarely needed, as Perl man
ages its memory quite well. But the option exists,
should a class wish to perform specific actions upon
the destruction of an instance.
MORE INFORMATION
The the perltie manpage section uses a good example of
tying scalars by associating process IDs with priority.
2001-02-22 perl v5.6.1 Tie::Scalar(3)
