Tie::Scalar

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 perltie 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::StdScalar
       package provides all the methods specified in  perltie. 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 perltie section not only documents
       these, but has sample code as well:

       TIESCALAR classname, LIST
	   The method invoked by the command "tie $scalar, classname". Asso-
	   ciates a new scalar instance with the specified class. "LIST"
	   would represent additional arguments (along the lines of Any-
	   DBM_File 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 referenced by
	   this.  This is rarely needed, as Perl manages its memory quite
	   well. But the option exists, should a class wish to perform spe-
	   cific actions upon the destruction of an instance.

MORE INFORMATION
       The perltie section uses a good example of tying scalars by associat-
       ing process IDs with priority.



perl v5.8.8			  2001-09-21		       Tie::Scalar(3)