


Tie::Scalar(3p)  Perl Programmers Reference Guide Tie::Scalar(3p)


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.





2001-05-24                 perl v5.6.1                          1





Tie::Scalar(3p)  Perl Programmers Reference Guide Tie::Scalar(3p)


       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.







































2001-05-24                 perl v5.6.1                          2


