1Tie::Scalar(3pm)       Perl Programmers Reference Guide       Tie::Scalar(3pm)
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NAME

6       Tie::Scalar, Tie::StdScalar - base class definitions for tied scalars
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SYNOPSIS

9           package NewScalar;
10           require Tie::Scalar;
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12           @ISA = (Tie::Scalar);
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14           sub FETCH { ... }           # Provide a needed method
15           sub TIESCALAR { ... }       # Overrides inherited method
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17           package NewStdScalar;
18           require Tie::Scalar;
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20           @ISA = (Tie::StdScalar);
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22           # All methods provided by default, so define only what needs be overridden
23           sub FETCH { ... }
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25           package main;
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27           tie $new_scalar, 'NewScalar';
28           tie $new_std_scalar, 'NewStdScalar';
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DESCRIPTION

31       This module provides some skeletal methods for scalar-tying classes.
32       See perltie for a list of the functions required in tying a scalar to a
33       package. The basic Tie::Scalar package provides a "new" method, as well
34       as methods "TIESCALAR", "FETCH" and "STORE". The Tie::StdScalar package
35       provides all the methods specified in  perltie. It inherits from
36       Tie::Scalar and causes scalars tied to it to behave exactly like the
37       built-in scalars, allowing for selective overloading of methods. The
38       "new" method is provided as a means of grandfathering, for classes that
39       forget to provide their own "TIESCALAR" method.
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41       For developers wishing to write their own tied-scalar classes, the
42       methods are summarized below. The perltie section not only documents
43       these, but has sample code as well:
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45       TIESCALAR classname, LIST
46           The method invoked by the command "tie $scalar, classname". Asso‐
47           ciates a new scalar instance with the specified class. "LIST" would
48           represent additional arguments (along the lines of AnyDBM_File and
49           compatriots) needed to complete the association.
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51       FETCH this
52           Retrieve the value of the tied scalar referenced by this.
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54       STORE this, value
55           Store data value in the tied scalar referenced by this.
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57       DESTROY this
58           Free the storage associated with the tied scalar referenced by
59           this.  This is rarely needed, as Perl manages its memory quite
60           well. But the option exists, should a class wish to perform spe‐
61           cific actions upon the destruction of an instance.
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MORE INFORMATION

64       The perltie section uses a good example of tying scalars by associating
65       process IDs with priority.
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69perl v5.8.8                       2001-09-21                  Tie::Scalar(3pm)
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