Unix/Linux Go Back    


CentOS 7.0 - man page for tie::scalar (centos section 3pm)

Linux & Unix Commands - Search Man Pages
Man Page or Keyword Search:   man
Select Man Page Set:       apropos Keyword Search (sections above)


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

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

SYNOPSIS
	   package NewScalar;
	   require Tie::Scalar;

	   @ISA = qw(Tie::Scalar);

	   sub FETCH { ... }	       # Provide a needed method
	   sub TIESCALAR { ... }       # Overrides inherited method

	   package NewStdScalar;
	   require Tie::Scalar;

	   @ISA = qw(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". Associates a new scalar
	   instance with the specified class. "LIST" would represent additional arguments (along
	   the lines of AnyDBM_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 specific actions upon the destruction of an instance.

   Tie::Scalar vs Tie::StdScalar
       "Tie::Scalar" provides all the necessary methods, but one should realize they do not do
       anything useful. Calling "Tie::Scalar::FETCH" or "Tie::Scalar::STORE" results in a
       (trappable) croak. And if you inherit from "Tie::Scalar", you must provide either a "new"
       or a "TIESCALAR" method.

       If you are looking for a class that does everything for you you don't define yourself, use
       the "Tie::StdScalar" class, not the "Tie::Scalar" one.

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

perl v5.16.3				    2013-02-26				 Tie::Scalar(3pm)
Unix & Linux Commands & Man Pages : ©2000 - 2018 Unix and Linux Forums


All times are GMT -4. The time now is 06:34 AM.