tie::scalar(3pm) [osx man page]

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 v5.16.2							    2012-08-26							  Tie::Scalar(3pm)

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

NAME

       Tie::Handle, Tie::StdHandle  - base class definitions for tied handles

SYNOPSIS

	   package NewHandle;
	   require Tie::Handle;

	   @ISA = qw(Tie::Handle);

	   sub READ { ... }	       # Provide a needed method
	   sub TIEHANDLE { ... }       # Overrides inherited method

	   package main;

	   tie *FH, 'NewHandle';

DESCRIPTION

       This module provides some skeletal methods for handle-tying classes. See perltie for a list of the functions required in tying a handle to
       a package.  The basic Tie::Handle package provides a "new" method, as well as methods "TIEHANDLE", "PRINT", "PRINTF" and "GETC".

       For developers wishing to write their own tied-handle classes, the methods are summarized below. The perltie section not only documents
       these, but has sample code as well:

       TIEHANDLE classname, LIST
	   The method invoked by the command "tie *glob, classname". Associates a new glob instance with the specified class. "LIST" would repre-
	   sent additional arguments (along the lines of AnyDBM_File and compatriots) needed to complete the association.

       WRITE this, scalar, length, offset
	   Write length bytes of data from scalar starting at offset.

       PRINT this, LIST
	   Print the values in LIST

       PRINTF this, format, LIST
	   Print the values in LIST using format

       READ this, scalar, length, offset
	   Read length bytes of data into scalar starting at offset.

       READLINE this
	   Read a single line

       GETC this
	   Get a single character

       CLOSE this
	   Close the handle

       OPEN this, filename
	   (Re-)open the handle

       BINMODE this
	   Specify content is binary

       EOF this
	   Test for end of file.

       TELL this
	   Return position in the file.

       SEEK this, offset, whence
	   Position the file.

	   Test for end of file.

       DESTROY this
	   Free the storage associated with the tied handle 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.

MORE INFORMATION

       The perltie section contains an example of tying handles.

COMPATIBILITY

       This version of Tie::Handle is neither related to nor compatible with the Tie::Handle (3.0) module available on CPAN. It was due to an
       accident that two modules with the same name appeared. The namespace clash has been cleared in favor of this module that comes with the
       perl core in September 2000 and accordingly the version number has been bumped up to 4.0.

perl v5.8.0							    2002-06-01							  Tie::Handle(3pm)

Linux and UNIX Man Pages

tie::scalar(3pm) [osx man page]

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