Tie::Handle - base class definitions for tied handles

- NAME
- SYNOPSIS
- DESCRIPTION
- MORE INFORMATION
- COMPATIBILITY

# NAME

Tie::Handle - 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 the perltie manpage 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 the perltie manpage 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 represent additional arguments (along the lines of the AnyDBM_File manpage 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 the perltie manpage 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.

Tie::Handle - base class definitions for tied handles