Tie::Handle

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



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". Asso-
           ciates a new glob instance with the specified class. "LIST" would
           represent 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 spe-
           cific 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 acci-
       dent 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 v5.8.6                       2001-09-21                    Tie::Handle(3)