base(3)          Perl Programmers Reference Guide         base(3)



NAME
       base - Establish IS-A relationship with base classes at
       compile time

SYNOPSIS
           package Baz;
           use base qw(Foo Bar);

DESCRIPTION
       Allows you to both load one or more modules, while setting
       up inheritance from those modules at the same time.
       Roughly similar in effect to

           package Baz;
           BEGIN {
               require Foo;
               require Bar;
               push @ISA, qw(Foo Bar);
           }

       If any of the listed modules are not loaded yet, base
       silently attempts to "require" them (and silently contin-
       ues if the "require" failed).  Whether to "require" a base
       class module is determined by the absence of a global
       variable $VERSION in the base package.  If $VERSION is not
       detected even after loading it,  will define $VER-
       SION in the base package, setting it to the string "-1,
       set by base.pm".

       Will also initialize the fields if one of the base classes
       has it.  Multiple inheritence of fields is NOT supported,
       if two or more base classes each have inheritable fields
       the 'base' pragma will croak.  See fields, public and pro-
       tected for a description of this feature.

DIAGNOSTICS
       Base class package "%s" is empty.
           base.pm was unable to require the base package,
           because it was not found in your path.

HISTORY
       This module was introduced with Perl 5.004_04.

CAVEATS
       Due to the limitations of the implementation, you must use
       base before you declare any of your own fields.

SEE ALSO
       fields



perl v5.8.8                 2001-09-21                    base(3)