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base - Establish IS-A relationship with base class at compile time


package Baz;
use base qw(Foo Bar);


Roughly similar in effect to

    require Foo;
    require Bar;
    push @ISA, qw(Foo Bar);

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 protected for a description of this feature.

When strict 'vars' is in scope, base also lets you assign to @ISA without having to declare @ISA with the 'vars' pragma first.

If any of the base classes are not loaded yet, base silently requires them (but it won't call the import method). Whether to require a base class package is determined by the absence of a global $VERSION in the base package. If $VERSION is not detected even after loading it, base will define $VERSION in the base package, setting it to the string -1, set by


This module was introduced with Perl 5.004_04.


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