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

NAME
       base - Establish	an ISA relationship with base classes at compile time

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

DESCRIPTION
       Unless you are using the	"fields" pragma, consider this module
       discouraged in favor of the lighter-weight "parent".

       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);
	   }

       When "base" tries to "require" a	module,	it will	not die	if it cannot
       find the	module's file, but will	die on any other error.	 After all
       this, should your base class be empty, containing no symbols, "base"
       will die. This is useful	for inheriting from classes in the same	file
       as yourself but where the filename does not match the base module name,
       like so:

	       # in Bar.pm
	       package Foo;
	       sub exclaim { "I	can have such a	thing?!" }

	       package Bar;
	       use base	"Foo";

       There is	no Foo.pm, but because "Foo" defines a symbol (the "exclaim"
       subroutine), "base" will	not die	when the "require" fails to load
       Foo.pm.

       "base" will also	initialize the fields if one of	the base classes has
       it.  Multiple inheritance of fields is NOT supported, if	two or more
       base classes each have inheritable fields the 'base' pragma will	croak.
       See fields for a	description of this feature.

       The base	class' "import"	method is not called.

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

       Class 'Foo' tried to inherit from itself
	   Attempting to inherit from yourself generates a warning.

	       package Foo;
	       use base	'Foo';

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 v5.43.6			  2021-01-24			       base(3)

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