vars(3)

NNAAMMEE
       vars - Perl pragma to predeclare global variable names

SSYYNNOOPPSSIISS
           use vars qw($frob @mung %seen);

DDEESSCCRRIIPPTTIIOONN
       This will predeclare all the variables whose names are in
       the list, allowing you to use them under "use strict", and
       disabling any typo warnings.

       Unlike pragmas that affect the $^H hints variable, the use
       vars and use subs declarations are not BLOCK-scoped.  They
       are thus effective for the entire file in which they
       appear.  You may not rescind such declarations with no
       vars or no subs.

       Packages such as the AAuuttooLLooaaddeerr and SSeellffLLooaaddeerr that delay
       loading of subroutines within packages can create problems
       with package lexicals defined using my(). While the vvaarrss
       pragma cannot duplicate the effect of package lexicals
       (total transparency outside of the package), it can act as
       an acceptable substitute by pre-declaring global symbols,
       ensuring their availability to the later-loaded routines.

       See the section on Pragmatic Modules in the perlmod
       manpage.