#! perl -slw
use strict;

sub t{
    ## Strict complient lexical access to a glob
    our %hash; 

    ## Localise it for use as an alias 
    ## to an inbound hash ref	
    local *hash =  shift; 

    ## no need to dereference the hashref
    print "$_ => $hash{ $_ }" for keys %hash;
}

my %hash = ( 'A'..'Z' );

t( \%hash );
__END__
P:\test>test
S => T
A => B
O => P
W => X
K => L
Y => Z
E => F
Q => R
M => N
C => D
I => J
G => H
U => V