#!/usr/bin/perl
use strict;
use warnings;
use Data::Dumper;

sub foo(%) {
    my %hash = @_;

    return Dumper \%hash;
}


my %bar = ( eins => 1, zwei => 2 );

my $baz = foo(%bar);
print $baz;
_ _END_ _
$VAR1 = {
          'eins' => 1,
          'zwei' => 2
        };