$hr->{'foo'}='bar';

do_something_mutley($hr);

sub do_something_mutley
{
 my $lhr=shift;
 my $baz=$lhr->{'foo'};
 # Various stuff would happen here.
 return ($baz);
}

##</code><code>##

$hr->{'foo'}='bar';

do_something_mutley($hr->{'foo'});

sub do_something_mutley
{
 my $baz=shift;
 # Various stuff would happen here.
 return ($baz);
}