my $ra = [ 'A', 'B', 'C' ];

print STDERR '1. ra = ' . Dumper( $ra );

test_ra( $ra );

print STDERR '2. ra = ' . Dumper( $ra );

exit;


sub test_ra
{
    my $data = shift;
    foreach my $item ( @{ $data } )
    {
        $item = 'Z';
    }
}