$x++;
$o->foo++;
$x=7
$o->foo = 7;
chomp($x);
chomp($o->foo);

sub truncate
{
  my $string = shift;
  if (length($$string) > 10)
  {
    $$string = substr($$string, 0, 10);
  }
}
truncate(\$x);
truncate(\{$o->foo});