sub path_actually_used {
   if (is_utf8($_[0]) {
      my $s = $_[0];
      utf8::encode($s);
      return $s;
   } else {
      return $_[0];
   }
}

##</code><code>##

my $s = chr(9734);
mkdir($s);           # ok
utf8::encode($s);
mkdir($s);           # ok
utf8::upgrade($s);
mkdir($s);           # not ok