Perl 5 version 12.3 documentation
Returns the length in characters of the value of EXPR. If EXPR is omitted, returns length of
$_. If EXPR is undefined, returns
Like all Perl character operations, length() normally deals in logical characters, not physical bytes. For how many bytes a string encoded as UTF-8 would take up, use
length(Encode::encode_utf8(EXPR))(you'll have to
use Encodefirst). See Encode and perlunicode.