(128..255) should be written C<\x{ab}> rather than C<\xab>, since the
former will turn into a two-byte UTF-8 code, while the latter will
continue to be interpreted as generating a 8-bit byte rather than a
-character. In fact, if C<-w> is turned on, it will produce a warning
+character. In fact, if the C<use warnings> pragma of the C<-w> switch
+is turned on, it will produce a warning
that you might be generating invalid UTF-8.
=item *