The last regexp matches, but is dangerous because the string
I<character> position is no longer synchronized to the string I<byte>
position. This generates the warning 'Malformed UTF-8
-character'. C<\C> is best used for matching the binary data in strings
+character'. The C<\C> is best used for matching the binary data in strings
with binary data intermixed with Unicode characters.
Let us now discuss the rest of the character classes. Just as with
$x =~ /foo(?!baz)/; # matches, 'baz' doesn't follow 'foo'
$x =~ /(?<!\s)foo/; # matches, there is no \s before 'foo'
+The C<\C> is unsupported in lookbehind, because the already
+treacherous definition of C<\C> would become even more so
+when going backwards.
+
=head2 Using independent subexpressions to prevent backtracking
The last few extended patterns in this tutorial are experimental as of