ss="identifier">regex_replace</span></code></a> all expect that
            the character sequence upon which they operate, is encoded in the same
            character encoding as the regular expression object with which they are
            used. For Unicode regular expressions that behavior is undesirable: while
            we may want to process the data in UTF-32 "chunks", the actual
            data is much more likely to encoded as either UTF-8 or UTF-16. Therefore
            the header &lt;boost/re