ing the POSIX wrapper
API to be used, the only option-setting sequences that have any effect are \B
and \Z, causing REG_NOTBOL and REG_NOTEOL, respectively, to be passed to
<b>regexec()</b>.
</P>
<P>
The use of \x{hh...} to represent UTF-8 characters is not dependent on the use
of the <b>/8</b> modifier on the pattern. It is recognized always. There may be
any number of hexadecimal digits inside the braces. The result is from one to
six bytes, encoded according to the original UTF-8 rules of RFC 2279. This
