/code></a>
        object whose matched member is false.
      </p>
<p>
        The overloads that accept a string, return a reference to the <a class="link" href="sub_match.html" title="sub_match"><code class="computeroutput"><span class="identifier">sub_match</span></code></a> object representing the
        character sequence that matched the named sub-expression <span class="emphasis"><em>n</em></span>.
        In the event that there is no such named sub-expression then returns a <a class="link" href="