n> <span class="identifier">A</span><span class="special">&gt;&amp;</span> <span class="identifier">n</span><span class="special">)</span> <span class="keyword">const</span><span class="special">;</span>
   <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">class</span> <span class="identifier">charT</span><span class="special">&gt;</span>
   <span class="identifier">const_reference</span> <a class="link" href="match_results.html#boost_regex.match_results.subscript"