comment">// types</span>
  <span class="keyword">typedef</span> <span class="keyword">void</span> <a name="boost.signals2.optional_last__idp75552224.result_type"></a><span class="identifier">result_type</span><span class="special">;</span>

  <span class="comment">// <a class="link" href="optional_last__idp75552224.html#idp75537808-bb">invocation</a></span>
  <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <a class="link" href="../../InputIterator.