>boost/signals2/signal.hpp</a>&gt;

</span><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> Signature<span class="special">,</span> 
         <span class="keyword">typename</span> Combiner <span class="special">=</span> <a class="link" href="optional_last_value.html" title="Class template optional_last_value">boost::signals2::optional_last_value</a><span class="special">&lt;</span><span class="identifier">R</span><span class="special">&gt;</span><sp