an class="special">,</span> 
         <span class="keyword">typename</span> Group <span class="special">=</span> <span class="keyword">int</span><span class="special">,</span> <span class="keyword">typename</span> GroupCompare <span class="special">=</span> std::less<span class="special">&lt;</span><span class="identifier">Group</span><span class="special">&gt;</span><span class="special">,</span> 
         <span class="keyword">typename</span> SlotFunction <span class="special">=</span> <a class="link" hre