ename</span> U<span class="special">&gt;</span> 
  <a name="idm14263-bb"></a><span class="identifier">category</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">initializer_list</span><span class="special">&lt;</span> <span class="identifier">U</span> <span class="special">&gt;</span> list<span class="special">,</span> <span class="identifier">metadata_type</span> meta <span class="special">=</span> <span class="special">{</span><s