cial">)</span><span class="special">;</span>
  <span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> Signature<span class="special">&gt;</span> <span class="emphasis"><em><span class="identifier">unspecified</span></em></span> <a class="link" href="imported_class.html#idp40228016-bb"><span class="identifier">call</span></a><span class="special">(</span><span class="keyword">const</span> <span class="identifier">std</span><span class="special">::</span><s