pan class="identifier">Base</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Derived</span><span class="special">&gt;</span>
<span class="keyword">struct</span> <span class="identifier">is_virtual_base_of</span> <span class="special">:</span> <span class="keyword">public</span> <em class="replaceable"><code><a class="link" href="integral_constant.html" title="integral_constant">true_type</a>-or-<a class="link" href="integral_constant.html" title="integral_cons