</span>
  <span class="special">{</span>
  <span class="keyword">static</span> <span class="keyword">const</span> <span class="identifier">value</span> <span class="special">=</span> <span class="identifier">unspecified</span><span class="special">;</span>
  <span class="keyword">typedef</span> <span class="identifier">mpl</span><span class="special">::</span><span class="identifier">bool_</span><span class="special">&lt;</span><span class="keyword">true</span><span class="special">-</span><span class="iden