<span class="special">&lt;</span><span class="keyword">typename</span> Ch<span class="special">,</span> <span class="keyword">typename</span> Traits<span class="special">,</span> <span class="keyword">typename</span> E<span class="special">,</span> 
             <span class="keyword">typename</span> Enabler <span class="special">=</span> <span class="keyword">void</span><span class="special">&gt;</span> 
      <span class="keyword">struct</span> <a class="link" href="../boost/property_tree/customize_stream.