ant</span><span class="special">&lt;</span> <span class="identifier">channel_type</span> <span class="special">&gt;</span> <a name="boost.log.sources.basic_channel_logger.channel_attribute"></a><span class="identifier">channel_attribute</span><span class="special">;</span>  <span class="comment">// Channel attribute type. </span>
  <span class="keyword">typedef</span> <span class="emphasis"><em><span class="identifier">unspecified</span></em></span>                                  <a name="boost.log.source