="comment">// Attribute contained value type. </span>
  <span class="keyword">typedef</span> <span class="identifier">base_type</span><span class="special">::</span><span class="identifier">mapped_type</span> <a name="boost.log.sinks.basic_custom_mapping.mapped_type"></a><span class="identifier">mapped_type</span><span class="special">;</span>           <span class="comment">// Mapped value type. </span>

  <span class="comment">// <a class="link" href="basic_custom_mapping.html#boost.log.sinks.basic_custom