e> 
        public
       construct/copy/destruct</h3>
<div class="orderedlist"><ol class="orderedlist" type="1"><li class="listitem"><pre class="literallayout"><a name="idp40061504-bb"></a><span class="identifier">checked_observer</span><span class="special">(</span><span class="identifier">observer_type</span> <span class="special">&amp;</span> observer<span class="special">,</span> <span class="identifier">checker_type</span> <span class="special">&amp;</span> checker<span class="special">)</span><span c