r">unique</span>
    <span class="special">{</span>
        <span class="comment">// swap is called by multi_pass::swap()</span>
        <span class="keyword">void</span> <span class="identifier">swap</span><span class="special">(</span><span class="identifier">unique</span><span class="special">&amp;);</span>

        <span class="comment">// destroy is called whenever the last copy of a multi_pass is</span>
        <span class="comment">// destructed (ownership_policy::release() returned true)</span>
    