an class="identifier">shared_ptr</span><span class="special">&lt;</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">ostream</span> <span class="special">&gt;(&amp;</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">clog</span><span class="special">,</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">null_deleter</span><span class="special">()));</span>

    <span cla