ption_ptr</span><span class="special">()</span> <span class="special">);</span>
        <span class="comment">// if no error, then yay, return value</span>
        <span class="keyword">if</span> <span class="special">(</span> <span class="special">!</span> <span class="identifier">error</span><span class="special">)</span> <span class="special">{</span>
            <span class="comment">// close the channel: no subsequent push() has to succeed</span>
            <span class="identifier">chanp</span><span c