l. Provided the program calls
          <code class="computeroutput"><span class="identifier">io_service</span><span class="special">.</span><span class="identifier">notify_fork</span><span class="special">()</span></code>
          at the appropriate times, Boost.Asio will recreate any internal file descriptors
          (such as the "self-pipe trick" descriptor used for waking up
          a reactor). The notification is usually performed as follows:
        </p>
<pre class="programlisting"><span class="i