  <span class="emphasis"><em>Shared</em></span> <span class="emphasis"><em>objects:</em></span> Unsafe.
        </p>
<h6>
<a name="boost_asio.reference.ip__icmp.resolver.h4"></a>
          <span class="phrase"><a name="boost_asio.reference.ip__icmp.resolver.requirements"></a></span><a class="link" href="resolver.html#boost_asio.reference.ip__icmp.resolver.requirements">Requirements</a>
        </h6>
<p>
          <span class="emphasis"><em>Header: </em></span><code class="literal">boost/asio/ip/icmp.hpp</co