   <tr>
          <td class="paramkey"></td>
          <td></td>
          <td class="paramtype">int&#160;</td>
          <td class="paramname"><em>max_qos_level</em>&#160;</td>
        </tr>
        <tr>
          <td></td>
          <td>)</td>
          <td></td><td></td>
        </tr>
      </table>
</div><div class="memdoc">

<p>Subscribe to a topic. </p>
<dl class="section pre"><dt>Precondition</dt><dd>mqtt_connect must have been called.</dd></dl>
<dl class="params"><dt>Parameters</dt><dd>
  <table cla