 or disconnected from the system.</p>
<dl class="params"><dt>Parameters</dt><dd>
  <table class="params">
    <tr><td class="paramdir">[in]</td><td class="paramname">cbfun</td><td>The new callback, or <code>NULL</code> to remove the currently set callback. </td></tr>
  </table>
  </dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>The previously set callback, or <code>NULL</code> if no callback was set or the library had not been <a class="el" href="intro_guide.html#intro_init">initialized</a>.</dd><