     </tr>
      </table>
</div><div class="memdoc">
<p>The returned strings are own by the library and MUST not be freed or altered. However, the returned array <code>keys</code> MUST be freed by the user.</p>
<dl class="params"><dt>Parameters</dt><dd>
  <table class="params">
    <tr><td class="paramname">req</td><td>the request. </td></tr>
    <tr><td class="paramname">keys</td><td>the memory location where the library will store the pointer to the array of keys. </td></tr>
    <tr><td class="paramname">