P request packet asking for ipaddr.</p>
<dl class="params"><dt>Parameters</dt><dd>
  <table class="params">
    <tr><td class="paramname">netif</td><td>the lwip network interface on which to send the request </td></tr>
    <tr><td class="paramname">ipaddr</td><td>the IP address for which to ask </td></tr>
  </table>
  </dd>
</dl>
<dl class="section return"><dt>Returns</dt><dd>ERR_OK if the request has been sent ERR_MEM if the ARP packet couldn't be allocated any other err_t on failure </dd></dl>

</div>
</d