name of the attribute value to extract. </p></td>
</tr>
<tr>
<td><p><span class="term"><code class="computeroutput">rec</code></span></p></td>
<td><p>A log record view. The attribute value will be sought among those associated with the record. </p></td>
</tr>
</tbody>
</table></div></td>
</tr>
<tr>
<td><p><span class="term">Returns:</span></p></td>
<td><p>The extracted value or a non-empty <code class="computeroutput">value_ref</code> that refers to the value. </p></td>
</tr>
<tr>
<td><p><span class="term">