title: Undefined Constant MYSQLI_ASYNC - Non blocking queries in PHP
body: <p>I understand that mysqlnd allows non blocking queries. However, I'm trying:</p>
  
  <pre><code>// goes without saying this code works correctly when second parameter is ommitted
  $link-&gt;query($myQuery, MYSQLI_ASYNC);
  </code></pre>
  
  <p>The error I get is:"Notice: use of undefined constant MYSQLI_ASYNC assumed 'MYSQLI_ASYNC' " 
  and ensuing errors.</p>
  
  <p>PHP Version: 5.3.5-1 ubuntu7.4</p>
  
  <hr>
  
  <p>I don't know if I actually have mysqlnd installed/activated, and I can't find a good resource on how to tell if it is.</p>
  
  <p>Help?</p>