title: Trouble using posix_kill in php
body: <p>I'm using <code>php 5.5.11</code> and when I try to call <code>posix_kill</code> I get the following error:<br>
      <code>Fatal error:  Call to undefined function posix_kill() in /var/www/.../someScript.php on line 861</code></p>
  
  <p>I'm not sure what more information is relevant, feel free to ask.</p>