title: Is "realpath" redundant in $absolutePath = realpath(__DIR__)? Is __DIR__ always canonical absolute path?
body: <p>Is it a sence to do something like </p>
  
  <pre><code> $dir = realpath(dirname(__FILE__));
   // or for php 5.3+:
   $dir = realpath(__DIR__)
  </code></pre>
  
  <p>Or magic constants like <strong>DIR</strong> and <strong>FILE</strong> always returns absolute path, so realpath is redundant?</p>