title: PHP: require_once library -> failed to open stream
body: <p>I might be a bit confused and may need your help with this.
  I'm inside <code>inc/newsletter.php</code> and want to include a library that is inside <code>lib/mailchimp-api-class</code> </p>
  
  <p>How do I refer to this class file?</p>
  
  <p>I thought it should be …</p>
  
  <p><code>require_once '../lib/mailchimp-api-class/MCAPI.class.php';</code></p>
  
  <p><img src="https://i.stack.imgur.com/zw6Bo.png" alt="enter image description here"></p>
  
  <p>However, this doesn't work … </p>
  
  <pre><code>Warning: require_once(../lib/mailchimp-api-class/MCAPI.class.php) [function.require-
  once]: failed to open stream: No such file or directory in /Users/myname/htdocs/wr/
  wp-content/themes/mytheme/inc/newsletter.php on line 6
  </code></pre>