title: require_once() adds line-break at the beginning of file
body: <p>This is part of my code:</p>
  
  <pre><code>&lt;?php
  ob_start();
  session_start();
  require_once('../engine/class.admin.php');
  $admin = new Admin;
   //some code
  if(!isset($_COOKIE['logged']) &amp;&amp; !isset($_SESSION['logged']) ) {
      //some code
  } else {
      require_once('header.php');
  }
  ob_flush();
  </code></pre>
  
  <p>When i'm trying to load this page, PHP adds a CRLF tags at the beginning of page. Everything looks good, when i remove both require_once() tags, it's impossible to run this code without these files. Where i need to start finding solution of my problem?</p>