title: 304 Not Modified issue
body: <p>Sorry for the probably wrong title. I am writing some code to handle If-Modified-Since and If-None-Match requests as part of caching. Everything works perfect except for that PHP returns some content (an empty line) after the headers. The page content should be empty instead. The code that I am using is:</p>
  
  <pre><code>&lt;?php
  $lastmod = filemtime($f);
  $etag = '"'.dechex($lastmod).'"';
  if ($_SERVER['HTTP_IF_MODIFIED_SINCE'] == $last_mod || $_SERVER['HTTP_IF_NONE_MATCH'] == $etag) {
    header('HTTP/1.1 304 Not Modified');
    header('Content-Length: 0');
    exit();
  }
  ?&gt;
  </code></pre>