title: How to fix Warning: preg_replace(): Empty regular expression?
body: <p>I use the Modified shop software.</p>
  
  <p>I want to generate a sitemap with a module.</p>
  
  <p>I get the following error message:</p>
  
  <blockquote>
    <p>Warning: preg_replace(): Empty regular expression in /www/htdocs/****/*****.de/inc/shopstat_hrefMask.inc.php on line 39</p>
  </blockquote>
  
  <p>On Line 39:</p>
  
  <pre><code>  $newstring  = preg_replace($search,$replace,$newstring);
  </code></pre>
  
  <p>What can I do before this to check whether the request is empty?</p>