title: Simulate a simple "warning" in PHP
body: <p>How can I simulate or force a warning in PHP? Is there a simple and common way to do this? Thank you!</p>
  
  <p>I need it for an example script, because a webserver doesn't send any output, if there is a warning at any script. <code>error_handling(E_ALL)</code> displays the <em>warning with regular output</em>, but <code>error_handling(0)</code> hides not only the warning, it also hides the regular output ...? </p>