title: Multiple echoes of an include error with set_error_handler
body: <p>Why is an include error echoed four times?</p>
  
  <p>Does the system attempts 4 times to "open stream"?</p>
  
  <p>I did :</p>
  
  <pre><code>function errorHandler($errno, $errstr, $errfile, $errline) {
      if ($errno == E_NOTICE ) {
          echo "&lt;br/&gt;".$errno."== E_NOTICE&lt;br/&gt;";
      }
      if ($errno == E_USER_NOTICE) {
          echo "&lt;br/&gt;".$errno."== E_USER_NOTICE&lt;br/&gt;";
      }
      if ($errno == E_DEPRECATED) {
          echo "&lt;br/&gt;".$errno."== E_DEPRECATED&lt;br/&gt;";
      }
      if ($errno == E_USER_DEPRECATED) {
          echo "&lt;br/&gt;".$errno."== E_USER_DEPRECATED&lt;br/&gt;";
      }
      if ($errno == E_STRICT) {
          echo "&lt;br/&gt;".$errno."== E_STRICT&lt;br/&gt;";
      }
      if ($errno == E_WARNING) {
          echo "&lt;br/&gt;".$errno."== E_WARNING&lt;br/&gt;";
      }
      if ($errno == E_USER_WARNING) {
          echo "&lt;br/&gt;".$errno."== E_USER_WARNING&lt;br/&gt;";
      }
      if ($errno == E_ERROR) {
          echo "&lt;br/&gt;".$errno."== E_ERROR&lt;br/&gt;";
      }
      if ($errno == E_USER_ERROR) {
          echo "&lt;br/&gt;".$errno."== E_USER_ERROR&lt;br/&gt;";
      }
  }
  set_error_handler("errorHandler"); 
  </code></pre>
  
  <p>Result :</p>
  
  <pre><code>2== E_WARNING
  
  2== E_WARNING
  
  2== E_WARNING
  
  2== E_WARNING
  </code></pre>