title: Catch not working and how to unset the exception handler
body: <p><strong>catch</strong> is not working because there is installed an exception handler using <strong>set_exception_handler()</strong> </p>
  
  <p>I need "catch" to work, so I guess I need to unset the exception handler somehow. Things such as <strong>set_exception_handler(NULL)</strong> isn't working.</p>
  
  <p><strong>Any ideas how to unset the exception handler?</strong></p>
  
  <pre><code>function my_exception_handler($exception) {
      error_log("caught exception: " . $exception-&gt;getMessage() );
  }
  
  set_exception_handler("my_exception_handler");
  
  // QUESTION: how does on unset it ?
  //set_exception_handler(NULL);
  
  try {
      throw new Exception('hello world');
      error_log("should not happen");
  } catch(Exception $e) {
      error_log("should happen: " . $e-&gt;getMessage());
  }
  </code></pre>
  
  <h2>Actual output:</h2>
  
  <p><em>caught exception: hello world</em></p>
  
  <h2>Desired output:</h2>
  
  <p><em>should happen: hello world</em></p>