PHP- Set a Top Level Exception Handler

The set_exception_handler() function sets a user-defined function to handle all uncaught exceptions.

<?php
 function myException($exception)
 {
 echo "<b>Exception:</b> " , $exception->getMessage();
 }

 set_exception_handler('myException');

 throw new Exception('Uncaught Exception occurred');
 ?>

The output of the code above should be something like this:

Exception:</strong> Uncaught Exception occurred

In the code above there was no “catch” block. Instead, the top level exception handler triggered. This function should be used to catch uncaught exceptions.

Rules for exceptions

• Code may be surrounded in a try block, to help catch potential exceptions
• Each try block or “throw” must have at least one corresponding catch block
• Multiple catch blocks can be used to catch different classes of exceptions
• Exceptions can be thrown (or re-thrown) in a catch block within a try block

A simple rule: If you throw something, you have to catch it.