string set_exception_handler ( callback $exception_handler );

<?php
   function exception_handler(exception) {
      echo "Uncaught exception is : " ,exception->getMessage(), "\n";
   }

   set_exception_handler('exception_handler');
   set_exception_handler();

   throw new Exception('Not Found Exception');
   echo "not included Executed\n";
?>

Uncaught exception is: Not Found Exception