How do i catch (custom)exceptions (with custom exception handler) that i have thrown in custom shutdown function ? I am not using any framework.

Example:

```
register_shutdown_function( 'shutdownFunction');
set_exception_handler(      'exceptionHandler');

function exceptionHandler(Exception $exception)
{
    // handle and log exception for later debugging...
}

function shutdownFunction()
{
    // something is not going right...
    if (someVariable != someValue)
        throw new RuntimeException('blah...'); // WILL NOT be caught by exception handler
}

// somewhere else in the code...
throw new Exception('something...'); // WILL be caught by exception handler (but not in shutdown function)

```

The script is using exceptions to communicate that it encountered an error during execution ie. unexpected variable passed to function, database failed to insert row etc...