Say we have a global inherited PEAR object (e.g. "$foo"), created in another script with a ErrorHandling state we don't know.

In our script, we have a critical section where this object must die if an error occurs :

<?
// begin of critical section
$foo->setErrorHandling(PEAR_ERROR_DIE);
// ... doing critical things

// end of critical section. previous error handler must be reactivated, but, hey, who is it ?
$foo->setErrorHandling(?);
?>

Solution : setErrorHandling() must return a "thing" which handle the previous error handling state.

<?
// begin of critical section
$previousErrorHandlingState = $foo->setErrorHandling(PEAR_ERROR_DIE);
// ... doing critical things

// end of critical section. previous error handler must be reactivated, and we know it.
$foo->setErrorHandling($previousErrorHandlingState);
?>