[development] Question about error_reporting()

[Juan Rodriguez]

Hi guys,

I am looking at the implementation of error_reporting:
http://api.drupal.org/api/function/error_handler/5

and I don't understand this line:

  if ($errno & (E_ALL ^ E_NOTICE)) {


does it means that all errors but E_NOTICE are gonna be reported ?
(what I really dont get is the meaning of the ^ php operator....)....

I am trying to understand this code because my watchdog table is
getting full of PHP warning
messages, and I was not able to found a configuration option to filter
this kind of messages.

Would it be possible to change the behaviour to report messages above
or below a specific level like
it is done in php.ini ?

Thanks in advance.