static function get_global_level () {
		$e = 0;
		$types = array_keys( self::$stack );
		foreach( $types as $t ) {
			$e |= $t;
		}
		return $e;
	}
static function get_global_level () {
		$e = 0;
		$types = array_keys( self::$stack );
		foreach( $types as $t ) {
			$e |= $t;
		}
		return $e;
	}
static function get_global_level ( ) { $ e = 0 ; $ types = array_keys ( self :: $ stack ) ; foreach ( $ types as $ t ) { $ e |= $ t ; } return $ e ; }
get system wide level of errors
@return int
get system wide level of errors