Description:
------------
---
From manual page: http://www.php.net/class.dateinterval
---

starting 5.5, the object has new properties that are not documented. The last update for doc standpoint is (PHP 5 >= 5.3.0)

DateInterval Object
(
/*  docummented  */
    [y] => 0
    [m] => 0
    [d] => 4
    [h] => 10
    [i] => 8
    [s] => 35
    [invert] => 0
    [days] => 4

/*  new in PHP 5.5, not documented */
    [weekday] => 0
    [weekday_behavior] => 0
    [first_last_day_of] => 0
    [special_type] => 0
    [special_amount] => 0
    [have_weekday_relative] => 0
    [have_special_relative] => 0
)