(PHP 5 >= 5.3.0, PHP 7) Checks if an iterator is attached

(PHP 5 >= 5.3.0, PHP 7) Check validity public

(PHP 5 >= 5.1.0, PHP 7) Get the current key

(PHP 5 >= 5.1.0, PHP 7) Check whether the inner iterator's current element has children

(PHP 5 >= 5.1.0, PHP 7) No purpose public

(PHP 5 >= 5.3.0, PHP 7) Pops a node from the end of the doubly linked list

(PHP 5 >= 5.3.0, PHP 7) Inserts an element in the queue by sifting it up.

(PHP 5 >= 5.1.0, PHP 7) Get max depth public

(PHP 5 >= 5.4.0, PHP 7) Calls the callback with the current value, the current key and the inner iterator

(PHP 5 >= 5.2.0, PHP 7) Get flags public int