(PECL spl_types >= 0.1.0) Returns all consts (possible values) as an array.

(PHP 5 >= 5.3.0, PHP 7) Compare priorities in order to place elements correctly in the heap while sifting

(PHP 5 >= 5.3.0, PHP 7) Return current node index

(PHP 5 >= 5.3.0, PHP 7) Checks whether the doubly linked list is empty.

(PHP 5 >= 5.3.0, PHP 7) Rewind iterator back to the start

(PHP 5 >= 5.3.0, PHP 7) Sets a new value at a specified index

(PHP 5 >= 5.5.0, PHP 7) Reinitialises the array after being unserialised

(PHP 5 >= 5.3.0, PHP 7) Counts the number of elements in the heap.

(PHP 5 >= 5.1.0, PHP 7) Exchange the array for another one.

(PHP 5 >= 5.3.6, PHP 7) Removes all objects except for those contained in another storage from the current