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

(PHP 5 >= 5.1.2, PHP 7) Gets file type public

(PHP 5 >= 5.1.0, PHP 7) Alias of

(PHP 5 >= 5.1.2, PHP 7) Tells if file is readable

(PHP 5 >= 5.3.0, PHP 7) Prepends the doubly linked list with an element

(PHP 5 >= 5.0.0, PHP 7) Creates a copy of the ArrayObject.

(PHP 5 >= 5.3.0, PHP 7) Pushes an element at the end of the doubly linked list

(PHP 5 >= 5.3.0, PHP 7) Move to previous entry

(PHP 5 >= 5.0.0, PHP 7) Returns whether the requested index exists

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