(PHP 5 >= 5.3.0, PHP 7) Peeks at the node from the top of the queue

(PHP 5 >= 5.1.2, PHP 7) Gets the inode change time

(PHP 5 >= 5.2.0, PHP 7) Sort the entries with a user-defined comparison function and maintain key association

(PHP 5 >= 5.1.0, PHP 7) Returns the inner iterator for the current entry.

(PHP 5 >= 5.2.2, PHP 7) Serializes the storage

(PHP 5 >= 5.3.0, PHP 7) Return current node pointed by the iterator

(PHP 5 >= 5.3.0, PHP 7) Returns a PHP array from the fixed array

(PHP 5 >= 5.2.0, PHP 7) Sort entries using a "natural order" algorithm

(PHP 5 >= 5.3.0, PHP 7) Constructs a new empty heap

(PHP 5, PHP 7) Rewind the iterator to the first element of the top level inner iterator