(PHP 5 >= 5.1.0, PHP 7) Has children public

(PHP 5 >= 5.3.0, PHP 7) Adds all objects from another storage

(PHP 5 >= 5.0.0, PHP 7) Get the number of public properties in the ArrayObject

(PHP 5 >= 5.3.0, PHP 7) Returns whether the requested index exists

(PHP 5 >= 5.1.0, PHP 7) Return current file position

(PHP 5 >= 5.2.2, PHP 7) Gets absolute path to file

(PHP 5 >= 5.1.0, PHP 7) Begin Iteration public

(PHP 5 >= 5.1.2, PHP 7) Tells if the entry is writable

(PHP 5 >= 5.4.0, PHP 7) Serializes the storage

(PHP 5 >= 5.1.0, PHP 7) Detach an observer