(PHP 5, PHP 7) Implements interface public bool

(PHP 7) Checks if null is allowed public bool

(PHP 5, PHP 7) Export public static string R

(PHP 5 >= 5.3.0, PHP 7) Creates an alias for a class

(PHP 5 >= 5.3.0, PHP 7) Call a static method

(PHP 5 >= 5.1.0, PHP 7) Computes the intersection of arrays using keys for comparison

(PHP 4 >= 4.0.1, PHP 5, PHP 7) Computes the intersection of arrays

(PHP 5 >= 5.2.0, PHP 7) Returns a list of all supported filters

(PHP 4, PHP 5, PHP 7) Returns the name of the class of an object

(PHP 4, PHP 5, PHP 7) Extract a slice of the array