(PHP 4 >= 4.0.4, PHP 5, PHP 7) Returns an array of all defined variables

(PHP 4 >= 4.0.6, PHP 5, PHP 7) Filters elements of an array using a callback function

(PHP 5 >= 5.1.0, PHP 7) Calculate the product of values in an array

(PHP 5, PHP 7) Export a reflection method. public

(PHP 5 >= 5.1.0, PHP 7) Sets static property value

(PHP 7) Gets the $this value of the generator

(PHP 5 >= 5.3.0, PHP 7) Gets namespace name

(PHP 5 >= 5.0.2, PHP 7) Checks if the interface has been defined

(PHP 5, PHP 7) Gets modifiers public int Ref

(PHP 7) Checks if the function has a specified return type