(PHP 4, PHP 5, PHP 7) Checks if the class has been defined

(PHP 4, PHP 5, PHP 7) Gets the class methods' names

(PHP 5 >= 5.4.0, PHP 7) Checks if the trait exists

(PHP 4, PHP 5, PHP 7) Get the default properties of the class

(PHP 4, PHP 5, PHP 7) Returns an array with the name of the defined classes

(PHP 4 >= 4.2.0, PHP 5, PHP 7) Checks if the object is of this class or has this class as one of its parents

(PHP 5 >= 5.3.0, PHP 7) the "Late Static Binding" class name

(PHP 5 >= 5.4.0, PHP 7) Returns an array of all declared traits

(PHP 4, PHP 5, PHP 7) Retrieves the parent class name for object or class

(PHP 5, PHP 7) Attempt to load undefined class