(PHP 5 >= 5.3.0, PHP 7) Activates the circular reference collector

(PECL apd 0.2-0.4) Throw an error, a callstack and then exit

(PECL weakref >= 0.2.0) Advances to the next map element

(PHP 5 >= 5.2.0, PHP 7) Returns the peak of memory allocated by PHP

(PHP 4, PHP 5, PHP 7) Gets the current PHP version

(PECL apc >= 3.0.0) Removes a stored variable from the cache

(PECL apc >= 3.1.1) Get current item public

(PECL apc >= 3.1.1) Constructs an APCIterator iterator object

(PECL runkit >= 0.7.0) Copies a method from class to another

(PECL uopz >= 1.0.0) Implements an interface at runtime