(PHP 5, PHP 7 >= 5.5.0, PHP 7) Sets the process title

(PHP 4 >= 4.3.0, PHP 5, PHP 7) Gets the current include_path configuration option

(PHP 4, PHP 5, PHP 7) Gets the version of the current Zend engine

(PHP 4, PHP 5, PHP 7) Sets the value of a configuration option

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

(PHP 4, PHP 5, PHP 7) Gets the value of an environment variable

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

(PHP 4, PHP 5, PHP 7) Returns an array with the names of included or required files

(PHP 4, PHP 5, PHP 7) Returns an array with the names of all modules compiled and loaded

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