(PHP 4 >= 4.0.3, PHP 5, PHP 7) Register a function for execution on each tick

(PHP 4, PHP 5, PHP 7) Register a function for execution on shutdown

(PHP 4, PHP 5, PHP 7) Returns an array comprising a function's argument list

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

(PHP 4 >= 4.0.4, PHP 5, PHP 7) Call a callback with an array of parameters

(PHP 4, PHP 5, PHP 7) Call the callback given by the first parameter

(PHP 4, PHP 5, PHP 7) Return an item from the argument list

(PHP 4, PHP 5, PHP 7) Returns the number of arguments passed to the function

(PHP 5 >= 5.3.0, PHP 7) Call a static method and pass the arguments as array

(PHP 4, PHP 5, PHP 7) Return TRUE if the given function has been defined