Function handling Functions

• call_user_func — Call the callback given by the first parameter
• call_user_func_array — Call a callback with an array of parameters
• create_function — Create a function dynamically by evaluating a string of code
• forward_static_call — Call a static method
• forward_static_call_array — Call a static method and pass the arguments as array
• func_get_arg — Return an item from the argument list
• func_get_args — Returns an array comprising a function's argument list
• func_num_args — Returns the number of arguments passed to the function
• function_exists — Return true if the given function has been defined
• get_defined_functions — Returns an array of all defined functions
• register_shutdown_function — Register a function for execution on shutdown
• register_tick_function — Register a function for execution on each tick
• unregister_tick_function — De-register a function for execution on each tick