I have the following function which does seem to work as intended.  However, AU3Check throws the errors listed below. Func _mouse_position(Const $l_param) With DllStructCreate($tagPOINT & ";dword;dword;dword;ulong_ptr;", $l_param) Local Const $position = [Abs(.X), Abs(.Y)] EndWith Return $position EndFunc "....au3"(395,8) : error: syntax error With DllStructCreate ~~~~~~~^ "....au3"(395,8) : error: Statement cannot be just an expression. With DllStructCreate ~~~~~~~^ "....