(defpackage "WIN32"
  (:modern t)
  (:use "FFI")
  (:shadowing-import-from "EXPORTING"
    #:defconstant #:defun #:defmacro
    #:def-c-type #:def-c-enum #:def-c-struct #:def-c-var #:def-call-out))

(in-package "WIN32")

(default-foreign-language :stdc-stdcall) ; WINAPI means __stdcall

(def-c-type handle c-pointer)
(def-c-type dword uint32)
(def-c-type word uint16)

(default-foreign-library "user32.dll")

(defconstant MB_OK 0)

(def-call-out MessageBoxA (:return-type int)
  (:arguments (parent handle) (text c-string) (caption c-string) (type uint)))

(win32:MessageBoxA nil "Hello, Win32 API World!" "Hello, World!" win32:MB_OK)