#define HANDLE_WM_COMMAND(hwnd, wParam, lParam, fn) \
    ((fn)((hwnd), (int)(LOWORD(wParam)), (HWND)(lParam), (UINT)HIWORD(wParam)), 0L)
#define FORWARD_WM_COMMAND(hwnd, id, hwndCtl, codeNotify, fn) \
    (void)(fn)((hwnd), WM_COMMAND, MAKEWPARAM((UINT)(id),(UINT)(codeNotify)), (LPARAM)(HWND)(hwndCtl))

#define HANDLE_WM_CREATE(hwnd, wParam, lParam, fn) \
    ((fn)((hwnd), (LPCREATESTRUCT)(lParam)) ? 0L : (LRESULT)-1L)
#define FORWARD_WM_CREATE(hwnd, lpCreateStruct, fn) \
    (BOOL)(DWORD)(fn)((hwnd), WM_CREATE, 0L, (LPARAM)(LPCREATESTRUCT)(lpCreateStruct))

#define HANDLE_WM_DESTROY(hwnd, wParam, lParam, fn) \
    ((fn)(hwnd), 0L)
#define FORWARD_WM_DESTROY(hwnd, fn) \
    (void)(fn)((hwnd), WM_DESTROY, 0L, 0L)

#define HANDLE_WM_ERASEBKGND(hwnd, wParam, lParam, fn) \
    (LRESULT)(DWORD)(BOOL)(fn)((hwnd), (HDC)(wParam))
#define FORWARD_WM_ERASEBKGND(hwnd, hdc, fn) \
   (BOOL)(DWORD)(fn)((hwnd), WM_ERASEBKGND, (WPARAM)(HDC)(hdc), 0L)

#define HANDLE_WM_LBUTTONDOWN(hwnd, wParam, lParam, fn) \
    ((fn)((hwnd), FALSE, (int)(short)LOWORD(lParam), (int)(short)HIWORD(lParam), (UINT)(wParam)), 0L)
#define FORWARD_WM_LBUTTONDOWN(hwnd, fDoubleClick, x, y, keyFlags, fn) \
    (void)(fn)((hwnd), (fDoubleClick) ? WM_LBUTTONDBLCLK : WM_LBUTTONDOWN, (WPARAM)(UINT)(keyFlags), MAKELPARAM((x), (y)))

#define HANDLE_WM_LBUTTONDBLCLK(hwnd, wParam, lParam, fn) \
    ((fn)((hwnd), TRUE, (int)(short)LOWORD(lParam), (int)(short)HIWORD(lParam), (UINT)(wParam)), 0L)

#define HANDLE_WM_LBUTTONUP(hwnd, wParam, lParam, fn) \
    ((fn)((hwnd), (int)(short)LOWORD(lParam), (int)(short)HIWORD(lParam), (UINT)(wParam)), 0L)
#define FORWARD_WM_LBUTTONUP(hwnd, x, y, keyFlags, fn) \
    (void)(fn)((hwnd), WM_LBUTTONUP, (WPARAM)(UINT)(keyFlags), MAKELPARAM((x), (y)))

#define HANDLE_WM_MOUSEMOVE(hwnd, wParam, lParam, fn) \
    ((fn)((hwnd), (int)(short)LOWORD(lParam), (int)(short)HIWORD(lParam), (UINT)(wParam)), 0L)
#define FORWARD_WM_MOUSEMOVE(hwnd, x, y, keyFlags, fn) \
    (void)(fn)((hwnd), WM_MOUSEMOVE, (WPARAM)(UINT)(keyFlags), MAKELPARAM((x), (y)))

#define HANDLE_WM_SETFOCUS(hwnd, wParam, lParam, fn) \
    ((fn)((hwnd), (HWND)(wParam)), 0L)
#define FORWARD_WM_SETFOCUS(hwnd, hwndOldFocus, fn) \
    (void)(fn)((hwnd), WM_SETFOCUS, (WPARAM)(HWND)(hwndOldFocus), 0L)

#define HANDLE_WM_KILLFOCUS(hwnd, wParam, lParam, fn) \
    ((fn)((hwnd), (HWND)(wParam)), 0L)
#define FORWARD_WM_KILLFOCUS(hwnd, hwndNewFocus, fn) \
    (void)(fn)((hwnd), WM_KILLFOCUS, (WPARAM)(HWND)(hwndNewFocus), 0L)

#define HANDLE_WM_SETTEXT(hwnd, wParam, lParam, fn) \
    ((fn)((hwnd), (LPCTSTR)(lParam)), 0L)
#define FORWARD_WM_SETTEXT(hwnd, lpszText, fn) \
    (void)(fn)((hwnd), WM_SETTEXT, 0L, (LPARAM)(LPCTSTR)(lpszText))

#define HANDLE_MSG(hwnd, message, fn)    \
    case (message): return HANDLE_##message((hwnd), (wParam), (lParam), (fn))