SubclassProc typedef Null safety

SubclassProc = LRESULT Function(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam, UINT_PTR uIdSubclass, DWORD_PTR dwRefData)

Application-defined callback function used with the RemoveWindowSubclass and SetWindowSubclass functions.

Implementation

typedef SubclassProc = LRESULT Function(HWND hWnd, UINT uMsg, WPARAM wParam,
    LPARAM lParam, UINT_PTR uIdSubclass, DWORD_PTR dwRefData);