How do I call SetWindowLong() in the 64-bit versions of Windows?

Question

In the header file WinUser.h, there is a part in which the constants of the second parameter of SetWindowLong() are defined.

// ...

#define GWL_WNDP         


        

Answer 1

    As specified in 
    //If config is _WIN64 then use new versioned macro

    #define GWLP_WNDPROC        (-4)
    #define GWLP_HINSTANCE      (-6)
    #define GWLP_HWNDPARENT     (-8)
    #define GWLP_USERDATA       (-21)
    #define GWLP_ID             (-12)

    //else for _WIN32

    #undef GWL_WNDPROC
    #undef GWL_HINSTANCE
    #undef GWL_HWNDPARENT
    #undef GWL_USERDATA