Hi all,
I am practising D with a win api GUI hobby project.
I have a Window class and it resides in module window.d
My WndProc function resides in another module named wnd_proc_module.d
Inside my WndProc, I get the Window class like this.

Window win = cast(Window) (cast(void*) GetWindowLongPtrW(hWnd, GWLP_USERDATA)) ;

So in many situations, I need to check some boolean properties of Window class and call some functions of Window class in WndProc.
But I don't want to expose those props and functions to the user. So if I make them private, I can't access them inside the WndProc function. How do solve this issue. Thanks in advance.

On Tuesday, 11 May 2021 at 09:10:02 UTC, Vinod K Chandran wrote:

Window win = cast(Window) (cast(void*) GetWindowLongPtrW(hWnd, GWLP_USERDATA)) ;

The package protection attribute should work here if the modules reside in the same package (directory)?

module mywindow.window;
import mywindow.wnd_proc_module.d
class Window {
    package int x, y;
}

module mywindow.wnd_proc_module.d
import mywindow.window;
class Proc {
    Window win;
    void doStuff() {
        win.x = 3;
    }
}

On Tuesday, 11 May 2021 at 09:10:02 UTC, Vinod K Chandran wrote:

Assuming window.d and wndproc.d are in the same package (and not the default global package), then you can use package instead of private.

On Tuesday, 11 May 2021 at 10:47:15 UTC, cc wrote:

Thanks. "package" scope worked.

On Tuesday, 11 May 2021 at 10:48:03 UTC, Mike Parker wrote:

On Tuesday, 11 May 2021 at 10:48:03 UTC, Mike Parker wrote:
>
> Assuming window.d and wndproc.d are in the same package (and
> not the default global package), then you can use `package`
> instead of `private`.

Thanks. "package" scope worked.
this is the code now.

```d
package :
        bool misBkClrChanged ;
        void setBkClrInternal(HDC dcHandle)
        {
            RECT rct;
            HBRUSH hBr = CreateSolidBrush(cast(COLORREF) this.mBackColor);
            GetClientRect(this.mHandle, &rct) ;
            FillRect(dcHandle, &rct, hBr) ;
            DeleteObject(hBr) ;
        }
// And this is the wndproc
case WM_ERASEBKGND :
{
    if(win.misBkClrChanged)
    {
         auto dch = cast(HDC) wParam ;
         win.setBkClrInternal(dch) ;
         return 1 ;
     }			}
     break ;
}