will this OO win32API example work with multiple windows?

i'm mainly focused on how this example uses wndproc as friend... im a little confused how it works and im just trying to figure out if and how this would wor开发者_开发知识库k with more than one window

http://www.uta.fi/~jl/pguibook/api2oo.html

Yes, it will work with more than one window because it stores a pointer to the C++ object with the corresponding HWND:

Window *wPtr;
...
SetWindowLongPtr(hWnd, 0, (LONG_PTR) wPtr);

and the global WndProc then retrieves that pointer and calls the object's methods through it:

wPtr = (Window*) ::GetWindowLongPtr(hWnd, 0);
wPtr->WndProc(message, wParam, lParam);

(Note that the original code uses SetWindowLong, and hence won't work in a 64-bit program - I've changed the code above to use SetWindowLongPtr.)