On 2/27/2011 8:52 AM, Simen kjaeraas wrote:
Tyro[a.c.edwards] <nos...@home.com> wrote:I'm trying to convert some c++ code that defines T func(par...) { Controller * pCtrl = WinGetLong<Controller *> (hwnd); . . . switch(msg) { case FirstMatch: pCtrl = new Controller (hwnd, reinterpret_cast<CREATESTRUCT *> (lParam)); break; } } I'm not sure why I need a pointer to the class, just trying to figure it out.Ah. You would not need a pointer to the class in D. Instead, your function would look something like this: T funct(par...) { auto pCtrl = WinGetLong!Controller(hwnd); ... switch(msg) { case FirstMatch: pCtrl = new Controller(hWnd, cast(CREATESTRUCT*)lParam); break; } } C++ classes are in some ways more akin to D structs, in that: class A {}; void foo(){ A bar; } bar would be allocated on the stack in C++, while in D bar would be a pointer to a class instance on the heap. (well, it would be null, but when you set it to something, that something would reside on the heap)
Ok, that's essentially what I have, except that I used Controller pCtrl vice auto. WinGetLong however, is a template that calls GetWindowLongPtrA() and casts it's result (in this case) to Controller. GetWindowLongPtrA() returns LONG_PTR (aka int) and therefore fails miserably on the cast attempt. On the reverse, there is a WinSetLong that attempts to cast Controller to int for use with SetWindowLongPtrA(). Neither of these functions complain when I use Controller* but I end up with the problem of trying to initialize a pointer with a reference to Controller.
