Re: Initializing a class pointer

[Simen kjaeraas]

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)

--
Simen