🚀 go-pugleaf

"Martin Golm" <golm@gmx.de> wrote in message
news:3FC72C07.F8402E63@gmx.de...
> Gary Setter wrote:
> > I see that your main window which is the frame for your edit window
reserves
> > memory for a pointer to a tWindow in
> >   wndclass.cbWndExtra = sizeof(tWindow*);
>
> Yes, I do that to forward the messages from the global window procedure
> to the appropriate window's window procedure.
> Interestingly enough this isn't working for the edit control. First I
> didn't use SetWindowLong() with the GWL_WNDPROC parameter. It simply
> didn't exist. Whenever my application received a message for the edit
> control it crashed, and the call stack was non-exisiting (just a lot of
> ???'s). This was because the pointer I cast to tWindow* didn't represent
> a tWindow descendant. Don't know why...
>

I don't understand. Why don't you think that GWL_WNDPROC existis?
I was able to get you app running. I posted some of your code below.

> > But if you can't why not use Get/SetWindowLong(hWnd,GWL_USERDATA) ?
> > That would let you use the same technique to tie that tEdit/tWindow
object
> > to the window handle in the static WndProc function.
>
> Sorry, I don't quite get the point?
>
That's  because I'm a native gibberish speaker ;-) Sorry :-(

Here is some of the code that I changed. The key is using the  GWL_USERDATA
offset, which is available for all windows including EDIT.


static LRESULT CALLBACK WndProc(HWND hWnd, UINT iMessage, WPARAM wParam,
LPARAM
lParam) {
  tWindow* pWindow = reinterpret_cast<tWindow*>(GetWindowLong(hWnd,
GWL_USERDATA));
  if (!pWindow) {
    if (iMessage == WM_CREATE) {
      LPCREATESTRUCT lpcs = reinterpret_cast<LPCREATESTRUCT>(lParam);
      pWindow = reinterpret_cast<tWindow*>(lpcs->lpCreateParams);
      SetWindowLong(hWnd, GWL_USERDATA, reinterpret_cast<long>(pWindow));
      return pWindow->WndProc(hWnd, iMessage, wParam, lParam);
    }
    return DefWindowProc(hWnd, iMessage, wParam, lParam);
  }
  return pWindow->WndProc(hWnd, iMessage, wParam, lParam);
}

void tEdit :: Create() {
  attr.style |= ES_AUTOHSCROLL | ES_LEFT | WS_TABSTOP;
  hWnd = CreateWindowEx(WS_EX_CLIENTEDGE, "EDIT", "", attr.style,
                        attr.left, attr.top, attr.width, attr.height,
                        parent ? parent->GetHandle() : 0, 0,
                        tApp::hInst, reinterpret_cast<void*>(this));
  if (!hWnd)
    throw tXWindow();
  orgWndProc = (WNDPROC)SetWindowLong(hWnd, GWL_WNDPROC,
   (LONG)::WndProc);
  SetWindowLong(hWnd,GWL_USERDATA,(long)this);
  if (!orgWndProc)
    throw tXWindow();
  if (parent)
    parent->AddChild(this);
}