Serge,
It looks like to me the right way to fix the problem you mentioned. It
doesn't make sense than an unlinked window (a window removed from the tree)
has still a pointer on another window that is still in the tree. (via it's
next, parent or child pointer).
So why not extending your patch and setting wndptr->child and wndptr->parent
to 0 also.
Stephane Lussier
Macadamian Technologies
> -----Original Message-----
> From: Serge Ivanov [mailto:[EMAIL PROTECTED]]
> Sent: Monday, June 12, 2000 10:43 AM
> To: [EMAIL PROTECTED]
> Subject: problems with DestroyWindow
>
>
> It looks like DestroyWindow has severe (potential?) problem.
> There are some
> situations when memory occupied be WND structure is released
> earlier than it
> is expected. It happens when window to be destroyed has any owned windows.
>
> The problem place is very end of DestroyWindow:
> windows/win.c: line 1417:
> ----
> /* Unlink now so we won't bother with the children later on */
>
> if( wndPtr->parent ) WIN_UnlinkWindow(hwnd);
>
> /* Destroy the window storage */
>
> WIN_ReleaseWndPtr(WIN_DestroyWindow( wndPtr ));
> retvalue = TRUE;
> end:
> WIN_ReleaseWndPtr(wndPtr);
> return retvalue;
> }
> ---
> Unlinked wndPtr still keeps pointer to the next window.
> WIN_DestroyWindow is supposed to clean up window data and returns locked
> pointer to next window. So we call WIN_ReleaseWndPtr to unlock it.
>
> Several lines above this point DestroyWindow calls itself to destroy owned
> windows. Sometimes owned window can have owner as next window in chain. So
> it goes to WIN_Release(WIN_Destroy) place. I can't figure out where we
> skipped
> lock increment, but WIN_Release recieves wndPtr with irefCount == 1 so it
> frees memory used by window.
>
> A possible solution is to zero next ptr in UnlinkWindow as follows:
> ----
> Index: win.c
> ===================================================================
> RCS file: /home/cvs/r/corelwine/windows/win.c,v
> retrieving revision 1.92
> diff -u -r1.18 win.c
> --- win.c 2000/06/08 01:01:09 1.92
> +++ win.c 2000/06/08 19:46:31
> @@ -320,6 +320,7 @@
> if (*ppWnd)
> {
> *ppWnd = wndPtr->next;
> + wndPtr->next = NULL;
> ret = TRUE;
> }
> WIN_ReleaseWndPtr(wndPtr);
> ----
> Or we can do it locally in DestroyWindow right after UnlinkWindow call.
>
> Any comments?
>
> --
> Serge Ivanov
> [EMAIL PROTECTED]
>
>
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