troubleshooting Question

CDialog::DoModal() in  amultithreaded application

Avatar of Krip
Krip asked on
Microsoft Development
10 Comments1 Solution1513 ViewsLast Modified:
Hi,

I have A class derived from CDialog.
At some point in the program a random thread (A socket's threadpool) would create a new instance of that class (I tried heap and stack creation both) and calls DoModal() on it. At some point after it's created, the modal's pumpmessage ends up calling the modal's main window parent's PreTranslate (which is the application window) and when that PreTranslte calls CDialog::PreTransle it crashes in CWnd::AssertValid() just above MS's friendly note:

// Note: if either of the above asserts fire and you are
// writing a multithreaded application, it is likely that
// you have passed a C++ object from one thread to another
// and have used that object in a way that was not intended.
// (only simple inline wrapper functions should be used)
//
// In general, CWnd objects should be passed by HWND from
// one thread to another.  The receiving thread can wrap
// the HWND with a CWnd object by using CWnd::FromHandle.
//
// It is dangerous to pass C++ objects from one thread to
// another, unless the objects are designed to be used in
// such a manner.

I assure you I do nothing of the sort.

So what up???
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