Question

Is the AfxMessageBox function thread safe?

I see the MFC code behind AfxMessageBox invoking such as AfxGetMainWnd()->GetSafeHwnd() and CCmdTarget::GetRoundingFrame_()->GetSafeHwnd(), and I’m wondering about its thread safety.

If I have multiple GUI threads, is it OK to invoke AfxMessageBox from either of them?

Answer 1

Yes it is thread-safe. From MSDN:

If AfxGetMainWnd is called from the application’s primary thread, it returns the application’s main window according to the above rules. If the function is called from a secondary thread in the application, the function returns the main window associated with the thread that made the call.