WXDLLEXPORT bool wxYieldIfNeeded();
// Yield to other apps/messages and disable user input
-WXDLLEXPORT bool wxSafeYield(wxWindow *win = NULL);
+WXDLLEXPORT bool wxSafeYield(wxWindow *win = NULL, bool onlyIfNeeded = FALSE);
// Enable or disable input to all top level windows
WXDLLEXPORT void wxEnableTopLevelWindows(bool enable = TRUE);