In Windows 3.x, a 16-bit Windows-based application could call the GetCaretBlinkTime function to save the current blink time, then call the SetCaretBlinkTime function to adjust the blink time during its processing of the WM_SETFOCUS message. The application would restore the saved blink time for the use of other applications by calling SetCaretBlinkTime during its processing of the WM_KILLFOCUS message. However, this technique does not work on Windows NT and Windows 95, because they are robust, multithreaded environments. Specifically, the deactivation of one application is not synchronized with the activation of another application, so that if one application hangs, another application can still be activated.
Win32-based applications should respect the blink time chosen by the user. The SetCaretBlinkTime function should only be called by an application that allows the user to set the blink time.