The function initiates keystroke intercept and immediately returns control to your Windows HLLAPI application. This frees your application to perform other tasks while waiting for keystrokes. Once initiated, the function will post a WinHLLAPIAsync message to the window specified by hWnd whenever the user sends a key to the PS. After notification, the intercepted keystrokes can be handled in any way that is allowed by a normal EHLLAPI application. Take note that the keystroke buffer is of limited size so each keystroke should be handled and removed from the buffer.