The WM_INPUTLANGCHANGEREQUEST message is posted to the application's top-level window when the user chooses an input language, either with an input language change hotkey or from the system languages menu. An application can accept the change by passing the message to the DefWindowProc function or reject the change (and prevent it from taking place) by returning immediately.
WM_INPUTLANGCHANGEREQUEST
fSysCharSet = (BOOL) wParam
hkl = (HKL) lParam;
Parameters
wParam
The lowest bit of this parameter is set if the handle of the keyboard layout can be used with the system character set. The other bits are reserved. For example, in the Russian-language version of Windows 95, this parameter has the low bit set for keyboard layout handles for English (US) and Russian, but cleared for other handles.
hkl
Value of lParam. Identifies the keyboard layout to switch to.
Return Values
This message is posted, not sent, to the application, so the return value is ignored. To accept the change, the application should pass the message on to DefWindowProc. To reject the change, the application should return zero without calling DefWindowProc.
See Also