Posted to the window with the focus when the user chooses a new input language, either with the hotkey (specified in the Keyboard control panel application) or from the indicator on the system taskbar. 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.
A window receives this message through its WindowProc function.
The new input locale. This parameter can be a combination of the following flags.
The input locale identifier. For more information, see Languages, Locales, and Keyboard Layouts.
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 to DefWindowProc. To reject the change, the application should return zero without calling DefWindowProc.
The language indicator is present on the taskbar only if you have installed more than one keyboard layout and if you have enabled the indicator using the Keyboard control panel application.
Minimum supported client
|Windows 2000 Professional [desktop apps only]|
Minimum supported server
|Windows 2000 Server [desktop apps only]|
Build date: 11/16/2013