This message is sent when the Windows initialization file, WIN.INI, changes. Any application that makes a change to WIN.INI should send this message to all top-level windows.
| Parameter | Description |
| wParam | Is not used. | |
| lParam | Points to a string that specifies the name of the section that has changed (the string does not include the square brackets). |
To send the WM_WININICHANGE message to all top-level windows, an application can use the SendMessage function with the hWnd parameter set to 0xFFFF.
Although it is incorrect to do so, some applications send this message with lParam set to NULL. If an application receives this message with a NULL lParam, it should check all sections in WIN.INI that affect the application.