WM_USERCHANGED
The
WM_USERCHANGED message is sent to all windows after the user has logged on or
off. When the user logs on or off, the system updates the user-specific
settings. The system sends this message immediately after updating the
settings.
WM_USERCHANGED
wParam = 0;
// not used, must be zero
lParam = 0;
// not used, must be zero
Return Values
An application
should return zero if it processes this message.