WM_FONTCHANGE
wParam = 0; /* not used, must be zero */
lParam = 0L; /* not used, must be zero */An application sends the WM_FONTCHANGE message to all top-level windows in the system after changing the pool of font resources.
This message has no parameters.
An application should return zero if it processes this message.
An application that adds or removes fonts from the system (for example, by using the AddFontResource or RemoveFontResource function) should send this message to all top-level windows.
To send the WM_FONTCHANGE message to all top-level windows, an application can call the SendMessage function with the hwnd parameter set to 0xFFFF.