This function retrieves information about a window class.
BOOL GetClassInfo( HINSTANCE hInstance, LPCTSTR lpClassName, LPWNDCLASS lpWndClass );
Handle to the instance of the application that created the class. To retrieve information about classes defined by the system (such as buttons or list boxes), set this parameter to NULL.
Long pointer to a null-terminated string that contains the class name. The name must be that of a preregistered class or a class registered by a previous call to the RegisterClass function. Alternatively, this parameter can be an atom. If so, it must be a class atom created by a previous call to the RegisterClass function. The atom must be in the low-order word of lpClassName; the high-order word must be zero.
Long pointer to a WNDCLASS structure that receives the information about the class.
Nonzero indicates that the function finds a matching class and successfully copies the data. Zero indicates failure. To get extended error information, call GetLastError.