The class cursor defines the shape of the cursor when it is in the client area of a window in the class. The system automatically sets the cursor to the given shape when the cursor enters the window's client area and ensures it keeps that shape while it remains in the client area. To assign a cursor shape to a window class, load a predefined cursor shape by using the LoadCursor function and then assign the returned cursor handle to the hCursor member of the WNDCLASSEX structure. Alternatively, provide a custom cursor resource and use the LoadCursor function to load it from the application's resources.
The system does not require a class cursor. If an application sets the hCursor member of the WNDCLASSEX structure to NULL, no class cursor is defined. The system assumes the window sets the cursor shape each time the cursor moves into the window. A window can set the cursor shape by calling the SetCursor function whenever the window receives the WM_MOUSEMOVE message. For more information about cursors, see Cursors.