You can specify a default menu, called a class menu, when you register a window class. To do so, you assign the name of the menu-template resource to the lpszMenuName member of the WNDCLASS structure used to register the class.
By default, every window is assigned the class menu for its window class so you do not need to explicitly load the menu and assign it to each window. You can override the class menu by specifying a different menu handle in a call to the CreateWindowEx function. You can also change a window's menu after it is created by using the SetMenu function. For more information, see Window Classes.