Windows provides several predefined system-global window classes. These classes define special control windows that carry out common input tasks, such as letting the user direct scrolling, type text, and select from a list of names. The predefined window classes are available to all applications and can be used any number of times to create any number of control windows. See the description of the CreateWindow function in the Microsoft Windows Programmer's Reference, Volume 2, for a list of the predefined window classes.