An X Window System Toolkit is a set of library functions layered on top of the X Window System Xlib functions that allows you to simplify the design of applications by providing an underlying set of common user interface functions. Included are mechanisms for defining and expanding interclient and intracomponent interaction independently, masking implementation details from both the application and component implementor.

The fundamental data type of the X Window System Toolkit is the widget. A widget is allocated dynamically and contains state information. Every widget belongs to one widget class that is allocated statically and initialized. The widget class contains the operations allowed on widgets of that class.

You must remap many of the X Widget and X Intrinsics routine names. This remapping is done in a header file called XT@REMAP.H. This file is automatically included by the INTRINSIC.H header file. In debugging your application, see the XT@REMAP.H file to find the remapped names of the X Toolkit routines.

Some of the X Window System header data sets have been renamed from their original distribution names, because of the data set naming conventions in the MVS™ environment. Such name changes are generally restricted to those header files used internally by the actual widget code, rather than the application header files, to minimize the number of changes required for an application to be ported to the MVS environment.

In porting applications to the MVS environment, you might have to make changes to header file names in Table 1.