Volume 6A: Motif Programming Manual

The Hello, World user interface

The icon Label and the PushButton are contained in a Form, which manages their positions. As in a typical Motif

program, an ApplicationShell at the root of the hierarchy contains the Form. A diagram of the hierarchy appears in the

figure.

The Hello, World widget hierarchy

23.3 Describing an Interface With UIL

An interface description in a UIL module consists of three things:

The widget hierarchy•

The initial resource settings of the individual widgets, which define the "look" of the interface•

The callbacks invoked in response to user actions, which define the "feel" of the application•

The UIL module for the "Hello, World" application is shown in the source code This module defines the widget

hierarchy starting at the Form. Its parent ApplicationShell is created by the C program, which we'll examine later. This

division is typical for an application that creates its interface with UIL because at least one widget must be created by

the program to be used as a parent for the UIL−defined widgets.

/* hello_world.uil −− Illustrate basic UIL programming concepts */

module hello_world

objects = { XmPushButton = gadget; }

23 Introduction to UIL 23.3 Describing an Interface With UIL

631

value

form_margin : 3; ! Value for all−around form margins.

object hello_main : XmForm {

controls {

XmLabel world;

XmPushButton hello;

};

arguments {

XmNshadowThickness = 0;

XmNresizePolicy ...