Volume 6A: Motif Programming Manual

Despite all we've just said, realize that the entire motivating factor behind this principle is to optimize the method by

which managers negotiate sizes and positions of their children. If a manager only has one child, it does not matter if

you create the manager widget as managed or not. Also, the geometry management constraints of some widgets are

such that no negotiation is required between the parent and the children. In these situations, it is not necessary to

create the manager as an unmanaged widget, even though it has children. We will explain these cases as they arise.

In the rest of this chapter, we examine the basic manager widget classes and present examples of how they can be

used. While geometry management is the most obvious and widely used aspect of the widget class, managers are also

responsible for keyboard traversal, gadget display, and gadget event handling. Many of the resources of the Manager

metaclass are inherited by each of its subclasses for handling these tasks.

9.3 The BulletinBoard Widget

The BulletinBoard is the most basic of the manager widget subclasses. The BulletinBoard widget does not enforce

position or size policies on its children, so it is rarely used by applications as a general geometry manager for widgets.

The BulletinBoard is the superclass for the Form widget and all of the predefined Motif dialog widgets. To support

these roles, the BulletinBoard has a number of resources that are used specifically for communicating with

DialogShells.

The BulletinBoard ...