Volume 7A: XView Programming Manual

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XView Internals

This chapter discusses the internal mechanisms that XView uses to implement the existing

object classes. The information in this chapter should give you the ability to build your own

objects that are “extensible” or are extensions of other existing classes. By writing exten-

sions to XView classes, you can modify their appearance or functionality. By creating new

classes, you can create objects that go beyond what the existing XView library provides.

However, you should be forewarned that building XView extensions is not intended to be a

solution to every problem. You are strongly encouraged to implement the type of object or

enhancements you need using the facilities provided by XView and the existing XView

objects. Furthermore, this chapter should be used as an introductory resource. It does not

contain enough information to fully explain how all the internal XView objects work, nor

does it give you the ability to build an entire library of user interface objects.

If OPEN LOOK compliance is important in your applications, you should be sure that you

fully understand the OPEN LOOK specifications before attempting to build new objects or

modify existing ones. Because the XView internals do not enforce user interface policy, you

could build non-OPEN LOOK-compliant user interface code. However, the existing XView

objects were written to conform to OPEN LOOK as much as possible. ...