AIX Version 4.3 Differences Guide

Chapter 8. Graphical Environment Enhancements
Prior to the release of AIX Version 4.3, IBM shipped X11 Release 5 and additional
backward-compatibility libraries plus Motif Version 1.2. AIX Version 4.3 provides
graphics updates to two existing products. The first update, release 6 of the
X-window system (X11R6), allows developers to use new extensions and
enhancements to existing extensions. The second update, MotifNext or Motif 2.1,
provides a range of new function including thread safe libraries and 64-bit
enablement.
8.1 X-Windows Architecture Review
The X-windows architecture consists of three basic components: The client,
protocol, and server. These components will be the subject of the following
sections.
8.1.1 Client
8.1.2 Protocol
The X Client is a software application that requests services from another
application called the server, possibly across a network. A typical example would
be a stock control application that used the services of an X Station to display
output and accept user input from a keyboard or other input device. It is normally
written in a high-level language, commonly C, and is linked with one or more of
the X libraries. The instructions that the application developer uses to interact
with the server are very low-level and allow them to open a connection with the
server, create and manipulate windows, draw elementary shapes (lines,
rectangles, circles, characters, and so on), and handle events, such as mouse
movements or keystrokes. To increase productivity, toolkits have been developed
that perform complex operations by calling several elementary subroutines. The
most elaborate toolkits, such as Athena or Motif, also contain widgets. Widgets
are program objects with a predefined appearance and behavior, such as a menu
push button. The standard toolkits provided with AIX are:
Xt
Xaw
Xmu
Xext
Xi
Xm
The basic X toolkit with hundreds of standard functions, also called
intrinsics.
The Athena Widget set from the X Consortium.
Miscellaneous utilities.
The extension library.
The input extension library. It manages the peripherals, that is,
keyboard and mouse.
The Motif library of widgets with a 3D-look.
The protocol is a formal description of the conversation that is carried out
between the client and the server. The server and clients exchange information
using messages. These messages are contained in packets that can be
transported over a network if necessary. There are four packet types:
Request Used by the client to ask the server to perform an action.
Reply
Used by the server to answer the client after a request has been
received.
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