Motif appears to be emerging as the de facto standard for widget sets used by programmers working with X. A programmer using a widget set such as Motif may still need to understand and use the Xlib interface, but the X toolkit interface and other X libraries (for example, an X extension that provides a set of 3D functions) are daunting. To give you an idea of the size of the system, the Xlib manual alone is over 1000 pages. For systems of this size and complexity, a good tutorial is essential. It cannot cover everything, but it does need to cover the basic ideas and a selected subset of the system in enough detail so that it provides programmers with the right tools to start building applications. Once the initial plunge is over, the rest of the system can be picked up as needed. The goal of this book is to provide just such a practical, digestible tutorial.
The book is divided into two main parts. The first 350 pages consist of a tutorial covering the basics of Motif and the main functions from outside Motif that would be used by Motif programmers. In the first two chapters, the author provides introductory material covering how X works, the various components that make up the X system, and how Motif applications are structured. The next seven chapters cover selected Motif components including sample programs (on an accompanying floppy disk). Another chapter covers the Common Desktop Environment (CDE) application program interface (API). Two more chapters are devoted to the X toolkit and some selected Xlib functions. The first part concludes with discussions of the Drag and Drop API and UIL, a language that can be used to build Motif applications.
The second part consists of several appendices, which take up almost 200 pages and give brief, manual-style descriptions of the widgets, data structures, and functions mentioned in the first part of the book. These listings are not complete, nor are the descriptions themselves; instead, they give just enough information to enable someone to begin to use and experiment with the API.
The sample programs that are provided in source form on the accompanying floppy can be loaded onto a machine with a Motif development environment, then compiled and run. These examples show care and thought. The major components and functions are demonstrated well, but the programs are short so that users can absorb them easily. More important, the size of these examples makes it feasible to make small changes to the programs and test them out.
The book does have a few problems. A couple of long listings of sample code contain comments and are in typewriter font. Perhaps someone reads these; I do not. Code fragments of just a few lines (less than ten) seem more appropriate. I do not understand why comments are needed and good typesetting is not. There is an implicit assumption in the book that CDE is the user’s window manager, and in a few places it seems that this assumption is pervasive. Perhaps this is the case with Motif 2.1, but if this is so, it means that anyone using a Motif-based program would need CDE. Not everyone wants to use CDE, myself included. For example, I found no mention of XTFILESEARCHPATH; instead, all resources are in directories with a “dt” component. Finally, some packages that might be of interest to Motif developers (such as GUI builders, Xmt, and Lesstif) are not mentioned. However, the appendix gives pointers to Motif resources on both the Web and Usenet.
This book is well organized and quite readable. It should serve well as a tutorial introduction to Motif, at least for professional programmers. It is not a textbook. While it is a bit terse, this is a good feature for those who are used to reading technical information (though it may make reading more difficult for some). I have never learned Motif, in part because I have never really needed it, but if I ever do need to learn it, I will use this book as a starting point.
