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The X Window System Programming and Applications with Xt. OSF/MOTIF Edition by Douglas A. Young

ISBN: 0-13-497074-8 Standard Edition 0-13-972167-3       Publisher: Prentice Hall       Pages: 553pp       Price: £26.05

Categories:   X Windows

Reviewed by Philip Kerrigan in C Vu 3-2 (Jan 1991)

The X window system with all its thousands of associated calls is very complex. I am using SCO Open Desktop and weighing the documentation provided I find that it comes in at 4 kilograms for a width of 23cm.

Douglas Young's book concentrates on telling you how to use all this, and it does it pretty well considering the complexity of X. Almost from the first it starts off with practical examples and it gradually builds up an entire library of useful utilities that can be used in your own programs. You should be sitting in front of a terminal compiling programs when reading this book, or you will lose a lot of its benefit.

The book starts with a brief but concentrated chapter describing X windows, how it works and how it is used. The next chapter starts explaining the naming conventions with a programming example, a simple hello program. My first surprise was that the executable was 500k, the second that it actually worked.

However I did have a few problems. Despite the standardisation of X, not every environment is the same. I had to add the socket library to the example make file before I could link, and not all the command line resources listed in chapter 3 worked. The book carefully distinguishes what things are part of each layer, always using the highest available function, Motif before Xt Intrinsics, and avoiding Xlib where possible.

Following chapters introduce the resource manager and contain useful tips on X-program design. A chapter on using widgets results in the production of a number of useful program fragments. This is followed by a chapter on events and event handling, including timeout events that allow the construction of an onscreen clock. Other chapters are on handling color (sic), raster images, graphics, texts and fonts, X graphics primitives, and inter-client communication.

Although many people might not want to go that far, the last three chapters, comprising almost 20% of the book, describe how to extend the X system by creating new custom widgets. The 14-page index is very clear, with the page numbers of the principle reference in bold, which I found very useful. At university I had a lecturer who always judged a book by its index ratio, and this gives 532/14=52. However, given the subject matter, it is still not good enough and does not refrence loops or address_mode.

Comment: Philip works in program development for a firm based in Milan. It is nice to find our overseas members actively contributing. I have an article of his on Unix scripts waiting for space. You will see it in either the March issue, or more likely (if the C++ enthusiasts do their stuff) in the May one. - Francis Glassborow.