Description
POSIX threads, or pthreads, allow multiple tasks to run concurrently within the same program. This book discusses when to use threads and how to make them efficient. It features realistic examples, a look behind the scenes at the implementation and performance issues, and special topics such as DCE and real-time extensions.
Full Description
Computers are just as busy as the rest of us nowadays. They have lots of tasks to do at once, and need some cleverness to get them all done at the same time.
That's why threads are seen more and more often as a new model for programming. Threads have been available for some time. The Mach operating system, the Distributed Computer Environment (DCE), and Windows NT all feature threads.
One advantage of most UNIX implementations, as well as DCE, is that they conform to a recently ratified POSIX standard (originally 1003.4a, now 1003.1c), which allows your programs to be portable between them. POSIX threads are commonly known as pthreads, after the word that starts all the names of the function calls. The standard is supported by Solaris, OSF/1, AIX, and several other UNIX-based operating systems.
The idea behind threads programming is to have multiple tasks running concurrently within the same program. They can share a single CPU as processes do, or take advantage of multiple CPUs when available. In either case, they provide a clean way to divide the tasks of a program while sharing data.
A window interface can read input on dozens of different buttons, each responsible for a separate task. A network server has to accept simultaneous calls from many clients, providing each with reasonable response time. A multiprocessor runs a number-crunching program on several CPUs at once, combining the results when all are done. All these kinds of applications can benefit from threads.
In this book you will learn not only what the pthread calls are, but when it is a good idea to use threads and how to make them efficient (which is the whole reason for using threads in the first place). The authors delves into performance issues, comparing threads to processes, contrasting kernel threads to user threads, and showing how to measure speed. He also describes in a simple, clear manner what all the advanced features are for, and how threads interact with the rest of the UNIX system.
Topics include:
- Basic design techniques
- Mutexes, conditions, and specialized synchronization techniques
- Scheduling, priorities, and other real-time issues
- Cancellation
- UNIX libraries and re-entrant routines
- Signals
- Debugging tips
- Measuring performance
- Special considerations for the Distributed Computing Environment (DCE)
Colophon
Our look is the result of reader comments, our own experimentation, and feedback from distribution channels. Distinctive covers complement our distinctive approach to technical topics, breathing personality and life into potentially dry subjects. The animal featured on the cover of Pthreads Programming is a silkworm. Silkworms produce silk when they secrete a fine, strong filament while spinning their cocoons. According to legend, the Empress Ling-chi discovered how to unwind the filament approximately 3000 years ago B.C., and thus produced the world's first silk fabric. Silkworms survive exclusively on certain strains of mulberry leaves. The cultivated silkworm no longer exists in the wild. Although silkworms have been cultivated on a relatively small scale elsewhere, few places have both the warm climate and the abundance of mulberry trees that silkworms require, and so Asia, specifically China, continues to be the main producer of silk. UNIX and its attendant programs can be unruly beasts. Nutshell Handbooks help you tame them.
Hanna Dyer designed the cover of this book, based on a series design by Edie Freedman. The image is a 19th-century engraving from the Dover Pictorial Archive. The cover layout was produced with Quark XPress 3.3 using the ITC Garamond font.
The inside layout was designed by Edie Freedman, Jennifer Niederst, and Nancy Priest. Text was prepared by Erik Ray in SGML DocBook 2.4 DTD. The print version of this book was created by translating the SGML source into a set of gtroff macros using a filter developed at ORA by Norman Walsh. Steve Talbott designed and wrote the underlying macro set on the basis of the GNU troff -gs macros; Lenny Muellner adapted them to SGML and implemented the book design. The GNU groff text formatter version 1.09 was used to generate PostScript output. The text and heading fonts are ITC Garamond Light and Garamond Book. The illustrations that appear in the book were created in Macromedia Freehand 5.0 by Chris Reilley. This colophon was written by Clairemarie Fisher O'Leary
