Advanced Unix Programming (2nd edition)

Book Preface

This book updates the 1985 edition of Advanced UNIX Programming to cover a few changes that have occurred in the last eighteen years. Well, maybe “few” isn’t the right word! And “updates” isn’t right either. Indeed, aside from a sentence here and there, this book is all new. The first edition included about 70 system calls; this one includes about 300. And none of the UNIX standards and implementations discussed in this book—POSIX, Solaris, Linux, FreeBSD, and Darwin (Mac OS X)—were even around in 1985. A few sentences from the 1985 Preface, however, are among those that I can leave almost unchanged:

The subject of this book is UNIX system calls—the interface between the UNIX kernel and the user programs that run on top of it. Those who interact only with commands, like the shell, text editors, and other application programs, may have little need to know much about system calls, but a thorough knowledge of them is essential for UNIX programmers. System calls are the only way to access kernel facilities such as the file system, the multitasking mechanisms, and the interprocess communication primitives. System calls define what UNIX is. Everything else—subroutines and commands—is built on this foundation. While the novelty of many of these higher-level programs has been responsible for much of UNIX’s renown, they could as well have been programmed on any modern operating system. When one describes UNIX as elegant, simple, efficient, reliable, and portable, one is referring not to the commands (some of which are none of these things), but to the kernel.

That’s all still true, except that, regrettably, the programming interface to the kernel is no longer elegant or simple. In fact, because UNIX development has splintered into many directions over the last couple of decades, and because the principal standards organization, The Open Group, sweeps up almost everything that’s out there (1108 functions altogether), the interface is clumsy, inconsistent, redundant, error-prone, and confusing. But it’s still efficient, reliably implemented, and portable, and that’s why UNIX and UNIX-like systems are so successful. Indeed, the UNIX system-call interface is the only widely implemented portable one we have and are likely to have in our lifetime

Contents

• Chapter 1 Fundamental Concepts
• Chapter 2 Basic File I/O
• Chapter 3 Advanced File I/O
• Chapter 4 Terminal I/O
• Chapter 5 Processes and Threads
• Chapter 6 Basic Interprocess Communication
• Chapter 7 Advanced Interprocess Communication
• Chapter 8 Networking and Sockets
• Chapter 9 Signals and Timers