Using C on the UNIX System

Over the past several years, the use of the UNIX operating system has become widespread as workstations and personal computers that use UNIX have become cheaper and more powerful. Several books have been published on the use of UNIX, and on the use of the C programming language, which is the primary language used with UNIX. However, very little has been written about programming in C specifically for the UNIX operating system.

As a result, those wanting to write systems programs under UNIX have had to learn the hard way, by perusing the often inadequate documentation provided with the operating system, and by examining the source code of existing utilities. Although that is a good way to discover some of the more intricate and clever ways of doing things, it really isn’t a satisfactory way to get started.

This book is an attempt to remedy that situation. It discusses in detail the use of most of the system calls and library routines available to the C programmer on the UNIX operating system.

It is not intended to be an introduction to C programming, nor can it really be considered an “advanced C programming guide.” Rather, it has been written for the person interested in learning to become a “systems programmer” for the UNIX operating system. The student who wishes to work for a university computer center, a systems programmer unfamiliar with UNIX who must now write programs for a UNIX PC or workstation, a bulletin board operator using a UNIX system to support his operation, and the researcher interested in writing his own tools to perform his work will find the material presented in this book useful.

The reader is expected to be fluent in C programming, including the more advanced concepts such as structures and pointers. The ideal reader will have been programming in C for at least six months, and will have had at least a minimal introduction to data structures and computer algorithms such as those used for sorting and searching. A junior (or perhaps a sophomore) in a college-level computer sciences curriculum should have no trouble with the concepts presented here.

Throughout this book small, heavily commented examples have been provided to demonstrate how the various routines being discussed are actually used. You will benefit by actually typing these examples in, compiling them, executing them, and then experimenting with them in order to observe first-hand how they operate.