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If you are an experienced C programmer with a working knowledge of UNIX, you cannot afford to be without this up-to-date tutorial on the system call interface and the most important functions found in the ANSI C library. Rich Stevens describes more than 200 system calls and functions; since he believes the best way to learn code is to read code, a brief example accompanies each description.
Building upon information presented in the first 15 chapters, the author offers chapter-long examples teaching you how to create a database library, a PostScript printer driver, a modem dialer, and a program that runs other programs under a pseudo terminal. To make your analysis and understanding of this code even easier, and to allow you to modify it, all of the code in the book is available via UUNET.
A 20-page appendix provides detailed function prototypes for all the UNIX, POSIX, and ANSI C functions that are described in the book, and lists the page on which each prototype function is described in detail. Additional tables throughout the text and a thorough index make Advanced Programming in the UNIX Environment an invaluable reference tool that all UNIX programmers - beginners to experts - will want on their bookshelves.
Advanced Programming in the UNIX Environment is applicable to all major UNIX releases, especially System V Release 4 and the latest release of 4.3BSD, including 386BSD. These real-world implementations allow you to more clearly understand the status of the current and future standards, including IEEE POSIX and XPG3.
(Each chapter begins with an Introduction and concludes with a Summary.)
Files and Directories.
Input and Output.
Programs and Processes.
ANSI C Features.
Unix Time Values.
System Calls and Library Functions.
System V Release 4.
Relationship of Standards and Implementations.
ANSI C Limits.
sysconf, pathconf, and fpathconf Functions.
FIPS 151-1 Requirements.
Summary of Limits.
Indeterminate Run-Time Limits.
Feature Test Macros.
Primitive System Data Types.
Conflicts Between Standards.
dup and dup2 Functions.
stat, fstat, and lstat Functions.
Set-User-ID and Set-Group-ID.
File Access Permissions.
Ownership of New Files and Directories.
chmod and fchmod Functions.
chown, fchown, and lchown Functions.
link, unlink, remove, and rename Functions.
symlink and readlink Functions.
mkdir and rmdir Functions.
chdir, fchdir, and getcwd Functions.
Special Device Files.
sync and fsync Functions.
Summary of File Access Permission Bits.
Streams and FILE Objects.
Standard Input, Standard Output, and Standard Error.
Opening a Stream.
Reading and Writing a Stream.
Standard I/O Efficiency.
Positioning a Stream.
Alternatives to Standard I/O.
Supplementary Group IDs.
Other Data Files.
Time and Date Routines.
Memory Layout of a C Program.
setjmp and longjmp Functions.
getrlimit and setrlimit Functions.
wait and waitpid Functions.
wait3 and wait4 Functions.
Changing User IDs and Group IDs.
tcgetpgrp and tcsetpgrp Functions.
Shell Execution of Programs.
Orphaned Process Groups.
Interrupted System Calls.
Reliable Signal Terminology and Semantics.
kill and raise Functions.
alarm and pause Functions.
sigsetjmp and siglongjmp Functions.
Special Input Characters.
Getting and Setting Terminal Attributes.
Terminal Option Flags.
Baud Rate Functions.
Line Control Functions.
Terminal Window Size.
termcap, terminfo, and curses.
System V Release 4.
readv and writev Functions.
readn and writen Functions.
Memory Mapped I/O.
SVR4 Streams log Driver.
4.3+BSD syslog Facility.
popen and pclose Functions.
System V IPC.
Identifiers and Keys.
Advantages and Disadvantages.
Passing File Descriptors.
System V Release 4.
An Open Server, Version 1.
Client-Server Connection Functions.
System V Release 4.
An Open Server, Version 2.
Centralized or Decentralized?
PostScript Communication Dynamics.
Server Source Code.
Client Source Code.
Opening Pseudo-Terminal Devices.
System V Release 4.
Using the pty Program.
Our Header File.
Standard Error Routines.
Like most operating systems, Unix provides numerous services to the programs that are running - open a file, read a file, start a new program, allocate a region of memory, get the current time-of-day, and so on. This has been termed the system call interface. Additionally, the standard C library provides numerous functions that are used by almost every C program (format a variable's value for output, compare two strings, etc.).
The system call interface and the library routines have traditionally been described in Sections 2 and 3 of the Unix Programmer's Manual. This book is not a duplication of these sections. Examples and rationale are missing from the Unix Programmer's Manual, and that's what this book provides.
This book also describes these standards. But instead of just describing the standards by themselves, we describe them in relation to popular implementations of the standards - System V Release 4 and the forthcoming 4.4BSD. This provides a real-world description, which is often lacking from the standard itself and from books that describe only the standard.
Almost every function and system call is demonstrated with a small, complete program. This lets us see the arguments and return values and is often easier to comprehend than the use of the function in a much larger program. But since some of the small programs are contrived examples, a few bigger examples are also included (Chapters 16, 17, 18, and 19). These larger examples demonstrate the programming techniques in larger, real-world examples.
All the examples have been included in the text directly from their source files. A machine-readable copy of all the examples is available via anonymous FTP from the Internet host ftp.uu.net in the file published/books/stevens.advprog.tar.Z. Obtaining the source code allows you to modify the programs from this text and experiment with them on your system.
4.3+BSD 4.3BSD 4.3BSD Tahoe 4.3BSD Reno 4.4BSD? | | BSD Net 1 | BSD Net 2 | | | | | | | | | | | | | | | | | +-+----+-------+---+--+---+---+----+-+---+---+-+--+-+ 1986 1987 1988 + 1989 + 1990 + 1991 1992 | | | + + | + SVR3.0 SVR3.1 SVR3.2+ + SVR4 + XPG3 ANSI C POSIX.1
In this text we use the term 4.3+BSD to refer to the Unix system from Berkeley that is somewhere between the BSD Net 2 release and 4.4BSD.
At the time of this writing, 4.4BSD was not released, so the system could not be called 4.4BSD. Nevertheless a simple name was needed to refer to this system and 4.3+BSD is used throughout the text.Most of the examples in this text have been run on four different versions of Unix:
I am especially grateful to Brian Kernighan for his help in the book. His numerous thorough reviews of the entire manuscript and his gentle prodding for better prose hopefully show in the final result. Steve Rago was also a great resource, both in reviewing the entire manuscript and answering many questions about the details and history of System V. My thanks to the other technical reviewers used by Addison-Wesley, who provided valuable comments on various portions of the manuscript: Maury Bach, Mark Ellis, Jeff Gitlin, Peter Honeyman, John Linderman, Doug McIlroy, Evi Nemeth, Craig Partridge, Dave Presotto, Gary Wilson, and Gary Wright.
Keith Bostic and Kirk McKusick at the U.C. Berkeley CSRG provided an account that was used to test the examples on the latest BSD system. (Many thanks to Peter Salus too.) Sam Nataros and Joachim Sacksen at UHC provided the copy of SVR4 used to test the examples. Trent Hein helped obtain the alpha and beta copies of BSD/386.
Other friends have helped in many small, but significant ways over the past few years: Paul Lucchina, Joe Godsil, Jim Hogue, Ed Tankus, and Gary Wright. My editor at Addison-Wesley, John Wait, has been a great friend through it all. He never complained when the due date slipped and the page count kept increasing. A special thanks to the National Optical Astronomy Observatories (NOAO), especially Sidney Wolff, Richard Wolff, and Steve Grandi, for providing computer time.
Real Unix books are written using troff and this book follows that time-honored tradition. Camera-ready copy of the book was produced by the author using the groff package written by James Clark. Many thanks to James Clark for providing this excellent system and for his rapid response to bug fixes. Perhaps someday I will really understand troff footer traps.
I welcome electronic mail from any readers with comments, suggestions, or bug fixes: firstname.lastname@example.org.
W. Richard Stevens