libc.texinfo

一个C源代码分析器

\input texinfo                  @c -*- Texinfo -*-
@comment %**start of header (This is for running Texinfo on a region.)
@setfilename libc.info
@settitle The GNU C Library
@setchapternewpage odd
@comment %**end of header (This is for running Texinfo on a region.)

@c This tells texinfo.tex to use the real section titles in xrefs in
@c place of the node name, when no section title is explicitly given.
@set xref-automatic-section-title
@smallbook

@c  I've already told people the printed edition will be 0.06
@set EDITION 0.06 DRAFT
@set VERSION 1.09 Beta
@set UPDATED 24 October 1994
@set ISBN 1-882114-53-1

@ifinfo
This file documents the GNU C library.

This is Edition @value{EDITION}, last updated @value{UPDATED},
of @cite{The GNU C Library Reference Manual}, for Version @value{VERSION}.

Copyright (C) 1993, 1994 Free Software Foundation, Inc.

Permission is granted to make and distribute verbatim copies of
this manual provided the copyright notice and this permission notice
are preserved on all copies.

@ignore
Permission is granted to process this file through TeX and print the
results, provided the printed document carries copying permission
notice identical to this one except for the removal of this paragraph
(this paragraph not being relevant to the printed manual).

@end ignore
Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided also that the
section entitled ``GNU Library General Public License'' is included
exactly as in the original, and provided that the entire resulting
derived work is distributed under the terms of a permission notice
identical to this one.

Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions,
except that the text of the translations of the section entitled ``GNU
Library General Public License'' must be approved for accuracy by the
Foundation.
@end ifinfo

@iftex
@shorttitlepage The GNU C Library Reference Manual
@end iftex
@titlepage
@center @titlefont{The GNU C Library}
@sp 1
@center @titlefont{Reference Manual}
@sp 2
@center Sandra Loosemore
@center with
@center Richard M. Stallman, Roland McGrath, and Andrew Oram
@sp 3
@center Edition @value{EDITION}
@sp 1
@center last updated @value{UPDATED}
@sp 1
@center for version @value{VERSION}
@page
@vskip 0pt plus 1filll
Copyright @copyright{} 1993, 1994 Free Software Foundation, Inc.
@sp 2
Published by the Free Software Foundation @*
675 Massachusetts Avenue, @*
Cambridge, MA 02139 USA @*
Printed copies are available for $50 each. @*
ISBN @value{ISBN} @*

Permission is granted to make and distribute verbatim copies of
this manual provided the copyright notice and this permission notice
are preserved on all copies.

Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided also that the
section entitled ``GNU Library General Public License'' is included
exactly as in the original, and provided that the entire resulting
derived work is distributed under the terms of a permission notice
identical to this one.

Permission is granted to copy and distribute translations of this manual
into another language, under the above conditions for modified versions,
except that the text of the translation of the section entitled ``GNU
Library General Public License'' must be approved for accuracy by the
Foundation.
@end titlepage
@page

@ifinfo
@node Top, Introduction, (dir), (dir)
@top Main Menu
This is Edition @value{EDITION}, last updated @value{UPDATED}, of
@cite{The GNU C Library Reference Manual}, for Version @value{VERSION}
of the GNU C Library.
@end ifinfo


@menu
* Introduction::                Purpose of the GNU C Library.
* Error Reporting::             How the GNU Library functions report
                                 error conditions.
* Memory Allocation::           Your program can allocate memory dynamically
                                 and manipulate it via pointers.
* Character Handling::          Character testing and conversion functions.
* String and Array Utilities::  Utilities for copying and comparing
                                 strings and arrays.
* Extended Characters::         Support for extended character sets.
* Locales::                     The country and language can affect
                                 the behavior of library functions.
* Searching and Sorting::       General searching and sorting functions.
* Pattern Matching::            Matching wildcards and regular expressions,
                                 and shell-style ``word expansion''.
* I/O Overview::                Introduction to the I/O facilities.
* Streams: I/O on Streams.      High-level, portable I/O facilities.
* Low-Level I/O::               Low-level, less portable I/O.
* File System Interface::       Functions for manipulating files.
* Pipes and FIFOs::             A simple interprocess communication mechanism.
* Sockets::                     A more complicated interprocess communication
                                 mechanism, with support for networking.
* Low-Level Terminal Interface::How to change the characteristics
                                 of a terminal device.
* Mathematics::                 Math functions (transcendental functions,
                                 random numbers, absolute value, etc.).
* Arithmetic::                  Low-level arithmetic functions.
* Date and Time::               Functions for getting the date and time,
                                 and for conversion between formats.
* Non-Local Exits::             The @code{setjmp} and @code{longjmp} facilities.
* Signal Handling::             All about signals; how to send them,
                                 block them, and handle them.
* Process Startup::             Writing the beginning and end of your program.
* Processes::                   How to create processes and run other programs.
* Job Control::                 All about process groups and sessions.
* Users and Groups::            How users are identified and classified.
* System Information::          Getting information about the
                                 hardware and software configuration
                                 of the machine a program runs on.
* System Configuration::        Parameters describing operating system limits.

Appendices

* Language Features::           C language features provided by the library. 

* Library Summary::             A summary showing the syntax, header file,
                                 and derivation of each library feature.
* Maintenance::                 How to install and maintain the GNU C Library.
* Copying::                     The GNU Library General Public License says
                                 how you can copy and share the GNU C Library.

Indices

* Concept Index::               Index of concepts and names.
* Type Index::                  Index of types and type qualifiers.
* Function Index::              Index of functions and function-like macros.
* Variable Index::              Index of variables and variable-like macros.
* File Index::                  Index of programs and files.

 --- The Detailed Node Listing ---

Introduction

* Getting Started::             Getting Started
* Standards and Portability::   Standards and Portability
* Using the Library::           Using the Library
* Roadmap to the Manual::       Roadmap to the Manual

Standards and Portability

* ANSI C::                      The American National Standard for the
                                 C programming language.  
* POSIX::                       The IEEE 1003 standards for operating systems.
* Berkeley Unix::               BSD and SunOS.
* SVID::                        The System V Interface Description.  

Using the Library

* Header Files::                How to use the header files in your programs.
* Macro Definitions::           Some functions in the library may really
                                 be implemented as macros.
* Reserved Names::              The C standard reserves some names for
                                 the library, and some for users.
* Feature Test Macros::         How to control what names are defined.

Error Reporting

* Checking for Errors::         How errors are reported by library functions.
* Error Codes::                 What all the error codes are.
* Error Messages::              Mapping error codes onto error messages.

Memory Allocation

* Memory Concepts::             An introduction to concepts and terminology.
* Dynamic Allocation and C::    How to get different kinds of allocation in C.
* Unconstrained Allocation::    The @code{malloc} facility allows fully general
                                 dynamic allocation.
* Obstacks::                    Obstacks are less general than malloc
                                 but more efficient and convenient.
* Variable Size Automatic::     Allocation of variable-sized blocks
                                 of automatic storage that are freed when the
                                 calling function returns.
* Relocating Allocator::        Waste less memory, if you can tolerate
                                 automatic relocation of the blocks you get.
* Memory Warnings::             Getting warnings when memory is nearly full.

Unconstrained Allocation

* Basic Allocation::            Simple use of @code{malloc}.
* Malloc Examples::             Examples of @code{malloc}.  @code{xmalloc}.
* Freeing after Malloc::        Use @code{free} to free a block you
                                 got with @code{malloc}.
* Changing Block Size::         Use @code{realloc} to make a block
                                 bigger or smaller.
* Allocating Cleared Space::    Use @code{calloc} to allocate a
                                 block and clear it.
* Efficiency and Malloc::       Efficiency considerations in use of
                                 these functions.
* Aligned Memory Blocks::       Allocating specially aligned memory:
                                 @code{memalign} and @code{valloc}.
* Heap Consistency Checking::   Automatic checking for errors.
* Hooks for Malloc::            You can use these hooks for debugging
				 programs that use @code{malloc}.
* Statistics of Malloc::        Getting information about how much
				 memory your program is using.
* Summary of Malloc::           Summary of @code{malloc} and related functions.

Obstacks

* Creating Obstacks::		How to declare an obstack in your program.
* Preparing for Obstacks::	Preparations needed before you can
				 use obstacks.
* Allocation in an Obstack::    Allocating objects in an obstack.
* Freeing Obstack Objects::     Freeing objects in an obstack.
* Obstack Functions::		The obstack functions are both
				 functions and macros.
* Growing Objects::             Making an object bigger by stages.
* Extra Fast Growing::		Extra-high-efficiency (though more
				 complicated) growing objects.
* Status of an Obstack::        Inquiries about the status of an obstack.
* Obstacks Data Alignment::     Controlling alignment of objects in obstacks.
* Obstack Chunks::              How obstacks obtain and release chunks. 
				Efficiency considerations.
* Summary of Obstacks::         

Automatic Storage with Variable Size

* Alloca Example::              Example of using @code{alloca}.
* Advantages of Alloca::        Reasons to use @code{alloca}.
* Disadvantages of Alloca::     Reasons to avoid @code{alloca}.
* GNU C Variable-Size Arrays::  Only in GNU C, here is an alternative
				 method of allocating dynamically and
				 freeing automatically.
Relocating Allocator

* Relocator Concepts::		How to understand relocating allocation.
* Using Relocator::		Functions for relocating allocation.

Character Handling

* Classification of Characters::Testing whether characters are
                                 letters, digits, punctuation, etc.
* Case Conversion::             Case mapping, and the like.

String and Array Utilities

* Representation of Strings::   Introduction to basic concepts.
* String/Array Conventions::    Whether to use a string function or an
				 arbitrary array function.
* String Length::               Determining the length of a string.
* Copying and Concatenation::   Functions to copy the contents of strings
				 and arrays.
* String/Array Comparison::     Functions for byte-wise and character-wise
				 comparison.
* Collation Functions::         Functions for collating strings.
* Search Functions::            Searching for a specific element or substring.
* Finding Tokens in a String::  Splitting a string into tokens by looking
				 for delimiters.

Extended Characters

* Extended Char Intro::         Multibyte codes versus wide characters.
* Locales and Extended Chars::  The locale selects the character codes.
* Multibyte Char Intro::        How multibyte codes are represented.
* Wide Char Intro::             How wide characters are represented.
* Wide String Conversion::      Converting wide strings to multibyte code
                                   and vice versa.
* Length of Char::              how many bytes make up one multibyte char.
* Converting One Char::         Converting a string character by character.
* Example of Conversion::       Example showing why converting 
				   one character at a time may be useful.
* Shift State::                 Multibyte codes with "shift characters".

Locales and Internationalization

* Effects of Locale::           Actions affected by the choice of locale.
* Choosing Locale::             How the user specifies a locale.
* Locale Categories::           Different purposes for which
                                 you can select a locale.
* Setting the Locale::          How a program specifies the locale.
* Standard Locales::            Locale names available on all systems.
* Numeric Formatting::          How to format numbers for the chosen locale.

Searching and Sorting 

* Comparison Functions::        Defining how to compare two objects.
				Since the sort and search facilities are
				general, you have to specify the ordering.
* Array Search Function::       The @code{bsearch} function.
* Array Sort Function::         The @code{qsort} function.
* Search/Sort Example::         An example program.

Pattern Matching

* Wildcard Matching::    Matching a wildcard pattern against a single string.
* Globbing::             Finding the files that match a wildcard pattern.
* Regular Expressions::  Matching regular expressions against strings.
* Word Expansion::       Expanding shell variables, nested commands,
                          arithmetic, and wildcards.
			  This is what the shell does with shell commands.

I/O Overview

* I/O Concepts::                Some basic information and terminology.
* File Names::                  How to refer to a file.

I/O Concepts

* Streams and File Descriptors:: The GNU Library provides two ways
                                  to access the contents of files.
* File Position::               The number of bytes from the