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@menu
* Introduction::                 Purpose of the GNU C Library.
* Error Reporting::              How library functions report errors.
* Memory Allocation::            Allocating memory dynamically and
                                   manipulating 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.
* Message Translation::          How to make the program speak the user's
                                   language.
* Searching and Sorting::        General searching and sorting functions.
* Pattern Matching::             Matching shell ``globs'' and regular
                                   expressions.
* I/O Overview::                 Introduction to the I/O facilities.
* I/O on Streams::               Hign-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 IPC mechanism, with
                                   networking support.
* Low-Level Terminal Interface:: How to change the characteristics of a
                                   terminal device.
* Mathematics::                  Math functions, useful constants, random
                                   numbers.
* Arithmetic::                   Low level arithmetic functions.
* Date and Time::                Functions for getting the date and time and
                                   formatting them nicely.
* Non-Local Exits::              Jumping out of nested function calls.
* Signal Handling::              How to send, block, and handle signals.
* 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.
* Name Service Switch::          Accessing system databases.
* Users and Groups::             How users are identified and classified.
* System Information::           Getting information about the hardware and
                                   operating system.
* System Configuration::         Parameters describing operating system
                                   limits.

Add-ons

* POSIX Threads::                The standard threads library.

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.
* Installation::                 How to install the GNU C library.
* Maintenance::                  How to enhance and port the GNU C Library.
* Contributors::                 Who wrote what parts of 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::             What this manual is for and how to use it.
* Standards and Portability::   Standards and sources upon which the GNU
                                 C library is based.
* Using the Library::           Some practical uses for the library.
* Roadmap to the Manual::       Overview of the remaining chapters in
                                 this manual.

Standards and Portability

* ISO C::                       The international standard for the C
                                 programming language.
* POSIX::                       The ISO/IEC 9945 (aka IEEE 1003) standards
                                 for operating systems.
* Berkeley Unix::               BSD and SunOS.
* SVID::                        The System V Interface Description.
* XPG::                         The X/Open Portability Guide.

Using the Library

* Header Files::                How to include 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::                 Error code macros; all of these expand
                                 into integer constant values.
* 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.
* Allocation Debugging::        Finding memory leaks and not freed memory.
* 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.

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}.
* Malloc Tunable Parameters::   Use @code{mallopt} to adjust allocation
                                 parameters.
* 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.

Allocation Debugging

* Tracing malloc::               How to install the tracing functionality.
* Using the Memory Debugger::    Example programs excerpts.
* Tips for the Memory Debugger:: Some more or less clever ideas.
* Interpreting the traces::      What do all these lines mean?

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::

Variable Size Automatic

* 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.
* Encode Binary Data::          Encoding and Decoding of Binary Data.
* Argz and Envz Vectors::       Null-separated string vectors.

Argz and Envz Vectors

* Argz Functions::              Operations on argz vectors.
* Envz Functions::              Additional operations on environment vectors.

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

* 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
                                 with library functions.
* Standard Locales::            Locale names available on all systems.
* Numeric Formatting::          How to format numbers according to the
                                 chosen locale.

Numeric Formatting

* General Numeric::             Parameters for formatting numbers and
                                 currency amounts.
* Currency Symbol::             How to print the symbol that identifies an
                                 amount of money (e.g. @samp{$}).
* Sign of Money Amount::        How to print the (positive or negative) sign
                                 for a monetary amount, if one exists.

Message Translation

* Message catalogs a la X/Open::  The @code{catgets} family of functions.
* The Uniforum approach::         The @code{gettext} family of functions.

Message catalogs a la X/Open

* The catgets Functions::      The @code{catgets} function family.
* The message catalog files::  Format of the message catalog files.
* The gencat program::         How to generate message catalogs files which
                                can be used by the functions.
* Common Usage::               How to use the @code{catgets} interface.

The Uniforum approach

* Message catalogs with gettext::  The @code{gettext} family of functions.
* Helper programs for gettext::    Programs to handle message catalogs
                                    for @code{gettext}.

Message catalogs with gettext

* Translation with gettext::    What has to be done to translate a message.
* Locating gettext catalog::    How to determine which catalog to be used.
* Using gettextized software::  The possibilities of the user to influence
                                 the way @code{gettext} works.

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.
* Hash Search Function::        The @code{hsearch} function.
* Tree Search Function::        The @code{tsearch} function.

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.

Globbing

* Calling Glob::             Basic use of @code{glob}.
* Flags for Globbing::       Flags that enable various options in @code{glob}.
* More Flags for Globbing::  GNU specific extensions to @code{glob}.

Regular Expressions

* POSIX Regexp Compilation::    Using @code{regcomp} to prepare to match.
* Flags for POSIX Regexps::     Syntax variations for @code{regcomp}.
* Matching POSIX Regexps::      Using @code{regexec} to match the compiled
                                   pattern that you get from @code{regcomp}.
* Regexp Subexpressions::       Finding which parts of the string were matched.
* Subexpression Complications:: Find points of which parts were matched.
* Regexp Cleanup::              Freeing storage; reporting errors.

Word Expansion

* Expansion Stages::    What word expansion does to a string.
* Calling Wordexp::     How to call @code{wordexp}.
* Flags for Wordexp::   Options you can enable in @code{wordexp}.
* Wordexp Example::     A sample program that does word expansion.

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
                                     beginning of the file.

File Names

* Directories::                 Directories contain entries for files.
* File Name Resolution::        A file name specifies how to look up a file.
* File Name Errors::            Error conditions relating to file names.
* File Name Portability::       File name portability and syntax issues.

I/O on Streams

* Streams::                     About the data type representing a stream.
* Standard Streams::            Streams to the standard input and output
                                 devices are created for you.
* Opening Streams::             How to create a stream to talk to a file.
* Closing Streams::             Close a stream when you are finished with it.
* Simple Output::               Unformatted output by characters and lines.
* Character Input::             Unformatted input by characters and words.
* Line Input::                  Reading a line or a record from a stream.
* Unreading::                   Peeking ahead/pushing back input just read.
* Block Input/Output::          Input and output operations on blocks of data.
* Formatted Output::            @code{printf} and related functions.
* Customizing Printf::          You can define new conversion specifiers for
                                 @code{printf} and friends.
* Formatted Input::             @code{scanf} and related functions.
* EOF and Errors::              How you can tell if an I/O error happens.
* Binary Streams::              Some systems distinguish between text files
                                 and binary files.
* File Positioning::            About random-access streams.
* Portable Positioning::        Random access on peculiar ISO C systems.
* Stream Buffering::            How to control buffering of streams.
* Other Kinds of Streams::      Streams that do not necessarily correspond
                                 to an open file.
* Formatted Messages::          Print strictly formatted messages.

Unreading

* Unreading Idea::              An explanation of unreading with pictures.
* How Unread::                  How to call @code{ungetc} to do unreading.

Formatted Output

* Formatted Output Basics::     Some examples to get you started.
* Output Conversion Syntax::    General syntax of conversion
                                 specifications.
* Table of Output Conversions:: Summary of output conversions and
                                 what they do.
* Integer Conversions::         Details about formatting of integers.
* Floating-Point Conversions::  Details about formatting of
                                 floating-point numbers.
* Other Output Conversions::    Details about formatting of strings,
                                 characters, pointers, and the like.
* Formatted Output Functions::  Descriptions of the actual functions.
* Dynamic Output::              Functions that allocate memory for the output.
* Variable Arguments Output::   @code{vprintf} and friends.
* Parsing a Template String::   What kinds of args does a given template
                                 call for?
* Example of Parsing::          Sample program using @code{parse_printf_format}.

Customizing Printf

* Registering New Conversions::         Using @code{register_printf_function}
                                         to register a new output conversion.
* Conversion Specifier Options::        The handler must be able to get
                                         the options specified in the
                                         template when it is called.
* Defining the Output Handler::         Defining the handler and arginfo
                                         functions that are passed as arguments
                                         to @code{register_printf_function}.
* Printf Extension Example::            How to define a @code{printf}
                                         handler function.
* Predefined Printf Handlers::          Predefined @code{printf} handlers.

Formatted Input

* Formatted Input Basics::      Some basics to get you started.
* Input Conversion Syntax::     Syntax of conversion specifications.
* Table of Input Conversions::  Summary of input conversions and what they do.
* Numeric Input Conversions::   Details of conversions for reading numbers.
* String Input Conversions::    Details of conversions for reading strings.
* Dynamic String Input::        String conversions that @code{malloc} the buffer.
* Other Input Conversions::     Details of miscellaneous other conversions.
* Formatted Input Functions::   Descriptions of the actual functions.
* Variable Arguments Input::    @code{vscanf} and friends.

Stream Buffering

* Buffering Concepts::          Terminology is defined here.
* Flushing Buffers::            How to ensure that output buffers are flushed.
* Controlling Buffering::       How to specify what kind of buffering to use.

Other Kinds of Streams

* String Streams::              Streams that get data from or put data in
                                 a string or memory buffer.
* Obstack Streams::             Streams that store data in an obstack.
* Custom Streams::              Defining your own streams with an arbitrary
                                 input data source and/or output data sink.

Custom Streams

* Streams and Cookies::         The @dfn{cookie} records where to fetch or
                                 store data that is read or written.
* Hook Functions::              How you should define the four @dfn{hook
                                 functions} that a custom stream needs.

Formatted Messages

* Printing Formatted Messages::   The @code{fmtmsg} function.
* Adding Severity Classes::       Add more severity classes.
* Example::                       How to use @code{fmtmsg} and @code{addseverity}.

Low-Level I/O

* Opening and Closing Files::           How to open and close file
                                         descriptors.
* Truncating Files::                    Change the size of a file.
* I/O Primitives::                      Reading and writing data.
* File Position Primitive::             Setting a descriptor's file
                                         position.
* Descriptors and Streams::             Converting descriptor to stream
                                         or vice-versa.
* Stream/Descriptor Precautions::       Precautions needed if you use both
                                         descriptors and streams.
* Scatter-Gather::                      Fast I/O to discontinous buffers.
* Memory-mapped I/O::                   Using files like memory.
* Waiting for I/O::                     How to check for input or output
                                         on multiple file descriptors.
* Synchronizing I/O::                   Making sure all I/O actions completed.
* Asynchronous I/O::                    Perform I/O in parallel.
* Control Operations::                  Various other operations on file
                                         descriptors.
* Duplicating Descriptors::             Fcntl commands for duplicating
                                         file descriptors.
* Descriptor Flags::                    Fcntl commands for manipulating
                                         flags associated with file
                                         descriptors.
* File Status Flags::                   Fcntl commands for manipulating
                                         flags associated with open files.
* File Locks::                          Fcntl commands for implementing
                                         file locking.
* Interrupt Input::                     Getting an asynchronous signal when
                                         input arrives.
* IOCTLs::                              Generic I/O Control operations.

Stream/Descriptor Precautions

* Linked Channels::        Dealing with channels sharing a file position.
* Independent Channels::   Dealing with separately opened, unlinked channels.
* Cleaning Streams::       Cleaning a stream makes it safe to use
                            another channel.

Asynchronous I/O

* Asynchronous Reads/Writes::    Asynchronous Read and Write Operations.
* Status of AIO Operations::     Getting the Status of AIO Operations.
* Synchronizing AIO Operations:: Getting into a consistent state.
* Cancel AIO Operations::        Cancelation of AIO Operations.
* Configuration of AIO::         How to optimize the AIO implementation.

File Status Flags

* Access Modes::                Whether the descriptor can read or write.
* Open-time Flags::             Details of @code{open}.
* Operating Modes::             Special modes to control I/O operations.
* Getting File Status Flags::   Fetching and changing these flags.

File System Interface

* Working Directory::           This is used to resolve relative
                                 file names.
* Accessing Directories::       Finding out what files a directory
                                 contains.
* Working on Directory Trees::  Apply actions to all files or a selectable
                                 subset of a directory hierarchy.
* Hard Links::                  Adding alternate names to a file.
* Symbolic Links::              A file that ``points to'' a file name.
* Deleting Files::              How to delete a file, and what that means.
* Renaming Files::              Changing a file's name.
* Creating Directories::        A system call just for creating a directory.
* File Attributes::             Attributes of individual files.
* Making Special Files::        How to create special files.
* Temporary Files::             Naming and creating temporary files.

Accessing Directories

* Directory Entries::           Format of one directory entry.
* Opening a Directory::         How to open a directory stream.
* Reading/Closing Directory::   How to read directory entries from the stream.
* Simple Directory Lister::     A very simple directory listing program.
* Random Access Directory::     Rereading part of the directory
                                 already read with the same stream.
* Scanning Directory Content::  Get entries for user selected subset of
                                 contents in given directory.
* Simple Directory Lister Mark II::  Revised version of the program.

File Attributes

* Attribute Meanings::          The names of the file attributes,
                                 and what their values mean.
* Reading Attributes::          How to read the attributes of a file.
* Testing File Type::           Distinguishing ordinary files,
                                 directories, links...
* File Owner::                  How ownership for new files is determined,
                                 and how to change it.
* Permission Bits::             How information about a file's access
                                 mode is stored.
* Access Permission::           How the system decides who can access a file.
* Setting Permissions::         How permissions for new files are assigned,
                                 and how to change them.
* Testing File Access::         How to find out if your process can
                                 access a file.
* File Times::                  About the time attributes of a file.

Pipes and FIFOs

* Creating a Pipe::             Making a pipe with the @code{pipe} function.
* Pipe to a Subprocess::        Using a pipe to communicate with a
                                 child process.
* FIFO Special Files::          Making a FIFO special file.
* Pipe Atomicity::              When pipe (or FIFO) I/O is atomic.

Sockets

* Socket Concepts::     Basic concepts you need to know about.
* Communication Styles::Stream communication, datagrams, and other styles.
* Socket Addresses::    How socket names (``addresses'') work.
* Interface Naming::    Identifying specific network interfaces.
* Local Namespace::     Details about the local namespace.
* Internet Namespace::  Details about the Internet namespace.
* Misc Namespaces::     Other namespaces not documented fully here.
* Open/Close Sockets::  Creating sockets and destroying them.
* Connections::         Operations on sockets with connection state.
* Datagrams::           Operations on datagram sockets.
* Inetd::               Inetd is a daemon that starts servers on request.
                           The most convenient way to write a server
                           is to make it work with Inetd.
* Socket Options::      Miscellaneous low-level socket options.
* Networks Database::   Accessing the database of network names.

Socket Addresses

* Address Formats::             About @code{struct sockaddr}.
* Setting Address::             Binding an address to a socket.
* Reading Address::             Reading the address of a socket.

Local Namespace

* Concepts: Local Namespace Concepts. What you need to understand.
* Details: Local Namespace Details.   Address format, symbolic names, etc.
* Example: Local Socket Example.      Example of creating a socket.

Internet Namespace

* Internet Address Formats::    How socket addresses are specified in the
                                 Internet namespace.
* Host Addresses::              All about host addresses of internet host.
* Protocols Database::          Referring to protocols by name.
* Ports::                       Internet port numbers.
* Services Database::           Ports may have symbolic names.
* Byte Order::                  Different hosts may use different byte
                                 ordering conventions; you need to
                                 canonicalize host address and port number.
* Inet Example::                Putting it all together.

Host Addresses

* Abstract Host Addresses::     What a host number consists of.
* Data type: Host Address Data Type.    Data type for a host number.
* Functions: Host Address Functions.    Functions to operate on them.
* Names: Host Names.            Translating host names to host numbers.

Open/Close Sockets

* Creating a Socket::           How to open a socket.
* Closing a Socket::            How to close a socket.
* Socket Pairs::                These are created like pipes.

Connections

* Connecting::               What the client program must do.
* Listening::                How a server program waits for requests.
* Accepting Connections::    What the server does when it gets a request.
* Who is Connected::         Getting the address of the
                                other side of a connection.
* Transferring Data::        How to send and receive data.
* Byte Stream Example::      An example program: a client for communicating
                              over a byte stream socket in the Internet namespace.
* Server Example::           A corresponding server program.
* Out-of-Band Data::         This is an advanced feature.

Transferring Data

* Sending Data::                Sending data with @code{send}.
* Receiving Data::              Reading data with @code{recv}.
* Socket Data Options::         Using @code{send} and @code{recv}.

Datagrams

* Sending Datagrams::    Sending packets on a datagram socket.
* Receiving Datagrams::  Receiving packets on a datagram socket.
* Datagram Example::     An example program: packets sent over a
                           datagram socket in the local namespace.
* Example Receiver::     Another program, that receives those packets.

Inetd

* Inetd Servers::
* Configuring Inetd::

Socket Options

* Socket Option Functions::     The basic functions for setting and getting
                                 socket options.
* Socket-Level Options::        Details of the options at the socket level.

Low-Level Terminal Interface

* Is It a Terminal::            How to determine if a file is a terminal
                                 device, and what its name is.
* I/O Queues::                  About flow control and typeahead.
* Canonical or Not::            Two basic styles of input processing.
* Terminal Modes::              How to examine and modify flags controlling
                                 details of terminal I/O: echoing,
                                 signals, editing.
* Line Control::                Sending break sequences, clearing
                                 terminal buffers @dots{}
* Noncanon Example::            How to read single characters without echo.
* Pseudo-Terminals::            How to open a pseudo-terminal.

Terminal Modes

* Mode Data Types::             The data type @code{struct termios} and
                                 related types.
* Mode Functions::              Functions to read and set the terminal
                                 attributes.
* Setting Modes::               The right way to set terminal attributes
                                 reliably.
* Input Modes::                 Flags controlling low-level input handling.
* Output Modes::                Flags controlling low-level output handling.
* Control Modes::               Flags controlling serial port behavior.
* Local Modes::                 Flags controlling high-level input handling.
* Line Speed::                  How to read and set the terminal line speed.
* Special Characters::          Characters that have special effects,
                                 and how to change them.
* Noncanonical Input::          Controlling how long to wait for input.

Special Characters

* Editing Characters::          Special characters that terminate lines and
                                  delete text, and other editing functions.
* Signal Characters::           Special characters that send or raise signals
                                  to or for certain classes of processes.
* Start/Stop Characters::       Special characters that suspend or resume
                                  suspended output.
* Other Special::               Other special characters for BSD systems:
                                  they can discard output, and print status.

Pseudo-Terminals

* Allocation::             Allocating a pseudo terminal.
* Pseudo-Terminal Pairs::  How to open both sides of a
                            pseudo-terminal in a single operation.

Mathematics

* Mathematical Constants::      Precise numeric values for often-used
                                 constants.
* Trig Functions::              Sine, cosine, tangent, and friends.
* Inverse Trig Functions::      Arcsine, arccosine, etc.
* Exponents and Logarithms::    Also pow and sqrt.
* Hyperbolic Functions::        sinh, cosh, tanh, etc.
* Special Functions::           Bessel, gamma, erf.
* Pseudo-Random Numbers::       Functions for generating pseudo-random
                                 numbers.
* FP Function Optimizations::   Fast code or small code.

Pseudo-Random Numbers

* ISO Random::                  @code{rand} and friends.
* BSD Random::                  @code{random} and friends.
* SVID Random::                 @code{drand48} and friends.

Arithmetic

* Floating Point Numbers::      Basic concepts.  IEEE 754.
* Floating Point Classes::      The five kinds of floating-point number.
* Floating Point Errors::       When something goes wrong in a calculation.
* Rounding::                    Controlling how results are rounded.
* Control Functions::           Saving and restoring the FPU's state.
* Arithmetic Functions::        Fundamental operations provided by the library.
* Complex Numbers::             The types.  Writing complex constants.
* Operations on Complex::       Projection, conjugation, decomposition.
* Integer Division::            Integer division with guaranteed rounding.
* Parsing of Numbers::          Converting strings to numbers.
* System V Number Conversion::  An archaic way to convert numbers to strings.

Floating Point Errors

* FP Exceptions::               IEEE 754 math exceptions and how to detect them.
* Infinity and NaN::            Special values returned by calculations.
* Status bit operations::       Checking for exceptions after the fact.
* Math Error Reporting::        How the math functions report errors.

Arithmetic Functions

* Absolute Value::              Absolute values of integers and floats.
* Normalization Functions::     Extracting exponents and putting them back.
* Rounding Functions::          Rounding floats to integers.
* Remainder Functions::         Remainders on division, precisely defined.
* FP Bit Twiddling::            Sign bit adjustment.  Adding epsilon.
* FP Comparison Functions::     Comparisons without risk of exceptions.
* Misc FP Arithmetic::          Max, min, positive difference, multiply-add.

Parsing of Numbers

* Parsing of Integers::         Functions for conversion of integer values.
* Parsing of Floats::           Functions for conversion of floating-point
                                 values.

Date and Time

* Processor Time::              Measures processor time used by a program.
* Calendar Time::               Manipulation of ``real'' dates and times.
* Setting an Alarm::            Sending a signal after a specified time.
* Sleeping::                    Waiting for a period of time.
* Resource Usage::              Measuring various resources used.
* Limits on Resources::         Specifying limits on resource usage.
* Priority::                    Reading or setting process run priority.

Processor Time

* Basic CPU Time::              The @code{clock} function.
* Detailed CPU Time::           The @code{times} function.

Calendar Time

* Simple Calendar Time::        Facilities for manipulating calendar time.
* High-Resolution Calendar::    A time representation with greater precision.
* Broken-down Time::            Facilities for manipulating local time.
* Formatting Date and Time::    Converting times to strings.
* TZ Variable::                 How users specify the time zone.
* Time Zone Functions::         Functions to examine or specify the time zone.
* Time Functions Example::      An example program showing use of some of
                                 the time functions.

Non-Local Exits

* Intro: Non-Local Intro.        When and how to use these facilities.
* Details: Non-Local Details.   Functions for nonlocal exits.
* Non-Local Exits and Signals::  Portability issues.

Signal Handling

* Concepts of Signals::         Introduction to the signal facilities.
* Standard Signals::            Particular kinds of signals with
                                 standard names and meanings.
* Signal Actions::              Specifying what happens when a
                                 particular signal is delivered.
* Defining Handlers::           How to write a signal handler function.
* Interrupted Primitives::      Signal handlers affect use of @code{open},
                                 @code{read}, @code{write} and other functions.
* Generating Signals::          How to send a signal to a process.
* Blocking Signals::            Making the system hold signals temporarily.
* Waiting for a Signal::        Suspending your program until a signal
                                 arrives.
* Signal Stack::                Using a Separate Signal Stack.
* BSD Signal Handling::         Additional functions for backward
                                 compatibility with BSD.

Concepts of Signals

* Kinds of Signals::            Some examples of what can cause a signal.
* Signal Generation::           Concepts of why and how signals occur.
* Delivery of Signal::          Concepts of what a signal does to the
                                 process.

Standard Signals

* Program Error Signals::       Used to report serious program errors.
* Termination Signals::         Used to interrupt and/or terminate the
                                 program.
* Alarm Signals::               Used to indicate expiration of timers.
* Asynchronous I/O Signals::    Used to indicate input is available.
* Job Control Signals::         Signals used to support job control.
* Operation Error Signals::     Used to report operational system errors.
* Miscellaneous Signals::       Miscellaneous Signals.
* Signal Messages::             Printing a message describing a signal.

Signal Actions

* Basic Signal Handling::       The simple @code{signal} function.
* Advanced Signal Handling::    The more powerful @code{sigaction} function.
* Signal and Sigaction::        How those two functions interact.
* Sigaction Function Example::  An example of using the sigaction function.
* Flags for Sigaction::         Specifying options for signal handling.
* Initial Signal Actions::      How programs inherit signal actions.

Defining Handlers

* Handler Returns::             Handlers that return normally, and what
                                 this means.
* Termination in Handler::      How handler functions terminate a program.
* Longjmp in Handler::          Nonlocal transfer of control out of a
                                 signal handler.
* Signals in Handler::          What happens when signals arrive while
                                 the handler is already occupied.
* Merged Signals::              When a second signal arrives before the
                                 first is handled.
* Nonreentrancy::               Do not call any functions unless you know they
                                 are reentrant with respect to signals.
* Atomic Data Access::          A single handler can run in the middle of
                                 reading or writing a single object.

Atomic Data Access

* Non-atomic Example::          A program illustrating interrupted access.
* Types: Atomic Types.          Data types that guarantee no interruption.
* Usage: Atomic Usage.          Proving that interruption is harmless.

Generating Signals

* Signaling Yourself::          A process can send a signal to itself.
* Signaling Another Process::   Send a signal to another process.
* Permission for kill::         Permission for using @code{kill}.
* Kill Example::                Using @code{kill} for Communication.

Blocking Signals

* Why Block::                           The purpose of blocking signals.
* Signal Sets::                         How to specify which signals to
                                         block.
* Process Signal Mask::                 Blocking delivery of signals to your
                                         process during normal execution.
* Testing for Delivery::                Blocking to Test for Delivery of
                                         a Signal.
* Blocking for Handler::                Blocking additional signals while a
                                         handler is being run.
* Checking for Pending Signals::        Checking for Pending Signals
* Remembering a Signal::                How you can get almost the same
                                         effect as blocking a signal, by
                                         handling it and setting a flag
                                         to be tested later.

Waiting for a Signal

* Using Pause::                 The simple way, using @code{pause}.
* Pause Problems::              Why the simple way is often not very good.
* Sigsuspend::                  Reliably waiting for a specific signal.

BSD Signal Handling

* BSD Handler::                 BSD Function to Establish a Handler.
* Blocking in BSD::             BSD Functions for Blocking Signals.

Process Startup

* Program Arguments::           Parsing your program's command-line arguments.
* Environment Variables::       How to access parameters inherited from
                                 a parent process.
* Program Termination::         How to cause a process to terminate and
                                 return status information to its parent.

Program Arguments

* Argument Syntax::             By convention, options start with a hyphen.
* Parsing Program Arguments::   Ways to parse program options and arguments.

Parsing Program Arguments

* Getopt::                      Parsing program options using @code{getopt}.
* Argp::                        Parsing program options using @code{argp_parse}.
* Suboptions::                  Some programs need more detailed options.
* Suboptions Example::          This shows how it could be done for @code{mount}.

Environment Variables

* Environment Access::          How to get and set the values of
                                 environment variables.
* Standard Environment::        These environment variables have
                                 standard interpretations.

Program Termination

* Normal Termination::          If a program calls @code{exit}, a
                                 process terminates normally.
* Exit Status::                 The @code{exit status} provides information
                                 about why the process terminated.
* Cleanups on Exit::            A process can run its own cleanup
                                 functions upon normal termination.
* Aborting a Program::          The @code{abort} function causes
                                 abnormal program termination.
* Termination Internals::       What happens when a process terminates.

Processes

* Running a Command::           The easy way to run another program.
* Process Creation Concepts::   An overview of the hard way to do it.
* Process Identification::      How to get the process ID of a process.
* Creating a Process::          How to fork a child process.
* Executing a File::            How to make a process execute another program.
* Process Completion::          How to tell when a child process has completed.
* Process Completion Status::   How to interpret the status value
                                 returned from a child process.
* BSD Wait Functions::          More functions, for backward compatibility.
* Process Creation Example::    A complete example program.

Job Control

* Concepts of Job Control::     Jobs can be controlled by a shell.
* Job Control is Optional::     Not all POSIX systems support job control.
* Controlling Terminal::        How a process gets its controlling terminal.
* Access to the Terminal::      How processes share the controlling terminal.
* Orphaned Process Groups::     Jobs left after the user logs out.
* Implementing a Shell::        What a shell must do to implement job control.
* Functions for Job Control::   Functions to control process groups.

Implementing a Shell

* Data Structures::             Introduction to the sample shell.
* Initializing the Shell::      What the shell must do to take
                                 responsibility for job control.
* Launching Jobs::              Creating jobs to execute commands.
* Foreground and Background::   Putting a job in foreground of background.
* Stopped and Terminated Jobs::  Reporting job status.
* Continuing Stopped Jobs::     How to continue a stopped job in
                                 the foreground or background.
* Missing Pieces::              Other parts of the shell.

Functions for Job Control

* Identifying the Terminal::    Determining the controlling terminal's name.
* Process Group Functions::     Functions for manipulating process groups.
* Terminal Access Functions::   Functions for controlling terminal access.

Name Service Switch

* NSS Basics::                  What is this NSS good for.
* NSS Configuration File::      Configuring NSS.
* NSS Module Internals::        How does it work internally.
* Extending NSS::               What to do to add services or databases.

NSS Configuration File

* Services in the NSS configuration::  Service names in the NSS configuration.
* Actions in the NSS configuration::  React appropriately to the lookup result.
* Notes on NSS Configuration File::  Things to take care about while
                                     configuring NSS.

NSS Module Internals

* NSS Module Names::            Construction of the interface function of
                                the NSS modules.
* NSS Modules Interface::       Programming interface in the NSS module
                                functions.

Extending NSS

* Adding another Service to NSS::  What is to do to add a new service.
* NSS Module Function Internals::  Guidelines for writing new NSS
                                        service functions.

Users and Groups

* User and Group IDs::          Each user has a unique numeric ID;
                                 likewise for groups.
* Process Persona::             The user IDs and group IDs of a process.
* Why Change Persona::          Why a program might need to change
                                 its user and/or group IDs.
* How Change Persona::          Changing the user and group IDs.
* Reading Persona::             How to examine the user and group IDs.

* Setting User ID::             Functions for setting the user ID.
* Setting Groups::              Functions for setting the group IDs.

* Enable/Disable Setuid::       Turning setuid access on and off.
* Setuid Program Example::      The pertinent parts of one sample program.
* Tips for Setuid::             How to avoid granting unlimited access.

* Who Logged In::               Getting the name of the user who logged in,
                                 or of the real user ID of the current process.

* User Accounting Database::    Keeping information about users and various
                                 actions in databases.

* User Database::               Functions and data structures for
                                 accessing the user database.
* Group Database::              Functions and data structures for
                                 accessing the group database.
* Database Example::            Example program showing the use of database
                                 inquiry functions.
* Netgroup Database::           Functions for accessing the netgroup database.

User Accounting Database

* Manipulating the Database::   Scanning and modifying the user
                                 accounting database.
* XPG Functions::               A standardized way for doing the same thing.
* Logging In and Out::          Functions from BSD that modify the user
                                 accounting database.

User Database

* User Data Structure::         What each user record contains.
* Lookup User::                 How to look for a particular user.
* Scanning All Users::          Scanning the list of all users, one by one.
* Writing a User Entry::        How a program can rewrite a user's record.

Group Database

* Group Data Structure::        What each group record contains.
* Lookup Group::                How to look for a particular group.
* Scanning All Groups::         Scanning the list of all groups.

Netgroup Database

* Netgroup Data::                  Data in the Netgroup database and where
                                   it comes from.
* Lookup Netgroup::                How to look for a particular netgroup.
* Netgroup Membership::            How to test for netgroup membership.

System Information

* Host Identification::         Determining the name of the machine.
* Hardware/Software Type ID::   Determining the hardware type of the
                                 machine and what operating system it is
                                 running.
* Filesystem handling::         Which is mounted and/or available?

System Configuration

* General Limits::           Constants and functions that describe
                                various process-related limits that have
                                one uniform value for any given machine.
* System Options::           Optional POSIX features.
* Version Supported::        Version numbers of POSIX.1 and POSIX.2.
* Sysconf::                  Getting specific configuration values
                                of general limits and system options.
* Minimums::                 Minimum values for general limits.

* Limits for Files::         Size limitations that pertain to individual files.
                                These can vary between file systems
                                or even from file to file.
* Options for Files::        Optional features that some files may support.
* File Minimums::            Minimum values for file limits.
* Pathconf::                 Getting the limit values for a particular file.

* Utility Limits::           Capacity limits of some POSIX.2 utility programs.
* Utility Minimums::         Minimum allowable values of those limits.

* String Parameters::        Getting the default search path.

Sysconf

* Sysconf Definition::        Detailed specifications of @code{sysconf}.
* Constants for Sysconf::     The list of parameters @code{sysconf} can read.
* Examples of Sysconf::       How to use @code{sysconf} and the parameter
                                 macros properly together.

POSIX Threads

* Basic Thread Operations::     Creating, terminating, and waiting for threads.
* Thread Attributes::           Tuning thread scheduling.
* Cancellation::                Stopping a thread before it's done.
* Cleanup Handlers::            Deallocating resources when a thread is
                                  cancelled.
* Mutexes::                     One way to synchronize threads.
* Condition Variables::         Another way.
* POSIX Semaphores::            And a third way.
* Thread-Specific Data::        Variables with different values in
                                  different threads.
* Threads and Signal Handling:: Why you should avoid mixing the two, and
                                  how to do it if you must.
* Miscellaneous Thread Functions:: A grab bag of utility routines.

Language Features

* Consistency Checking::        Using @code{assert} to abort if
                                 something ``impossible'' happens.
* Variadic Functions::          Defining functions with varying numbers
                                 of args.
* Null Pointer Constant::       The macro @code{NULL}.
* Important Data Types::        Data types for object sizes.
* Data Type Measurements::      Parameters of data type representations.

Variadic Functions

* Why Variadic::                Reasons for making functions take
                                 variable arguments.
* How Variadic::                How to define and call variadic functions.
* Variadic Example::            A complete example.

How Variadic

* Variadic Prototypes::  How to make a prototype for a function
                          with variable arguments.
* Receiving Arguments::  Steps you must follow to access the
                          optional argument values.
* How Many Arguments::   How to decide whether there are more arguments.
* Calling Variadics::    Things you need to know about calling
                          variable arguments functions.
* Argument Macros::      Detailed specification of the macros
                          for accessing variable arguments.
* Old Varargs::          The pre-ISO way of defining variadic functions.

Data Type Measurements

* Width of Type::           How many bits does an integer type hold?
* Range of Type::           What are the largest and smallest values
                             that an integer type can hold?
* Floating Type Macros::    Parameters that measure the floating point types.
* Structure Measurement::   Getting measurements on structure types.

Floating Type Macros

* Floating Point Concepts::     Definitions of terminology.
* Floating Point Parameters::   Details of specific macros.
* IEEE Floating Point::         The measurements for one common
                                 representation.

Installation

* Tools for Installation::      We recommend using these tools to build.
* Supported Configurations::    What systems the GNU C library runs on.
* Tips for Installation::       Useful hints for the installation.
* Reporting Bugs::              How to report bugs (if you want to
                                get them fixed) and other troubles
                                you may have with the GNU C library.

Maintenance

* Source Layout::         How to add new functions or header files
                             to the GNU C library.
* Porting::               How to port the GNU C library to
                             a new machine or operating system.

Porting

* Hierarchy Conventions::       The layout of the @file{sysdeps} hierarchy.
* Porting to Unix::             Porting the library to an average
                                   Unix-like system.
@end menu