glibc/manual/top-menu.texi
Ulrich Drepper d8f2b9ea8c Update.
1998-09-16  Ulrich Drepper  <drepper@cygnus.com>

	* nscd/grpcache.c (save_grp): Partly undo last change.

	* nscd/pwdcache.c (save_pwd): Undo last change.
1998-09-16 18:29:58 +00:00

1172 lines
53 KiB
Plaintext

@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.
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.
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.
* Locale Information:: How to access the information for the locale.
* Formatting Numbers:: A dedicated function to format numbers.
Locale Information
* The Lame Way to Locale Data:: ISO C's @code{localeconv}.
* The Elegant and Fast Way:: X/Open's @code{nl_langinfo}.
The Lame Way to Locale Data
* 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.
* Tilde Expansion:: Details of how tilde expansion works.
* Variable Substitution:: Different types of variable substitution.
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.
* File Size:: Manually changing the size 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