Table of Contents

1. Introduction

1.1 Getting Started
1.2 Standards and Portability

1.2.1 ISO C
1.2.2 POSIX (The Portable Operating System Interface)
1.2.3 Berkeley Unix
1.2.4 SVID (The System V Interface Description)
1.2.5 XPG (The X/Open Portability Guide)

1.3 Using the Library

1.3.1 Header Files
1.3.2 Macro Definitions of Functions
1.3.3 Reserved Names
1.3.4 Feature Test Macros

1.4 Roadmap to the Manual

2. Error Reporting

2.1 Checking for Errors
2.2 Error Codes
2.3 Error Messages

3. Virtual Memory Allocation And Paging

3.1 Process Memory Concepts
3.2 Allocating Storage For Program Data

3.2.1 Memory Allocation in C Programs

3.2.1.1 Dynamic Memory Allocation

3.2.2 Unconstrained Allocation

3.2.2.1 Basic Memory Allocation
3.2.2.2 Examples of malloc
3.2.2.3 Freeing Memory Allocated with malloc
3.2.2.4 Changing the Size of a Block
3.2.2.5 Allocating Cleared Space
3.2.2.6 Efficiency Considerations for malloc
3.2.2.7 Allocating Aligned Memory Blocks
3.2.2.8 Malloc Tunable Parameters
3.2.2.9 Heap Consistency Checking
3.2.2.10 Memory Allocation Hooks
3.2.2.11 Statistics for Memory Allocation with malloc
3.2.2.12 Summary of malloc-Related Functions

3.2.3 Allocation Debugging

3.2.3.1 How to install the tracing functionality
3.2.3.2 Example program excerpts
3.2.3.3 Some more or less clever ideas
3.2.3.4 Interpreting the traces

3.2.4 Obstacks

3.2.4.1 Creating Obstacks
3.2.4.2 Preparing for Using Obstacks
3.2.4.3 Allocation in an Obstack
3.2.4.4 Freeing Objects in an Obstack
3.2.4.5 Obstack Functions and Macros
3.2.4.6 Growing Objects
3.2.4.7 Extra Fast Growing Objects
3.2.4.8 Status of an Obstack
3.2.4.9 Alignment of Data in Obstacks
3.2.4.10 Obstack Chunks
3.2.4.11 Summary of Obstack Functions

3.2.5 Automatic Storage with Variable Size

3.2.5.1 alloca Example
3.2.5.2 Advantages of alloca
3.2.5.3 Disadvantages of alloca
3.2.5.4 GNU C Variable-Size Arrays

3.3 Resizing the Data Segment
3.4 Locking Pages

3.4.1 Why Lock Pages
3.4.2 Locked Memory Details
3.4.3 Functions To Lock And Unlock Pages

4. Character Handling

4.1 Classification of Characters
4.2 Case Conversion
4.3 Character class determination for wide characters
4.4 Notes on using the wide character classes
4.5 Mapping of wide characters.

5. String and Array Utilities

5.1 Representation of Strings
5.2 String and Array Conventions
5.3 String Length
5.4 Copying and Concatenation
5.5 String/Array Comparison
5.6 Collation Functions
5.7 Search Functions

5.7.1 Compatibility String Search Functions

5.8 Finding Tokens in a String
5.9 strfry
5.10 Trivial Encryption
5.11 Encode Binary Data
5.12 Argz and Envz Vectors

5.12.1 Argz Functions
5.12.2 Envz Functions

6. Character Set Handling

6.1 Introduction to Extended Characters
6.2 Overview about Character Handling Functions
6.3 Restartable Multibyte Conversion Functions

6.3.1 Selecting the conversion and its properties
6.3.2 Representing the state of the conversion
6.3.3 Converting Single Characters
6.3.4 Converting Multibyte and Wide Character Strings
6.3.5 A Complete Multibyte Conversion Example

6.4 Non-reentrant Conversion Function

6.4.1 Non-reentrant Conversion of Single Characters
6.4.2 Non-reentrant Conversion of Strings
6.4.3 States in Non-reentrant Functions

6.5 Generic Charset Conversion

6.5.1 Generic Character Set Conversion Interface
6.5.2 A complete iconv example
6.5.3 Some Details about other iconv Implementations
6.5.4 The iconv Implementation in the GNU C library

6.5.4.1 Format of `gconv-modules' files
6.5.4.2 Finding the conversion path in iconv
6.5.4.3 iconv module data structures
6.5.4.4 iconv module interfaces

7. Locales and Internationalization

7.1 What Effects a Locale Has
7.2 Choosing a Locale
7.3 Categories of Activities that Locales Affect
7.4 How Programs Set the Locale
7.5 Standard Locales
7.6 Accessing Locale Information

7.6.1 localeconv: It is portable but ...

7.6.1.1 Generic Numeric Formatting Parameters
7.6.1.2 Printing the Currency Symbol
7.6.1.3 Printing the Sign of a Monetary Amount

7.6.2 Pinpoint Access to Locale Data

7.7 A dedicated function to format numbers

8. Message Translation

8.1 X/Open Message Catalog Handling

8.1.1 The catgets function family
8.1.2 Format of the message catalog files
8.1.3 Generate Message Catalogs files
8.1.4 How to use the catgets interface

8.1.4.1 Not using symbolic names
8.1.4.2 Using symbolic names
8.1.4.3 How does to this allow to develop

8.2 The Uniforum approach to Message Translation

8.2.1 The gettext family of functions

8.2.1.1 What has to be done to translate a message?
8.2.1.2 How to determine which catalog to be used
8.2.1.3 Additional functions for more complicated situations
8.2.1.4 How to specify the output character set gettext uses
8.2.1.5 How to use gettext in GUI programs
8.2.1.6 User influence on gettext

8.2.2 Programs to handle message catalogs for gettext

9. Searching and Sorting

9.1 Defining the Comparison Function
9.2 Array Search Function
9.3 Array Sort Function
9.4 Searching and Sorting Example
9.5 The hsearch function.
9.6 The tsearch function.

10. Pattern Matching

10.1 Wildcard Matching
10.2 Globbing

10.2.1 Calling glob
10.2.2 Flags for Globbing
10.2.3 More Flags for Globbing

10.3 Regular Expression Matching

10.3.1 POSIX Regular Expression Compilation
10.3.2 Flags for POSIX Regular Expressions
10.3.3 Matching a Compiled POSIX Regular Expression
10.3.4 Match Results with Subexpressions
10.3.5 Complications in Subexpression Matching
10.3.6 POSIX Regexp Matching Cleanup

10.4 Shell-Style Word Expansion

10.4.1 The Stages of Word Expansion
10.4.2 Calling wordexp
10.4.3 Flags for Word Expansion
10.4.4 wordexp Example
10.4.5 Details of Tilde Expansion
10.4.6 Details of Variable Substitution

11. Input/Output Overview

11.1 Input/Output Concepts

11.1.1 Streams and File Descriptors
11.1.2 File Position

11.2 File Names

11.2.1 Directories
11.2.2 File Name Resolution
11.2.3 File Name Errors
11.2.4 Portability of File Names

12. Input/Output on Streams

12.1 Streams
12.2 Standard Streams
12.3 Opening Streams
12.4 Closing Streams
12.5 Simple Output by Characters or Lines
12.6 Character Input
12.7 Line-Oriented Input
12.8 Unreading

12.8.1 What Unreading Means
12.8.2 Using ungetc To Do Unreading

12.9 Block Input/Output
12.10 Formatted Output

12.10.1 Formatted Output Basics
12.10.2 Output Conversion Syntax
12.10.3 Table of Output Conversions
12.10.4 Integer Conversions
12.10.5 Floating-Point Conversions
12.10.6 Other Output Conversions
12.10.7 Formatted Output Functions
12.10.8 Dynamically Allocating Formatted Output
12.10.9 Variable Arguments Output Functions
12.10.10 Parsing a Template String
12.10.11 Example of Parsing a Template String

12.11 Customizing printf

12.11.1 Registering New Conversions
12.11.2 Conversion Specifier Options
12.11.3 Defining the Output Handler
12.11.4 printf Extension Example
12.11.5 Predefined printf Handlers

12.12 Formatted Input

12.12.1 Formatted Input Basics
12.12.2 Input Conversion Syntax
12.12.3 Table of Input Conversions
12.12.4 Numeric Input Conversions
12.12.5 String Input Conversions
12.12.6 Dynamically Allocating String Conversions
12.12.7 Other Input Conversions
12.12.8 Formatted Input Functions
12.12.9 Variable Arguments Input Functions

12.13 End-Of-File and Errors
12.14 Recovering from errors
12.15 Text and Binary Streams
12.16 File Positioning
12.17 Portable File-Position Functions
12.18 Stream Buffering

12.18.1 Buffering Concepts
12.18.2 Flushing Buffers
12.18.3 Controlling Which Kind of Buffering

12.19 Other Kinds of Streams

12.19.1 String Streams
12.19.2 Obstack Streams
12.19.3 Programming Your Own Custom Streams

12.19.3.1 Custom Streams and Cookies
12.19.3.2 Custom Stream Hook Functions

12.20 Formatted Messages

12.20.1 Printing Formatted Messages
12.20.2 Adding Severity Classes
12.20.3 How to use fmtmsg and addseverity

13. Low-Level Input/Output

13.1 Opening and Closing Files
13.2 Input and Output Primitives
13.3 Setting the File Position of a Descriptor
13.4 Descriptors and Streams
13.5 Dangers of Mixing Streams and Descriptors

13.5.1 Linked Channels
13.5.2 Independent Channels
13.5.3 Cleaning Streams

13.6 Fast Scatter-Gather I/O
13.7 Memory-mapped I/O
13.8 Waiting for Input or Output
13.9 Synchronizing I/O operations
13.10 Perform I/O Operations in Parallel

13.10.1 Asynchronous Read and Write Operations
13.10.2 Getting the Status of AIO Operations
13.10.3 Getting into a Consistent State
13.10.4 Cancellation of AIO Operations
13.10.5 How to optimize the AIO implementation

13.11 Control Operations on Files
13.12 Duplicating Descriptors
13.13 File Descriptor Flags
13.14 File Status Flags

13.14.1 File Access Modes
13.14.2 Open-time Flags
13.14.3 I/O Operating Modes
13.14.4 Getting and Setting File Status Flags

13.15 File Locks
13.16 Interrupt-Driven Input
13.17 Generic I/O Control operations

14. File System Interface

14.1 Working Directory
14.2 Accessing Directories

14.2.1 Format of a Directory Entry
14.2.2 Opening a Directory Stream
14.2.3 Reading and Closing a Directory Stream
14.2.4 Simple Program to List a Directory
14.2.5 Random Access in a Directory Stream
14.2.6 Scanning the Content of a Directory
14.2.7 Simple Program to List a Directory, Mark II

14.3 Working with Directory Trees
14.4 Hard Links
14.5 Symbolic Links
14.6 Deleting Files
14.7 Renaming Files
14.8 Creating Directories
14.9 File Attributes

14.9.1 The meaning of the File Attributes
14.9.2 Reading the Attributes of a File
14.9.3 Testing the Type of a File
14.9.4 File Owner
14.9.5 The Mode Bits for Access Permission
14.9.6 How Your Access to a File is Decided
14.9.7 Assigning File Permissions
14.9.8 Testing Permission to Access a File
14.9.9 File Times
14.9.10 File Size

14.10 Making Special Files
14.11 Temporary Files

15. Pipes and FIFOs

15.1 Creating a Pipe
15.2 Pipe to a Subprocess
15.3 FIFO Special Files
15.4 Atomicity of Pipe I/O

16. Sockets

16.1 Socket Concepts
16.2 Communication Styles
16.3 Socket Addresses

16.3.1 Address Formats
16.3.2 Setting the Address of a Socket
16.3.3 Reading the Address of a Socket

16.4 Interface Naming
16.5 The Local Namespace

16.5.1 Local Namespace Concepts
16.5.2 Details of Local Namespace
16.5.3 Example of Local-Namespace Sockets

16.6 The Internet Namespace

16.6.1 Internet Socket Address Formats
16.6.2 Host Addresses

16.6.2.1 Internet Host Addresses
16.6.2.2 Host Address Data Type
16.6.2.3 Host Address Functions
16.6.2.4 Host Names

16.6.3 Internet Ports
16.6.4 The Services Database
16.6.5 Byte Order Conversion
16.6.6 Protocols Database
16.6.7 Internet Socket Example

16.7 Other Namespaces
16.8 Opening and Closing Sockets

16.8.1 Creating a Socket
16.8.2 Closing a Socket
16.8.3 Socket Pairs

16.9 Using Sockets with Connections

16.9.1 Making a Connection
16.9.2 Listening for Connections
16.9.3 Accepting Connections
16.9.4 Who is Connected to Me?
16.9.5 Transferring Data

16.9.5.1 Sending Data
16.9.5.2 Receiving Data
16.9.5.3 Socket Data Options

16.9.6 Byte Stream Socket Example
16.9.7 Byte Stream Connection Server Example
16.9.8 Out-of-Band Data

16.10 Datagram Socket Operations

16.10.1 Sending Datagrams
16.10.2 Receiving Datagrams
16.10.3 Datagram Socket Example
16.10.4 Example of Reading Datagrams

16.11 The inetd Daemon

16.11.1 inetd Servers
16.11.2 Configuring inetd

16.12 Socket Options

16.12.1 Socket Option Functions
16.12.2 Socket-Level Options

16.13 Networks Database

17. Low-Level Terminal Interface

17.1 Identifying Terminals
17.2 I/O Queues
17.3 Two Styles of Input: Canonical or Not
17.4 Terminal Modes

17.4.1 Terminal Mode Data Types
17.4.2 Terminal Mode Functions
17.4.3 Setting Terminal Modes Properly
17.4.4 Input Modes
17.4.5 Output Modes
17.4.6 Control Modes
17.4.7 Local Modes
17.4.8 Line Speed
17.4.9 Special Characters

17.4.9.1 Characters for Input Editing
17.4.9.2 Characters that Cause Signals
17.4.9.3 Special Characters for Flow Control
17.4.9.4 Other Special Characters

17.4.10 Noncanonical Input

17.5 BSD Terminal Modes
17.6 Line Control Functions
17.7 Noncanonical Mode Example
17.8 Pseudo-Terminals

17.8.1 Allocating Pseudo-Terminals
17.8.2 Opening a Pseudo-Terminal Pair

18. Syslog

18.1 Overview of Syslog
18.2 Submitting Syslog Messages

18.2.1 openlog
18.2.2 syslog, vsyslog
18.2.3 closelog
18.2.4 setlogmask
18.2.5 Syslog Example

19. Mathematics

19.1 Predefined Mathematical Constants
19.2 Trigonometric Functions
19.3 Inverse Trigonometric Functions
19.4 Exponentiation and Logarithms
19.5 Hyperbolic Functions
19.6 Special Functions
19.7 Known Maximum Errors in Math Functions
19.8 Pseudo-Random Numbers

19.8.1 ISO C Random Number Functions
19.8.2 BSD Random Number Functions
19.8.3 SVID Random Number Function

19.9 Is Fast Code or Small Code preferred?

20. Arithmetic Functions

20.1 Integers
20.2 Integer Division
20.3 Floating Point Numbers
20.4 Floating-Point Number Classification Functions
20.5 Errors in Floating-Point Calculations

20.5.1 FP Exceptions
20.5.2 Infinity and NaN
20.5.3 Examining the FPU status word
20.5.4 Error Reporting by Mathematical Functions

20.6 Rounding Modes
20.7 Floating-Point Control Functions
20.8 Arithmetic Functions

20.8.1 Absolute Value
20.8.2 Normalization Functions
20.8.3 Rounding Functions
20.8.4 Remainder Functions
20.8.5 Setting and modifying single bits of FP values
20.8.6 Floating-Point Comparison Functions
20.8.7 Miscellaneous FP arithmetic functions

20.9 Complex Numbers
20.10 Projections, Conjugates, and Decomposing of Complex Numbers
20.11 Parsing of Numbers

20.11.1 Parsing of Integers
20.11.2 Parsing of Floats

20.12 Old-fashioned System V number-to-string functions

21. Date and Time

21.1 Time Basics
21.2 Elapsed Time
21.3 Processor And CPU Time

21.3.1 CPU Time Inquiry
21.3.2 Processor Time Inquiry

21.4 Calendar Time

21.4.1 Simple Calendar Time
21.4.2 High-Resolution Calendar
21.4.3 Broken-down Time
21.4.4 High Accuracy Clock
21.4.5 Formatting Calendar Time
21.4.6 Convert textual time and date information back

21.4.6.1 Interpret string according to given format
21.4.6.2 A More User-friendly Way to Parse Times and Dates

21.4.7 Specifying the Time Zone with TZ
21.4.8 Functions and Variables for Time Zones
21.4.9 Time Functions Example

21.5 Setting an Alarm
21.6 Sleeping

22. Resource Usage And Limitation

22.1 Resource Usage
22.2 Limiting Resource Usage
22.3 Process CPU Priority And Scheduling

22.3.1 Absolute Priority

22.3.1.1 Using Absolute Priority

22.3.2 Realtime Scheduling
22.3.3 Basic Scheduling Functions
22.3.4 Traditional Scheduling

22.3.4.1 Introduction To Traditional Scheduling
22.3.4.2 Functions For Traditional Scheduling

23. Non-Local Exits

23.1 Introduction to Non-Local Exits
23.2 Details of Non-Local Exits
23.3 Non-Local Exits and Signals

24. Signal Handling

24.1 Basic Concepts of Signals

24.1.1 Some Kinds of Signals
24.1.2 Concepts of Signal Generation
24.1.3 How Signals Are Delivered

24.2 Standard Signals

24.2.1 Program Error Signals
24.2.2 Termination Signals
24.2.3 Alarm Signals
24.2.4 Asynchronous I/O Signals
24.2.5 Job Control Signals
24.2.6 Operation Error Signals
24.2.7 Miscellaneous Signals
24.2.8 Signal Messages

24.3 Specifying Signal Actions

24.3.1 Basic Signal Handling
24.3.2 Advanced Signal Handling
24.3.3 Interaction of signal and sigaction
24.3.4 sigaction Function Example
24.3.5 Flags for sigaction
24.3.6 Initial Signal Actions

24.4 Defining Signal Handlers

24.4.1 Signal Handlers that Return
24.4.2 Handlers That Terminate the Process
24.4.3 Nonlocal Control Transfer in Handlers
24.4.4 Signals Arriving While a Handler Runs
24.4.5 Signals Close Together Merge into One
24.4.6 Signal Handling and Nonreentrant Functions
24.4.7 Atomic Data Access and Signal Handling

24.4.7.1 Problems with Non-Atomic Access
24.4.7.2 Atomic Types
24.4.7.3 Atomic Usage Patterns

24.5 Primitives Interrupted by Signals
24.6 Generating Signals

24.6.1 Signaling Yourself
24.6.2 Signaling Another Process
24.6.3 Permission for using kill
24.6.4 Using kill for Communication

24.7 Blocking Signals

24.7.1 Why Blocking Signals is Useful
24.7.2 Signal Sets
24.7.3 Process Signal Mask
24.7.4 Blocking to Test for Delivery of a Signal
24.7.5 Blocking Signals for a Handler
24.7.6 Checking for Pending Signals
24.7.7 Remembering a Signal to Act On Later

24.8 Waiting for a Signal

24.8.1 Using pause
24.8.2 Problems with pause
24.8.3 Using sigsuspend

24.9 Using a Separate Signal Stack
24.10 BSD Signal Handling

24.10.1 BSD Function to Establish a Handler
24.10.2 BSD Functions for Blocking Signals

25. The Basic Program/System Interface

25.1 Program Arguments

25.1.1 Program Argument Syntax Conventions
25.1.2 Parsing Program Arguments

25.2 Parsing program options using getopt

25.2.1 Using the getopt function
25.2.2 Example of Parsing Arguments with getopt
25.2.3 Parsing Long Options with getopt_long
25.2.4 Example of Parsing Long Options with getopt_long

25.3 Parsing Program Options with Argp

25.3.1 The argp_parse Function
25.3.2 Argp Global Variables
25.3.3 Specifying Argp Parsers
25.3.4 Specifying Options in an Argp Parser

25.3.4.1 Flags for Argp Options

25.3.5 Argp Parser Functions

25.3.5.1 Special Keys for Argp Parser Functions
25.3.5.2 Functions For Use in Argp Parsers
25.3.5.3 Argp Parsing State

25.3.6 Combining Multiple Argp Parsers
25.3.7 Flags for argp_parse
25.3.8 Customizing Argp Help Output

25.3.8.1 Special Keys for Argp Help Filter Functions

25.3.9 The argp_help Function
25.3.10 Flags for the argp_help Function
25.3.11 Argp Examples

25.3.11.1 A Minimal Program Using Argp
25.3.11.2 A Program Using Argp with Only Default Options
25.3.11.3 A Program Using Argp with User Options
25.3.11.4 A Program Using Multiple Combined Argp Parsers

25.3.12 Argp User Customization

25.3.12.1 Parsing of Suboptions

25.3.13 Parsing of Suboptions Example

25.4 Environment Variables

25.4.1 Environment Access
25.4.2 Standard Environment Variables

25.5 System Calls
25.6 Program Termination

25.6.1 Normal Termination
25.6.2 Exit Status
25.6.3 Cleanups on Exit
25.6.4 Aborting a Program
25.6.5 Termination Internals

26. Processes

26.1 Running a Command
26.2 Process Creation Concepts
26.3 Process Identification
26.4 Creating a Process
26.5 Executing a File
26.6 Process Completion
26.7 Process Completion Status
26.8 BSD Process Wait Functions
26.9 Process Creation Example

27. Job Control

27.1 Concepts of Job Control
27.2 Job Control is Optional
27.3 Controlling Terminal of a Process
27.4 Access to the Controlling Terminal
27.5 Orphaned Process Groups
27.6 Implementing a Job Control Shell

27.6.1 Data Structures for the Shell
27.6.2 Initializing the Shell
27.6.3 Launching Jobs
27.6.4 Foreground and Background
27.6.5 Stopped and Terminated Jobs
27.6.6 Continuing Stopped Jobs
27.6.7 The Missing Pieces

27.7 Functions for Job Control

27.7.1 Identifying the Controlling Terminal
27.7.2 Process Group Functions
27.7.3 Functions for Controlling Terminal Access

28. System Databases and Name Service Switch

28.1 NSS Basics
28.2 The NSS Configuration File

28.2.1 Services in the NSS configuration File
28.2.2 Actions in the NSS configuration
28.2.3 Notes on the NSS Configuration File

28.3 NSS Module Internals

28.3.1 The Naming Scheme of the NSS Modules
28.3.2 The Interface of the Function in NSS Modules

28.4 Extending NSS

28.4.1 Adding another Service to NSS
28.4.2 Internals of the NSS Module Functions

29. Users and Groups

29.1 User and Group IDs
29.2 The Persona of a Process
29.3 Why Change the Persona of a Process?
29.4 How an Application Can Change Persona
29.5 Reading the Persona of a Process
29.6 Setting the User ID
29.7 Setting the Group IDs
29.8 Enabling and Disabling Setuid Access
29.9 Setuid Program Example
29.10 Tips for Writing Setuid Programs
29.11 Identifying Who Logged In
29.12 The User Accounting Database

29.12.1 Manipulating the User Accounting Database
29.12.2 XPG User Accounting Database Functions
29.12.3 Logging In and Out

29.13 User Database

29.13.1 The Data Structure that Describes a User
29.13.2 Looking Up One User
29.13.3 Scanning the List of All Users
29.13.4 Writing a User Entry

29.14 Group Database

29.14.1 The Data Structure for a Group
29.14.2 Looking Up One Group
29.14.3 Scanning the List of All Groups

29.15 User and Group Database Example
29.16 Netgroup Database

29.16.1 Netgroup Data
29.16.2 Looking up one Netgroup
29.16.3 Testing for Netgroup Membership

30. System Management

30.1 Host Identification
30.2 Platform Type Identification
30.3 Controlling and Querying Mounts

30.3.1 The `fstab' file
30.3.2 The `mtab' file
30.3.3 Other (Non-libc) Sources of Mount Information

30.4 System Parameters
30.5 Getting the system load average

31. System Configuration Parameters

31.1 General Capacity Limits
31.2 Overall System Options
31.3 Which Version of POSIX is Supported
31.4 Using sysconf

31.4.1 Definition of sysconf
31.4.2 Constants for sysconf Parameters
31.4.3 Examples of sysconf

31.5 Minimum Values for General Capacity Limits
31.6 Limits on File System Capacity
31.7 Optional Features in File Support
31.8 Minimum Values for File System Limits
31.9 Using pathconf
31.10 Utility Program Capacity Limits
31.11 Minimum Values for Utility Limits
31.12 String-Valued Parameters

32. DES Encryption and Password Handling

32.1 Legal Problems
32.2 Reading Passwords
32.3 Encrypting Passwords
32.4 DES Encryption

33. POSIX Threads

33.1 Basic Thread Operations
33.2 Thread Attributes
33.3 Cancellation
33.4 Cleanup Handlers
33.5 Mutexes
33.6 Condition Variables
33.7 POSIX Semaphores
33.8 Thread-Specific Data
33.9 Threads and Signal Handling
33.10 Threads and Fork
33.11 Streams and Fork
33.12 Miscellaneous Thread Functions

A. C Language Facilities in the Library

A.1 Explicitly Checking Internal Consistency
A.2 Variadic Functions

A.2.1 Why Variadic Functions are Used
A.2.2 How Variadic Functions are Defined and Used

A.2.2.1 Syntax for Variable Arguments
A.2.2.2 Receiving the Argument Values
A.2.2.3 How Many Arguments Were Supplied
A.2.2.4 Calling Variadic Functions
A.2.2.5 Argument Access Macros

A.2.3 Example of a Variadic Function

A.2.3.1 Old-Style Variadic Functions

A.3 Null Pointer Constant
A.4 Important Data Types
A.5 Data Type Measurements

A.5.1 Computing the Width of an Integer Data Type
A.5.2 Range of an Integer Type
A.5.3 Floating Type Macros

A.5.3.1 Floating Point Representation Concepts
A.5.3.2 Floating Point Parameters
A.5.3.3 IEEE Floating Point

A.5.4 Structure Field Offset Measurement

B. Summary of Library Facilities
C. Installing the GNU C Library

C.1 Configuring and compiling GNU Libc
C.2 Installing the C Library
C.3 Recommended Tools for Compilation
C.4 Supported Configurations
C.5 Specific advice for Linux systems
C.6 Reporting Bugs

D. Library Maintenance

D.1 Adding New Functions
D.2 Porting the GNU C Library

D.2.1 Layout of the `sysdeps' Directory Hierarchy
D.2.2 Porting the GNU C Library to Unix Systems

E. Contributors to the GNU C Library