C POSIX library
`<assert.h>` `<complex.h>` `<ctype.h>` `<dirent.h>` `<dlfcn.h>` `<errno.h>` `<fcntl.h>` `<fenv.h>` `<float.h>` `<inttypes.h>` `<iso646.h>` `<limits.h>` `<locale.h>` `<math.h>` `<pthread.h>` `<setjmp.h>` `<signal.h>` `<stdarg.h>` `<stdbool.h>` `<stddef.h>` `<stdint.h>` `<stdio.h>` `<stdlib.h>` `<string.h>` `<sys/stat.h>` `<tgmath.h>` `<time.h>` `<unistd.h>` `<utime.h>` `<wchar.h>` `<wctype.h>`
v t e

<assert.h>
<complex.h>
<ctype.h>
<dirent.h>
<dlfcn.h>
<errno.h>
<fcntl.h>
<fenv.h>
<float.h>
<inttypes.h>
<iso646.h>
<limits.h>
<locale.h>
<math.h>
<pthread.h>
<setjmp.h>
<signal.h>
<stdarg.h>
<stdbool.h>
<stddef.h>
<stdint.h>
<stdio.h>
<stdlib.h>
<string.h>
<sys/stat.h>
<tgmath.h>
<time.h>
<unistd.h>
<utime.h>
<wchar.h>
<wctype.h>

The C POSIX library is a specification of a C standard library for POSIX systems. It was developed at the same time as the ANSI C standard. Some effort was made to make POSIX compatible with standard C; POSIX includes additional functions to those introduced in standard C.

C POSIX library header files

Header file	Description	First released
`<aio.h>`	Asynchronous input and output	Issue 5
`<arpa/inet.h>`	Functions for manipulating numeric IP addresses (part of Berkeley sockets)	Issue 6
`<assert.h>`	Verify assumptions	Issue 1
`<complex.h>`	Complex Arithmetic, see C mathematical functions	Issue 6
`<cpio.h>`	Magic numbers for the cpio archive format	Issue 3
`<ctype.h>`	Character types	Issue 1
`<dirent.h>`	Allows the opening and listing of directories	Issue 2
`<dlfcn.h>`	Dynamic linking	Issue 5
`<errno.h>`	Retrieving Error Number	Issue 1
`<fcntl.h>`	File opening, locking and other operations	Issue 1
`<fenv.h>`	Floating-Point Environment (FPE), see C mathematical functions	Issue 6
`<float.h>`	Floating-point types, see C data types	Issue 4
`<fmtmsg.h>`	Message display structures	Issue 4
`<fnmatch.h>`	Filename matching	Issue 4
`<ftw.h>`	File tree traversal	Issue 1
`<glob.h>`	Pathname "globbing" (pattern-matching)	Issue 4
`<grp.h>`	User group information and control	Issue 1
`<iconv.h>`	Codeset conversion facility	Issue 4
`<inttypes.h>`	Fixed sized integer types, see C data types	Issue 5
`<iso646.h>`	Alternative spellings, see C alternative tokens	Issue 5
`<langinfo.h>`	Language information constants – builds on C localization functions	Issue 2
`<libgen.h>`	Pathname manipulation	Issue 4
`<limits.h>`	Implementation-defined constants, see C data types	Issue 1
`<locale.h>`	Category macros, see C localization functions	Issue 3
`<math.h>`	Mathematical declarations, see C mathematical functions	Issue 1
`<monetary.h>`	String formatting of monetary units	Issue 4
`<mqueue.h>`	Message queue	Issue 5
`<ndbm.h>`	NDBM database operations	Issue 4
`<net/if.h>`	Listing of local network interfaces	Issue 6
`<netdb.h>`	Translating protocol and host names into numeric addresses (part of Berkeley sockets)	Issue 6
`<netinet/in.h>`	Defines Internet protocol and address family (part of Berkeley sockets)	Issue 6
`<netinet/tcp.h>`	Additional TCP control options (part of Berkeley sockets)	Issue 6
`<nl_types.h>`	Localization message catalog functions	Issue 2
`<poll.h>`	Asynchronous file descriptor multiplexing	Issue 4
`<pthread.h>`	Defines an API for creating and manipulating POSIX threads	Issue 5
`<pwd.h>`	passwd (user information) access and control	Issue 1
`<regex.h>`	Regular expression matching	Issue 4
`<sched.h>`	Execution scheduling	Issue 5
`<search.h>`	Search tables	Issue 1
`<semaphore.h>`	POSIX semaphores	Issue 5
`<setjmp.h>`	Stack environment declarations	Issue 1
`<signal.h>`	Signals, see C signal handling	Issue 1
`<spawn.h>`	Process spawning	Issue 6
`<stdarg.h>`	Handle Variable Argument List	Issue 4
`<stdbool.h>`	Boolean type and values, see C data types	Issue 6
`<stddef.h>`	Standard type definitions, see C data types	Issue 4
`<stdint.h>`	Integer types, see C data types	Issue 6
`<stdio.h>`	Standard buffered input/output, see C file input/output	Issue 1
`<stdlib.h>`	Standard library definitions, see C standard library	Issue 3
`<string.h>`	Several String Operations, see C string handling	Issue 1
`<strings.h>`	Case-insensitive string comparisons	Issue 4
`<stropts.h>`	Stream manipulation, including ioctl	Issue 4
`<sys/ipc.h>`	Inter-process communication (IPC)	Issue 2
`<sys/mman.h>`	Memory management, including POSIX shared memory and memory mapped files	Issue 4
`<sys/msg.h>`	POSIX message queues	Issue 2
`<sys/resource.h>`	Resource usage, priorities, and limiting	Issue 4
`<sys/select.h>`	Synchronous I/O multiplexing	Issue 6
`<sys/sem.h>`	XSI (SysV style) semaphores	Issue 2
`<sys/shm.h>`	XSI (SysV style) shared memory	Issue 2
`<sys/socket.h>`	Main Berkeley sockets header	Issue 6
`<sys/stat.h>`	File information (stat et al.)	Issue 1
`<sys/statvfs.h>`	File System information	Issue 4
`<sys/time.h>`	Time and date functions and structures	Issue 4
`<sys/times.h>`	File access and modification times	Issue 1
`<sys/types.h>`	Various data types used elsewhere	Issue 1
`<sys/uio.h>`	Vectored I/O operations	Issue 4
`<sys/un.h>`	Unix domain sockets	Issue 6
`<sys/utsname.h>`	Operating system information, including uname	Issue 1
`<sys/wait.h>`	Status of terminated child processes (see wait)	Issue 3
`<syslog.h>`	System error logging	Issue 4
`<tar.h>`	Magic numbers for the tar archive format	Issue 3
`<termios.h>`	Allows terminal I/O interfaces	Issue 3
`<tgmath.h>`	Type-Generic Macros, see C mathematical functions	Issue 6
`<time.h>`	Type-Generic Macros, see C date and time functions	Issue 1
`<trace.h>`	Tracing of runtime behavior (DEPRECATED)	Issue 6
`<ulimit.h>`	Resource limiting (DEPRECATED in favor of <sys/resource.h>)	Issue 1
`<unistd.h>`	Various essential POSIX functions and constants	Issue 1
`<utime.h>`	inode access and modification times	Issue 3
`<utmpx.h>`	User accounting database functions	Issue 4
`<wchar.h>`	Wide-Character Handling, see C string handling	Issue 4
`<wctype.h>`	Wide-Character Classification and Mapping Utilities, see C character classification	Issue 5
`<wordexp.h>`	Word-expansion like the shell would perform	Issue 4

C POSIX library header files

References

Further reading