# info > standards

---
type: CommandReference
command: standards
mode: man
section: 7
source: man-pages
---

## Quick Reference

- `V7` — Version 7 UNIX (1979)
- `4.2BSD` — First BSD with TCP/IP and sockets API (1983)
- `System V` — AT&T commercial UNIX (1983)
- `C89` — First ANSI C standard (1989)
- `C99` — ISO C revision (1999)
- `POSIX.1-2001 / SUSv3` — Combined POSIX & Single UNIX Spec (2001)
- `POSIX.1-2008 / SUSv4` — Updated POSIX & SUS (2008)
- `LFS` — Large File Summit spec (1996, 64‑bit offsets on 32‑bit systems)

## Name

standards — C and UNIX Standards

## Description

The **CONFORMING TO** section of many manual pages references these standards:

### Early UNIX

- **V7** — Version 7 (Seventh Edition) UNIX, AT&T/Bell Labs, 1979. After this, UNIX diverged into BSD and System V.

### BSD

- **4.2BSD** — 1983, first with TCP/IP stack and sockets API.
- **4.3BSD** — 1986, successor to 4.2BSD.
- **4.4BSD** — 1993, last major Berkeley release.

### System V

- **System V** — AT&T commercial release, 1983.
- **SVr2** — 1985, described in SVID 1.
- **SVr3** — 1986, described in SVID 2.
- **SVr4** — 1989, described in SVID 3 (definitive System V release).
- **SVID 4** — 1995, available online at <http://www.sco.com/developers/devspecs/>.

### C Language Standards

- **C89** — ANSI X3.159-1989, also ISO/IEC 9899:1990 (ISO C90).
- **C99** — ISO/IEC 9899:1999.
- **C11** — ISO/IEC 9899:2011.

### POSIX

- **POSIX.1-1988** — IEEE Std 1003.1-1988, first POSIX standard.
- **POSIX.1-1990** — IEEE 1003.1-1990, ISO/IEC 9945-1:1990.
- **POSIX.2** — IEEE 1003.2-1992 (commands and utilities).
- **POSIX.1b** (formerly POSIX.4) — IEEE 1003.1b-1993, real-time facilities.
- **POSIX.1c** (formerly POSIX.4a) — IEEE 1003.1c-1995, threads interfaces.
- **POSIX.1d** — IEEE 1003.1d-1999, additional real-time extensions.
- **POSIX.1g** — IEEE 1003.1g-2000, networking APIs.
- **POSIX.1j** — IEEE 1003.1j-2000, advanced real-time extensions.
- **POSIX.1-1996** — Merged POSIX.1b and POSIX.1c.
- **POSIX.1-2001 / SUSv3** — Austin Group consolidation, 2001. Includes XBD, XSH, XCU, XRAT. Two conformance levels: POSIX and XSI (UNIX 03). Aligned with C99. Technical Corrigenda TC1 (2003) and TC2 (2004).
- **POSIX.1-2008 / SUSv4** — 2008 revision. Many optional interfaces become mandatory. Some marked obsolete. Also X/Open Curses Issue 7. Two conformance levels. TC1 (2013) and TC2 (2016).
- **SUSv4 2016 edition** — POSIX.1-2008 + TC1+TC2 + XCurses.
- **POSIX.1-2017** — Technically identical to POSIX.1-2008 with TC1+TC2.
- **SUSv4 2018 edition** — POSIX.1-2017 + XCurses.

### X/Open Portability Guide

- **XPG3** — 1989, based on POSIX.1-1988.
- **XPG4** — 1992, incorporates POSIX.2.
- **XPG4v2** — 1994 (Spec 1170), 1170 interfaces.

### Single UNIX Specification

- **SUS (SUSv1)** — Repackaging of XPG4v2 + other X/Open standards. UNIX 95 branding.
- **SUSv2** — 1997, UNIX 98 branding. See <http://www.unix.org/version2/>.

### LFS

- **LFS** — Large File Summit specification, 1996. Enables 64‑bit file offsets on 32‑bit systems. See <https://www.opengroup.org/platform/lfs.html>.

Manual pages for POSIX/SUS interfaces are available in sections 0p (headers), 1p (commands), and 3p (functions); e.g., `man 3p open`.

## See Also

- [getconf(1)](https://www.chedong.com/phpMan.php/man/getconf/1/markdown)
- [confstr(3)](https://www.chedong.com/phpMan.php/man/confstr/3/markdown)
- [pathconf(3)](https://www.chedong.com/phpMan.php/man/pathconf/3/markdown)
- [sysconf(3)](https://www.chedong.com/phpMan.php/man/sysconf/3/markdown)
- [attributes(7)](https://www.chedong.com/phpMan.php/man/attributes/7/markdown)
- [feature_test_macros(7)](https://www.chedong.com/phpMan.php/man/turetestmacros/7/markdown)
- [libc(7)](https://www.chedong.com/phpMan.php/man/libc/7/markdown)
- [posixoptions(7)](https://www.chedong.com/phpMan.php/man/posixoptions/7/markdown)
- [system_data_types(7)](https://www.chedong.com/phpMan.php/man/systemdatatypes/7/markdown)