standards - phpMan

STANDARDS(7) Linux Programmer's Manual STANDARDS(7)

NAME
Standards - C and UNIX Standards

DESCRIPTION
The CONFORMING TO section that appears in many manual pages identifies various
standards to which the documented interface conforms. The following list briefly
describes these standards.

V7 Version 7, the ancestral UNIX from Bell Labs.

4.2BSD This is an implementation standard defined by the 4.2 release of the Berke-
ley Software Distribution, released by the University of California at
Berkeley. This was the first Berkeley release that contained a TCP/IP stack
and the sockets API. 4.2BSD was released in 1983.

Earlier major BSD releases included 3BSD (1980), 4BSD (1980), and 4.1BSD
(1981).

4.3BSD The successor to 4.2BSD, released in 1986.

4.4BSD The successor to 4.3BSD, released in 1993. This was the last major Berkeley
release.

System V
This is an implementation standard defined by AT&T's milestone 1983 release
of its commercial System V (five) release. The previous major AT&T release
was System III, released in 1981.

System V release 2 (SVr2)
This was the next System V release, made in 1985. The SVr2 was formally
described in the System V Interface Definition version 1 (SVID 1) published
in 1985.

System V release 3 (SVr3)
This was the successor to SVr2, released in 1986. This release was formally
described in the System V Interface Definition version 2 (SVID 2).

System V release 4 (SVr4)
This was the successor to SVr3, released in 1989. This version of System V
is described in the "Programmer's Reference Manual: Operating System API
(Intel processors)" (Prentice-Hall 1992, ISBN 0-13-951294-2) This release
was formally described in the System V Interface Definition version 3 (SVID
3), and is considered the definitive System V release.

SVID 4 System V Interface Definition version 4, issued in 1995. Available online
at http://www.sco.com/developers/devspecs/ .

C89 This was the first C language standard, ratified by ANSI (American National
Standards Institute) in 1989 (X3.159-1989). Sometimes this is known as ANSI
C, but since C99 is also an ANSI standard, this term is ambiguous. This
standard was also ratified by ISO (International Standards Organization) in
1990 (ISO/IEC 9899:1990), and is thus occasionally referred to as ISO C90.

C99 This revision of the C language standard was ratified by ISO in 1999
(ISO/IEC 9899:1999).

POSIX.1-1990
"Portable Operating System Interface for Computing Environments". IEEE
1003.1-1990 part 1, ratified by ISO in 1990 (ISO/IEC 9945-1:1990). Further
information can be found in Donald Lewine's "POSIX Programmer's Guide"
(O'Reilly & Associates, Inc., 1991, ISBN 0-937175-73-0). The term "POSIX"
was coined by Richard Stallman.

POSIX.2
IEEE Std 1003.2-1992, describing commands and utilities, ratified by ISO in
1993 (ISO/IEC 9945-2:1993).

POSIX.1b (formerly known as POSIX.4)
IEEE Std 1003.1b-1993 describing real-time facilities for portable operating
systems, ratified by ISO in 1996 (ISO/IEC 9945-1:1996). For further infor-
mation, see "POSIX.4: Programming for the real world" by Bill O. Gallmeister
(O'Reilly & Associates, Inc. ISBN 1-56592-074-0).

POSIX.1c
IEEE Std 1003.1c-1995 describing the POSIX threads interfaces.

POSIX.1d
IEEE Std 1003.1c-1999 describing additional real-time extensions.

POSIX.1g
IEEE Std 1003.1g-2000 describing networking APIs (including sockets).

POSIX.1j
IEEE Std 1003.1j-2000 describing advanced real-time extensions.

POSIX.1-1996
A 1996 revision of POSIX.1 which incorporated POSIX.1b and POSIX.1c.

XPG3 Released in 1989, this was the first significant release of the X/Open
Portability Guide, produced by the X/Open Company, a multi-vendor consor-
tium. This multi-volume guide was based on the POSIX standards.

XPG4 A revision of the X/Open Portability Guide, released in 1992.

XPG4v2 A 1994 revision of XPG4. This is also referred to as Spec 1170, where 1170
referred to the number of interfaces defined by this standard.

SUS (SUSv1)
Single UNIX Specification. This was a repackaging of XPG4v2 and other
X/Open standards (X/Open Curses Issue 4 version 2, X/Open Networking Service
(XNS) Issue 4). Systems conforming to this standard can be branded UNIX 95.

SUSv2 Single UNIX Specification version 2. Sometimes also referred to as XPG5.
This standard appeared in 1997. Systems conforming to this standard can be
branded UNIX 98. See also http://www.UNIX-systems.org/version2/ .)

POSIX.1-2001, SUSv3
This was a 2001 revision and consolidation of the POSIX.1, POSIX.2, and SUS
standards into a single document, conducted under the auspices of the Austin
group (http://www.opengroup.org/austin/ .) The standard is available online
at http://www.unix-systems.org/version3/ , and the interfaces that it
describes are also available in the Linux manual pages package under sec-
tions 1p and 3p (e.g., "man 3p open").

The standard defines two levels of conformance: POSIX conformance, which is
a baseline set of interfaces required of a conforming system; and XSI Con-
formance, which additionally mandates a set of interfaces (the "XSI exten-
sion") which are only optional for POSIX conformance. XSI-conformant sys-
tems can be branded UNIX 03. (XSI conformance constitutes the Single UNIX
Specification version 3 (SUSv3).)

The POSIX.1-2001 document is broken into four parts:

XBD: Definitions, terms and concepts, header file specifications.

XSH: Specifications of functions (i.e., system calls and library functions
in actual implementations).

XCU: Specifications of commands and utilities (i.e., the area formerly
described by POSIX.2).

XRAT: Informative text on the other parts of the standard.

POSIX.1-2001 is aligned with C99, so that all of the library functions stan-
dardised in C99 are also standardised in POSIX.1-1001.

Two Technical Corrigenda (minor fixes and improvements) of the original 2001
standard have occurred: TC1 in 2003 (referred to as POSIX.1-2003), and TC2
in 2004 (referred to as POSIX.1-2004).