1STANDARDS(7)               Linux Programmer's Manual              STANDARDS(7)
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NAME

6       Standards - C and UNIX Standards
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DESCRIPTION

9       The  CONFORMING TO section that appears in many manual pages identifies
10       various standards to which the documented interface conforms.  The fol‐
11       lowing list briefly describes these standards.
12
13       V7     Version 7, the ancestral UNIX from Bell Labs.
14
15       4.2BSD This is an implementation standard defined by the 4.2 release of
16              the Berkeley Software Distribution, released by  the  University
17              of  California at Berkeley.  This was the first Berkeley release
18              that contained a TCP/IP stack and the sockets API.   4.2BSD  was
19              released in 1983.
20
21              Earlier  major  BSD  releases included 3BSD (1980), 4BSD (1980),
22              and 4.1BSD (1981).
23
24       4.3BSD The successor to 4.2BSD, released in 1986.
25
26       4.4BSD The successor to 4.3BSD, released in 1993.  This  was  the  last
27              major Berkeley release.
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29       System V
30              This  is  an implementation standard defined by AT&T's milestone
31              1983 release of its commercial System  V  (five)  release.   The
32              previous major AT&T release was System III, released in 1981.
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34       System V release 2 (SVr2)
35              This  was the next System V release, made in 1985.  The SVr2 was
36              formally described in the System V Interface Definition  version
37              1 (SVID 1) published in 1985.
38
39       System V release 3 (SVr3)
40              This  was the successor to SVr2, released in 1986.  This release
41              was formally described in the System V Interface Definition ver‐
42              sion 2 (SVID 2).
43
44       System V release 4 (SVr4)
45              This  was the successor to SVr3, released in 1989.  This version
46              of System V is described in the "Programmer's Reference  Manual:
47              Operating  System  API  (Intel processors)" (Prentice-Hall 1992,
48              ISBN 0-13-951294-2) This release was formally described  in  the
49              System V Interface Definition version 3 (SVID 3), and is consid‐
50              ered the definitive System V release.
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52       SVID 4 System V Interface Definition version 4, issued in 1995.  Avail‐
53              able online at http://www.sco.com/developers/devspecs/ .
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55       C89    This was the first C language standard, ratified by ANSI (Ameri‐
56              can National Standards Institute) in 1989 (X3.159-1989).   Some‐
57              times  this  is  known  as ANSI C, but since C99 is also an ANSI
58              standard, this term is ambiguous.  This standard was also  rati‐
59              fied  by  ISO  (International  Standards  Organization)  in 1990
60              (ISO/IEC 9899:1990), and is thus occasionally referred to as ISO
61              C90.
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63       C99    This  revision of the C language standard was ratified by ISO in
64              1999 (ISO/IEC 9899:1999).
65
66       POSIX.1-1990
67              "Portable Operating  System  Interface  for  Computing  Environ‐
68              ments".   IEEE  1003.1-1990  part  1,  ratified  by  ISO in 1990
69              (ISO/IEC 9945-1:1990).  Further information can be found in Don‐
70              ald  Lewine's "POSIX Programmer's Guide" (O'Reilly & Associates,
71              Inc., 1991, ISBN 0-937175-73-0).  The term "POSIX" was coined by
72              Richard Stallman.
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74       POSIX.2
75              IEEE  Std  1003.2-1992, describing commands and utilities, rati‐
76              fied by ISO in 1993 (ISO/IEC 9945-2:1993).
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78       POSIX.1b (formerly known as POSIX.4)
79              IEEE Std 1003.1b-1993 describing real-time facilities for porta‐
80              ble   operating  systems,  ratified  by  ISO  in  1996  (ISO/IEC
81              9945-1:1996).  For further information, see  "POSIX.4:  Program‐
82              ming  for the real world" by Bill O. Gallmeister (O'Reilly & As‐
83              sociates, Inc. ISBN 1-56592-074-0).
84
85       POSIX.1c
86              IEEE Std 1003.1c-1995 describing the POSIX threads interfaces.
87
88       POSIX.1d
89              IEEE Std 1003.1c-1999  describing  additional  real-time  exten‐
90              sions.
91
92       POSIX.1g
93              IEEE  Std  1003.1g-2000  describing  networking  APIs (including
94              sockets).
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96       POSIX.1j
97              IEEE Std 1003.1j-2000 describing advanced real-time extensions.
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99       POSIX.1-1996
100              A 1996 revision  of  POSIX.1  which  incorporated  POSIX.1b  and
101              POSIX.1c.
102
103       XPG3   Released  in 1989, this was the first significant release of the
104              X/Open Portability Guide, produced  by  the  X/Open  Company,  a
105              multi-vendor  consortium.   This multi-volume guide was based on
106              the POSIX standards.
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108       XPG4   A revision of the X/Open Portability Guide, released in 1992.
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110       XPG4v2 A 1994 revision of XPG4.  This is also referred to as Spec 1170,
111              where  1170 referred to the number of interfaces defined by this
112              standard.
113
114       SUS (SUSv1)
115              Single UNIX Specification.  This was a repackaging of XPG4v2 and
116              other  X/Open standards (X/Open Curses Issue 4 version 2, X/Open
117              Networking Service (XNS) Issue 4).  Systems conforming  to  this
118              standard can be branded UNIX 95.
119
120       SUSv2  Single UNIX Specification version 2.  Sometimes also referred to
121              as XPG5.  This standard appeared in 1997.  Systems conforming to
122              this standard can be branded UNIX 98.  See also http://www.UNIX-
123              systems.org/version2/ .)
124
125       POSIX.1-2001, SUSv3
126              This was a 2001  revision  and  consolidation  of  the  POSIX.1,
127              POSIX.2,  and  SUS  standards  into a single document, conducted
128              under  the  auspices  of  the  Austin  group   (http://www.open
129              group.org/austin/  .)   The  standard  is  available  online  at
130              http://www.unix-systems.org/version3/ , and the interfaces  that
131              it  describes are also available in the Linux manual pages pack‐
132              age under sections 1p and 3p (e.g., "man 3p open").
133
134              The standard defines two levels of  conformance:  POSIX  confor‐
135              mance,  which is a baseline set of interfaces required of a con‐
136              forming system; and XSI Conformance, which additionally mandates
137              a  set  of  interfaces  (the  "XSI  extension")  which  are only
138              optional for POSIX conformance.  XSI-conformant systems  can  be
139              branded  UNIX  03.  (XSI conformance constitutes the Single UNIX
140              Specification version 3 (SUSv3).)
141
142              The POSIX.1-2001 document is broken into four parts:
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144              XBD: Definitions, terms and  concepts,  header  file  specifica‐
145              tions.
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147              XSH: Specifications of functions (i.e., system calls and library
148              functions in actual implementations).
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150              XCU: Specifications of commands and utilities  (i.e.,  the  area
151              formerly described by POSIX.2).
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153              XRAT: Informative text on the other parts of the standard.
154
155              POSIX.1-2001  is  aligned  with  C99, so that all of the library
156              functions  standardised  in  C99  are   also   standardised   in
157              POSIX.1-1001.
158
159              Two  Technical  Corrigenda (minor fixes and improvements) of the
160              original 2001 standard have occurred: TC1 in 2003  (referred  to
161              as POSIX.1-2003), and TC2 in 2004 (referred to as POSIX.1-2004).
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SEE ALSO

164       feature_test_macros(7)
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168Linux                             2006-08-03                      STANDARDS(7)
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