man7/standards.7

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  26 .TH STANDARDS 7 2012-08-05 "Linux" "Linux Programmer's Manual"
  27 .SH NAME
  28 standards \- C and UNIX Standards
  29 .SH DESCRIPTION
  30 The CONFORMING TO section that appears in many manual pages identifies
  31 various standards to which the documented interface conforms.
  32 The following list briefly describes these standards.
  33 .TP
  34 .B V7
  35 Version 7, the ancestral UNIX from Bell Labs.
  36 .TP
  37 .B 4.2BSD
  38 This is an implementation standard defined by the 4.2 release
  39 of the
  40 .IR "Berkeley Software Distribution",
  41 released by the University of California at Berkeley.
  42 This was the first Berkeley release that contained a TCP/IP
  43 stack and the sockets API.
  44 4.2BSD was released in 1983.
  45
  46 Earlier major BSD releases included \fI3BSD\fP (1980), \fI4BSD\fP (1980),
  47 and \fI4.1BSD\fP (1981).
  48 .TP
  49 .B 4.3BSD
  50 The successor to 4.2BSD, released in 1986.
  51 .TP
  52 .B 4.4BSD
  53 The successor to 4.3BSD, released in 1993.
  54 This was the last major Berkeley release.
  55 .TP
  56 .B System V
  57 This is an implementation standard defined by AT&T's milestone 1983
  58 release of its commercial System V (five) release.
  59 The previous major AT&T release was
  60 .IR "System III" ,
  61 released in 1981.
  62 .TP
  63 .B System V release 2 (SVr2)
  64 This was the next System V release, made in 1985.
  65 The SVr2 was formally described in the
  66 .I "System V Interface Definition version 1"
  67 .RI ( "SVID 1" )
  68 published in 1985.
  69 .TP
  70 .B System V release 3 (SVr3)
  71 This was the successor to SVr2, released in 1986.
  72 This release was formally described in the
  73 .I "System V Interface Definition version 2"
  74 .RI ( "SVID 2" ).
  75 .TP
  76 .B System V release 4 (SVr4)
  77 This was the successor to SVr3, released in 1989.
  78 This version of System V is described in the "Programmer's Reference
  79 Manual: Operating System API (Intel processors)" (Prentice-Hall
  80 1992, ISBN 0-13-951294-2)
  81 This release was formally described in the
  82 .I "System V Interface Definition version 3"
  83 .RI ( "SVID 3" ),
  84 and is considered the definitive System V release.
  85 .TP
  86 .B SVID 4
  87 System V Interface Definition version 4, issued in 1995.
  88 Available online at
  89 .UR http://www.sco.com\:/developers\:/devspecs/
  90 .UE .
  91 .TP
  92 .B C89
  93 This was the first C language standard, ratified by ANSI
  94 (American National Standards Institute) in 1989
  95 .RI ( X3.159-1989 ).
  96 Sometimes this is known as
  97 .IR "ANSI C" ,
  98 but since C99 is also an
  99 ANSI standard, this term is ambiguous.
 100 This standard was also ratified by
 101 ISO (International Standards Organization) in 1990
 102 .RI ( "ISO/IEC 9899:1990" ),
 103 and is thus occasionally referred to as
 104 .IR "ISO C90" .
 105 .TP
 106 .B C99
 107 This revision of the C language standard was ratified by ISO in 1999
 108 .RI ( "ISO/IEC 9899:1999" ).
 109 Available online at
 110 .UR http://www.open-std.org\:/jtc1\:/sc22\:/wg14\:/www\:/standards
 111 .UE .
 112 .TP
 113 .B POSIX.1-1990
 114 "Portable Operating System Interface for Computing Environments".
 115 IEEE 1003.1-1990 part 1, ratified by ISO in 1990
 116 .RI ( "ISO/IEC 9945-1:1990" ).
 117 The term "POSIX" was coined by Richard Stallman.
 118 .TP
 119 .B POSIX.2
 120 IEEE Std 1003.2-1992,
 121 describing commands and utilities, ratified by ISO in 1993
 122 .RI ( "ISO/IEC 9945-2:1993" ).
 123 .TP
 124 .BR POSIX.1b " (formerly known as \fIPOSIX.4\fP)"
 125 IEEE Std 1003.1b-1993
 126 describing real-time facilities
 127 for portable operating systems, ratified by ISO in 1996
 128 .RI ( "ISO/IEC 9945-1:1996" ).
 129 .TP
 130 .B POSIX.1c
 131 IEEE Std 1003.1c-1995 describing the POSIX threads interfaces.
 132 .TP
 133 .B POSIX.1d
 134 IEEE Std 1003.1c-1999 describing additional real-time extensions.
 135 .TP
 136 .B POSIX.1g
 137 IEEE Std 1003.1g-2000 describing networking APIs (including sockets).
 138 .TP
 139 .B POSIX.1j
 140 IEEE Std 1003.1j-2000 describing advanced real-time extensions.
 141 .TP
 142 .B POSIX.1-1996
 143 A 1996 revision of POSIX.1 which incorporated POSIX.1b and POSIX.1c.
 144 .TP
 145 .B XPG3
 146 Released in 1989, this was the first significant release of the
 147 .IR "X/Open Portability Guide" ,
 148 produced by the
 149 X/Open Company, a multivendor consortium.
 150 This multivolume guide was based on the POSIX standards.
 151 .TP
 152 .B XPG4
 153 A revision of the X/Open Portability Guide, released in 1992.
 154 .TP
 155 .B XPG4v2
 156 A 1994 revision of XPG4.
 157 This is also referred to as
 158 .IR "Spec 1170" ,
 159 where 1170 referred to the number of interfaces
 160 defined by this standard.
 161 .TP
 162 .B SUS  (SUSv1)
 163 Single UNIX Specification.
 164 This was a repackaging of XPG4v2 and other X/Open standards
 165 (X/Open Curses Issue 4 version 2,
 166 X/Open Networking Service (XNS) Issue 4).
 167 Systems conforming to this standard can be branded
 168 .IR "UNIX 95" .
 169 .TP
 170 .B SUSv2
 171 Single UNIX Specification version 2.
 172 Sometimes also referred to as
 173 .IR XPG5 .
 174 This standard appeared in 1997.
 175 Systems conforming to this standard can be branded
 176 .IR "UNIX 98" .
 177 See also
 178 .UR http://www.UNIX-systems.org\:/version2/
 179 .UE .)
 180 .TP
 181 .B POSIX.1-2001, SUSv3
 182 This was a 2001 revision and consolidation of the
 183 POSIX.1, POSIX.2, and SUS standards into a single document,
 184 conducted under the auspices of the Austin group
 185 .UR http://www.opengroup.org\:/austin/
 186 .UE .
 187 The standard is available online at
 188 .UR http://www.unix-systems.org\:/version3/
 189 .UE ,
 190 and the interfaces that it describes are also available in the Linux
 191 manual pages package under sections 1p and 3p (e.g., "man 3p open").
 192
 193 The standard defines two levels of conformance:
 194 .IR "POSIX conformance" ,
 195 which is a baseline set of interfaces required of a conforming system;
 196 and
 197 .IR "XSI Conformance",
 198 which additionally mandates a set of interfaces
 199 (the "XSI extension") which are only optional for POSIX conformance.
 200 XSI-conformant systems can be branded
 201 .IR "UNIX 03" .
 202 (XSI conformance constitutes the
 203 .I "Single UNIX Specification version 3"
 204 .RI ( SUSv3 ).)
 205
 206 The POSIX.1-2001 document is broken into four parts:
 207
 208 .BR XBD :
 209 Definitions, terms and concepts, header file specifications.
 210
 211 .BR XSH :
 212 Specifications of functions (i.e., system calls and library
 213 functions in actual implementations).
 214
 215 .BR XCU :
 216 Specifications of commands and utilities
 217 (i.e., the area formerly described by POSIX.2).
 218
 219 .BR XRAT :
 220 Informative text on the other parts of the standard.
 221
 222 POSIX.1-2001 is aligned with C99, so that all of the
 223 library functions standardized in C99 are also
 224 standardized in POSIX.1-2001.
 225
 226 Two Technical Corrigenda (minor fixes and improvements)
 227 of the original 2001 standard have occurred:
 228 TC1 in 2003 (referred to as
 229 .IR POSIX.1-2003 ),
 230 and TC2 in 2004 (referred to as
 231 .IR POSIX.1-2004 ).
 232 .TP
 233 .B POSIX.1-2008, SUSv4
 234 Work on the next revision of POSIX.1/SUS was completed and
 235 ratified in 2008.
 236
 237 The changes in this revision are not as large as those
 238 that occurred for POSIX.1-2001/SUSv3,
 239 but a number of new interfaces are added
 240 and various details of existing specifications are modified.
 241 Many of the interfaces that were optional in
 242 POSIX.1-2001 become mandatory in the 2008 revision of the standard.
 243 A few interfaces that are present in POSIX.1-2001 are marked
 244 as obsolete in POSIX.1-2008, or removed from the standard altogether.
 245
 246 The revised standard is broken into the same four parts as POSIX.1-2001,
 247 and again there are two levels of conformance: the baseline
 248 .IR "POSIX Conformance" ,
 249 and
 250 .IR "XSI Conformance" ,
 251 which mandates an additional set of interfaces
 252 beyond those in the base specification.
 253
 254 In general, where the CONFORMING TO section of a manual page
 255 lists POSIX.1-2001, it can be assumed that the interface also
 256 conforms to POSIX.1-2008, unless otherwise noted.
 257
 258 Further information can be found on the Austin group web site,
 259 .UR http://www.opengroup.org\:/austin/
 260 .UE .
 261 .SH SEE ALSO
 262 .BR feature_test_macros (7),
 263 .BR libc (7),
 264 .BR posixoptions (7)