"IEEE Std 1003.1-2001 defines a standard operating system interface and environment@ including a command interpreter (or ""shell"")@ and common utility programs to support applications portability at the source code level. It is intended to be used by both applications developers and system implementors. IEEE Std 1003.1-2001 comprises four major components (each in an associated volume): 1. General terms@ concepts@ and interfaces common to all volumes of IEEE Std 1003.1-2001@ including utility conventions and C-language header definitions@ are included in the Base Definitions volume of IEEE Std 1003.1-2001. 2. Definitions for system service functions and subroutines@ language-specific system services for the C programming language@ function issues@ including portability@ error handling@ and error recovery@ are included in the System Interfaces volume of IEEE Std 1003.1-2001. 3. Definitions for a standard source code-level interface to command interpretation services (a ""shell"") and common utility programs for application programs are included in the Shell and Utilities volume of IEEE Std 1003.1-2001. 4. Extended rationale that did not fit well into the rest of the document structure@ containing historical information concerning the contents of IEEE Std 1003.1-2001 and why features were included or discarded by the standard developers@ is included in the Rationale (Informative) volume of IEEE Std 1003.1-2001. The following areas are outside of the scope of IEEE Std 1003.1-2001: ? Graphics interfaces ? Database management system interfaces ? Record I/O considerations ? Object or binary code portability ? System configuration and resource availability IEEE Std 1003.1-2001 describes the external characteristics and facilities that are of importance to applications developers@ rather than the internal construction techniques employed to achieve these capabilities. Special emphasis is placed on those functions and facilities that are needed in a wide variety of commercial applications. The facilities provided in IEEE Std 1003.1-2001 are drawn from the following base documents: ? IEEE Std 1003.1-1996 (POSIX-1) (incorporating IEEE Stds 1003.1-1990@ 1003.1b-1993@ 1003.1c-1995@ and 1003.1i-1995) ? The following amendments to the POSIX.1-1990 standard: - IEEE P1003.1a draft standard (Additional System Services) - IEEE Std 1003.1d-1999 (Additional Realtime Extensions) - IEEE Std 1003.1g-2000 (Protocol-Independent Interfaces (PII)) - IEEE Std 1003.1j-2000 (Advanced Realtime Extensions) - IEEE Std 1003.1q-2000 (Tracing) ? IEEE Std 1003.2-1992 (POSIX-2) (includes IEEE Std 1003.2a-1992) ? The following amendments to the ISO POSIX-2: 1993 standard: - IEEE P1003.2b draft standard (Additional Utilities) - IEEE Std 1003.2d-1994 (Batch Environment) ? Open Group Technical Standard@ February 1997@ System Interface Definitions@ Issue 5 (XBD5) (ISBN: 1-85912-186-1@ C605) ? Open Group Technical Standard@ February 1997@ Commands and Utilities@ Issue 5 (XCU5) (ISBN: 1-85912-191-8@ C604) ? Open Group Technical Standard@ February 1997@ System Interfaces and Headers@ Issue 5 (XSH5) (in 2 Volumes) (ISBN: 1-85912-181-0@ C606) Note: XBD5@ XCU5@ and XSH5 are collectively referred to as the Base Specifications. ? Open Group Technical Standard@ January 2000@ Networking Services@ Issue 5.2 (XNS5.2) (ISBN: 1-85912-241-8@ C808) ? ISO/IEC 9899: 1999@ Programming Languages - C. IEEE Std 1003.1-2001 uses the Base Specifications as its organizational basis and adds the following additional functionality to them@ drawn from the base documents above: ? Normative text from the ISO POSIX-1: 1996 standard and the ISO POSIX-2: 1993 standard not included in the Base Specifications ? The amendments to the POSIX.1-1990 standard and the ISO POSIX-2: 1993 standard listed above@ except for parts of IEEE Std 1003.1g-2000 ? Portability Considerations ? Additional rationale and notes The following features@ marked legacy or obsolescent in the base documents@ are not carried forward into IEEE Std 1003.1-2001. Other features from the base documents marked legacy or obsolescent are carried forward unless otherwise noted. From XSH5@ the following legacy interfaces@ headers@ and external variables are not carried forward: advance()@ brk()@ chroot()@ compile()@ cuserid()@ gamma()@ getdtablesize()@ getpagesize()@ getpass()@ getw()@ putw()@ re_comp()@ re_exec()@ regcmp()@ regex()@ sbrk()@ sigstack ()@ step()@ ttyslot()@ valloc()@ wait3()@ ?re_comp.h?g@ ?regexp.h?@ ?varargs.h?@ loc1@ __loc1@ loc2@ locs From XCU5@ the following legacy utilities are not carried forward: calendar@ cancel@ cc@ col@ cpio@ cu@ dircmp@ dis@ egrep@ fgrep@ line@ lint@ lpstat@ mail@ pack@ pcat@ pg@ spell@ sum@ tar@ unpack@ uulog@ uuname@ uupick@ uuto In addition@ legacy features within non-legacy reference pages (for example@ headers) are not carried forward. From the ISO POSIX-1: 1996 standard@ the following obsolescent features are not carried forward: Page 112@ CLK_TCK Page 197 tcgetattr() rate returned option From the ISO POSIX-2: 1993 standard@ obsolescent features within the following pages are not carried forward: Page 75@ zero-length prefix within PATH Page 156@ 159 set Page 178@ awk@ use of no argument and no parentheses with length Page 259@ ed Page 272@ env Page 282@ find -perm[-]onum Page 295-296@ egrep Page 299-300@ head Page 305-306@ join Page 309-310@ kill Page 431-433@ 435-436@ sort Page 444-445@ tail Page 453@ 455-456@ touch Page 464-465@ tty Page 472@ uniq Page 515-516@ ex Page 542-543@ expand Page 563-565@ more Page 574-576@ newgrp Page 578@ nice Page 594-596@ renice Page 597-598@ split Page 600-601@ strings Page 624-625@ vi Page 693@ lex The c89 utility (which specified a compiler for the C Language specified by the ISO/IEC 9899: 1990 standard) has been replaced by a c99 utility (which specifies a compiler for the C Language specified by the ISO/IEC 9899: 1999 standard). From XSH5@ text marked OH (Optional Header) has been reviewed on a case-by-case basis and removed where appropriate. The XCU5 text marked OF (Output Format Incompletely Specified) and UN (Possibly Unsupportable Feature) has been reviewed on a case-by-case basis and removed where appropriate. For the networking interfaces@ the base document is the XNS@ Issue 5.2 specification. The following parts of the XNS@ Issue 5.2 specification are out of scope and not included in IEEE Std 1003.1-2001: ? Part 3 (XTI) ? Part 4 (Appendixes) Since there is much duplication between the XNS@ Issue 5.2 specification and IEEE Std 1003.1g-2000@ material only from the following sections of IEEE Std 1003.1g-2000 has been included: ? General terms related to sockets (Section 2.2.2) ? Socket concepts (Sections 5.1 through 5.3@ inclusive) ? The pselect() function (Sections 6.2.2.1 and 6.2.3) ? The sockatmark () function (Section 5.4.13) ? The ?sys/select.h? header (Section 6.2) Emphasis is placed on standardizing existing practice for existing users@ with changes and additions limited to correcting deficiencies in the following areas: ? Issues raised by IEEE or ISO/IEC Interpretations against IEEE Std 1003.1 and IEEE Std 1003.2 ? Issues raised in corrigenda for the Base Specifications and working group resolutions from The Open Group ? Corrigenda and resolutions passed by The Open Group for the XNS@ Issue 5.2 specification ? Changes to make the text self-consistent with the additional material merged ? A reorganization of the options in order to facilitate profiling@ both for smaller profiles such as IEEE Std 1003.13@ and larger profiles such as the Single UNIX Specification ? Alignment with the ISO/IEC 9899: 1999 standard"