Editing Single UNIX Specification (section)

===1994: Single UNIX Specification===
In 1994, the X/Open Company released the '''Single UNIX Specification'''.<ref name=unixorgsus/> The SUS was made up of documents that were part of the X/Open Common Applications Environment (CAE):<ref name=unixorgsus/>
* System Interface Definitions, Issue 4, Version 2<ref>{{cite book|url=https://pubs.opengroup.org/onlinepubs/009656599/toc.pdf|title=X/Open CAE Specification System Interface Definitions, Issue 4, Version 2|date=1994|publisher=X/Open Company}}</ref>
* System Interfaces and Headers, Issue 4, Version 2<ref>{{cite book|url=https://pubs.opengroup.org/onlinepubs/9695969499/toc.pdf|title=X/Open CAE Specification System Interfaces and Headers, Issue 4, Version 2|date=1994|publisher=X/Open Company}}</ref>
* Commands and Utilities, Issue 4, Version 2<ref>{{cite book|url=https://pubs.opengroup.org/onlinepubs/009656399/toc.pdf|title=X/Open CAE Specification Commands and Utilities, Issue 4, Version 2|date=1994|publisher=X/Open Company}}</ref>
* Networking Services, Issue 4<ref>{{cite book|url=https://pubs.opengroup.org/onlinepubs/009656199/toc.pdf|title=X/Open CAE Specification Networking Services, Issue 4|date= 1994 |publisher=X/Open Company}}</ref>

This was a repackaging of the [[X/Open Portability Guide]] (XPG), Issue 4, Version 2.

Sources differ on whether X/Open Curses, Issue 4, Version 2 was part of this SUS;<ref name=unixorgsus/><ref>{{Cite web|title=Single UNIX® Specification, Version 1 Document Set (UNIX 95)|url=https://publications.opengroup.org/c43x|access-date=May 25, 2021|website=opengroup.org}}</ref> its copyright date is given as 1996.<ref>{{cite book|url=https://pubs.opengroup.org/onlinepubs/009638999/toc.pdf|title=X/Open Curses, Issue 4, Version 2|date=1996|publisher=X/Open Company |isbn=1-85912-171-3}}</ref> X/Open Curses, Issue 4 was published in 1995.<ref>{{cite book|url=https://books.google.com/books?id=PYFCAAAACAAJ|title=X/Open Curses, Issue 4|date=1995|publisher=X/Open Company |isbn=9781859120774 }}</ref>

In October 1994, X/Open indicated they were going to refer to Spec 1170 as '"Single-Unix" specification'.<ref>{{cite magazine|url=https://books.google.com/books?id=Ilp0BEVTY3gC&pg=PA49|title=X/Open test suites advance|first=Jean S.|last=Bozman|magazine=[[Computerworld]]|volume=28|issue=43|page=49|date=October 24, 1994}}</ref>

The SUS was at the core of the UNIX 95 brand.<ref>{{cite web|url=https://www.opengroup.org/openbrand/register/xum4.htm|title=Open Brand - UNIX 95|website=[[The Open Group]]}}</ref>

This version had 1168 programming interfaces.<ref name=v3howmanyapis/>

This version of SUS was drawn from the following sources:<ref name=unixorgsus/>
* XPG4 Base by X/Open
* [[System V Interface Definition]], (SVID) Edition 3, Level 1 calls by AT&T
* Application Environment Specification (AES) by the [[Open Software Foundation]] (OSF)
* Interfaces found in common use and not yet covered by a formal specification, drawn from a survey of major applications.