Editing UTF-8 (section)

== Standards ==
The official name for the encoding is {{code|UTF-8}}, the spelling used in all Unicode Consortium documents. The [[hyphen-minus]] is required and no spaces are allowed. Some other names used are:

* Most standards are also case-insensitive and <code>utf-8</code> is often used.{{citation needed|date=March 2023}}
* Web standards (which include [[Cascading Style Sheets|CSS]], [[HTML]], [[XML]], and [[HTTP headers]]) also allow {{code|utf8}} and many other aliases<!-- e.g. "unicode20utf8" for UTF-8, likely not useful to list any or all, just stating "many"-->.<ref>{{cite web|url=https://encoding.spec.whatwg.org/#names-and-labels|title=Encoding Standard § 4.2. Names and labels|publisher=[[WHATWG]]|access-date=2018-04-29}}</ref>
* The official [[Internet Assigned Numbers Authority]] lists {{code|csUTF8}} as the only alias,<ref name="IANA_2013_CS">{{cite web |publisher=[[Internet Assigned Numbers Authority]] |url=https://www.iana.org/assignments/character-sets |title=Character Sets |date=2013-01-23 |access-date=2013-02-08}}</ref> which is rarely used.
* In some locales {{code|UTF-8N}} means UTF-8 ''without'' a [[byte order mark|byte-order mark]] (BOM), and in this case {{code|UTF-8}} ''may'' imply there ''is'' a BOM.<ref>{{cite web |url=https://suika.fam.cx/~wakaba/wiki/sw/n/BOM |title=BOM | work = suikawiki |archive-url=https://web.archive.org/web/20090117052232/https://suika.fam.cx/~wakaba/wiki/sw/n/BOM |archive-date=2009-01-17 |language=ja}}</ref><ref>{{cite web |author-last=Davis |author-first=Mark |author-link=Mark Davis (Unicode) |title=Forms of Unicode |publisher=[[IBM]] |url=https://www-128.ibm.com/developerworks/library/utfencodingforms/index.html |access-date=2013-09-18 |archive-url=https://web.archive.org/web/20050506211548/https://www-128.ibm.com/developerworks/library/utfencodingforms/index.html |archive-date=2005-05-06}}</ref>
* In [[Windows]], UTF-8 is [[Windows code page|codepage]] <code>65001</code><ref>{{Cite web |url=https://www.dostips.com/forum/viewtopic.php?t=5357 |title=UTF-8 codepage 65001 in Windows 7 - part I |author=Liviu |quote=Previously under XP (and, unverified, but probably Vista, too) for loops simply did not work while codepage 65001 was active |language=en-gb |date=2014-02-07 |access-date=2018-01-30}}</ref> with the symbolic name <code>CP_UTF8</code> in source code.
* In [[MySQL]], UTF-8 is called <code>utf8mb4</code>,<ref>{{Cite web |title=MySQL :: MySQL 8.0 Reference Manual :: 10.9.1 The utf8mb4 Character Set (4-Byte UTF-8 Unicode Encoding) |url=https://dev.mysql.com/doc/refman/8.0/en/charset-unicode-utf8mb4.html |work=MySQL 8.0 Reference Manual |publisher=[[Oracle Corporation]] |access-date=2023-03-14}}</ref> while {{code|utf8}} and {{code|utf8mb3}} refer to the obsolete [[CESU-8]] variant.<ref name="mysql3-utf8mb3">{{Cite web |title=MySQL :: MySQL 8.0 Reference Manual :: 10.9.2 The utf8mb3 Character Set (3-Byte UTF-8 Unicode Encoding) |url=https://dev.mysql.com/doc/refman/8.0/en/charset-unicode-utf8mb3.html |work=MySQL 8.0 Reference Manual |publisher=[[Oracle Corporation]] |access-date=2023-02-24}}</ref>
* In [[Oracle Database]] (since version 9.0), <code>AL32UTF8</code><ref>{{Cite web |title=Database Globalization Support Guide |url=https://docs.oracle.com/cd/E11882_01/server.112/e10729/ch6unicode.htm |access-date=2023-03-16 |website=docs.oracle.com |language=en}}</ref> means UTF-8, while {{code|UTF-8}} means CESU-8.
* In HP [[Printer Command Language|PCL]], the Symbol-ID for UTF-8 is <code>18N</code>.<ref>{{Cite web|url=https://pclhelp.com/pcl-symbol-sets/ |archive-url=https://web.archive.org/web/20150219212843/http://pclhelp.com/pcl-symbol-sets/|url-status=dead|archive-date=2015-02-19|title=HP PCL Symbol Sets {{!}} Printer Control Language (PCL & PXL) Support Blog|date=2015-02-19|access-date=2018-01-30}}</ref>

There are several current definitions of UTF-8 in various standards documents:

* {{IETF RFC|3629|link=no}} / STD 63 (2003), which establishes UTF-8 as a standard internet protocol element
* {{IETF RFC|5198|link=no}} defines UTF-8 [[Unicode equivalence|NFC]] for Network Interchange (2008)
* ISO/IEC 10646:2020/Amd 1:2023<!-- §9.1 (2023? or 2020)--><ref>[https://www.iso.org/standard/83362.html ISO/IEC 10646].</ref>
* ''The Unicode Standard, Version 16.0.0'' (2024)<ref>''[https://www.unicode.org/versions/Unicode16.0.0/ The Unicode Standard, Version 16.0]'' [https://www.unicode.org/versions/Unicode15.0.0/ch03.pdf#G31703 §3.9 D92, §3.10 D95], 2021.</ref>

They supersede the definitions given in the following obsolete works:

* ''The Unicode Standard, Version 2.0'', Appendix A (1996)
* ISO/IEC 10646-1:1993 Amendment 2 / Annex R (1996)
* {{IETF RFC|2044|link=no}} (1996)
* {{IETF RFC|2279|link=no}} (1998)
* ''The Unicode Standard, Version 3.0'', §2.3 (2000) plus Corrigendum #1 : UTF-8 Shortest Form (2000)
* ''Unicode Standard Annex #27: Unicode 3.1'' (2001)<ref>[https://www.unicode.org/reports/tr27/tr27-3.html ''Unicode Standard Annex #27: Unicode 3.1''], 2001.</ref>
* <!-- Is there a reason to single out 5.0 and 6.0, but not e.g. 15? Skip all after 3.0, since only then encoding of UTF-8 changed? -->''The Unicode Standard, Version 5.0'' (2006)<ref>[https://www.unicode.org/versions/Unicode5.0.0/ ''The Unicode Standard, Version 5.0''] [https://www.unicode.org/versions/Unicode5.0.0/ch03.pdf §3.9–§3.10 ch. 3], 2006.</ref>
* ''The Unicode Standard, Version 6.0'' (2010)<ref>[https://www.unicode.org/versions/Unicode6.0.0/ ''The Unicode Standard, Version 6.0''] [https://www.unicode.org/versions/Unicode6.0.0/ch03.pdf §3.9 D92, §3.10 D95], 2010.</ref>

They are all the same in their general mechanics, with the main differences being on issues such as allowed range of code point values and safe handling of invalid input.