Locale (computer software)

2025-10-13T20:05:55Z

70.113.149.47: /* Specifics for Microsoft platforms */

{{Short description|Parameters defining locale in computer}}
{{other uses|Locale (disambiguation)}}

In [[computing]], a '''locale''' is a set of [[parameter]]s that defines the user's language, region and any special variant preferences that the user wants to see in their [[user interface]]. Usually a locale identifier consists of at least a language code and a country/region code.
Locale is an important aspect of [[i18n]].
== General locale settings ==

These settings usually include the following display (output) format settings:

* Number format setting (LC_NUMERIC, C/C++)
* Character classification, case conversion settings (LC_CTYPE, C/C++)
* Date-time format setting (LC_TIME, C/C++)
* String [[collation]] setting (LC_COLLATE, C/C++)
* Currency format setting (LC_MONETARY, C/C++)
* Paper size setting (LC_PAPER, ISO 30112)
* Color temperature setting
* UI font setting (especially for [[CJKV]] language)
* Location setting (country or region)
* [[Windows code pages|ANSI character set]] setting (for [[Microsoft Windows]])

The locale settings are about formatting output given a locale. So, the time zone information and daylight saving time are not usually part of the locale settings.
Less usual is the input format setting, which is mostly defined on a per application basis.

== Programming and markup language support ==
In these environments,

{{div col|colwidth=18em}}
* [[C (programming language)|C]]
* [[C++]]
* [[Eiffel (programming language)|Eiffel]]
* [[Java (programming language)|Java]]
* [[.NET Framework]]
* [[REBOL]]
* [[Ruby (programming language)|Ruby]]
* [[Perl]]
* [[PHP]]
* [[Python (programming language)|Python]]
* [[XML]]
* [[JavaServer Pages|JSP]]
* [[JavaScript]]

{{div col end}}

and other (nowadays) [[Unicode]]-based environments, they are defined in a format similar to [[BCP 47]]. They are usually defined with just [[ISO 639]] (language) and [[ISO 3166-1 alpha-2]] (2-letter country) codes.

== International standards ==

In standard C and C++, locale is defined in "categories" of {{tt|LC_COLLATE}} (text collation), {{tt|LC_CTYPE}} (character class), {{tt|LC_MONETARY}} (currency format), {{tt|LC_NUMERIC}} (number format), and {{tt|LC_TIME}} (time format). The special {{tt|LC_ALL}} category can be used to set all locale settings.<ref>{{cite web |title=LC_ALL, LC_COLLATE, LC_CTYPE, LC_MONETARY, LC_NUMERIC, LC_TIME - cppreference.com |url=https://en.cppreference.com/w/c/locale/LC_categories |website=en.cppreference.com}}</ref>

There is no standard locale names associated with C and C++ standards besides a "minimal locale" name "C", although the POSIX format is a commonly used baseline.

=== POSIX platforms ===

On [[POSIX]] platforms such as [[Unix]], [[Linux]] and others, locale identifiers are defined in a way similar to the [[BCP 47]] definition of language tags, but the locale variant modifier is defined differently, and the [[character set]] is optionally included as a part of the identifier. The POSIX or "XPG" format is {{mono|<nowiki>[language[_territory][.codeset][@modifier]]</nowiki>}}. (For example, [[Australian English]] using the [[UTF-8]] encoding is {{mono|en_AU.UTF-8}}.)<ref>{{cite web |title=Environment Variables |url=https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap08.html |website=pubs.opengroup.org}}</ref> Separately, [[ISO/IEC 15897]] describes a different form, {{mono|<nowiki>language_territory+audience+application,sponsor_version</nowiki>}}, though it's highly dubious whether it is used at all.<ref>{{cite web |title=ISO/IEC JTC1/SC22 N610 [draft ISO/IEC 15897:1998(E)] Information technology — Procedures for registration of cultural elements |url=https://www.open-std.org/jtc1/sc22/wg20/docs/n610.pdf |access-date=8 June 2023 |date=1998-11-17|quote=For Narrative Cultural Specifications and POSIX Locales the token identifier will be: 8_9+11+12,13_14}}</ref>


In the next example there is an output of command <code>locale</code> for [[Czech language]] (cs), [[Czech Republic]] (CZ) with explicit [[UTF-8]] encoding:

$ '''locale'''
LANG=cs_CZ.UTF-8
LC_CTYPE="cs_CZ.UTF-8"
LC_NUMERIC="cs_CZ.UTF-8"
LC_TIME="cs_CZ.UTF-8"
LC_COLLATE="cs_CZ.UTF-8"
LC_MONETARY="cs_CZ.UTF-8"
LC_MESSAGES="cs_CZ.UTF-8"
LC_PAPER="cs_CZ.UTF-8"
LC_NAME="cs_CZ.UTF-8"
LC_ADDRESS="cs_CZ.UTF-8"
LC_TELEPHONE="cs_CZ.UTF-8"
LC_MEASUREMENT="cs_CZ.UTF-8"
LC_IDENTIFICATION="cs_CZ.UTF-8"
LC_ALL=

== Specifics for Microsoft platforms ==

{{outdated|section|date=October 2025}}

Windows uses specific [https://web.archive.org/web/20170228045725/https://msdn.microsoft.com/en-us/library/39cwe7zf(vs.71).aspx language] and [https://web.archive.org/web/20160610104759/https://msdn.microsoft.com/en-us/library/cdax410z(VS.71).aspx territory] strings.
The ''locale identifier'' (LCID) for [[managed code|unmanaged code]] on [[Microsoft Windows]] is a number such as 1033 for English (United States), or 2057 for English (United Kingdom), or 1041 for Japanese (Japan). These numbers consist of a language code (lower 10 bits) and a culture code (upper bits), and are therefore often written in [[hexadecimal]] notation, such as 0x0409, 0x0809 or 0x0411.
[[Microsoft]] is starting to introduce managed code [[application programming interface]]s (APIs) for .NET that use this format. One of the first to be generally released is a function to mitigate issues with [[internationalized domain name]]s,<ref>{{cite web |url=https://msdn.microsoft.com/library/windows/desktop/dd317795.aspx |title=DownlevelGetLocaleScripts function (Windows) |work=[[Microsoft Developer Network|MSDN]] |publisher=[[Microsoft]] |accessdate=2017-12-11}}</ref> but more are in [[Windows Vista]] Beta 1.

Starting with Windows Vista, new functions<ref name="microsoft">{{cite web |url=https://docs.microsoft.com/en-us/windows/win32/intl/locale-names |title=Locale Names (Windows) |work=[[Microsoft Developer Network|MSDN]] |publisher=[[Microsoft]] |accessdate=2017-12-11}}</ref> that use [[BCP 47]] locale names have been introduced to replace nearly all LCID-based APIs.

A POSIX-like locale name format of {{mono|language[_country-region[.code-page]]}} is available in the UCRT (Universal C Run Time) of Windows 10 and 11.<ref>{{cite web |title=Locale Names, Languages, and Country-Region Strings |url=https://learn.microsoft.com/en-us/cpp/c-runtime-library/locale-names-languages-and-country-region-strings?view=msvc-140 |website=learn.microsoft.com |language=en-us |date=19 October 2022}}</ref>

==See also==
* [[Internationalization and localization]]
* [[ISO 639]] [[language code]]s
* [[ISO 3166-1 alpha-2]] [[region code]]s
* [[ISO 15924]] [[script code]]s
* [[IETF language tag]]
* [[C localization functions]]
* [[CCSID]]
* [[Code page]]
* [[Common Locale Data Repository]]
* [[Date and time representation by country]]
* AppLocale

==References==
{{Reflist}}

== External links ==
{{linkfarm|date=September 2019}}
{{wiktionary|locale}}
* [https://tools.ietf.org/html/bcp47 BCP 47]
* [https://www.iana.org/assignments/language-subtag-registry Language Subtag Registry]
* [https://www.unicode.org/cldr/ Common Locale Data Repository]
* {{Javadoc:SE|package=java.util|java/util|Locale}} [[Javadoc]] API documentation
* [https://msdn.microsoft.com/en-us/library/dd318716 Locale and Language information from Microsoft]
* [https://msdn.microsoft.com/en-us/library/cc233965.aspx MS-LCID: Windows Language Code Identifier (LCID) Reference from Microsoft]
* [https://msdn.microsoft.com/en-us/library/cc233968.aspx Microsoft LCID list]
* [https://msdn.microsoft.com/en-us/library/0h88fahh.aspx Microsoft LCID chart with decimal equivalents]
* [https://www.opengroup.org/onlinepubs/007908799/xbd/envvar.html POSIX Environment Variables]
* [https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap07.html Low Level Technical details on defining a POSIX locale]
* [http://demo.icu-project.org/icu-bin/locexp ICU Locale Explorer]
* [https://wiki.debian.org/Locale Debian Wiki on Locales]
* Article "[https://cantrip.org/locale.html The Standard C++ Locale]" by [[Nathan C. Myers]]
* [http://www.die.net/doc/linux/man/man7/locale.7.html locale(7): Description of multi-language support] - Linux man page
* [http://incubator.apache.org/stdcxx/doc/stdlibug/VII.html Apache C++ Standard Library Locale User's Guide]
* [https://web.archive.org/web/20110520132147/http://www.collation-charts.org/ Sort order charts for various operating system locales and database collations]
* [http://www.freesource.info/wiki/Lokalizacija/NATSPECDescription NATSPEC Library]
* [https://www.debian.org/doc/manuals/reference/ch-tune.en.html#s-env-locale Description of locale-related UNIX environment variables in Debian Linux Reference Manual]
* [https://docs.translatehouse.org/projects/localization-guide/en/latest/guide/start.html?id=guide/start#locales Guides to locales and locale creation on various platforms]

[[Category:Unix user management and support-related utilities]]
[[Category:Unix SUS2008 utilities]]
[[Category:Internationalization and localization]]

wiki143 - User contributions [en]

Locale (computer software)