locale — description of multilanguage support
#include <locale.h>
A locale is a set of language and cultural rules. These cover aspects such as language for messages, different character sets, lexicographic conventions, and so on. A program needs to be able to determine its locale and act accordingly to be portable to different cultures.
The header <locale.h>
declares data types, functions and macros which are useful in
this task.
The functions it declares are setlocale(3) to set the current locale, and localeconv(3) to get information about number formatting.
There are different categories for locale information a program might need; they are declared as macros. Using them as the first argument to the setlocale(3) function, it is possible to set one of these to the desired locale:
LC_ADDRESS (GNU extension, since glibc
2.2)Change settings that describe the formats (e.g.,
postal addresses) used to describe locations and
geography-related items. Applications that need this
information can use nl_langinfo(3) to
retrieve nonstandard elements, such as _NL_ADDRESS_COUNTRY_NAME (country
name, in the language of the locale) and _NL_ADDRESS_LANG_NAME (language name,
in the language of the locale), which return strings
such as "Deutschland" and "Deutsch" (for
German-language locales). (Other element names are
listed in <langinfo.h>
LC_COLLATEThis category governs the collation rules used for sorting and regular expressions, including character equivalence classes and multicharacter collating elements. This locale category changes the behavior of the functions strcoll(3) and strxfrm(3), which are used to compare strings in the local alphabet. For example, the German sharp s is sorted as "ss".
LC_CTYPEThis category determines the interpretation of byte sequences as characters (e.g., single versus multibyte characters), character classifications (e.g., alphabetic or digit), and the behavior of character classes. On glibc systems, this category also determines the character transliteration rules for iconv(1) and iconv(3). It changes the behavior of the character handling and classification functions, such as isupper(3) and toupper(3), and the multibyte character functions such as mblen(3) or wctomb(3).
LC_IDENTIFICATION (GNU extension, since
glibc 2.2)Change settings that relate to the metadata for the
locale. Applications that need this information can use
nl_langinfo(3) to
retrieve nonstandard elements, such as _NL_IDENTIFICATION_TITLE (title of
this locale document) and _NL_IDENTIFICATION_TERRITORY
(geographical territory to which this locale document
applies), which might return strings such as "English
locale for the USA" and "USA". (Other element names are
listed in <langinfo.h>
LC_MONETARYThis category determines the formatting used for monetary-related numeric values. This changes the information returned by localeconv(3), which describes the way numbers are usually printed, with details such as decimal point versus decimal comma. This information is internally used by the function strfmon(3).
LC_MESSAGESThis category affects the language in which messages
are displayed and what an affirmative or negative
answer looks like. The GNU C library contains the
gettext(3), ngettext(3), and
rpmatch(3) functions
to ease the use of this information. The GNU gettext
family of functions also obey the environment variable
LANGUAGE (containing a
colon-separated list of locales) if the category is set
to a valid locale other than "C". This category also
affects the behavior of catopen(3).
LC_MEASUREMENT (GNU extension, since
glibc 2.2)Change the settings relating to the measurement
system in the locale (i.e., metric versus US customary
units). Applications can use nl_langinfo(3) to
retrieve the nonstandard _NL_MEASUREMENT_MEASUREMENT element,
which returns a pointer to a character that has the
value 1 (metric) or 2 (US customary units).
LC_NAME (GNU extension, since glibc
2.2)Change settings that describe the formats used to
address persons. Applications that need this
information can use nl_langinfo(3) to
retrieve nonstandard elements, such as _NL_NAME_NAME_MR (general salutation
for men) and _NL_NAME_NAME_MS (general salutation
for women) elements, which return strings such as
"Herr" and "Frau" (for German-language locales). (Other
element names are listed in <langinfo.h>
LC_NUMERICThis category determines the formatting rules used for nonmonetary numeric values—for example, the thousands separator and the radix character (a period in most English-speaking countries, but a comma in many other regions). It affects functions such as printf(3), scanf(3), and strtod(3). This information can also be read with the localeconv(3) function.
LC_PAPER (GNU extension, since glibc
2.2)Change the settings relating to the dimensions of
the standard paper size (e.g., US letter versus A4).
Applications that need the dimensions can obtain them
by using nl_langinfo(3) to
retrieve the nonstandard _NL_PAPER_WIDTH and _NL_PAPER_HEIGHT elements, which
return int
values specifying the dimensions in millimeters.
LC_TELEPHONE (GNU extension, since
glibc 2.2)Change settings that describe the formats to be used
with telephone services. Applications that need this
information can use nl_langinfo(3) to
retrieve nonstandard elements, such as _NL_TELEPHONE_INT_PREFIX
(international prefix used to call numbers in this
locale), which returns a string such as "49" (for
Germany). (Other element names are listed in
<langinfo.h>
LC_TIMEThis category governs the formatting used for date and time values. For example, most of Europe uses a 24-hour clock versus the 12-hour clock used in the United States. The setting of this category affects the behavior of functions such as strftime(3) and strptime(3).
LC_ALLAll of the above.
If the second argument to setlocale(3) is an empty
string, "", for the
default locale, it is determined using the following
steps:
If there is a non-null environment variable
LC_ALL, the value of
LC_ALL is used.
If an environment variable with the same name as one of the categories above exists and is non-null, its value is used for that category.
If there is a non-null environment variable
LANG, the value of
LANG is used.
Values about local numeric formatting is made available in a struct lconv returned by the localeconv(3) function, which has the following declaration:
struct lconv { char * decimal_point;char * thousands_sep;
of radix character */char * grouping;
group; elements with higher indices are
further left. An element with value CHAR_MAX
means that no further grouping is done. An
element with value 0 means that the previous
element is used for all groups further left. */char * int_curr_symbol;
from ISO 4217. Fourth char is the
separator. Fifth char is \(aq\\0\(aq. */char * currency_symbol;char * mon_decimal_point;char * mon_thousands_sep;char * mon_grouping;char * positive_sign;char * negative_sign;char int_frac_digits;char frac_digits;char p_cs_precedes;
positive value, 0 if succeeds */char p_sep_by_space;
from a positive value */char n_cs_precedes;
negative value, 0 if succeeds */char n_sep_by_space;
from a negative value */
0 Parentheses surround the quantity and currency_symbol.
1 The sign string precedes the quantity and currency_symbol.
2 The sign string succeeds the quantity and currency_symbol.
3 The sign string immediately precedes the currency_symbol.
4 The sign string immediately succeeds the currency_symbol. */char p_sign_posn;char n_sign_posn;};
POSIX.1-2008 standardized a number of extensions to the locale API, based on implementations that first appeared in version 2.3 of the GNU C library. These extensions are designed to address the problem that the traditional locale APIs do not mix well with multithreaded applications and with applications that must deal with multiple locales.
The extensions take the form of new functions for creating and manipulating locale objects (newlocale(3), freelocale(3), duplocale(3), and uselocale(3)) and various new library functions with the suffix "_l" (e.g., toupper_l(3)) that extend the traditional locale-dependent APIs (e.g., toupper(3)) to allow the specification of a locale object that should apply when executing the function.
The following environment variable is used by newlocale(3) and setlocale(3), and thus affects all unprivileged localized programs:
LOCPATHA list of pathnames, separated by colons (':'), that
should be used to find locale data. If this variable is
set, only the individual compiled locale data files
from LOCPATH and the
system default locale data path are used; any available
locale archives are not used (see localedef(1)). The
individual compiled locale data files are searched for
under subdirectories which depend on the currently used
locale. For example, when en_GB.UTF-8 is used for
a category, the following subdirectories are searched
for, in this order: en_GB.UTF-8, en_GB.utf8, en_GB, en.UTF-8, en.utf8, and en.
/usr/lib/locale/locale-archiveUsual default locale archive location.
/usr/lib/localeUsual default path for compiled individual locale files.
iconv(1), locale(1), localedef(1), catopen(3), gettext(3), iconv(3), localeconv(3), mbstowcs(3), newlocale(3), ngettext(3), nl_langinfo(3), rpmatch(3), setlocale(3), strcoll(3), strfmon(3), strftime(3), strxfrm(3), uselocale(3), wcstombs(3), locale(5), charsets(7), unicode(7), utf-8(7)
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description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
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Copyright (c) 1993 by Thomas Koenig (ig25rz.uni-karlsruhe.de) and Copyright (C) 2014 Michael Kerrisk <mtk.manpagesgmail.com> %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. %%%LICENSE_END Modified Sat Jul 24 17:28:34 1993 by Rik Faith <faithcs.unc.edu> Modified Sun Jun 01 17:16:34 1997 by Jochen Hein <jochen.heindelphi.central.de> Modified Thu Apr 25 00:43:19 2002 by Bruno Haible <brunoclisp.org> |