| NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | CONFORMING TO | NOTES | SEE ALSO | COLOPHON | The Linux Programming Interface |
SETLOCALE(3) Linux Programmer's Manual SETLOCALE(3)
setlocale - set the current locale
#include <locale.h>
char *setlocale(int category, const char *locale);
The setlocale() function is used to set or query the program's current locale.
If locale is not NULL, the program's current locale is modified according to
the arguments. The argument category determines which parts of the program's
current locale should be modified.
LC_ALL for all of the locale.
LC_COLLATE
for regular expression matching (it determines the meaning of range
expressions and equivalence classes) and string collation.
LC_CTYPE
for regular expression matching, character classification, conversion,
case-sensitive comparison, and wide character functions.
LC_MESSAGES
for localizable natural-language messages.
LC_MONETARY
for monetary formatting.
LC_NUMERIC
for number formatting (such as the decimal point and the thousands
separator).
LC_TIME
for time and date formatting.
The argument locale is a pointer to a character string containing the required
setting of category. Such a string is either a well-known constant like "C"
or "da_DK" (see below), or an opaque string that was returned by another call
of setlocale().
If locale is "", each part of the locale that should be modified is set
according to the environment variables. The details are implementation-
dependent. For glibc, first (regardless of category), the environment
variable LC_ALL is inspected, next the environment variable with the same name
as the category (LC_COLLATE, LC_CTYPE, LC_MESSAGES, LC_MONETARY, LC_NUMERIC,
LC_TIME) and finally the environment variable LANG. The first existing
environment variable is used. If its value is not a valid locale
specification, the locale is unchanged, and setlocale() returns NULL.
The locale "C" or "POSIX" is a portable locale; its LC_CTYPE part corresponds
to the 7-bit ASCII character set.
A locale name is typically of the form
language[_territory][.codeset][@modifier], where language is an ISO 639
language code, territory is an ISO 3166 country code, and codeset is a
character set or encoding identifier like ISO-8859-1 or UTF-8. For a list of
all supported locales, try "locale -a", cf. locale(1).
If locale is NULL, the current locale is only queried, not modified.
On startup of the main program, the portable "C" locale is selected as
default. A program may be made portable to all locales by calling:
setlocale(LC_ALL, "");
after program initialization, by using the values returned from a
localeconv(3) call for locale-dependent information, by using the multibyte
and wide character functions for text processing if MB_CUR_MAX > 1, and by
using strcoll(3), wcscoll(3) or strxfrm(3), wcsxfrm(3) to compare strings.
A successful call to setlocale() returns an opaque string that corresponds to
the locale set. This string may be allocated in static storage. The string
returned is such that a subsequent call with that string and its associated
category will restore that part of the process's locale. The return value is
NULL if the request cannot be honored.
C89, C99, POSIX.1-2001.
Linux (that is, glibc) supports the portable locales "C" and "POSIX". In the
good old days there used to be support for the European Latin-1 "ISO-8859-1"
locale (e.g., in libc-4.5.21 and libc-4.6.27), and the Russian "KOI-8" (more
precisely, "koi-8r") locale (e.g., in libc-4.6.27), so that having an
environment variable LC_CTYPE=ISO-8859-1 sufficed to make isprint(3) return
the right answer. These days non-English speaking Europeans have to work a
bit harder, and must install actual locale files.
locale(1), localedef(1), isalpha(3), localeconv(3), nl_langinfo(3),
rpmatch(3), strcoll(3), strftime(3), charsets(7), locale(7)
This page is part of release 3.32 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can be found
at http://www.kernel.org/doc/man-pages/.
GNU 2008-12-05 SETLOCALE(3)
HTML rendering created 2010-12-03 by Michael Kerrisk, author of The Linux Programming Interface