SETLOCALE(3) Linux Programmer's Manual SETLOCALE(3)
NAME
setlocale - set the current locale
SYNOPSIS
#include
char *setlocale(int category, const char *locale);
DESCRIPTION
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 colla-
tion.
LC_CTYPE
for regular expression matching, character classification, con-
version, case-sensitive comparison, and wide character func-
tions.
LC_MESSAGES
for localizable natural-language messages.
LC_MONETARY
for monetary formatting.
LC_NUMERIC
for number formatting (such as the decimal point and the thou-
sands 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 implemen-
tation dependent. For glibc, first (regardless of category), the
environment variable LC_ALL is inspected, next the environment vari-
able with the same name as the category (LC_COLLATE, LC_CTYPE, LC_MES-
SAGES, 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 cor-
responds to the 7-bit ASCII character set.
A locale name is typically of the form language[_territory][.code-
set][@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 sup-
ported 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() call for locale - dependent infor-
mation, by using the multi-byte and wide character functions for text
processing if MB_CUR_MAX > 1, and by using strcoll(), wcscoll() or
strxfrm(), wcsxfrm() to compare strings.
RETURN VALUE
A successful call to setlocale() returns an opaque string that corre-
sponds 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 pro-
cess's locale. The return value is NULL if the request cannot be hon-
ored.
CONFORMING TO
ANSI C, POSIX.1
NOTES
Linux (that is, GNU libc) supports the portable locales "C" and
"POSIX". In the good old days there used to be support for the Euro-
pean 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() return the right
answer. These days non-English speaking Europeans have to work a bit
harder, and must install actual locale files.
SEE ALSO
locale(1), localedef(1), strcoll(3), isalpha(3), localeconv(3), strf-
time(3), charsets(4), locale(7), nl_langinfo(3)
GNU 1999-07-04 SETLOCALE(3)
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