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 accord‐ ing to the arguments. The argument category determines which parts of the program's current locale should be modified. LCALL for all of the locale. LCCOLLATE for regular expression matching (it determines the meaning of range expressions and equivalence classes) and string collation. LCCTYPE for regular expression matching, character classification, con‐ version, case-sensitive comparison, and wide character func‐ tions. LCMESSAGES
for localizable natural-language messages. LCMONETARY for monetary formatting. LCNUMERIC for number formatting (such as the decimal point and the thou‐ sands separator). LCTIME 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 "daDK" (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 implementa‐
tion-dependent. For glibc, first (regardless of category), the envi‐ ronment variable LCALL is inspected, next the environment variable with the same name as the category (LCCOLLATE, LCCTYPE, LCMESSAGES, LCMONETARY, LCNUMERIC, LCTIME) 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 set‐ locale() returns NULL. The locale "C" or "POSIX" is a portable locale; its LCCTYPE 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 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(LCALL, ""); 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 MBCURMAX > 1, and by using strcoll(3), wcscoll(3) or strxfrm(3), wcsxfrm(3) 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 stor‐ age. 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. CONFORMING TO
C89, C99, POSIX.1-2001. NOTES 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
LCCTYPE=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. SEE ALSO locale(1), localedef(1), isalpha(3), localeconv(3), nllanginfo(3), rpmatch(3), strcoll(3), strftime(3), charsets(7), locale(7) COLOPHON
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GNU 2008-12-05 SETLOCALE(3)