SETLOCALE(3)						     Linux Programmer's Manual						      SETLOCALE(3)

NAME

       setlocale - set the current locale

SYNOPSIS

       #include <locale.h>

       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 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 implemen-
       tation-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 vari-
       able 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 multi-
       byte 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.

RETURN VALUE

       A successful call to setlocale() returns an opaque string that corresponds 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 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.

SEE ALSO

       locale(1), localedef(1), isalpha(3), localeconv(3), nl_langinfo(3), rpmatch(3), strcoll(3), strftime(3), charsets(7), locale(7)

COLOPHON

       This page is part of release 3.53 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)