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 deter-
       mines 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 charac-
              ter 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_MONE-
       TARY,  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.

RETURN VALUE
       A  successful  call to setlocale() returns an opaque string that corresponds to the locale set.  This string may be allo-
       cated 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.

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 3.25 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)