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 argu-
       ments.  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-sensi-
              tive 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 environ-
       ment 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.

RETURN VALUE
       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.

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 suf-
       ficed to make isprint(3) return the right answer.  These days non-English  speaking  Euro-
       peans 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),  str-
       coll(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)