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  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_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
       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 3.54 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/.