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.

       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()  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(), wstrcoll() or strxfrm(),  wstrxfrm()
       to compare strings.

RETURN VALUE

       A  successful  call  to  setlocale()  returns a 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

       ANSI C, POSIX.1

NOTES

       Linux (that is, GNU libc) 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() 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), strcoll(3), isalpha(3), localeconv(3), strftime(3), charsets(4),
       locale(7)