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/.

GNU                                                2008-12-05                                       SETLOCALE(3)