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)

GNU                                               July 4, 1999                                      SETLOCALE(3)