SETLOCALE(3)               Linux Programmer's Manual              SETLOCALE(3)

       setlocale - set the current locale

       #include <locale.h>

       char *setlocale(int category, const char *locale);

       The setlocale() function is used to set or query the program's current

       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.

              for regular expression matching (it determines the meaning of
              range expressions and equivalence classes) and string collation.

              for regular expression matching, character classification,
              conversion, case-sensitive comparison, and wide character

              for localizable natural-language messages.

              for monetary formatting.

              for number formatting (such as the decimal point and the
              thousands separator).

              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() 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(), wcscoll() or
       strxfrm(), wcsxfrm() to compare strings.

       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

       C99, POSIX.1-2001.

       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.

       locale(1), localedef(1), isalpha(3), localeconv(3), nl_langinfo(3),
       rpmatch(3), strcoll(3), strftime(3), charsets(4), locale(7)

GNU                               1999-07-04                      SETLOCALE(3)