setlocale.3

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



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() 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.

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
       C99, POSIX.1-2001.

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



GNU                                1999-07-04                       SETLOCALE(3)