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.

       Category            Governs
       LC_ALL              All of the locale
       LC_ADDRESS          Formatting of addresses and
                           geography-related items (*)
       LC_COLLATE          String collation
       LC_CTYPE            Character classification
       LC_IDENTIFICATION   Metadata describing the locale (*)
       LC_MEASUREMENT      Settings related to measurements
                           (metric versus US customary) (*)
       LC_MESSAGES         Localizable natural-language messages
       LC_MONETARY         Formatting of monetary values
       LC_NAME             Formatting of salutations for persons (*)
       LC_NUMERIC          Formatting of nonmonetary numeric values
       LC_PAPER            Settings related to the standard paper size (*)
       LC_TELEPHONE        Formats to be used with telephone services (*)
       LC_TIME             Formatting of date and time values

       The categories marked with an asterisk in the above table are GNU extensions.  For further information  on  these  locale  categories,  see
       locale(7).

       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 an empty string, "", 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 (see the table above), and finally the environment variable LANG.  The first exist-
       ing 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; it exists on all conforming systems.

       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" (see 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 multi-
       byte 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 stor-
       age.  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.

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       +------------+---------------+----------------------------+
       |Interface   | Attribute     | Value                      |
       +------------+---------------+----------------------------+
       |setlocale() | Thread safety | MT-Unsafe const:locale env |
       +------------+---------------+----------------------------+

CONFORMING TO

       POSIX.1-2001, POSIX.1-2008, C89, C99.

       The  C standards specify only the categories LC_ALL, LC_COLLATE, LC_CTYPE, LC_MONETARY, LC_NUMERIC, and LC_TIME.  POSIX.1 adds LC_MESSAGES.
       The remaining categories are GNU extensions.

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 4.15 of the Linux man-pages project.  A description of the project, information about reporting bugs, and  the
       latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

GNU                                                                 2017-09-15                                                        SETLOCALE(3)