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  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;  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", 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.

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.

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 4.09 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/.

---

Free and Open Source Software