newlocale(3)

NAME

   newlocale, freelocale - create, modify, and free a locale object

SYNOPSIS

   #include <locale.h>

   locale_t newlocale(int category_mask, const char *locale,
                      locale_t base);

   void freelocale(locale_t locobj);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

   newlocale(), freelocale():
       Since glibc 2.10:
              _XOPEN_SOURCE >= 700
       Before glibc 2.10:
              _GNU_SOURCE

DESCRIPTION

   The  newlocale()  function  creates a new locale object, or modifies an
   existing object, returning a reference to the new or modified object as
   the function result.  Whether the call creates a new object or modifies
   an existing object is determined by the value of base:

   *  If base is (locale_t) 0, a new object is created.

   *  If base refers to valid existing  locale  object  (i.e.,  an  object
      returned  by  a  previous call to newlocale() or duplocale(3)), then
      that object is modified by the call.  If the call is successful, the
      contents of base are unspecified (in particular, the object referred
      to by base may be freed, and a new object created).  Therefore,  the
      caller  should  ensure  that  it stops using base before the call to
      newlocale(), and should subsequently refer to  the  modified  object
      via  the  reference  returned  as  the function result.  If the call
      fails, the contents of base remain valid and unchanged.

   If  base  is  the   special   locale   object   LC_GLOBAL_LOCALE   (see
   duplocale(3)),  or is not (locale_t) 0 and is not a valid locale object
   handle, the behavior is undefined.

   The category_mask argument is a bit  mask  that  specifies  the  locale
   categories  that  are  to  be  set  in a newly created locale object or
   modified in an existing object.  The mask is constructed by  a  bitwise
   OR  of  the  constants LC_ADDRESS_MASK, LC_CTYPE_MASK, LC_COLLATE_MASK,
   LC_IDENTIFICATION_MASK,     LC_MEASUREMENT_MASK,      LC_MESSAGES_MASK,
   LC_MONETARY_MASK,    LC_NUMERIC_MASK,    LC_NAME_MASK,   LC_PAPER_MASK,
   LC_TELEPHONE_MASK, and LC_TIME_MASK.  Alternatively, the  mask  can  be
   specified  as  LC_ALL_MASK,  which  is  equivalent  to ORing all of the
   preceding constants.

   For each category specified in  category_mask,  the  locale  data  from
   locale  will  be  used in the object returned by newlocale().  If a new
   locale object is being created, data for all categories  not  specified
   in category_mask is taken from the default ("POSIX") locale.

   The  following  preset  values of locale are defined for all categories
   that can be specified in category_mask:

   "POSIX"
          A minimal locale environment for C language programs.

   "C"    Equivalent to "POSIX".

   ""     An implementation-defined native  environment  corresponding  to
          the  values  of  the  LC_*  and  LANG environment variables (see
          locale(7)).

   freelocale()
   The freelocale() function deallocates  the  resources  associated  with
   locobj, a locale object previously returned by a call to newlocale() or
   duplocale(3).  If locobj is LC_GLOBAL_LOCALE or  is  not  valid  locale
   object handle, the results are undefined.

   Once a locale object has been freed, the program should make no further
   use of it.

RETURN VALUE

   On success, newlocale() returns a handle that can be used in  calls  to
   duplocale(3),  freelocale(),  and  other functions that take a locale_t
   argument.  On error, newlocale() returns (locale_t) 0, and  sets  errno
   to indicate the cause of the error.

ERRORS

   EINVAL One  or  more bits in category_mask do not correspond to a valid
          locale category.

   EINVAL locale is NULL.

   ENOENT locale is not a string pointer referring to a valid locale.

   ENOMEM Insufficient memory to create a locale object.

VERSIONS

   The newlocale() and freelocale() functions first  appeared  in  version
   2.3 of the GNU C library.

CONFORMING TO

   POSIX.1-2008.

NOTES

   Each  locale  object created by newlocale() should be deallocated using
   freelocale(3).

EXAMPLE

   The program below takes up to two command-line  arguments,  which  each
   identify  locales.   The first argument is required, and is used to set
   the LC_NUMERIC category in a locale object created  using  newlocale().
   The  second  command-line argument is optional; if it is present, it is
   used to set the LC_TIME category of the locale object.

   Having created and initialized the  locale  object,  the  program  then
   applies  it using uselocale(3), and then tests the effect of the locale
   changes by:

   1. Displaying a floating-point number with  a  fractional  part.   This
      output  will  be  affected  by  the  LC_NUMERIC  setting.   In  many
      European-language locales, the fractional  part  of  the  number  is
      separated from the integer part using a comma, rather than a period.

   2. Displaying  the date.  The format and language of the output will be
      affected by the LC_TIME setting.

   The following shell sessions show some example runs of this program.

   Set the LC_NUMERIC category to fr_FR (French):

       $ ./a.out fr_FR
       123456,789
       Fri Mar  7 00:25:08 2014

   Set the LC_NUMERIC category to fr_FR (French), and the LC_TIME category
   to it_IT (Italian):

       $ ./a.out fr_FR it_IT
       123456,789
       ven 07 mar 2014 00:26:01 CET

   Specify  the LC_TIME setting as an empty string, which causes the value
   to be taken from environment variable settings  (which,  here,  specify
   mi_NZ, New Zealand Māori):

       $ LC_ALL=mi_NZ ./a.out fr_FR ""
       123456,789
       Te Paraire, te 07 o Poutū-te-rangi, 2014 00:38:44 CET

   Program source
   #define _XOPEN_SOURCE 700
   #include <stdio.h>
   #include <stdlib.h>
   #include <locale.h>
   #include <time.h>

   #define errExit(msg)    do { perror(msg); exit(EXIT_FAILURE); \
                           } while (0)

   int
   main(int argc, char *argv[])
   {
       char buf[100];
       time_t t;
       size_t s;
       struct tm *tm;
       locale_t loc, nloc;

       if (argc < 2) {
           fprintf(stderr, "Usage: %s locale1 [locale2]\n", argv[0]);
           exit(EXIT_FAILURE);
       }

       /* Create a new locale object, taking the LC_NUMERIC settings
          from the locale specified in argv[1] */

       loc = newlocale(LC_NUMERIC_MASK, argv[1], (locale_t) 0);
       if (loc == (locale_t) 0)
           errExit("newlocale");

       /* If a second command-line argument was specified, modify the
          locale object to take the LC_TIME settings from the locale
          specified in argv[2]. We assign the result of this newlocale()
          call to 'nloc' rather than 'loc', since in some cases, we might
          want to preserve 'loc' if this call fails. */

       if (argc > 2) {
           nloc = newlocale(LC_TIME_MASK, argv[2], loc);
           if (nloc == (locale_t) 0)
               errExit("newlocale");
           loc = nloc;
       }

       /* Apply the newly created locale to this thread */

       uselocale(loc);

       /* Test effect of LC_NUMERIC */

       printf("%8.3f\n", 123456.789);

       /* Test effect of LC_TIME */

       t = time(NULL);
       tm = localtime(&t);
       if (tm == NULL)
           errExit("time");

       s = strftime(buf, sizeof(buf), "%c", tm);
       if (s == 0)
           errExit("strftime");

       printf("%s\n", buf);

       /* Free the locale object */

       freelocale(loc);

       exit(EXIT_SUCCESS);
   }

SEE ALSO

   locale(1),   duplocale(3),   setlocale(3),   uselocale(3),   locale(5),
   locale(7)

COLOPHON

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   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/.

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