newlocale(3) - Linux manual page (original) (raw)


newlocale(3) Library Functions Manual newlocale(3)

NAME top

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

LIBRARY top

   Standard C library (_libc_, _-lc_)

SYNOPSIS top

   **#include <locale.h>**

   **locale_t newlocale(int** _categorymask_**, 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 top

   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 _(localet) 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)](../man3/duplocale.3.html)),
      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)](../man3/duplocale.3.html)), or is not _(localet) 0_ and is not a valid locale
   object handle, the behavior is undefined.

   The _categorymask_ 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 _categorymask_, 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 _categorymask_ is taken from the default ("POSIX")
   locale.

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

   "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)](../man7/locale.7.html)).

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 top

   On success, **newlocale**() returns a handle that can be used in calls
   to [duplocale(3)](../man3/duplocale.3.html), **freelocale**(), and other functions that take a
   _localet_ argument.  On error, **newlocale**() returns _(localet) 0_,
   and sets _[errno](../man3/errno.3.html)_ to indicate the error.

ERRORS top

   **EINVAL** One or more bits in _categorymask_ 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.

STANDARDS top

   POSIX.1-2008.

HISTORY top

   glibc 2.3.

NOTES top

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

EXAMPLES top

   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)](../man3/uselocale.3.html), 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 _frFR_ (French):

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

   Set the **LC_NUMERIC** category to _frFR_ (French), and the **LC_TIME**
   category to _itIT_ (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 _miNZ_, 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 <locale.h> #include <stdio.h> #include <stdlib.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. */

       uselocale(LC_GLOBAL_LOCALE);    /* So 'loc' is no longer in use */
       freelocale(loc);

       exit(EXIT_SUCCESS);
   }

SEE ALSO top

   [locale(1)](../man1/locale.1.html), [duplocale(3)](../man3/duplocale.3.html), [setlocale(3)](../man3/setlocale.3.html), [uselocale(3)](../man3/uselocale.3.html), [locale(5)](../man5/locale.5.html),
   [locale(7)](../man7/locale.7.html)

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Linux man-pages 6.10 2024-07-23 newlocale(3)


Pages that refer to this page:duplocale(3), isalpha(3), locale_t(3type), nl_langinfo(3), toupper(3), uselocale(3), locale(5), locale(7)