LOCALE(7)		   Linux Programmer's Manual		     LOCALE(7)



NAME
       locale - description of multilanguage support

SYNOPSIS
       #include <locale.h>

DESCRIPTION
       A  locale is a set of language and cultural rules.  These cover aspects
       such as language for messages, different character sets,	 lexicographic
       conventions,  and  so  on.  A program needs to be able to determine its
       locale and act accordingly to be portable to different cultures.

       The header <locale.h> declares data types, functions and	 macros	 which
       are useful in this task.

       The  functions  it declares are setlocale(3) to set the current locale,
       and localeconv(3) to get information about number formatting.

       There are different categories for locale information a	program	 might
       need; they are declared as macros.  Using them as the first argument to
       the setlocale(3) function, it is possible to set one of	these  to  the
       desired locale:

       LC_ADDRESS (GNU extension, since glibc 2.2)
	      Change   settings	  that	describe  the  formats	(e.g.,	postal
	      addresses) used  to  describe  locations	and  geography-related
	      items.  Applications that need this information can use nl_lang-
	      info(3)	to   retrieve	nonstandard    elements,    such    as
	      _NL_ADDRESS_COUNTRY_NAME	(country  name, in the language of the
	      locale) and _NL_ADDRESS_LANG_NAME (language name,	 in  the  lan-
	      guage of the locale), which return strings such as "Deutschland"
	      and "Deutsch" (for  German-language  locales).   (Other  element
	      names are listed in <langinfo.h>.)

       LC_COLLATE
	      This  category  governs the collation rules used for sorting and
	      regular expressions, including character equivalence classes and
	      multicharacter collating elements.  This locale category changes
	      the behavior of the functions strcoll(3) and  strxfrm(3),	 which
	      are used to compare strings in the local alphabet.  For example,
	      the German sharp s is sorted as "ss".

       LC_CTYPE
	      This category determines the interpretation of byte sequences as
	      characters (e.g., single versus multibyte characters), character
	      classifications (e.g., alphabetic or digit), and the behavior of
	      character	 classes.  On glibc systems, this category also deter-
	      mines the	 character  transliteration  rules  for	 iconv(1)  and
	      iconv(3).	 It changes the behavior of the character handling and
	      classification functions, such as isupper(3) and toupper(3), and
	      the multibyte character functions such as mblen(3) or wctomb(3).

       LC_IDENTIFICATION (GNU extension, since glibc 2.2)
	      Change  settings	that  relate  to  the metadata for the locale.
	      Applications that need this information can  use	nl_langinfo(3)
	      to   retrieve  nonstandard  elements,  such  as  _NL_IDENTIFICA-
	      TION_TITLE (title of this locale document)  and  _NL_IDENTIFICA-
	      TION_TERRITORY (geographical territory to which this locale doc-
	      ument applies), which might  return  strings  such  as  "English
	      locale  for the USA" and "USA".  (Other element names are listed
	      in <langinfo.h>.)

       LC_MONETARY
	      This category  determines	 the  formatting  used	for  monetary-
	      related  numeric	values.	 This changes the information returned
	      by localeconv(3), which describes the way	 numbers  are  usually
	      printed,	with  details  such  as	 decimal  point versus decimal
	      comma.  This information is  internally  used  by	 the  function
	      strfmon(3).

       LC_MESSAGES
	      This  category  affects  the language in which messages are dis-
	      played and what an affirmative or negative  answer  looks	 like.
	      The  GNU	C  library  contains  the gettext(3), ngettext(3), and
	      rpmatch(3) functions to ease the use of this  information.   The
	      GNU  gettext family of functions also obey the environment vari-
	      able LANGUAGE (containing a colon-separated list of locales)  if
	      the category is set to a valid locale other than "C".  This cat-
	      egory also affects the behavior of catopen(3).

       LC_MEASUREMENT (GNU extension, since glibc 2.2)
	      Change the settings relating to the measurement  system  in  the
	      locale  (i.e.,  metric versus US customary units).  Applications
	      can use nl_langinfo(3) to retrieve the nonstandard  _NL_MEASURE-
	      MENT_MEASUREMENT element, which returns a pointer to a character
	      that has the value 1 (metric) or 2 (US customary units).

       LC_NAME (GNU extension, since glibc 2.2)
	      Change settings that describe the formats used to	 address  per-
	      sons.   Applications that need this information can use nl_lang-
	      info(3)	to   retrieve	nonstandard    elements,    such    as
	      _NL_NAME_NAME_MR	  (general    salutation    for	   men)	   and
	      _NL_NAME_NAME_MS (general salutation for women) elements,	 which
	      return  strings  such  as "Herr" and "Frau" (for German-language
	      locales).	 (Other element names are listed in <langinfo.h>.)

       LC_NUMERIC
	      This category determines the formatting rules used for  nonmone-
	      tary  numeric  values--for  example, the thousands separator and
	      the radix character (a period  in	 most  English-speaking	 coun-
	      tries, but a comma in many other regions).  It affects functions
	      such as printf(3), scanf(3), and	strtod(3).   This  information
	      can also be read with the localeconv(3) function.

       LC_PAPER (GNU extension, since glibc 2.2)
	      Change  the  settings relating to the dimensions of the standard
	      paper size (e.g., US letter versus A4).  Applications that  need
	      the  dimensions  can  obtain  them  by  using  nl_langinfo(3) to
	      retrieve the nonstandard	_NL_PAPER_WIDTH	 and  _NL_PAPER_HEIGHT
	      elements,	 which	return int values specifying the dimensions in
	      millimeters.

       LC_TELEPHONE (GNU extension, since glibc 2.2)
	      Change settings that describe the formats to be used with	 tele-
	      phone services.  Applications that need this information can use
	      nl_langinfo(3)  to  retrieve  nonstandard	 elements,   such   as
	      _NL_TELEPHONE_INT_PREFIX (international prefix used to call num-
	      bers in this locale), which returns a string such as  "49"  (for
	      Germany).	 (Other element names are listed in <langinfo.h>.)

       LC_TIME
	      This category governs the formatting used for date and time val-
	      ues.  For example, most of Europe uses a	24-hour	 clock	versus
	      the  12-hour  clock  used	 in the United States.	The setting of
	      this category affects the behavior of functions  such  as	 strf-
	      time(3) and strptime(3).

       LC_ALL All of the above.

       If  the second argument to setlocale(3) is an empty string, "", for the
       default locale, it is determined using the following steps:

       1.     If there is a non-null environment variable LC_ALL, the value of
	      LC_ALL is used.

       2.     If an environment variable with the same name as one of the cat-
	      egories above exists and is non-null, its value is used for that
	      category.

       3.     If  there	 is a non-null environment variable LANG, the value of
	      LANG is used.

       Values about local numeric formatting is made  available	 in  a	struct
       lconv  returned	by the localeconv(3) function, which has the following
       declaration:

	 struct lconv {

	     /* Numeric (nonmonetary) information */

	     char *decimal_point;     /* Radix character */
	     char *thousands_sep;     /* Separator for digit groups to left
					 of radix character */
	     char *grouping; /* Each element is the number of digits in a
				group; elements with higher indices are
				further left.  An element with value CHAR_MAX
				means that no further grouping is done.	 An
				element with value 0 means that the previous
				element is used for all groups further left. */

	     /* Remaining fields are for monetary information */

	     char *int_curr_symbol;   /* First three chars are a currency symbol
					 from ISO 4217.	 Fourth char is the
					 separator.  Fifth char is '\0'. */
	     char *currency_symbol;   /* Local currency symbol */
	     char *mon_decimal_point; /* Radix character */
	     char *mon_thousands_sep; /* Like thousands_sep above */
	     char *mon_grouping;      /* Like grouping above */
	     char *positive_sign;     /* Sign for positive values */
	     char *negative_sign;     /* Sign for negative values */
	     char  int_frac_digits;   /* International fractional digits */
	     char  frac_digits;	      /* Local fractional digits */
	     char  p_cs_precedes;     /* 1 if currency_symbol precedes a
					 positive value, 0 if succeeds */
	     char  p_sep_by_space;    /* 1 if a space separates currency_symbol
					 from a positive value */
	     char  n_cs_precedes;     /* 1 if currency_symbol precedes a
					 negative value, 0 if succeeds */
	     char  n_sep_by_space;    /* 1 if a space separates currency_symbol
					 from a negative value */
	     /* Positive and negative sign positions:
		0 Parentheses surround the quantity and currency_symbol.
		1 The sign string precedes the quantity and currency_symbol.
		2 The sign string succeeds the quantity and currency_symbol.
		3 The sign string immediately precedes the currency_symbol.
		4 The sign string immediately succeeds the currency_symbol. */
	     char  p_sign_posn;
	     char  n_sign_posn;
	 };

   POSIX.1-2008 extensions to the locale API
       POSIX.1-2008 standardized a number of extensions	 to  the  locale  API,
       based  on implementations that first appeared in version 2.3 of the GNU
       C library.  These extensions are designed to address the	 problem  that
       the traditional locale APIs do not mix well with multithreaded applica-
       tions and with applications that must deal with multiple locales.

       The extensions take the form of new functions for creating and  manipu-
       lating  locale  objects (newlocale(3), freelocale(3), duplocale(3), and
       uselocale(3)) and various new library functions with  the  suffix  "_l"
       (e.g.,  toupper_l(3)) that extend the traditional locale-dependent APIs
       (e.g., toupper(3)) to allow the specification of a locale  object  that
       should apply when executing the function.

ENVIRONMENT
       The  following  environment variable is used by newlocale(3) and setlo-
       cale(3), and thus affects all unprivileged localized programs:

       LOCPATH
	      A list of pathnames, separated by colons (':'), that  should  be
	      used  to	find  locale  data.  If this variable is set, only the
	      individual compiled locale data files from LOCPATH and the  sys-
	      tem  default locale data path are used; any available locale ar-
	      chives are not used (see localedef(1)).  The individual compiled
	      locale  data  files  are searched for under subdirectories which
	      depend  on  the  currently  used	locale.	  For  example,	  when
	      en_GB.UTF-8 is used for a category, the following subdirectories
	      are searched for, in this order: en_GB.UTF-8, en_GB.utf8, en_GB,
	      en.UTF-8, en.utf8, and en.

FILES
       /usr/lib/locale/locale-archive
	      Usual default locale archive location.

       /usr/lib/locale
	      Usual default path for compiled individual locale files.

CONFORMING TO
       POSIX.1-2001.

SEE ALSO
       iconv(1),  locale(1),  localedef(1),  catopen(3), gettext(3), iconv(3),
       localeconv(3), mbstowcs(3), newlocale(3), ngettext(3),  nl_langinfo(3),
       rpmatch(3),    setlocale(3),   strcoll(3),   strfmon(3),	  strftime(3),
       strxfrm(3), uselocale(3),  wcstombs(3),	locale(5),  charsets(7),  uni-
       code(7), utf-8(7)

COLOPHON
       This  page  is  part of release 4.10 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/.



Linux				  2015-07-23			     LOCALE(7)