Provided by: manpages_4.13-3_all bug

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_langinfo(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 language 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  determines 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_IDENTIFICATION_TITLE    (title     of     this     locale     document)     and
              _NL_IDENTIFICATION_TERRITORY  (geographical territory to which this locale document
              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  displayed  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
              variable LANGUAGE (containing a colon-separated list of locales) if the category is
              set  to  a valid locale other than "C".  This category 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_MEASUREMENT_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 persons.  Applications
              that need this information can use nl_langinfo(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 nonmonetary numeric values—
              for example, the thousands separator and the radix  character  (a  period  in  most
              English-speaking  countries,  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  telephone  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 numbers 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 values.   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
              strftime(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 categories 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 applications and with applications that must deal with multiple locales.

       The extensions take the form of new functions for creating and manipulating 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 setlocale(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 system default locale data path  are  used;  any  available  locale
              archives  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), unicode(7), utf-8(7)

COLOPHON

       This page is part of release 4.13 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/.