LOCALE(7)                  Linux Programmer's Manual                 LOCALE(7)
NAME
       locale - Description of multi-language 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,  etc.   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() to set the current locale,
       and localeconv() to get information about number formatting.

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

       LC_COLLATE
              This  is used to change the behaviour of the functions strcoll()
              and strxfrm(), which are used to compare strings  in  the  local
              alphabet.  For example, the German sharp s is sorted as "ss".

       LC_CTYPE
              This changes the behaviour of the character handling and classi-
              fication functions, such as isupper()  and  toupper(),  and  the
              multi-byte character functions such as mblen() or wctomb().

       LC_MONETARY
              changes the information returned by localeconv() which describes
              the way numbers are usually printed, with details such as  deci-
              mal  point versus decimal comma.  This information is internally
              used by the function strfmon().

       LC_MESSAGES
              changes the language messages are displayed in and how an affir-
              mative  or  negative  answer looks like.  The GNU C-library con-
              tains the gettext(), ngettext(), and rpmatch() functions to ease
              the  use  of these information.  The GNU gettext family of func-
              tions also obey the environment variable LANGUAGE.

       LC_NUMERIC
              changes the information used by the printf() and scanf()  family
              of  functions, when they are advised to use the locale-settings.
              This information can also be read with  the  localeconv()  func-
              tion.

       LC_TIME
              changes  the behaviour of the strftime() function to display the
              current time in a locally acceptable form; for example, most  of
              Europe uses a 24-hour clock versus the 12-hour clock used in the
              United States.

       LC_ALL All of the above.

       If the second argument to setlocale() is  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() function, which  has  the  following
       declaration:

         struct lconv {

           /* Numeric (non-monetary) 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 ' '. */
           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;   /* Int'l 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;
         };

CONFORMING TO
       POSIX.1-2001.

       The GNU gettext functions are specified in LI18NUX2000.

SEE ALSO
       locale(1),   localedef(1),   gettext(3),   localeconv(3),  ngettext(3),
       nl_langinfo(3),  rpmatch(3),  setlocale(3),   strcoll(3),   strfmon(3),
       strftime(3), strxfrm(3)

Linux                             1993-04-24                         LOCALE(7)