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

       locale - Description of multi-language support

       #include <locale.h>

       A  locale  is a set of language and cultural rules.  These
       cover aspects such as  language  for  messages,  different
       character  sets,  lexigraphic conventions, etc.  A program
       needs to be able to determine its locale and  act  accord-
       ingly 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  cur-
       rent  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:

              This  is  used to change the behaviour of the func-
              tions strcoll() and strxfrm(), which  are  used  to
              compare  strings  in the local alphabet.  For exam-
              ple, the German sharp s is sorted as "ss".

              This changes the behaviour of  the  character  han-
              dling  and  classification functions, such as isup-
              per() and toupper(), and the  multi-byte  character
              functions such as mblen() or wctomb().

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

              changes  the language messages are displayed in and
              how an affirmative or negative answer  looks  like.
              The  GNU  C-library contains the rpmatch() function
              to ease the use of these information.

              changes the informations 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() function.

              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 vs. the US' 12-hour clock.

       LC_ALL All of the above.

       If the second argument to setlocale() is empty string, "",
       for the default locale, it is determined using the follow-
       ing 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() function,
       which has the following declaration:
       struct lconv
         /* Numeric (non-monetary) information.  */

         char *decimal_point;        /* Decimal point character.  */
         char *thousands_sep;        /* Thousands separator.  */
         /* Each element is the number of digits in each group;
            elements with higher indices are farther 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 farther left.  */
         char *grouping;

         /* Monetary information.  */

         /* First three chars are a currency symbol from ISO 4217.
            Fourth char is the separator.  Fifth char is ' '.  */
         char *int_curr_symbol;
         char *currency_symbol; /* Local currency symbol.  */
         char *mon_decimal_point;    /* Decimal point character.  */
         char *mon_thousands_sep;    /* Thousands separator.  */
         char *mon_grouping;         /* Like `grouping' element (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.  */
         /* 1 if currency_symbol precedes a positive value, 0 if succeeds.  */
         char p_cs_precedes;
         /* 1 if a space separates currency_symbol from a positive value.  */
         char p_sep_by_space;
         /* 1 if currency_symbol precedes a negative value, 0 if succeeds.  */
         char n_cs_precedes;
         /* 1 if a space separates currency_symbol from a negative value.  */
         char n_sep_by_space;
         /* 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;


       setlocale(3),  localeconv(3),  locale(1),  localedef(1)  ,
       rpmatch(3),   strfmon(3),  strcoll(3),  strxfrm(3),  strf-

Linux                     April 24, 1993                        1