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 char-
     acter sets, lexigraphic 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

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

          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".

          This changes the behaviour of  the  character  handling
          and  classification  functions,  such  as isupper() 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.

          All of the above.

     If the second argument to setlocale() is empty string,   for
     the  default  locale,  it  is determined using the following

     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),    rpmatch(3),
     strfmon(3), strcoll(3), strftime(3)