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, 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 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
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; /* 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;
};
CONFORMS TO
POSIX.1
Linux 1993-04-24 locale(7)