Chapter 6. LOCALE technology

54

Bruno Haible's Unicode HOWTO (

ftp://ftp.ilog.fr/pub/Users/haible/utf8/Unicode HOWTO.

html

) also recommends this model.

6.1 Locale Categories and

setlocale()

In LOCALE model, the behaviors of some C functions are dependent on LOCALE environment.

LOCALE environment is divided into six categories and each of these categories can be set inde 

pendently using

setlocale()

.

The followings are the six categories:

LC_CTYPE Category related to encodings. Characters which are encoded by LC_CTYPE dependent

encoding is called multibyte characters. Note that multibyte character doesn't need to be

multibyte.

LC_CTYPE dependent functions are: character testing functions such as

islower()

and

so on, multibyte character functions such as

mblen()

and so on, multibyte string functions

such as

mbstowcs()

and so on, and so on.

LC_COLLATE Category related to sorting.

strcoll()

and so on are LC_COLLATE dependent.

LC_MESSAGES Category related to the language for messages the software outputs. This cate 

gory is used for

gettext

.

LC_MONETARY Category related to format to show monetary numbers, for example, currency

mark, comma or period, columns, and so on.

localeconv()

is the only function which is

LC_MONETARY dependent.

LC_NUMERIC Category related to format to show general numbers, for example, character for

decimal point.

Formatted I/O functions such as

printf()

, string conversion functions such as

atof()

,

and so on are LC_NUMERIC dependent.

LC_TIME Category related to format to show time and date, such as name of months and weeks,

order of date, month, and year, and so on.

strftime()

and so on are LC_TIME dependent.

setlocale()

is a function to set LOCALE. Usage is char *

setlocale(

int category, const char

*locale

);

. Header file of

locale.h

is needed for prototype declaration and definition of macros

for category names. For example,

setlocale(LC_TIME,  de_DE );

.

For category, the following macros can be used: LC_CTYPE, LC_COLLATE, LC_MONETARY,

LC_NUMERIC, LC_TIME, and LC_ALL. For locale, specific locale name,

NULL

, or

can be spec 

ified.