1 .\" $NetBSD: nls.7,v 1.15 2009/04/09 02:51:54 joerg Exp $
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35 .Nd Native Language Support Overview
37 Native Language Support (NLS) provides commands for a single
38 worldwide operating system base.
39 An internationalized system has no built-in assumptions or dependencies
40 on language-specific or cultural-specific conventions such as:
42 .Bl -bullet -offset indent -compact
44 Character classifications
46 Character comparison rules
48 Character collation order
50 Numeric and monetary formatting
52 Date and time formatting
59 All information pertaining to cultural conventions and language is
60 obtained at program run time.
62 .Dq Internationalization
65 refers to the operation by which system software is developed to support
66 multiple cultural-specific and language-specific conventions.
67 This is a generalization process by which the system is untied from
68 calling only English strings or other English-specific conventions.
72 refers to the operations by which the user environment is customized to
73 handle its input and output appropriate for specific language and cultural
75 This is a specialization process, by which generic methods already
76 implemented in an internationalized system are used in specific ways.
77 The formal description of cultural conventions for some country, together
78 with all associated translations targeted to the native language, is
83 provides extensive support to programmers and system developers to
84 enable internationalized software to be developed.
86 also supplies a large variety of locales for system localization.
87 .Ss Localization of Information
88 All locale information is accessible to programs at run time so that
89 data is processed and displayed correctly for specific cultural
90 conventions and language.
92 A locale is divided into categories.
93 A category is a group of language-specific and culture-specific conventions
94 as outlined in the list above.
95 ISO C specifies the following six standard categories supported by
98 .Bl -tag -compact -width ".Ev LC_MONETARY"
100 string-collation order information
102 character classification, case conversion, and other character attributes
104 the format for affirmative and negative responses
106 rules and symbols for formatting monetary numeric information
108 rules and symbols for formatting nonmonetary numeric information
110 rules and symbols for formatting time and date information
113 Localization of the system is achieved by setting appropriate values
114 in environment variables to identify which locale should be used.
115 The environment variables have the same names as their respective
122 environment variables are used.
125 environment variable specifies a colon-separated list of directory names
126 where the message catalog files of the NLS database are located.
131 environment variables also determine the current locale.
133 The values of these environment variables contains a string format as:
135 language[_territory][.codeset][@modifier]
138 Valid values for the language field come from the ISO639 standard which
139 defines two-character codes for many languages.
140 Some common language codes are:
141 .Bl -column "PERSIAN (farsi)" "Sy Code" "OCEANIC/INDONESIAN"
142 .It Sy Language Name Ta Sy Code Ta Sy Language Family
143 .It ABKHAZIAN AB IBERO-CAUCASIAN
144 .It AFAN (OROMO) OM HAMITIC
146 .It AFRIKAANS AF GERMANIC
147 .It ALBANIAN SQ INDO-EUROPEAN (OTHER)
148 .It AMHARIC AM SEMITIC
149 .It ARABIC AR SEMITIC
150 .It ARMENIAN HY INDO-EUROPEAN (OTHER)
151 .It ASSAMESE AS INDIAN
152 .It AYMARA AY AMERINDIAN
153 .It AZERBAIJANI AZ TURKIC/ALTAIC
154 .It BASHKIR BA TURKIC/ALTAIC
156 .It BENGALI BN INDIAN
159 .It BISLAMA Ta BI Ta ""
161 .It BULGARIAN BG SLAVIC
163 .It BYELORUSSIAN BE SLAVIC
164 .It CAMBODIAN KM ASIAN
165 .It CATALAN CA ROMANCE
167 .It CORSICAN CO ROMANCE
168 .It CROATIAN HR SLAVIC
170 .It DANISH DA GERMANIC
171 .It DUTCH NL GERMANIC
172 .It ENGLISH EN GERMANIC
173 .It ESPERANTO EO INTERNATIONAL AUX.
174 .It ESTONIAN ET FINNO-UGRIC
175 .It FAROESE FO GERMANIC
176 .It FIJI FJ OCEANIC/INDONESIAN
177 .It FINNISH FI FINNO-UGRIC
178 .It FRENCH FR ROMANCE
179 .It FRISIAN FY GERMANIC
180 .It GALICIAN GL ROMANCE
181 .It GEORGIAN KA IBERO-CAUCASIAN
182 .It GERMAN DE GERMANIC
183 .It GREEK EL LATIN/GREEK
184 .It GREENLANDIC KL ESKIMO
185 .It GUARANI GN AMERINDIAN
186 .It GUJARATI GU INDIAN
187 .It HAUSA HA NEGRO-AFRICAN
188 .It HEBREW HE SEMITIC
190 .It HUNGARIAN HU FINNO-UGRIC
191 .It ICELANDIC IS GERMANIC
192 .It INDONESIAN ID OCEANIC/INDONESIAN
193 .It INTERLINGUA IA INTERNATIONAL AUX.
194 .It INTERLINGUE IE INTERNATIONAL AUX.
195 .It INUKTITUT Ta IU Ta ""
196 .It INUPIAK IK ESKIMO
198 .It ITALIAN IT ROMANCE
199 .It JAPANESE JA ASIAN
200 .It JAVANESE JV OCEANIC/INDONESIAN
201 .It KANNADA KN DRAVIDIAN
202 .It KASHMIRI KS INDIAN
203 .It KAZAKH KK TURKIC/ALTAIC
204 .It KINYARWANDA RW NEGRO-AFRICAN
205 .It KIRGHIZ KY TURKIC/ALTAIC
206 .It KURUNDI RN NEGRO-AFRICAN
208 .It KURDISH KU IRANIAN
209 .It LAOTHIAN LO ASIAN
210 .It LATIN LA LATIN/GREEK
211 .It LATVIAN LV BALTIC
212 .It LINGALA LN NEGRO-AFRICAN
213 .It LITHUANIAN LT BALTIC
214 .It MACEDONIAN MK SLAVIC
215 .It MALAGASY MG OCEANIC/INDONESIAN
216 .It MALAY MS OCEANIC/INDONESIAN
217 .It MALAYALAM ML DRAVIDIAN
218 .It MALTESE MT SEMITIC
219 .It MAORI MI OCEANIC/INDONESIAN
220 .It MARATHI MR INDIAN
221 .It MOLDAVIAN MO ROMANCE
222 .It MONGOLIAN Ta MN Ta ""
223 .It NAURU Ta NA Ta ""
225 .It NORWEGIAN NO GERMANIC
226 .It OCCITAN OC ROMANCE
228 .It PASHTO PS IRANIAN
229 .It PERSIAN (farsi) FA IRANIAN
231 .It PORTUGUESE PT ROMANCE
232 .It PUNJABI PA INDIAN
233 .It QUECHUA QU AMERINDIAN
234 .It RHAETO-ROMANCE RM ROMANCE
235 .It ROMANIAN RO ROMANCE
236 .It RUSSIAN RU SLAVIC
237 .It SAMOAN SM OCEANIC/INDONESIAN
238 .It SANGHO SG NEGRO-AFRICAN
239 .It SANSKRIT SA INDIAN
240 .It SCOTS GAELIC GD CELTIC
241 .It SERBIAN SR SLAVIC
242 .It SERBO-CROATIAN SH SLAVIC
243 .It SESOTHO ST NEGRO-AFRICAN
244 .It SETSWANA TN NEGRO-AFRICAN
245 .It SHONA SN NEGRO-AFRICAN
247 .It SINGHALESE SI INDIAN
248 .It SISWATI SS NEGRO-AFRICAN
250 .It SLOVENIAN SL SLAVIC
251 .It SOMALI SO HAMITIC
252 .It SPANISH ES ROMANCE
253 .It SUNDANESE SU OCEANIC/INDONESIAN
254 .It SWAHILI SW NEGRO-AFRICAN
255 .It SWEDISH SV GERMANIC
256 .It TAGALOG TL OCEANIC/INDONESIAN
258 .It TAMIL TA DRAVIDIAN
259 .It TATAR TT TURKIC/ALTAIC
260 .It TELUGU TE DRAVIDIAN
263 .It TIGRINYA TI SEMITIC
264 .It TONGA TO OCEANIC/INDONESIAN
265 .It TSONGA TS NEGRO-AFRICAN
266 .It TURKISH TR TURKIC/ALTAIC
267 .It TURKMEN TK TURKIC/ALTAIC
268 .It TWI TW NEGRO-AFRICAN
269 .It UIGUR Ta UG Ta ""
270 .It UKRAINIAN UK SLAVIC
272 .It UZBEK UZ TURKIC/ALTAIC
273 .It VIETNAMESE VI ASIAN
274 .It VOLAPUK VO INTERNATIONAL AUX.
276 .It WOLOF WO NEGRO-AFRICAN
277 .It XHOSA XH NEGRO-AFRICAN
278 .It YIDDISH YI GERMANIC
279 .It YORUBA YO NEGRO-AFRICAN
280 .It ZHUANG Ta ZA Ta ""
281 .It ZULU ZU NEGRO-AFRICAN
284 For example, the locale for the Danish language spoken in Denmark
285 using the ISO 8859-1 character set is da_DK.ISO8859-1.
286 The da stands for the Danish language and the DK stands for Denmark.
287 The short form of da_DK is sufficient to indicate this locale.
289 The environment variable settings are queried by their priority level
290 in the following manner:
295 environment variable is set, all six categories use the locale it
300 environment variable is not set, each individual category uses the
301 locale specified by its corresponding environment variable.
305 environment variable is not set, and a value for a particular
307 environment variable is not set, the value of the
309 environment variable specifies the default locale for all categories.
312 environment variable should be set in /etc/profile, since it makes it
313 most easy for the user to override the system default using the individual
319 environment variable is not set, a value for a particular
321 environment variable is not set, and the value of the
323 environment variable is not set, the locale for that specific
324 category defaults to the C locale.
325 The C or POSIX locale assumes the ASCII character set and defines
326 information for the six categories.
329 A character is any symbol used for the organization, control, or
330 representation of data.
331 A group of such symbols used to describe a
332 particular language make up a character set.
333 It is the encoding values in a character set that provide
334 the interface between the system and its input and output devices.
336 The following character sets are supported in
338 .Bl -tag -width ISO_8859_family
340 The American Standard Code for Information Exchange (ASCII) standard
341 specifies 128 Roman characters and control codes, encoded in a 7-bit
342 character encoding scheme.
344 Industry-standard character sets specified by the ISO/IEC 8859
346 The standard is divided into 15 numbered parts, with each
347 part specifying broad script similarities.
348 Examples include Western European, Central European, Arabic, Cyrillic,
349 Hebrew, Greek, and Turkish.
350 The character sets use an 8-bit character encoding scheme which is
351 compatible with the ASCII character set.
353 The Unicode character set is the full set of known abstract characters of
354 all real-world scripts. It can be used in environments where multiple
355 scripts must be processed simultaneously.
356 Unicode is compatible with ISO 8859-1 (Western European) and ASCII.
357 Many character encoding schemes are available for Unicode, including UTF-8,
359 These encoding schemes are multi-byte encodings.
360 The UTF-8 encoding scheme uses 8-bit, variable-width encodings which is
361 compatible with ASCII.
362 The UTF-16 encoding scheme uses 16-bit, variable-width encodings.
363 The UTF-32 encoding scheme using 32-bit, fixed-width encodings.
366 A font set contains the glyphs to be displayed on the screen for a
367 corresponding character in a character set.
368 A display must support a suitable font to display a character set.
369 If suitable fonts are available to the X server, then X clients can
370 include support for different character sets.
372 includes support for Unicode with UTF-8 encoding.
374 is useful for displaying all the characters in an X font.
379 console provides support for loading a variety of fonts using the
381 utility. Available fonts can be found in
382 .Pa /usr/share/syscons/fonts .
383 .Ss Internationalization for Programmers
384 To facilitate translations of messages into various languages and to
385 make the translated messages available to the program based on a
386 user's locale, it is necessary to keep messages separate from the
387 programs and provide them in the form of message catalogs that a
388 program can access at run time.
390 Access to locale information is provided through the
395 See their respective man pages for further information.
397 Message source files containing application messages are created by
398 the programmer and converted to message catalogs.
399 These catalogs are used by the application to retrieve and display
403 supports two message catalog interfaces: the X/Open
405 interface and the Uniforum
410 interface has the advantage that it belongs to a standard which is
412 Unfortunately the interface is complicated to use and
413 maintenance of the catalogs is difficult.
414 The implementation also doesn't support different character sets.
417 interface has not been standardized yet, however it is being supported
418 by an increasing number of systems.
419 It also provides many additional tools which make programming and
420 catalog maintenance much easier.
421 .Ss Support for Multi-byte Encodings
422 Some character sets with multi-byte encodings may be difficult to decode,
423 or may contain state (i.e., adjacent characters are dependent).
424 ISO C specifies a set of functions using 'wide characters' which can handle
425 multi-byte encodings properly.
426 The behaviour of these functions is affected
429 category of the current locale.
431 A wide character is specified in ISO C
432 as being a fixed number of bits wide and is stateless.
433 There are two types for wide characters:
438 is a type which can contain one wide character and operates like 'char'
439 type does for one character.
441 can contain one wide character or WEOF (wide EOF).
443 There are functions that operate on
445 and substitute for functions operating on 'char'.
451 There are some additional functions that operate on
459 Wide characters should be used for all I/O processing which may rely
460 on locale-specific strings.
461 The two primary issues requiring special use of wide characters are:
462 .Bl -bullet -offset indent
464 All I/O is performed using multibyte characters.
465 Input data is converted into wide characters immediately after
466 reading and data for output is converted from wide characters to
467 multi-byte encoding immediately before writing.
468 Conversion is controlled by the
478 Wide characters are used directly for I/O, using
489 They are also used for formatted I/O functions for wide characters
501 and wide character identifier of %lc, %C, %ls, %S for conventional
502 formatted I/O functions.
510 .Xr gettext 3 Pq Pa devel/gettext ,
514 This man page is incomplete.