MirBSD manpage: Encode::Supported(3p)



     Encode::Supported -- Encodings supported by Encode


     Encoding Names

     Encoding names are case insensitive. White space in names is
     ignored.  In addition, an encoding may have aliases. Each
     encoding has one "canonical" name.  The "canonical" name is
     chosen from the names of the encoding by picking the first
     in the following sequence (with a few exceptions).

     +   The name used by the Perl community.  That includes
         'utf8' and 'ascii'. Unlike aliases, canonical names
         directly reach the method so such frequently used words
         like 'utf8' don't need to do alias lookups.

     +   The MIME name as defined in IETF RFCs.  This includes
         all "iso-"s.

     +   The name in the IANA registry.

     +   The name used by the organization that defined it.

     In case de jure canonical names differ from that of the
     Encode module, they are always aliased if it ever be imple-
     mented.  So you can safely tell if a given encoding is
     implemented or not just by passing the canonical name.

     Because of all the alias issues, and because in the general
     case encodings have state, "Encode" uses an encoding object
     internally once an operation is in progress.

Supported Encodings

     As of Perl 5.8.0, at least the following encodings are
     recognized. Note that unless otherwise specified, they are
     all case insensitive (via alias) and all occurrence of
     spaces are replaced with '-'. In other words, "ISO 8859 1"
     and "iso-8859-1" are identical.

     Encodings are categorized and implemented in several dif-
     ferent modules but you don't have to "use Encode::XX" to
     make them available for most cases.  Encode.pm will automat-
     ically load those modules on demand.

     Built-in Encodings

     The following encodings are always available.

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       Canonical     Aliases                      Comments & References
       ascii         US-ascii ISO-646-US                         [ECMA]
       ascii-ctrl                                      Special Encoding
       iso-8859-1    latin1                                       [ISO]
       null                                            Special Encoding
       utf8          UTF-8                                    [RFC2279]

     null and ascii-ctrl are special.  "null" fails for all char-
     acter so when you set fallback mode to PERLQQ, HTMLCREF or
     XMLCREF, ALL CHARACTERS will fall back to character refer-
     ences.  Ditto for "ascii-ctrl" except for control charac-
     ters.  For fallback modes, see Encode.

     Encode::Unicode -- other Unicode encodings

     Unicode coding schemes other than native utf8 are supported
     by Encode::Unicode, which will be autoloaded on demand.

       UCS-2BE       UCS-2, iso-10646-1                      [IANA, UC]
       UCS-2LE                                                     [UC]
       UTF-16                                                      [UC]
       UTF-16BE                                                    [UC]
       UTF-16LE                                                    [UC]
       UTF-32                                                      [UC]
       UTF-32BE      UCS-4                                         [UC]
       UTF-32LE                                                    [UC]
       UTF-7                                                  [RFC2152]

     To find how (UCS-2|UTF-(16|32))(LE|BE)? differ from one
     another, see Encode::Unicode.

     UTF-7 is a special encoding which "re-encodes" UTF-16BE into
     a 7-bit encoding.  It is implemented seperately by

     Encode::Byte -- Extended ASCII

     Encode::Byte implements most single-byte encodings except
     for Symbols and EBCDIC. The following encodings are based on
     single-byte encodings implemented as extended ASCII.  Most
     of them map \x80-\xff (upper half) to non-ASCII characters.

     ISO-8859 and corresponding vendor mappings
         Since there are so many, they are presented in table
         format with languages and corresponding encoding names
         by vendors.  Note that the table is sorted in order of
         ISO-8859 and the corresponding vendor mappings are
         slightly different from that of ISO.  See

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         <http://czyborra.com/charsets/iso8859.html> for details.

           Lang/Regions  ISO/Other Std.  DOS     Windows Macintosh  Others
           N. America    (ASCII)         cp437        AdobeStandardEncoding
                                         cp863 (DOSCanadaF)
           W. Europe     iso-8859-1      cp850   cp1252  MacRoman  nextstep
                                         cp860 (DOSPortuguese)
           Cntrl. Europe iso-8859-2      cp852   cp1250  MacCentralEurRoman
           Latin3[1]     iso-8859-3
           Latin4[2]     iso-8859-4
           Cyrillics     iso-8859-5      cp855   cp1251  MacCyrillic
             (See also next section)     cp866           MacUkrainian
           Arabic        iso-8859-6      cp864   cp1256  MacArabic
                                         cp1006          MacFarsi
           Greek         iso-8859-7      cp737   cp1253  MacGreek
                                         cp869 (DOSGreek2)
           Hebrew        iso-8859-8      cp862   cp1255  MacHebrew
           Turkish       iso-8859-9      cp857   cp1254  MacTurkish
           Nordics       iso-8859-10     cp865
                                         cp861           MacIcelandic
           Thai          iso-8859-11[3]  cp874           MacThai
           (iso-8859-12 is nonexistent. Reserved for Indics?)
           Baltics       iso-8859-13     cp775           cp1257
           Celtics       iso-8859-14
           Latin9 [4]    iso-8859-15
           Latin10       iso-8859-16
           Vietnamese    viscii                  cp1258  MacVietnamese

           [1] Esperanto, Maltese, and Turkish. Turkish is now on 8859-9.
           [2] Baltics.  Now on 8859-10, except for Latvian.
           [3] TIS 620 +  Non-Breaking Space (0xA0 / U+00A0)
           [4] Nicknamed Latin0; the Euro sign as well as French and Finnish
               letters that are missing from 8859-1 were added.

         All cp* are also available as ibm-*, ms-*, and windows-*
         .  See also

         Macintosh encodings don't seem to be registered in such
         entities as IANA.  "Canonical" names in Encode are based
         upon Apple's Tech Note 1150.  See
         for details.

     KOI8 - De Facto Standard for the Cyrillic world

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         Though ISO-8859 does have ISO-8859-5, the KOI8 series is
         far more popular in the Net.   Encode comes with the
         following KOI charsets. For gory details, see

           koi8-r cp878                                           [RFC1489]
           koi8-u                                                 [RFC2319]

     gsm0338 - Hentai Latin 1
         GSM0338 is for GSM handsets. Though it shares
         alphanumerals with ASCII, control character ranges and
         other parts are mapped very differently, mainly to store
         Greek characters.  There are also escape sequences
         (starting with 0x1B) to cover e.g. the Euro sign.  Some
         special cases like a trailing 0x00 byte or a lone 0x1B
         byte are not well-defined and decode() will return an
         empty string for them. One possible workaround is

            $gsm =~ s/\x00\z/\x00\x00/;
            $uni = decode("gsm0338", $gsm);
            $uni .= "\xA0" if $gsm =~ /\x1B\z/;

         Note that the Encode implementation of GSM0338 does not
         implement the reuse of Latin capital letters as Greek
         capital letters (for example, the 0x5A is U+005A (LATIN

         The GSM0338 is also covered in Encode::Byte even though
         it is not an "extended ASCII" encoding.

     CJK: Chinese, Japanese, Korean (Multibyte)

     Note that Vietnamese is listed above.  Also read "Encoding
     vs Charset" below.  Also note that these are implemented in
     distinct modules by countries, due to the size concerns
     (simplified Chinese is mapped to 'CN', continental China,
     while traditional Chinese is mapped to 'TW', Taiwan).
     Please refer to their respective documentation pages.

     Encode::CN -- Continental China

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           Standard      DOS/Win Macintosh                Comment/Reference
           euc-cn [1]            MacChineseSimp
           (gbk)         cp936 [2]
           gb12345-raw                      { GB12345 without CES }
           gb2312-raw                       { GB2312  without CES }

           [1] GB2312 is aliased to this.  See L<Microsoft-related naming mess>
           [2] gbk is aliased to this.  See L<Microsoft-related naming mess>

     Encode::JP -- Japan
           Standard      DOS/Win Macintosh                Comment/Reference
           shiftjis      cp932   macJapanese
           iso-2022-jp                                            [RFC1468]
           iso-2022-jp-1                                          [RFC2237]
           jis0201-raw  { JIS X 0201 (roman + halfwidth kana) without CES }
           jis0208-raw  { JIS X 0208 (Kanji + fullwidth kana) without CES }
           jis0212-raw  { JIS X 0212 (Extended Kanji)         without CES }

     Encode::KR -- Korea
           Standard      DOS/Win Macintosh                Comment/Reference
           euc-kr                MacKorean                        [RFC1557]
                         cp949 [1]
           iso-2022-kr                                            [RFC1557]
           johab                                  [KS X 1001:1998, Annex 3]
           ksc5601-raw                              { KSC5601 without CES }

           [1] ks_c_5601-1987, (x-)?windows-949, and uhc are aliased to this.
           See below.

     Encode::TW -- Taiwan
           Standard      DOS/Win Macintosh                Comment/Reference
           big5-eten     cp950   MacChineseTrad {big5 aliased to big5-eten}

     Encode::HanExtra -- More Chinese via CPAN
         Due to the size concerns, additional Chinese encodings
         below are distributed separately on CPAN, under the name

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           Standard      DOS/Win Macintosh                Comment/Reference
           big5ext                                   CMEX's Big5e Extension
           big5plus                                  CMEX's Big5+ Extension
           cccii         Chinese Character Code for Information Interchange
           euc-tw                             EUC (Extended Unix Character)
           gb18030                          GBK with Traditional Characters

     Encode::JIS2K -- JIS X 0213 encodings via CPAN
         Due to size concerns, additional Japanese encodings
         below are distributed separately on CPAN, under the name

           Standard      DOS/Win Macintosh                Comment/Reference

     Miscellaneous encodings

         See perlebcdic for details.


         For symbols  and dingbats.


         Strictly speaking, MIME header encoding documented in
         RFC 2047 is more of encapsulation than encoding.  How-
         ever, their support in modern world is imperative so

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         they are supported.

           MIME-Header                                            [RFC2047]
           MIME-B                                                 [RFC2047]
           MIME-Q                                                 [RFC2047]

         This one is not a name of encoding but a utility that
         lets you pick up the most appropriate encoding for a
         data out of given suspects.  See Encode::Guess for

Unsupported encodings

     The following encodings are not supported as yet; some
     because they are rarely used, some because of technical dif-
     ficulties.  They may be supported by external modules via
     CPAN in the future, however.

     ISO-2022-JP-2 [RFC1554]
         Not very popular yet.  Needs Unicode Database or
         equivalent to implement encode() (because it includes
         JIS X 0208/0212, KSC5601, and GB2312 simultaneously,
         whose code points in Unicode overlap.  So you need to
         lookup the database to determine to what character set a
         given Unicode character should belong).

     ISO-2022-CN [RFC1922]
         Not very popular.  Needs CNS 11643-1 and -2 which are
         not available in this module.  CNS 11643 is supported
         (via euc-tw) in Encode::HanExtra. Autrijus Tang may add
         support for this encoding in his module in future.

     Various HP-UX encodings
         The following are unsupported due to the lack of mapping

           '8'  - arabic8, greek8, hebrew8, kana8, thai8, and turkish8
           '15' - japanese15, korean15, and roi15

     Cyrillic encoding ISO-IR-111
         Anton Tagunov doubts its usefulness.

     ISO-8859-8-1 [Hebrew]
         None of the Encode team knows Hebrew enough (ISO-8859-8,
         cp1255 and MacHebrew are supported because and just
         because there were mappings available at
         <http://www.unicode.org/>).  Contributions welcome.

     ISIRI 3342, Iran System, ISIRI 2900 [Farsi]

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     Thai encoding TCVN

     Vietnamese encodings VPS
         Though Jungshik Shin has reported that Mozilla supports
         this encoding, it was too late before 5.8.0 for us to
         add it.  In the future, it may be available via a
         separate module.  See
         if you are interested in helping us.

     Various Mac encodings
         The following are unsupported due to the lack of mapping

           MacArmenian,  MacBengali,   MacBurmese,   MacEthiopic
           MacExtArabic, MacGeorgian,  MacKannada,   MacKhmer
           MacLaotian,   MacMalayalam, MacMongolian, MacOriya
           MacSinhalese, MacTamil,     MacTelugu,    MacTibetan

         The rest which are already available are based upon the
         vendor mappings at

     (Mac) Indic encodings
         The maps for the following are available at
         <http://www.unicode.org/> but remain unsupport because
         those encodings need algorithmical approach, currently
         unsupported by enc2xs:


         For details, please see "Unicode mapping issues and
         notes:" at

         I believe this issue is prevalent not only for Mac Ind-
         ics but also in other Indic encodings, but the above
         were the only Indic encodings maps that I could find at
         <http://www.unicode.org/> .

Encoding vs. Charset -- terminology
     We are used to using the term (character) encoding and char-
     acter set interchangeably.  But just as confusing the terms
     byte and character is dangerous and the terms should be

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     differentiated when needed, we need to differentiate encod-
     ing and character set.

     To understand that, here is a description of how we make
     computers grok our characters.

     +   First we start with which characters to include.  We
         call this collection of characters character repertoire.

     +   Then we have to give each character a unique ID so your
         computer can tell the difference between 'a' and 'A'.
         This itemized character repertoire is now a character

     +   If your computer can grow the character set without
         further processing, you can go ahead and use it.  This
         is called a coded character set (CCS) or raw character
         encoding.  ASCII is used this way for most cases.

     +   But in many cases, especially multi-byte CJK encodings,
         you have to tweak a little more.  Your network connec-
         tion may not accept any data with the Most Significant
         Bit set, and your computer may not be able to tell if a
         given byte is a whole character or just half of it.  So
         you have to encode the character set to use it.

         A character encoding scheme (CES) determines how to
         encode a given character set, or a set of multiple char-
         acter sets.  7bit ISO-2022 is an example of a CES.  You
         switch between character sets via escape sequences.

     Technically, or mathematically, speaking, a character set
     encoded in such a CES that maps character by character may
     form a CCS.  EUC is such an example.  The CES of EUC is as

     +   Map ASCII unchanged.

     +   Map such a character set that consists of 94 or 96
         powered by N members by adding 0x80 to each byte.

     +   You can also use 0x8e and 0x8f to indicate that the fol-
         lowing sequence of characters belongs to yet another
         character set.  To each following byte is added the
         value 0x80.

     By carefully looking at the encoded byte sequence, you can
     find that the byte sequence conforms a unique number.  In
     that sense, EUC is a CCS generated by a CES above from up to
     four CCS (complicated?).  UTF-8 falls into this category.
     See "UTF-8" in perlUnicode to find out how UTF-8 maps
     Unicode to a byte sequence.

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     You may also have found out by now why 7bit ISO-2022 cannot
     comprise a CCS.  If you look at a byte sequence \x21\x21,
     you can't tell if it is two !'s or IDEOGRAPHIC SPACE.  EUC
     maps the latter to \xA1\xA1 so you have no trouble differen-
     tiating between "!!". and " ".

Encoding Classification (by Anton Tagunov and Dan Kogai)
     This section tries to classify the supported encodings by
     their applicability for information exchange over the Inter-
     net and to choose the most suitable aliases to name them in
     the context of such communication.

     +   To (en|de)code encodings marked by "(**)", you need
         "Encode::HanExtra", available from CPAN.

     Encoding names

       US-ASCII    UTF-8    ISO-8859-*  KOI8-R
       Shift_JIS   EUC-JP   ISO-2022-JP ISO-2022-JP-1
       EUC-KR      Big5     GB2312

     are registered with IANA as preferred MIME names and may be
     used over the Internet.

     "Shift_JIS" has been officialized by JIS X 0208:1997.
     "Microsoft-related naming mess" gives details.

     "GB2312" is the IANA name for "EUC-CN". See
     "Microsoft-related naming mess" for details.

     "GB_2312-80" raw encoding is available as "gb2312-raw" with
     Encode. See Encode::CN for details.

       KOI8-U        [RFC2319]

     have not been registered with IANA (as of March 2002) but
     seem to be supported by major web browsers. The IANA name
     for "EUC-CN" is "GB2312".


     is heavily misused. See "Microsoft-related naming mess" for

     "KS_C_5601-1987" raw encoding is available as "kcs5601-raw"
     with Encode. See Encode::KR for details.

       UTF-16 UTF-16BE UTF-16LE

     are IANA-registered "charset"s. See [RFC 2781] for details.
     Jungshik Shin reports that UTF-16 with a BOM is well

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     accepted by MS IE 5/6 and NS 4/6. Beware however that

     +   "UTF-16" support in any software you're going to be
         using/interoperating with has probably been less tested
         then "UTF-8" support

     +   "UTF-8" coded data seamlessly passes traditional command
         piping ("cat", "more", etc.) while "UTF-16" coded data
         is likely to cause confusion (with its zero bytes, for

     +   it is beyond the power of words to describe the way HTML
         browsers encode non-"ASCII" form data. To get a general
         impression, visit
         While encoding of form data has stabilized for "UTF-8"
         encoded pages (at least IE 5/6, NS 6, and Opera 6 behave
         consistently), be sure to expect fun (and cross-browser
         discrepancies) with "UTF-16" encoded pages!

     The rule of thumb is to use "UTF-8" unless you know what
     you're doing and unless you really benefit from using

       ISO-IR-165    [RFC1345]
       GB 12345
       GB 18030 (**)  (see links bellow)
       EUC-TW   (**)

     are totally valid encodings but not registered at IANA. The
     names under which they are listed here are probably the most
     widely-known names for these encodings and are recommended

       BIG5PLUS (**)

     is a proprietary name.

     Microsoft-related naming mess

     Microsoft products misuse the following names:

         Microsoft extension to "EUC-KR".

         Proper names: "CP949", "UHC", "x-windows-949" (as used
         by Mozilla).

         for details.

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         Encode aliases "KS_C_5601-1987" to "cp949" to reflect
         this common misusage. Raw "KS_C_5601-1987" encoding is
         available as "kcs5601-raw".

         See Encode::KR for details.

         Microsoft extension to "EUC-CN".

         Proper names: "CP936", "GBK".

         "GB2312" has been registered in the "EUC-CN" meaning at
         IANA. This has partially repaired the situation:
         Microsoft's "GB2312" has become a superset of the offi-
         cial "GB2312".

         Encode aliases "GB2312" to "euc-cn" in full agreement
         with IANA registration. "cp936" is supported separately.
         Raw "GB_2312-80" encoding is available as "gb2312-raw".

         See Encode::CN for details.

         Microsoft extension to "Big5".

         Proper name: "CP950".

         Encode separately supports "Big5" and "cp950".

         Microsoft's understanding of "Shift_JIS".

         JIS has not endorsed the full Microsoft standard how-
         ever. The official "Shift_JIS" includes only JIS X 0201
         and JIS X 0208 character sets, while Microsoft has
         always used "Shift_JIS" to encode a wider character
         repertoire. See "IANA" registration for "Windows-31J".

         As a historical predecessor, Microsoft's variant prob-
         ably has more rights for the name, though it may be
         objected that Microsoft shouldn't have used JIS as part
         of the name in the first place.

         Unambiguous name: "CP932". "IANA" name (also used by
         Mozilla, and provided as an alias by Encode):

         Encode separately supports "Shift_JIS" and "cp932".


     character repertoire
         A collection of unique characters.  A character set in

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         the strictest sense. At this stage, characters are not

     coded character set (CCS)
         A character set that is mapped in a way computers can
         use directly. Many character encodings, including EUC,
         fall in this category.

     character encoding scheme (CES)
         An algorithm to map a character set to a byte sequence.
         You don't have to be able to tell which character set a
         given byte sequence belongs.  7-bit ISO-2022 is a CES
         but it cannot be a CCS.  EUC is an example of being both
         a CCS and CES.

     charset (in MIME context)
         has long been used in the meaning of "encoding", CES.

         While the word combination "character set" has lost this
         meaning in MIME context since [RFC 2130], the "charset"
         abbreviation has retained it. This is how [RFC 2277] and
         [RFC 2278] bless "charset":

          This document uses the term "charset" to mean a set of rules for
          mapping from a sequence of octets to a sequence of characters, such
          as the combination of a coded character set and a character encoding
          scheme; this is also what is used as an identifier in MIME "charset="
          parameters, and registered in the IANA charset registry ...  (Note
          that this is NOT a term used by other standards bodies, such as ISO).
          [RFC 2277]

     EUC Extended Unix Character.  See ISO-2022.

         A CES that was carefully designed to coexist with ASCII.
         There are a 7 bit version and an 8 bit version.

         The 7 bit version switches character set via escape
         sequence so it cannot form a CCS.  Since this is more
         difficult to handle in programs than the 8 bit version,
         the 7 bit version is not very popular except for
         iso-2022-jp, the de facto standard CES for e-mails.

         The 8 bit version can form a CCS.  EUC and ISO-8859 are
         two examples thereof.  Pre-5.6 perl could use them as
         string literals.

     UCS Short for Universal Character Set.  When you say just
         UCS, it means Unicode.

         ISO/IEC 10646 encoding form: Universal Character Set

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         coded in two octets.

         A character set that aims to include all character
         repertoires of the world.  Many character sets in vari-
         ous national as well as industrial standards have
         become, in a way, just subsets of Unicode.

     UTF Short for Unicode Transformation Format.  Determines how
         to map a Unicode character into a byte sequence.

         A UTF in 16-bit encoding.  Can either be in big endian
         or little endian.  The big endian version is called
         UTF-16BE (equal to UCS-2 + surrogate support) and the
         little endian version is called UTF-16LE.

See Also

     Encode, Encode::Byte, Encode::CN, Encode::JP, Encode::KR,
     Encode::TW, Encode::EBCDIC, Encode::Symbol
     Encode::MIME::Header, Encode::Guess


         European Computer Manufacturers Association

         ECMA-035 (eq "ISO-2022")

             The specification of ISO-2022 is available from the
             link above.

         Internet Assigned Numbers Authority

         Assigned Charset Names by IANA

             Most of the "canonical names" in Encode derive from
             this list so you can directly apply the string you
             have extracted from MIME header of mails and web

     ISO International Organization for Standardization

     RFC Request For Comments -- need I say more?
         <http://www.rfc-editor.org/>, <http://www.rfc.net/>,

perl v5.8.8                2005-02-05                          14


     UC  Unicode Consortium <http://www.unicode.org/>

         Unicode Glossary

             The glossary of this document is based upon this

     Other Notable Sites


         Contains a lot of useful information, especially gory
         details of ISO vs. vendor mappings.


         Somewhat obsolete (last update in 1996), but still use-
         ful.  Also try


         You will find brief info on "EUC-CN", "GBK" and mostly
         on "GB 18030".

     Jungshik Shin's Hangul FAQ

         And especially its subject 8.


         A comprehensive overview of the Korean ("KS *") stan-

     debian.org: "Introduction to i18n"
         A brief description for most of the mentioned CJK encod-
         ings is contained in

     Offline sources

     "CJKV Information Processing" by Ken Lunde
         CJKV Information Processing 1999 O'Reilly & Associates,
         ISBN : 1-56592-224-7

         The modern successor of "CJK.inf".

         Features a comprehensive coverage of CJKV character sets
         and encodings along with many other issues faced by

perl v5.8.8                2005-02-05                          15


         anyone trying to better support CJKV languages/scripts
         in all the areas of information processing.

         To purchase this book, visit
         <http://www.oreilly.com/catalog/cjkvinfo/> or your
         favourite bookstore.

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