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(16 code points)
|Assigned||5 code points|
|Unused||9 reserved code points |
|Unicode version history|
Specials is a short Unicode block allocated at the very end of the Basic Multilingual Plane, at U+FFF0–FFFF. Of these 16 code points, five are assigned as of Unicode 12.0:
Unicode is a computing industry standard for the consistent encoding, representation, and handling of text expressed in most of the world's writing systems. The standard is maintained by the Unicode Consortium, and as of May 2019 the most recent version, Unicode 12.1, contains a repertoire of 137,994 characters covering 150 modern and historic scripts, as well as multiple symbol sets and emoji. The character repertoire of the Unicode Standard is synchronized with ISO/IEC 10646, and both are code-for-code identical.
In linguistics and pedagogy, an interlinear gloss is a gloss placed between lines, such as between a line of original text and its translation into another language. When glossed, each line of the original text acquires one or more lines of transcription known as an interlinear text or interlinear glossed text (IGT)—interlinear for short. Such glosses help the reader follow the relationship between the source text and its translation, and the structure of the original language. In its simplest form, an interlinear gloss is simply a literal, word-for-word translation of the source text.
In computing, a compound document is a document type typically produced using word processing software, and is a regular text document intermingled with non-text elements such as spreadsheets, pictures, digital videos, digital audio, and other multimedia features. It can also be used to collect several documents into one.
FFFE and FFFF are not unassigned in the usual sense, but guaranteed not to be Unicode characters at all. They can be used to guess a text's encoding scheme, since any text containing these is by definition not a correctly encoded Unicode text. Unicode's U+FEFF BYTE ORDER MARK character can be inserted at the beginning of a Unicode text to signal its endianness: a program reading such a text and encountering 0xFFFE would then know that it should switch the byte order for all the following characters.
In computing, endianness refers to the order of bytes within a binary representation of a number. It can also be used more generally to refer to the internal ordering of any representation, such as the digits in a numeral system or the sections of a date.
The replacement character � (often a black diamond with a white question mark or an empty square box) is a symbol found in the Unicode standard at code point U+FFFD in the Specials table. It is used to indicate problems when a system is unable to render a stream of data to a correct symbol. It is usually seen when the data is invalid and does not match any character:
Consider a text file containing the German word "für" in the ISO-8859-1 encoding (
0x66 0xFC 0x72). This file is now opened with a text editor that assumes the input is UTF-8. The first and last byte are valid UTF-8 encodings of ASCII, but the middle byte (
0xFC) is not a valid byte in UTF-8. Therefore, a text editor could replace this byte with the replacement character symbol to produce a valid string of Unicode code points. The whole string now displays like this: "f�r".
A text file is a kind of computer file that is structured as a sequence of lines of electronic text. A text file exists stored as data within a computer file system. In operating systems such as CP/M and MS-DOS, where the operating system does not keep track of the file size in bytes, the end of a text file is denoted by placing one or more special characters, known as an end-of-file marker, as padding after the last line in a text file. On modern operating systems such as Microsoft Windows and Unix-like systems, text files do not contain any special EOF character, because file systems on those operating systems keep track of the file size in bytes. There are for most text files a need to have end-of-line delimiters, which are done in a few different ways depending on operating system. Some operating systems with record-orientated file systems may not use new line delimiters and will primarily store text files with lines separated as fixed or variable length records.
UTF-8 is a variable width character encoding capable of encoding all 1,112,064 valid code points in Unicode using one to four 8-bit bytes. The encoding is defined by the Unicode Standard, and was originally designed by Ken Thompson and Rob Pike. The name is derived from UnicodeTransformation Format – 8-bit.
In character encoding terminology, a code point or code position is any of the numerical values that make up the code space. Many code points represent single characters but they can also have other meanings, such as for formatting.
A poorly implemented text editor might save the replacement in UTF-8 form; the text file data will then look like this:
0x66 0xEF 0xBF 0xBD 0x72, which will be displayed in ISO-8859-1 as "fï¿½r" (see mojibake). Since the replacement is the same for all errors this makes it impossible to recover the original character. A better (but harder to implement) design is to preserve the original bytes, including the error, and only convert to the replacement when displaying the text. This will allow the text editor to save the original byte sequence, while still showing the error indicator to the user.
Mojibake is the garbled text that is the result of text being decoded using an unintended character encoding. The result is a systematic replacement of symbols with completely unrelated ones, often from a different writing system.
It has become increasingly common[ when? ] for software to interpret invalid UTF-8 by guessing the bytes are in another byte-based encoding such as ISO-8859-1. This allows correct display of both valid and invalid UTF-8 pasted together. If a web page uses ISO-8859-1 (or Windows-1252) but specifies the encoding as UTF-8, most web browsers used to display all non-ASCII characters as �, but newer browsers[ when? ] translate the erroneous bytes individually to characters in Windows-1252, so the replacement character is less frequently seen.
| Specials    |
Official Unicode Consortium code chart (PDF)
The following Unicode-related documents record the purpose and process of defining specific characters in the Specials block:
|Version||Final code points||Count||UTC ID||L2 ID||WG2 ID||Document|
|1.0.0||U+FFFD||1||(to be determined)|
|U+FFFE..FFFF||2||(to be determined)|
|L2/01-295R||Moore, Lisa (2001-11-06), "Motion 88-M2", Minutes from the UTC/L2 meeting #88|
|L2/01-355||N2369 (html, doc)||Davis, Mark (2001-09-26), Request to allow FFFF, FFFE in UTF-8 in the text of ISO/IEC 10646|
|L2/02-154||N2403||Umamaheswaran, V. S. (2002-04-22), "9.3 Allowing FFFF and FFFE in UTF-8", Draft minutes of WG 2 meeting 41, Hotel Phoenix, Singapore, 2001-10-15/19|
|2.1||U+FFFC||1||UTC/1995-056||Sargent, Murray (1995-12-06), Recommendation to encode a WCH_EMBEDDING character|
|UTC/1996-002||Aliprand, Joan; Hart, Edwin; Greenfield, Steve (1996-03-05), "Embedded Objects", UTC #67 Minutes|
|N1365||Sargent, Murray (1996-03-18), Proposal Summary - Object Replacement Character|
|N1353||Umamaheswaran, V. S.; Ksar, Mike (1996-06-25), "8.14", Draft minutes of WG2 Copenhagen Meeting # 30|
|L2/97-288||N1603||Umamaheswaran, V. S. (1997-10-24), "7.3", Unconfirmed Meeting Minutes, WG 2 Meeting # 33, Heraklion, Crete, Greece, 20 June - 4 July 1997|
|L2/98-004R||N1681||Text of ISO 10646 - AMD 18 for PDAM registration and FPDAM ballot, 1997-12-22|
|L2/98-070||Aliprand, Joan; Winkler, Arnold, "Additional comments regarding 2.1", Minutes of the joint UTC and L2 meeting from the meeting in Cupertino, February 25-27, 1998|
|L2/98-318||N1894||Revised text of 10646-1/FPDAM 18, AMENDMENT 18: Symbols and Others, 1998-10-22|
|3.0||U+FFF9..FFFB||3||L2/97-255R||Aliprand, Joan (1997-12-03), "3.D Proposal for In-Line Notation (ruby)", Approved Minutes - UTC #73 & L2 #170 joint meeting, Palo Alto, CA - August 4-5, 1997|
|L2/98-055||Freytag, Asmus (1998-02-22), Support for Implementing Inline and Interlinear Annotations|
|L2/98-070||Aliprand, Joan; Winkler, Arnold, "3.C.5. Support for implementing inline and interlinear annotations", Minutes of the joint UTC and L2 meeting from the meeting in Cupertino, February 25-27, 1998|
|L2/98-099||N1727||Freytag, Asmus (1998-03-18), Support for Implementing Interlinear Annotations as used in East Asian Typography|
|L2/98-158||Aliprand, Joan; Winkler, Arnold (1998-05-26), "Inline and Interlinear Annotations", Draft Minutes - UTC #76 & NCITS Subgroup L2 #173 joint meeting, Tredyffrin, Pennsylvania, April 20-22, 1998|
|L2/98-286||N1703||Umamaheswaran, V. S.; Ksar, Mike (1998-07-02), "8.14", Unconfirmed Meeting Minutes, WG 2 Meeting #34, Redmond, WA, USA; 1998-03-16--20|
|L2/98-270||Hiura, Hideki; Kobayashi, Tatsuo (1998-07-29), Suggestion to the inline and interlinear annotation proposal|
|L2/98-281R (pdf, html)||Aliprand, Joan (1998-07-31), "In-Line and Interlinear Annotation (III.C.1.c)", Unconfirmed Minutes - UTC #77 & NCITS Subgroup L2 # 174 JOINT MEETING, Redmond, WA -- July 29-31, 1998|
|L2/98-363||N1861||Sato, T. K. (1998-09-01), Ruby markers|
|L2/98-372||N1884R2 (pdf, doc)||Whistler, Ken; et al. (1998-09-22), Additional Characters for the UCS|
|L2/98-416||N1882.zip||Support for Implementing Interlinear Annotations, 1998-09-23|
|L2/98-329||N1920||Combined PDAM registration and consideration ballot on WD for ISO/IEC 10646-1/Amd. 30, AMENDMENT 30: Additional Latin and other characters, 1998-10-28|
|L2/98-421R||Suignard, Michel; Hiura, Hideki (1998-12-04), Notes concerning the PDAM 30 interlinear annotation characters|
|L2/99-010||N1903 (pdf, html, doc)||Umamaheswaran, V. S. (1998-12-30), "8.2.15", Minutes of WG 2 meeting 35, London, U.K.; 1998-09-21--25|
|L2/98-419 (pdf, doc)||Aliprand, Joan (1999-02-05), "Interlinear Annotation Characters", Approved Minutes -- UTC #78 & NCITS Subgroup L2 # 175 Joint Meeting, San Jose, CA -- December 1-4, 1998|
|UTC/1999-021||Duerst, Martin; Bosak, Jon (1999-06-08), W3C XML CG statement on annotation characters|
|L2/99-176R||Moore, Lisa (1999-11-04), "W3C Liaison Statement on Annotation Characters", Minutes from the joint UTC/L2 meeting in Seattle, June 8-10, 1999|
|L2/01-301||Whistler, Ken (2001-08-01), "E. Indicated as "strongly discouraged" for plain text interchange", Analysis of Character Deprecation in the Unicode Standard|
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