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Specials is a short Unicode
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
Unicode
10.0:

U+FFF9 INTERLINEAR ANNOTATION ANCHOR, marks start of annotated text U+FFFA INTERLINEAR ANNOTATION SEPARATOR, marks start of annotating character(s) U+FFFB INTERLINEAR ANNOTATION TERMINATOR, marks end of annotation block U+FFFC  OBJECT REPLACEMENT CHARACTER, placeholder in the text for another unspecified object, for example in a compound document. U+FFFD � REPLACEMENT CHARACTER used to replace an unknown, unrecognized or unrepresentable character U+FFFE <noncharacter-FFFE> not a character. U+FFFF <noncharacter-FFFF> not a character.

FFFE and FFFF are not unassigned in the usual sense, but guaranteed not to be a Unicode
Unicode
character 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
Unicode
text. Unicode's U+FEFF Byte order mark character can be inserted at the beginning of a Unicode
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.

Contents

1 Replacement character 2 Unicode
Unicode
chart 3 History 4 See also 5 References 6 External links

Replacement character[edit]

Replacement character

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 codepoint 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
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
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
Unicode
code points. The whole string now displays like this: "f�r". 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
ISO-8859-1
as "f�r" (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. It has become increasingly common for software to interpret invalid UTF-8
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
UTF-8
pasted together. If a web page uses ISO-8859-1
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 translate the erroneous bytes individually to characters in Windows-1252, so the replacement character is less frequently seen. Unicode
Unicode
chart[edit]

Specials[1][2][3] Official Unicode
Unicode
Consortium code chart (PDF)

  0 1 2 3 4 5 6 7 8 9 A B C D E F

U+FFFx

 IA  A  IA  S  IA  T  OBJ  �

Notes

1.^ As of Unicode
Unicode
version 10.0 2.^ Grey areas indicate non-assigned code points 3.^ Black areas indicate noncharacters - Unicode
Unicode
will never use these codepoints for encoding characters

History[edit] The following Unicode-related documents record the purpose and process of defining specific characters in the Specials block:

Version Final code points[a] Count UTC ID L2 ID WG2 ID Document

1.0.0 U+FFFD 1

(to be determined)

2.1 U+FFFC 1

(to be determined)

3.0 U+FFF9..FFFB 3

L2/98-055

Freytag, Asmus (1998-02-22), Support for Implementing Inline and Interlinear Annotations 

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 

L2/98-270

Hiura, Hideki; Kobayashi, Tatsuo (1998-07-29), Suggestion to the inline and interlinear annotation proposal 

L2/98-281R

Aliprand, Joan (1998-07-31), "In-Line and Interlinear Annotation", 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 

L2/98-416 N1882 Support for Implementing Interlinear Annotations, 1998-09-23 

L2/98-312

Whistler, Ken (1998-09-29), "8", Resolutions from SC2/WG2 meeting in London with comments from Ken Whistler 

L2/98-421R

Suignard, Michel; Hiura, Hideki (1998-12-04), Notes concerning the PDAM 30 interlinear annotation characters 

L2/98-419

Aliprand, Joan (1999-02-05), "nterlinear 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 

L2/01-301

Whistler, Ken (2001-08-01), "E. Indicated as "strongly discouraged" for plain text interchange", Analysis of Character Deprecation in the Unicode
Unicode
Standard 

^ Proposed code points and characters names may differ from final code points and names

See also[edit]

Unicode
Unicode
control characters UTF-8 Mojibake

References[edit]

^ " Unicode
Unicode
character database". The Unicode
Unicode
Standard. Retrieved 2016-07-09.  ^ "Enumerated Versions of The Unicode
Unicode
Standard". The Unicode
Unicode
Standard. Retrieved 2016-07-09. 

External links[edit]

Unicode's Specials table Decodeunicode's entry for the replacement character

v t e

Unicode

Unicode

Unicode
Unicode
Consortium ISO/IEC 10646 (Universal Character Set) Versions

Code points

Blocks Universal Character Set Character charts Character property Planes Private Use Areas

Characters

Special
Special
purpose

BOM Combining Grapheme Joiner Left-to-right mark / Right-to-left mark Soft hyphen Word joiner Zero-width joiner Zero-width non-joiner Zero-width space

Lists

Characters CJK Unified Ideographs Combining character Duplicate characters Numerals Scripts Spaces Symbols Halfwidth and fullwidth

Processing

Algorithms

Bi-directional text Collation

ISO 14651

Equivalence Variation sequences International Ideographs Core

Comparison

BOCU-1 CESU-8 Punycode SCSU UTF-1 UTF-7 UTF-8 UTF-9/UTF-18 UTF-16/UCS-2 UTF-32/UCS-4 UTF-EBCDIC

On pairs of code points

Combining character Compatibility characters Duplicate characters Equivalence Homoglyph Precomposed character

list

Z-variant Variation sequences Regional Indicator Symbol Fitzpatrick modifiers

Usage

Domain names (IDN) Email Fonts HTML

entity references numeric references

Input International Ideographs Core

Related standards

Common Locale Data Repository (CLDR) GB 18030 ISO/IEC 8859 ISO 15924

Related topics

Anomalies ConScript Unicode
Unicode
Registry Ideographic Rapporteur Group International Components for Unicode People involved with Unicode Han unification

Scripts and symbols in Unicode

Common and inherited scripts

Combining marks Diacritics Punctuation Space Numbers

Modern scripts

Adlam Arabic

diacritics

Armenian Balinese Bamum Batak Bengali Bopomofo Braille Buhid Burmese Canadian Aboriginal Chakma Cham Cherokee CJK Unified Ideographs
CJK Unified Ideographs
(Han) Cyrillic Deseret Devanagari Ge'ez Georgian Greek Gujarati Gurmukhī Hangul Hanja Hanunó'o Hebrew

diacritics

Hiragana Javanese Kanji Kannada Katakana Kayah Li Khmer Lao Latin Lepcha Limbu Lisu (Fraser) Lontara Malayalam Masaram Gondi Mende Kikakui Miao (Pollard) Mongolian Mro N'Ko New Tai Lue Newa Nushu Ol Chiki Oriya Osage Osmanya Pahawh Hmong Pau Cin Hau Rejang Samaritan Saurashtra Shavian Sinhala Sorang Sompeng Sundanese Sylheti Nagari Syriac Tagbanwa Tai Le Tai Tham Tai Viet Tamil Telugu Thaana Thai Tibetan Tifinagh Tirhuta Vai Warang Citi Yi

Ancient and historic scripts

Ahom Anatolian hieroglyphs Ancient North Arabian Avestan Bassa Vah Bhaiksuki Brāhmī Carian Caucasian Albanian Coptic Cuneiform Cypriot Egyptian hieroglyphs Elbasan Glagolitic Gothic Grantha Hatran Imperial Aramaic Inscriptional Pahlavi Inscriptional Parthian Kaithi Kharosthi Khojki Khudawadi Linear A Linear B Lycian Lydian Mahajani Mandaic Manichaean Marchen Meetei Mayek Meroitic Modi Multani Nabataean Ogham Old Hungarian Old Italic Old Permic Old Persian cuneiform Old Turkic Palmyrene 'Phags-pa Phoenician Psalter Pahlavi Runic Śāradā Siddham South Arabian Soyombo Tagalog (Baybayin) Takri Tangut Ugaritic Zanabazar Square

Notational scripts

Duployan SignWriting

Symbols

Cultural, political, and religious symbols Currency Mathematical operators and symbols Phonetic symbols (in

.