Unicode control characters: Difference between revisions

Revision as of 14:36, 20 December 2020

Revision as of 14:38, 20 December 2020

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Many '''[[Unicode]] control characters''' are used to control the interpretation or display of text, but these characters themselves have no visual or spatial representation. For example, the [[null character]] ({{unichar|0000|NULL|nlink=control characters}}) is used in C-programming application environments to indicate the end of a string of characters. In this way, these programs only require a single starting memory address for a string (as opposed to a starting address and a length), since the string ends once the program reads the null character.

In the narrowest sense, a control character is one with the [[Unicode character property#General Category|general category]] {{code|Cc}}, which comprises the [[C0 and C1 control codes]], a concept defined in [[ISO/IEC 2022]] and inherited by Unicode, with the most common set being defined in [[ISO/IEC 6429]]. In a broader sense, other non-printing format characters, such as those used in [[bidirectional text]], are also referred to as control characters.;<ref>{{cite web |url=http://kvota.net/guadec/localised-desktop-talk/ |title=Towards a localised desktop |quotation=For some cases where automatic decision making doesn't work, you can manually add specific direction markers by right-clicking the text field, choosing "Insert Unicode control character" from the menu, and selecting appropriate direction mark. This would allow you, for instance, to start your RTL text with an otherwise LTR word (such as "GNOME"). |first=Danilo |last=Segan}}</ref> these are mostly assigned to the general category {{code|Cf}} (format), used for format effectors introduced and defined by Unicode itself.

== Category "Cc" control codes (C0 and C1) ==