Unicode control characters

Many <a href="/facts/Unicode/DDu3MfPV">Unicode</a> characters are used to control the interpretation or display of text, but these characters themselves have no visual or spatial representation. For example, the <a href="/facts/Null_character/IMYNHNxR">null character</a> (U+0000 <a href="/facts/Control_characters/jkWgHvfC">NULL</a>) 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 <a href="/facts/String_(computer_science)/4ChJu5WS">string</a> (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 code is a character with the <a href="/facts/Unicode_character_property/bIHntH9z">general category</a> Cc, which comprises the <a href="/facts/C0_and_C1_control_codes/bBp1dGVl">C0 and C1 control codes</a>, a concept defined in <a href="/facts/ISO%2fIEC_2022/3vbwU2Bx">ISO/IEC 2022</a> and inherited by Unicode, with the most common set being defined in <a href="/facts/ISO%2fIEC_6429/29l9Yalv">ISO/IEC 6429</a>. Control codes are handled distinctly from ordinary Unicode characters, for example, by not being assigned character names (although they are assigned normative formal aliases). In a broader sense, other non-printing format characters, such as those used in <a href="/facts/Bidirectional_text/7xafVLBG">bidirectional text</a>, are also referred to as control characters by software; these are mostly assigned to the general category Cf (format), used for format effectors introduced and defined by Unicode itself.

Unicode control characters open-in-new

Unicode control characters