Editing Carriage return (section)

==Computers==

In [[computing]], the carriage return is one of the [[control characters]] in [[ASCII|ASCII code]], [[Unicode]], [[EBCDIC]], and many other codes. It commands a [[computer printer|printer]], or other output system such as the display of a [[system console]], to move the position of the [[cursor (computers)|cursor]] to the first position on the same line. It was mostly used along with [[line feed]] (LF), a move to the next line, so that together they start a new line. Together, this sequence can be referred to as '''CRLF'''.<ref>{{cite web|url=https://developer.mozilla.org/en-US/docs/Glossary/CRLF|title=CRLF|website=[[MDN Web Docs]]|archive-url=https://web.archive.org/web/20240304190635/https://developer.mozilla.org/en-US/docs/Glossary/CRLF|archive-date=2024-03-04|access-date=2024-03-04|url-status=live}}</ref>

The carriage return and line feed functions were split for practical reasons:

* Carriage return by itself provided the ability to overprint the line with new text. This could be used to produce bold or accented characters, underscores, struck-out text, and some composite symbols.
* Early mechanical printers were too slow to return the carriage in the time it took to process one character.{{why|date=January 2022}} Therefore, the time spent sending the line feed was not wasted (often several more characters had to be sent to ensure the carriage return had happened before sending a printing character). This is why the carriage return was always sent first.
* It was then also possible to fit multiple line feed operations into the time taken for a single carriage return—for example for printing doublespaced text, headers/footers or title pages—to save print and transmission time without the need for additional circuitry or mechanical complexity to "filter out" spurious additional CR signals.

As early as 1901, [[Baudot code]] contained separate carriage return and line feed characters.

Many computer programs use the carriage return character, alone or with a line feed, to signal the end of a line of text, but other characters are also used for this function (see [[newline]]); others use it only for a [[paragraph break]] (a "hard return"). Some standards which introduce their own representations for line and paragraph control (for example [[HTML]]) and many programming languages treat carriage return and line feed as [[Whitespace (computer science)|whitespace]].

In both ASCII and Unicode, the carriage return is assigned [[code point]] 13 (or 0D in [[hexadecimal]]); it may also be seen as control+M or {{mono|^M}}. In character and string constants in the [[C (programming language)|C programming language]] and in many other languages (including representations of [[regular expression]]s<ref>{{cite web|url=https://www.jetbrains.com/help/objc/regular-expression-syntax-reference.html#regex-syntax-reference|title=Regular expression syntax reference|publisher=[[JetBrains]]|archive-url=https://web.archive.org/web/20231003183817/https://www.jetbrains.com/help/objc/regular-expression-syntax-reference.html#regex-syntax-reference|archive-date=2023-10-03|access-date=2024-03-04|url-status=live}}</ref><ref>{{cite web|url=https://www.regular-expressions.info/quickstart.html|title=Regular Expressions Quick Start|author=Jan Goyvaerts|website=regular-expressions.info|archive-url=https://web.archive.org/web/20240221173001/https://www.regular-expressions.info/quickstart.html|archive-date=2024-02-21|access-date=2024-03-04|url-status=live}}</ref>) influenced by C, <code>\r</code> denotes this character.<ref>{{cite book |author=Eric S. Roberts |title=The Art and Science of C |publisher=[[Addison-Wesley]] |date=1995 |page=311}}</ref>