Kernel normal form, or KNF, is the
coding style used in the development of code for the
BSD
The Berkeley Software Distribution or Berkeley Standard Distribution (BSD) is a discontinued operating system based on Research Unix, developed and distributed by the Computer Systems Research Group (CSRG) at the University of California, Berk ...
operating systems. Based on the original KNF concept from the
Computer Systems Research Group
The Computer Systems Research Group (CSRG) was a research group at the University of California, Berkeley that was dedicated to enhancing AT&T Unix operating system and funded by Defense Advanced Research Projects Agency.
History
Professor Bo ...
, it dictates a
programming style
Programming style, also known as code style, is a set of rules or guidelines used when writing the source code for a computer program. It is often claimed that following a particular programming style will help programmers read and understand sour ...
to which contributed code should adhere prior to its inclusion into the
codebase
In software development, a codebase (or code base) is a collection of source code used to build a particular software system, application, or software component. Typically, a codebase includes only human-written source code files; thus, a codeb ...
. KNF started out as a codification of how
Ken Thompson
Kenneth Lane Thompson (born February 4, 1943) is an American pioneer of computer science. Thompson worked at Bell Labs for most of his career where he designed and implemented the original Unix operating system. He also invented the B programmi ...
and
Dennis Ritchie
Dennis MacAlistair Ritchie (September 9, 1941 – October 12, 2011) was an American computer scientist. He is most well-known for creating the C programming language and, with long-time colleague Ken Thompson, the Unix operating system and B p ...
formatted the original
UNIX
Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and ot ...
C source code. It describes such things as how to name variables, use indents and the use of
ANSI C
ANSI C, ISO C, and Standard C are successive standards for the C programming language published by the American National Standards Institute (ANSI) and ISO/IEC JTC 1/SC 22/WG 14 of the International Organization for Standardization (ISO) and the ...
or
K&R C
C (''pronounced like the letter c'') is a general-purpose computer programming language. It was created in the 1970s by Dennis Ritchie, and remains very widely used and influential. By design, C's features cleanly reflect the capabilities o ...
code styles. Each BSD variant has its own KNF rules, which have evolved over time to differ from each other in small ways.
The SunOS kernel and userland also uses a similar indentation style that was derived from AT&T style documents and that is sometimes known as Bill Joy Normal Form. The correctness of the indentation of a list of source files can be verified by a style checker program written by Bill Shannon. This style checker program is called cstyle.
See also
*
Programming style
Programming style, also known as code style, is a set of rules or guidelines used when writing the source code for a computer program. It is often claimed that following a particular programming style will help programmers read and understand sour ...
*
Indent style
In computer programming, an indentation style is a convention governing the indentation of blocks of code to convey program structure. This article largely addresses the free-form languages, such as C and its descendants, but can be (and often ...
References
External links
*
*
Berkeley Software Distribution
Source code
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