|Original author(s)||Stephen C. Johnson|
|Developer(s)||AT&T Bell Laboratories|
|Initial release||July 26, 1978|
|Type||Static program analysis tools|
|License||Originally proprietary commercial software, now free software under a BSD-like license|
Lint, or a linter, is a static code analysis tool used to flag programming errors, bugs, stylistic errors and suspicious constructs. The term originates from a Unix utility that examined C language source code.
Stephen C. Johnson, a computer scientist at Bell Labs, came up with lint in 1978 while debugging the yacc grammar he was writing for C and dealing with portability issues stemming from porting Unix to a 32-bit machine. The term "lint" was derived from lint, the name for the tiny bits of fiber and fluff shed by clothing, as the command should act like the lint trap in a clothes dryer, detecting small errors to great effect. In 1979, lint was used outside of Bell Labs for the first time, in the seventh version (V7) of Unix.
Over the years, different versions of lint have been developed for many C and C++ compilers, and while modern-day compilers have lint-like functions, lint-like tools have also advanced their capabilities. For example, Gimpel's PC-Lint, introduced in 1985 and used to analyze C++ source code, is still for sale.
The analysis performed by lint-like tools can also be performed by an optimizing compiler, which aims to generate faster code. In his original 1978 paper, Johnson addressed this issue, concluding that "the general notion of having two programs is a good one" because they concentrate on different things, thereby allowing the programmer to "concentrate at one stage of the programming process solely on the algorithms, data structures, and correctness of the program, and then later retrofit, with the aid of lint, the desirable properties of universality and portability".
Even though modern compilers have evolved to include many of lint's historical functions, lint-like tools have also evolved to detect an even wider variety of suspicious constructs. These include "warnings about syntax errors, uses of undeclared variables, calls to deprecated functions, spacing and formatting conventions, misuse of scope, implicit fallthrough in switch statements, missing license headers, [and]...dangerous language features".
Lint-like tools have also been developed for other aspects of language, including grammar and style guides.
Fortran compilers using space-squeezing techniques[a] (e.g. IBM 1130) made it impossible for the compiler to see the problem with lines like:
- .... DO 120 J=1.256 ... 120 CONTINUE
which is why programs like Lint for Fortran can be helpful.
- ^ Software: reads the source statements into memory, discards comment lines, removes spaces except in text literals, concatenates continuation lines
- ^ a b c d Johnson, Stephen C. (25 October 1978). "Lint, a C Program Checker". Comp. Sci. Tech. Rep. Bell Labs: 78–1273. CiteSeerX 10.1.1.56.1841. Archived from the original on 2022-01-12.
- ^ "UNIX is free!". lemis.com. 2002-01-24.
- ^ Broderick, Bill (January 23, 2002). "Dear Unix enthusiasts" (PDF). Caldera International. Archived from the original (PDF) on February 19, 2009.
- ^ "About SublimeLinter". The SublimeLinter Community, revision 1cecc79c. Retrieved 2020-03-29.
- ^ a b Morris, Richard (1 October 2009). "Stephen Curtis Johnson: Geek of the Week". Red Gate Software. Retrieved 19 January 2018.
- ^ "Arcanist User Guide: Lint". Phabricator. Retrieved 19 January 2018.
- ^ Jones, Nigel (1 May 2002). "How to Use Lint for Static Code Analysis". Barr Group.
- ^ Lint for Fortran: Denis W. Haskin (May 2, 1988). "Shaking down your FORTRAN programs". Digital Review. pp. 41–47.
similar to DEC's Source Code Analyzer, .. comes into play much earlier .. before users compile their programs
- ^ "COMP-FORTRAN-90 Archives".
Fortran90-lint, for Fortran 90 program analysis, also other tools, from www.cleanscape.net
- ^ "Chapter 2. Basic Debugger Usage".
There is a public domain version of lint for FORTRAN 77 called ftnchek
- Darwin, Ian F. (1991). Checking C Programs with Lint: C Programming Utility (Revised ed.). United States: O'Reilly Media. ISBN 978-0937175309.
- "LINT(1)". FreeBSD General Commands Manual (FreeBSD 11.2). 2015-03-23.