Flycheck is a modern on-the-fly syntax checking extension for GNU Emacs 24, intended as replacement for the older Flymake extension which is part of GNU Emacs.
It uses various syntax checking and linting tools to check the contents of buffers, and reports warnings and errors directly in the buffer or in an optional error list (see Flycheck manual for more information):
Out of the box Flycheck supports over 40 different programming languages with more than 80 different syntax checking tools, and comes with a simple interface to define new syntax checkers.
Many 3rd party extensions provide new syntax checkers and other features like alternative error displays or mode line indicators.
Installation
Flycheck needs GNU Emacs 24 on a Unix system, and additionally external syntax checking programs for the languages you use. See Supported Languages for more information.
Flycheck does not officially support Windows, but tries to maintain Windows compatibility and should generally work fine on Windows, too. However, we can neither answer questions about Windows nor fix bugs that only occur on Windows without the help of active Windows users. Please watch out for known Windows issues!
Install Flycheck from MELPA (development snapshots) or MELPA Stable (releases) with:
M-x package-install RET flycheck
Then add the following to your init file:
(add-hook 'after-init-hook #'global-flycheck-mode)
If you don’t know where your init file is, look at the value of the variable
user-init-file with C-h v user-init-file.
See Installation for more information, and Quick start for a quick tour through Flycheck’s setup and major features.
Support & Contribution
Please ask questions about Flycheck on Stack Exchange or in our Gitter chat. We try to answer all questions as fast and as precise as possible.
To report problems or bugs, please use our issue tracker. Our contribution guidelines help you to create good bug reports; please take a look.
We welcome patches and pull requests that fix bugs or provide new features. Please read our Contribution guidelines for help and guidelines before submitting pull requests. When making larger changes to Flycheck or implementing new features we recommend that you first open a separate issue or ask in our Gitter channel to discuss you intended changes.
All contributors and all participants in our communication channels are expected to follow our Code of Conduct.
License
Flycheck is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.
Flycheck is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.
You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.
See COPYING for details.
The Flycheck documenation is free documentation: you can copy, distribute and/or modify it under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is available at https://github.com/flycheck/flycheck/blob/master/doc/fdl.txt.
Alternatively, you may copy, distribute and/or modify the Flycheck documentation under the terms of the Creative Commons Attribution-ShareAlike 4.0 International Public License. A copy of the license can be obtained at https://creativecommons.org/licenses/by-sa/4.0/legalcode.
Permission is granted to copy, distribute and/or modify the Flycheck logo in
/flycheck.svg under the terms of the Creative Commons Attribution-ShareAlike
4.0 International Public License. A copy of the license can be obtained at
https://creativecommons.org/licenses/by-sa/4.0/legalcode.