GNU cflow

GNU cflow analyzes a collection of C source files and prints a graph, charting control flow within the program.

GNU cflow is able to produce both direct and inverted flowgraphs for C sources. Optionally a cross-reference listing can be generated. Two output formats are implemented: POSIX and GNU (extended).

The package also provides Emacs major mode for examining the produced flowcharts in Emacs.

A sample of a direct flowchart is available online.


Cflow can be found on the main GNU ftp server (download Cflow via HTTPSdownload Cflow via HTTP or download Cflow via FTP), and its mirrors; please use a mirror if possible.


Documentation for Cflow is online, as is documentation for most GNU software. It can also be accessed by running info cflow or man cflow, or by looking at /usr/share/doc/cflow/, or similar directories on your system. A brief summary is available by running cflow --help.

Mailing lists

Cflow has the following mailing lists:

Announcements about Cflow and most other GNU software are made on the info-gnu mailing list (archives).

Security reports that should not be made immediately public can be sent directly to the maintainer. If there is no response to an urgent issue, you can escalate to the general security mailing list for advice.

Getting involved

Development of Cflow, and GNU in general, is a volunteer effort, and you can contribute. For information, please read How to help GNU. If you'd like to get involved, it's a good idea to join the discussion mailing list (see above).

Development tools
For development sources, issue trackers, and other information, please see the Cflow project page at
Trying the latest test release (when available) is always appreciated. Test releases can be found on the GNU “alpha” server (HTTPSHTTPFTP) and its mirrors.
To translate the program messages into other languages, please refer to the Translation Project page for Cflow. New translations or updates to the existing strings will not be incorporated into Cflow if they are sent elsewhere. For more information, see the Translation Project home page.
Cflow is currently maintained by Sergey Poznyakoff. Please use the mailing lists for contact.


Cflow 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.