Free software programmed in C

dvdisaster is a computer program aimed to enhance data survivability on optical discs by creating error detection and correction data, which is used for data recovery. dvdisaster works exclusively at the image level. This program can be used either to generate Error-Correcting Code (ECC) data from an existing media or to augment an ISO image with ECC data prior to being written onto a medium. dvdisaster is free software available under the GNU General Public License.

routing software

PortAudio is an open-source computer library for audio playback and recording. It is a cross-platform library, so programs using it can run on many different computer operating systems, including Windows, Mac OS X and Linux. PortAudio supports Core Audio, ALSA, and MME, DirectSound, ASIO and WASAPI on Windows. Like other libraries whose primary goal is portability, PortAudio is written in the C programming language. It has also been implemented in the languages PureBasic and Lazarus/Free Pascal. PortAudio is based on a callback paradigm, similar to JACK and ASIO.

fractal-generating computer program

MP3Gain is an audio normalization software tool. The tool is available on multiple platforms and is free software. It analyzes the MP3 and reversibly changes its volume. The volume can be adjusted for single files or as album where all files would have the same perceived loudness. It is an implementation of ReplayGain. In 2015 Debian and Ubuntu removed it from their repositories due to a lack of an active maintainer.

NEdit, the Nirvana editor, is a text editor and source code editor for the X Window System. It has an interface similar to text editors on Microsoft Windows and Macintosh, rather than to older UNIX editors like Emacs. It was initially developed by Mark Edel for Fermilab and released under a restrictive licence, but later relicenced under the GPL-2.0-or-later (plus Motif clause) and became an independent open-source project maintained by a team of developers. Nedit was also distributed with the IRIX operating system.

Powerful text editor for MATE

minimalist web browser based on WebKit/GTK+

XPilot is a multiplayer video game. It is open source and runs on many platforms. Although its 2D graphics have improved over time, they still resemble the style of Thrust. Gameplay includes Capture the Flag, base defense, racing and deathmatches. XPilot uses a client–server architecture, in which a central metaserver receives information from all XPilot servers on the Internet.

uWSGI is an open source software application that "aims at developing a full stack for building hosting services". It is named after the Web Server Gateway Interface (WSGI), which was the first plugin supported by the project. uWSGI is maintained by the Italian-based software company unbit.

Xdelta is a command line tool for delta encoding, which stores or transmits the difference (deltas) between sequential data, instead of entire files. This is similar to diff and patch, except diff computes and shows the difference between two complete files, while patch is primarily designed for human-readable text files; Xdelta is designed for binary files and does not generate human readable output.

driver framework by Microsoft

web server

Ngspice is an open-source mixed-level/mixed-signal electronic circuit simulator. It is a successor of the latest stable release of Berkeley SPICE, version 3f.5, which was released in 1993. A small group of maintainers and the user community contribute to the ngspice project by providing new features, enhancements and bug fixes.

optical character recognition software

software tool

Guvcview (GTK+ UVC Viewer) is a webcam application, i.e. software to handle UVC streams, for the Linux desktop, started by Paulo Assis in 2008. The application is written in C and is free and open-source software released under GPL-2.0-or-later.

eSpeak is a free and open-source, cross-platform, compact, software speech synthesizer. It uses a formant synthesis method, providing many languages in a relatively small file size. eSpeakNG (Next Generation) is a continuation of the original developer's project with more feedback from native speakers.

IPPOLIT is an open-source chess program released by authors using pseudonyms, Yakov Petrovich Golyadkin, Igor Igorovich Igoronov, Roberto Pescatore, Yusuf Ralf Weisskopf, Ivan Skavinsky Skavar, and Decembrists.

monitoring application

suite of programs and libraries originally written by the German physics and mathematics professor Helmut Dersch

Mitro was a password manager for individuals and teams that securely saved users' logins, and allowed users to log in and share access.

HomeBank is a personal accounting software package that runs on BSD Unix, Linux, Windows, macOS (via MacPorts or Homebrew) and AmigaOS.

text editor

program for quickly and interactively computing with real and complex numbers and matrices, or intervals

Textadept is a free software minimalist text editor designed for computer programming. Distributed under the MIT license, it is written in C, C++ and Lua and is extensible using Lua. Textadept can use either a graphical user interface or a text-based user interface when running in a terminal window. Textadept uses the Scintilla editing component. Textadept's developer makes the curses wrapper library for Scintilla used by Textadept available separately.

free and open-source software suite for electronic design automation

The Router Advertisement Daemon (radvd) is an open-source software product that implements link-local advertisements of IPv6 router addresses and IPv6 routing prefixes using the Neighbor Discovery Protocol (NDP) as specified in .

AOLserver is AOL's open source web server. AOLserver is multithreaded, Tcl-enabled, and used for large scale, dynamic web sites.

OpenVSP (also Open Vehicle Sketch Pad) is an open-source parametric aircraft geometry tool originally developed by NASA. It can be used to create 3D models of aircraft and to support engineering analysis of those models.

NcFTP is an FTP client program which debuted in 1991 as the first alternative FTP client. It was created as an alternative to the standard UNIX ftp program, and offers a number of additional features and greater ease of use.

'LiVES (LiVES Editing System)' is a free and open-source video editing software and VJ tool, released under the GNU General Public License version 3 or later. There are binary versions available for most popular Linux distributions (including Debian, Ubuntu, Fedora, Suse, Gentoo, Slackware, Arch Linux, Mandriva and Mageia). There are also ports for BSD, and it will run under Solaris and IRIX. It has been compiled under OS X Leopard, but not thoroughly tested on that platform. In early 2019, a version for Microsoft Windows was announced, with a release slated for in the second half of 2019.

ALTQ (ALTernate Queueing) is the network scheduler for Berkeley Software Distribution. ALTQ provides queueing disciplines, and other components related to quality of service (QoS), required to realize resource sharing. It is most commonly implemented on BSD-based routers. ALTQ is included in the base distribution of FreeBSD, NetBSD, and DragonFly BSD, and was integrated into the pf packet filter of OpenBSD but later replaced by a new queueing subsystem (it was deprecated with OpenBSD 5.5 release, and completely removed with 5.6 in 2014).

__NOTOC__ climm (previously mICQ) is a free CLI-based instant messaging client that runs on a wide variety of platforms, including AmigaOS, BeOS, Windows (using either Cygwin or MinGW), OS X, NetBSD/OpenBSD/FreeBSD, Linux, Solaris, HP-UX, and AIX.

AutoDock is a molecular modeling simulation software. It is especially effective for protein-ligand docking. AutoDock 4 is available under the GNU General Public License. AutoDock is one of the most cited docking software applications in the research community. It is used by the FightAIDS@Home and OpenPandemics - COVID-19 projects run at World Community Grid, to search for antivirals against HIV/AIDS and COVID-19. In February 2007, a search of the ISI Citation Index showed more than 1,100 publications had been cited using the primary AutoDock method papers. As of 2009, this number surpassed 1,

GoodbyeDPI is a free and open-source software tool for bypassing deep packet inspection (DPI) systems and Internet censorship. It was created by Russian developer ValdikSS in 2016 and is distributed under the Apache License via GitHub.

digital audio editor and live playback tool

gtk-gnutella is a peer-to-peer file sharing application which runs on the gnutella network. gtk-gnutella uses the GTK+ toolkit for its graphical user interface. Released under the GNU General Public License, gtk-gnutella is free software.

thumb|Minicom running a Windows Server 2003 EMS prompt

bhyve (pronounced "bee hive", formerly written as BHyVe for "BSD hypervisor") is a type-2 (hosted) hypervisor initially written for FreeBSD. It can also be used on a number of illumos based distributions including SmartOS, OpenIndiana, and OmniOS. A port of bhyve to macOS called xhyve is also available.

giFT Internet File Transfer (giFT) is a computer software daemon that allows several file sharing protocols to be used with a simple client having a graphical user interface (GUI). The client dynamically loads plugins implementing the protocols, as they are required.

Premake is a software development tool for generating build configuration files for platform specific build tools based on configuration files that are platform agnostic. The tool is open-source.

NanoVM is an open-source implementation of the Java virtual machine. The NanoVM was initially developed to run on the Atmel AVR ATmega8 used in the Asuro Robot. It was ported to run on the C't-Bot and the Nibo-robot and can easily be ported to other AVR-based systems.

Free Range Routing or FRRouting or FRR is a network routing software suite running on Unix-like platforms, particularly Linux, Solaris, OpenBSD, FreeBSD and NetBSD. It was created as a fork from Quagga, which itself was a fork of GNU Zebra. FRRouting is distributed under the terms of the GNU General Public License v2 (GPL2).

In computing, klibc is a minimalistic subset of the standard C library developed by H. Peter Anvin. It was developed mainly to be used during the Linux startup process, and it is part of the early user space, i.e. components used during kernel startup, but which do not run in kernel mode. These components do not have access to the standard library (usually glibc or musl) used by normal userspace programs.

cdrtools (formerly known as cdrecord) is a collection of independent projects of free software/open source computer programs for CD and DVD authoring.

libHaru is a free, open-source, cross platform library for generating PDF files for applications written in C or C++. It is not intended for reading and editing existing PDF files.

Gtranslator is a specialized computer-assisted translation software and po file editor for the internationalization and localization (i18n) of software that uses the gettext system. It handles all forms of gettext po files and includes features such as Find/Replace, Translation Memory, different Translator Profiles, Messages Table (for having an overview of the translations/messages in the po file), Easy Navigation and Editing of translation messages and comments of the translation where accurate. Gtranslator includes also a plugin system with plugins such as Alternate Language, Insert Tags, O

Vinagre is a discontinued VNC, SSH, RDP and SPICE client for the GNOME desktop environment, superseded by GNOME Connections. Vinagre was included in GNOME 2.22. It has several features, like the ability to connect to multiple servers simultaneously and to switch between them using tabs, VNC servers browsing and bookmarking. In version 2.29, Vinagre added controlling frame compression, better scaling and color depth. Version 2.30 added improved SSH tunneling and better support for copy-paste features between client and server.

GNU MCSim is a suite of simulation software. It allows users to design statistical or simulation models, perform Monte Carlo simulations, and Bayesian inference through (tempered) Markov chain Monte Carlo (MCMC) simulations. The latest version allows parallel computing of Monte Carlo or MCMC simulations.

eBPF is a technology that can run programs in a privileged context such as the operating system kernel. It is the successor to the Berkeley Packet Filter (BPF, with the "e" originally meaning "extended") filtering mechanism in Linux and is also used in non-networking parts of the Linux kernel.

Toybox is a free and open-source software implementation of over 200 Unix command line utilities. The Toybox project was started in 2006, and became a 0BSD licensed BusyBox alternative. Toybox is used for most of Android's command-line tools in all currently supported Android versions, and is also used to build Android on Linux and macOS. All of the tools are tested on Linux, and many of them also work on BSD and macOS.

Streamripper is a stand-alone client, or Winamp plugin, that records Internet radio streams in the MP3 or Vorbis formats, programmed by Jon Clegg and maintained by Gregory Sharp.

Gnopernicus was a free GNOME desktop application that provided Assistive Technologies (AT) for blind and visually impaired users. Gnopernicus is no longer actively developed and has been replaced by Orca in GNOME.