A curated list of C good stuff. This list contains only freedom-respecting
code, and sellers who aren't evil for physical resources.
This is released under a Creative Commons-Attribution-ShareAlike license,
version 4. You can find its text in the LICENSE file.
An important note: This project does not index anything C++-related; only
pure C stuff is considered.
Note for contributors: If you want to make a pull request, please read
This includes such things as computer vision, neural nets, machine learning, and
other such things. Basically, if your university calls it AI, it lives here.
- ccv - C-based/Cached/Core Computer Vision library; modern computer
- FANN - Fast Artifical Neural Network library; an implementation of
neural networks. GPL-2.0.
- Genann - A simple ANN in C89, without additional dependencies. Zlib.
- libdeep - A deep learning library. BSD-3-Clause.
These are tools to automate the building and testing of projects in C.
- Autoconf - An extensible package of M4 macros that produce shell
scripts to automatically configure software source code packages. Part of the
- Automake - A tool for automatically generating
compliant with the GNU Coding Standards. Requires the use of Autoconf. Part of
the Autotools. GPL-3.0+.
- GNU Make - A tool which controls the generation of executables and other
non-source files of a program. GPL-3.0+.
- Libtool - A generic library support script. Part of the
- Meson - An extremely fast, user-friendly build system. Based on Ninja. Apache-2.0.
- Premake - A command-line utility which reads a scripted definition of a
software project and uses it to generate project files for Visual Studio and
GNU Make. Other targets are also being worked on. BSD-3-Clause.
- tup - A very fast, file-based, cross-platform build
- zproject - A project generator and build system support.
This section also includes compiler-related and compilation-related tooling.
- ccache - A compiler cache designed to speed up recompilation. GPL-3.0+.
- Clang - A compiler for LLVM. Supports C11. NCSA.
- distcc - A program to allow builds to be distributed among several
- GCC - Provides a C compiler as part of its compiler set. Supports
- PCC - A venerable compiler. Supports C99. Various licenses, all free.
- blosc - An extremely fast, multi-threaded, meta-compressor
library. Various licenses, all free.
- clzip - C version of the high-quality data compressor Lzip (LZMA
- CRoaring - C implementation of Roaring bitmaps. Apache-2.0.
- DENSITY - A super-fast compression library. BSD-3-Clause.
- heatshrink - A data compression/decompression library for embedded and
real-time systems. ISC.
- huffandpuff - A minimal Huffman encoder and decoder. Public domain.
- libbzip2 - A patent-free, high-quality data compression
- lz4 - Library for an extremely fast compression algorithm.
- lzo - A very fast data compression library. GPL-2.0+.
- shoco - A compressor for small text strings. MIT.
- SIMDComp - A simple library for compressing lists of integers using
binary packing. Makes use of SIMD instructions on x86. BSD-3-Clause.
- smaz - An efficient string compression library. BSD-3-Clause.
- squash - A compression abstraction library, complete with some
- TurboPFor - Fastest integer compression. GPL-2.0+.
- TurboRLE - Most efficient run-length encoding. GPL-2.0+.
- zip - A really really small zip archive processing library.
- Zlib - A massively-spiffy yet delicately-unobtrusive compression
- Zstandard - A fast, lossless compression algorithm, targeting real-time
compression scenarios at zlib-level or better compression ratios.
Concurrency and Parallelism
- cchan - A small library for channel constructs for inter-thread
communication. Public domain.
- cf4ocl - The C Framework for OpenCL; a cross-platform object-oriented
framework for developing and benchmarking OpenCL projects.
- checkedthreads - No race condition goes unnoticed! A simple library for
parallelism, with built-in checking for race conditions. BSD-2-Clause.
- ck - Concurrency primitives, safe memory reclamation mechanisms and
non-blocking data structures. BSD-2-Clause.
- libconcurrent - Concurrent programming library, using coroutines, for
- libdill - A library which makes structured concurrent programming
- libhl - A library implementing a thread-safe API to manage a range of data
structures. Also provides some supporting functions and structures for
concurrent and lockfree programming. LGPL-3.0.
- liburcu - A data synchronization library, which scales linearly with the
number of cores. LGPL-2.1+.
- mill - Go-style concurrency. MIT.
- OpenMP - A set of pragmas designed to allow for easy parallelization of
code. Standard (licensing not applicable).
- OpenMPI - A message passing interface implementation. BSD-3-Clause.
- pal - An optimized library for maths, parallel processing and data
- PETSc - A suite of data structures and routines for scalable parallel
solution of scientific applications modelled by partial differential
- pth - A portable implementation for non-preemptive priority-based
scheduling for multiple threads of execution. GPL-3.0+.
- pthreads - The POSIX thread library. Standard (no license applicable).
- TinyCThread - A portable, small implementation of the C11 threads
This is mostly library implementations of well-known cryptographic algorithms or
- GNU SASL - An implementation of the Simple Authentication and Security
Layer and a few common SASL mechanism. GPL-3.0+.
- GnuTLS - A secure communication library, implementing SSL, TLS and
- libgcrypt - A general-purpose cryptography library, with a range of
available ciphers. LGPL-2.1+.
- OpenSSL - Implementation of the SSL and TLS protocols. Also includes a
library. Dual Licensed under the OpenSSL License and the SSLeay License.
- liboqs - A library for quantum-resistant cryptographicl algorithms.
- libsodium - A modern and easy-to-use crypto library. MIT.
- libtomcrypt - A fairly comprehensive, modular and portable
cryptographic toolkit. Public domain.
- mbed TLS - Another crypto implementation. Apache-2.0.
- MIRACL - Multiprecision Integer and Rational Arithmetic Cryptographic
Library; an SDK for elliptic curve cryptography. AGPL-1.0+.
- retter - A collection of hash functions, ciphers, tools, libraries and
materials related to cryptography and security. Public domain.
- s2n - A C99 implementation of the TLS/SSL protocols, designed to be
simple, fast and with security as a priority. Apache-2.0.
This lists databases and data stores with C APIs.
- BerkeleyDB - A library for a high-performance embedded database for
key-value data. AGPL-1.0.
- Hiredis - A minimalistic client library for Redis. BSD-3-Clause.
- libmongoc - A high-performance client library for MongoDB. Apache-2.0.
- LMDB - An ultra-fast, ultra-compact key-value embedded data store. OLDAP-2.8.
- MariaDB - A robust, scalable and reliable SQL server, designed to be a
drop-in replacement for MySQL. BSD-3-Clause.
- PostgreSQL - A powerful object-relational database system. PostgreSQL.
- recutils - A set of tools and a library for accessing human-editable,
plaintext database files called recfiles. GPL-3.0+.
- Redis - An advanced key-value store. BSD-3-Clause.
- sophia - A modern, embeddable key-value database. BSD-2-Clause.
- sparkey - A simple constant key/value storage library. Designed for
read-heavy loads with infrequent, large bulk inserts. Apache-2.0.
- SQLite - A self-contained, serverless, zero-configuration, transactional
SQL database engine. Public domain.
- UnQLite - A self-contained, serverless, zero-configuration,
transactional NoSQL engine. BSD-2-Clause.
- WhiteDB - A lightweight database library, operating entirely in main
Because we all have to do it sometimes. This includes various tools for making
debugging easier or better, as well as libraries or code that allows better
- C-Reduce - A tool that takes a large C file with a property of interest
and automatically produces a much smaller C file that has the same
property. Intended to help create minimal bug-demonstrating cases in complex
- CBMC - C Bounded Model Checker; a tool for verification of array
bounds, pointer safety and user-specified assertions. BSD-4-Clause.
- cflow - Analyzes a collection of source files and prints a graph
charting control flow in the program. GPL-3.0+.
- Complexity - A tool for measuring the complexity of source
- CScout - A source code analyzer and refactoring browser for C
- DDD - A graphical front-end for a range of command-line
- debug - A one-header library for easier 'printf debugging'.
- GDB - The GNU Project debugger. GPL-3.0+.
- lldb - The LLVM debugger. NCSA.
- rr - A debugger that records non-deterministic executions to allow for
deterministic debugging. BSD-2-Clause.
- Valgrind - A range of dynamic analysis tools, including a leak
- Cxref - Generates documentation in either LaTeX, HTML, RTF or
- DocOnce - A modestly-tagged markup language that can be used to
generate a range of formats. BSD-3-Clause.
- Doxygen - The de-facto standard tool for generating documentation from
annotated sources. Can generate a large range of formats. GPL-2.0.
- GTK-Doc - A tool for generating documentation from annotated
sources. Has support for the Autotools. GPL-2.0.
These are specifically fancier, IDE-type editors. If you want a programmer's
text editor, look elsewhere. Besides, whatever choice you make most likely
supports C anyway.
This section has big libraries that provide data structures and other stuff you
expect of a 'modern' standard library.
- APR - Apache Portable Runtime; another library of cross-platform utility
- C Algorithms - A collection of common algorithms and data structures. ISC.
- Collections-C - A library of generic data structures. LGPL-3.0+.
- CPL - The Common Pipeline Library; a set of libraries designed to be a
comprehensive, efficient and robust software toolkit. GPL-2.0.
- EFL - A large collection of useful data structures and
functions. Various licenses, all free.
- GLib - A library of utility functions and structures, designed to be
portable, efficient and powerful. LGPL-2.1.
- GIO - A modern and easy-to-use VFS API. LGPL-2.1.
- GObject - An object-oriented system and object model. LGPL-2.1.
- libcork - Utility functions and structures, designed for
resource-constrained systems. Can be embedded. BSD-3-Clause.
- libnih - A lightweight library of functions and
- libU - A small library of basic utilities, including memory allocation,
string manipulation and logging. BSD-3-Clause.
- offbrand - A collection of generic, reference-counted data structures.
- PBL - A large library of utilities, featuring data structures, among
other things. LGPL-2.1+.
- qlibc - A simple and powerful library, designed as a replacement for
GLib while focusing on being small and light. BSD-2-Clause.
- stb - A range of single-file libraries. Public domain.
- TBOX - A multi-platform library with a large number of
These are provided as examples of C game programming code.
These are libraries of all sorts that are useful for game programming.
- Allegro - A cross-platform, video game development and multimedia
- Chipmunk2D - A fast and lightweight 2D game physics library. MIT.
- CSFML - A binding for SFML. Zlib.
- Epoxy - A library for handling OpenGL function pointer management. MIT.
- FreeGLUT - An alternative to the OpenGL Utility Toolkit. Allows the
creation and management of windows with OpenGL contexts. X11.
- GLFW - A multi-platform library for creating windows with OpenGL
- kazmath - A maths library for games. BSD-2-Clause.
- libao - A cross-platform audio library with a wide variety of
- raylib - A simple and easy-to-use library to learn video game
- RetroArch - The reference frontend for libretro. GPL-3.0.
- SDL2 - A cross-platform library designed to provide low-level access to
audio, keyboard, mouse, joystick and graphics hardware via OpenGL. Zlib.
- sdl-gpu - A library for high-performance, modern 2D graphics. Based on
- SIGIL - Sound, Input and Graphics Integration Library; a simple
alternative to other libraries for doing all those things. Various licenses,
- klib - Small and lightweight implementations of common algorithms and
data structures. MIT.
- SGLIB - A simple generic library. Any OSI-approved license.
- Cairo - A 2D graphics library. LGPL-2.1 or MPL-1.1.
- Cogl - A GPU graphics and utilities API. MIT.
- Clutter - A UI library based on OpenGL. LGPL-2.1.
- giflib - A library for reading and writing gif images. MIT.
- graphene - A thin layer of graphical data types. MIT.
- heman - A tiny library of image utilities dealing with height maps,
normal maps, distance fields and the like. MIT.
- libcaca - An ASCII renderer for terminal-based interfaces. WTFPL.
- libgd - A library for the dynamic creation of images by programmers. MIT.
- libimagequant - Small, portable library for high-quality conversion of
RGBA images to 8-bit indexed colour images. GPL-3.0+.
- libjpeg-turbo - A faster library for reading and writing JPEG
files. Various licences.
- libpng - The official PNG reference library. Libpng.
- libRSVG - A library to render SVG files using Cairo. LGPL-2.1+.
- libsixel - A library implementing the SIXEL protocol, allowing beautiful
graphics in your terminal. MIT.
- libvips - An image processing library. LGPL-2.1+.
- libxmi - A function library for rasterizing 2D vector
- lightmapper - A single-file library for lightmap baking, using an
existing OpenGL renderer. Public domain.
- mozjpeg - An improved JPEG encoder. BSD-3-Clause.
- nanovg - Anti-aliased 2D vector drawing library on top of OpenGL, for
UI and visualizations. Zlib.
- OpenGL - The industry standard for high-performance graphics, with a
native C binding. Various licenses.
Graphical User Interface
These are specifically widget toolkits, or things meant to be used in a
similar way to them.
- GTK+ - A cross-platform widget toolkit. LGPL-2.1.
- IUP - Another cross-platform widget toolkit. MIT.
- nuklear - A small, C89, single-header widget toolkit. Public domain.
- tinyfiledialogs - A single-file library for simple dialogs. Compatible
with many other toolkits and OSes. Zlib.
- Tk - A basic widget toolkit. Part of Tcl/Tk. TCL.
- XForms Toolkit - A widget toolkit designed for the XWindow
- cJSON - Ultra-lightweight JSON parser. MIT.
- Jansson - A library for encoding, decoding and manipulating JSON. MIT.
- jsmn - A minimalistic JSON parser. MIT.
- jfes - A simple JSON engine without any dependencies. MIT.
- json-c - A library for working with JSON. MIT.
- WJElement - Advanced JSON manipulation library, with support for JSON
Schema. LGPL-2.0+ or LGPL-2.1+ or LGPL-3.0+.
- YAJL - A fast streaming JSON parser library. ISC
Learning, Reference and Tutorials
This is a list of resources for learning C programming in general, or something
useful relating to C programming.
Reference resources online
Beginner resources online
Intermediate resources online
Advanced resources online
Online self-study courses
Lexing and Parsing
This details libraries specifically for lexical analysis (or lexing) and
syntactic analysis (or parsing).
- flex - The fast lexical analyzer generator. BSD-2-Clause.
- GNU Bison - A general-purpose parser generator that converts an
annotated context-free grammar into a range of parsers. GPL-3.0+.
- hammer - Parser combinators for binary formats. GPL-2.0.
- mpc - A parser combinator library. BSD-2-Clause.
- re2c - A lexer generator, producing very fast lexers, with access to its
internals. Public domain.
Whether a different, faster
malloc or outright garbage collection, anything
to do with managing C memory lives here.
- FFMPEG - A complete, cross-platform solution to record, convert and
stream audio and video. LGPL-2.1+
- GStreamer - A framework for audio and visual media. LGPL-2.1+.
- libmpv - A music-playing library. Compile with
--disable-cplayer --enable-libmpv-shared to not have the music
- libsndfile - A library for reading and writing sound files. Supports
many formats. LGPL-2.1 or LGPL-3.0.
- libsoundio - A library for cross-platform, real-time audio input and
output. Has a range of back-ends. MIT.
- lodepng - A simple PNG image decoder and encoder, requiring no other
- Soundpipe - A lightweight music DSP library. MIT.
Networking and Internet
- asnlc - A compiler of ASN.1 specifications into C source code. BSD-2-Clause.
- CHL - C Hypertext Library - A library for writing web applications in
- czmq - A high-level binding for ZeroMQ. MPL-2.0
- GNU adns - An advanced, easy-to-use, asynch-capable DNS client library
and utilities. GPL-3.0+.
- gumbo-parser - An HTML5 parsing library in C99. Apache-2.0.
- http-parser - An HTTP request/response parser. MIT.
- ldns - A library to simplify DNS programming. BSD-3-Clause.
- libcurl - A client-side URL transfer library, supporting a wide range of
- LibEtPan - A mail library providing an efficient network for IMAP,
SMTP, POP and NNTP. BSD-3-Clause.
- libev - Yet another event loop. BSD-2-Clause.
- libevent - An event loop replacement for network servers. BSD-3-Clause.
- libhttpd - A library to add basic web server capabilities to an
application or embedded device. GPL-2.0.
- libidn - An implementation of the Stringprep, Punycode and IDNA
- libmicrohttpd - A small library that makes it easy to run an HTTP
server as part of another application. LGPL-2.1+.
- libonion - HTTP server library, designed to be easy to
- libquickmail - A library intended to give developers a way to send
email from their applications. Supports multiple To/Cc/Bcc recipients and
attachments without size limits. GPL-3.0+.
- libsoup - A GNOME HTTP client/server library. Uses
- LibVNCServer - Cross-platform libraries to implement VNC server and/or
client functionality. GPL-2.0+.
- libwebsock - An easy-to-use and powerful web socket library.
- lwan - An experimental, scalable, high-performance HTTP
- mongoose - Embedded web server. GPL-2.0.
- nanomsg - A C-based implementation of ZeroMQ. MIT.
- oSip - A SIP implementation without additional
- socket99 - A C99 wrapper for the BSD sockets API. ISC.
- twitc - A mini library for interacting with the Twitter OAuth API. MIT.
- trezor-crypto - Heavily-optimized crypto algorithms for embedded
- Wslay - A WebSocket library. Implements version 13 of the WebSocket
protocol, as described in RFC 6455. MIT.
- zyre - A framework for proximity-based peer-to-peer applications. MPL-2.0.
- balde - A microframework based on GLib. LGPL-2.1.
- facil.io - A mini-framework for web applications. Includes a fast HTTP and
Websocket server, and also supports custom protocols. MIT.
- KLone - A fully-featured, multi-platform, web application development
framework, targeted especially at embedded systems and
- Kore - An easy-to-use web application framework for writing scalable
web APIs in C. ISC.
- apophenia - A library for statistical and scientific
- Arb - Library for arbitrary-precision interval arithmetic.
- ATLAS - Automatically Tuned Linear Algebra Software. BSD-3-Clause.
- clBLAS - BLAS functions written in OpenCL. Apache-2.0.
- Cuba - A library for multidimensional numerical
- FFTW - The Fastest Fourier Transform in the West; a highly-optimized
fast Fourier transform routine. GPL-2.0+.
- FLINT - Fast Library for Number Theory; a library supporting arithmetic
with numbers, polynomials, power series and matrices, among
- GLPK - GNU Linear Programming Kit; a package designed for solving
large-scale linear programming, mixed integer programming and other related
- GMP - GNU Multple Precision Arithmetic Library; a library for
arbitrary-precision arithmetic. GPL-2.0 or LGPL-3.0.
- GNU MPC - A library for complex number arithmetic. LGPL-3.0+.
- GNU MPFR - A library for arbitrary-precision floating-point
- GNU MPRIA - A portable mathematics library for multi-precision rational
interval arithmetic. GPL-3.0+.
- GSL - The GNU Scientific Library; a sophisticated numerical
- KISS FFT - A very simple fast Fourier transform library. BSD-3-Clause.
- LAPACKE - An interface to LAPACK. BSD-3-Clause.
- LibTomMath - A portable, number-theoretic, multiple-precision integer
library. Supports algebra, digit manipulation, modular reductions, and various
number-theoretic routines. Public domain.
- LibTomPoly - A polynomial-related maths library. Public domain.
- PARI/GP - A computer algebra system for number theory; includes a
compiler to C. GPL-2.0+.
- PETSc - A suite of data structures and routines for scalable parallel
solution of scientific applications modelled by partial differential
- SCS - Splitting Conic Solver; a numerical optimization package for
solving large-scale convex cone problems. MIT.
- SLEPc - A software library for the solution of large, sparse eigenvalue
problems on parallel computers. LGPL-3.0.
- TomsFastMath - A set of assembly-level-optimized maths operations,
suitable for cryptographic use. Public domain.
- Yeppp! - Very fast, SIMD-optimized mathematical library. BSD-3-Clause.
- gperftools - A collection of utilities for measuring and improving
- gprof - A performance analysis tool. Part of GNU binutils.
- OProfile - A statistical profiler for GNU/Linux. Can profile any code
(including the kernel!) with low overhead and without recompilation. GPL-2.0.
- perf - A Linux kernel-based profiler with a lot of functionality.
"Some people, when confronted with a problem, think 'I know, I'll use regular
expressions'. Now they have two problems." - Jamie Zawinski.
- Onigmo - A fork of Oniguruma, supporting more advanced regexps.
- Oniguruma - A regex library supporting a wide range of encodings, and
incorporating many security-oriented fixes. BSD-2-Clause.
- PCRE - An implementation of regexes identical to that of
Perl 5. BSD-3-Clause.
- SLRE - Super Light Regular Expression library; a very small
implementation of a subset of Perl regex syntax. GPL-2.0.
- TRE - A POSIX-compliant, feature-full regex library. BSD-2-Clause.
- binn - A binary serialization format, meant to be compact, fast and
- c-capnproto - An implementation of the Cap'n Proto serialization
- cmp - An implementation of the MessagePack serialization
- flatcc - FlatBuffers compiler and library. Apache-2.0.
- libavro - An implementation of the Avro data serialization system. Apache-2.0.
- mpack - Another implementation of the MessagePack serialization
- OPIC - Object Persistence in C; a revolutionary serialization framework,
with matching on-disk and in-memory representations. GPL-3.0+.
- protobuf-c - An implementation of Google Protocol Buffer. BSD-2-Clause.
- tpl - A small binary serialization library. MIT.
- xdr - External Data Representation; a standard for data
serialization. Standard (no license applicable).
Source Code Collections
This contains collections of small source code. If you want something big and
integrated, check the Frameworks section.
- CCAN - Modelled after Perl's CPAN, this is a big collection of code
that does stuff. The full list is here. Various licenses, all free.
- clib - Something of a package manager. Comes with
a bunch of libraries of its own. MIT.
- gnulib - A collection of common GNU code. Various licenses, all free.
- libdjb - A collection of libraries doing various things. (Apparently)
- par - A bunch of single-file libraries. MIT.
This contains standard C libraries.
- bstrlib - The Better String Library. BSD-3-Clause or GPL-2.0.
- ICU - International Components for Unicode; a library for Unicode
- libunistring - A library for manipulating Unicode
- libgiconv - A text conversion library. LGPL-2.1.
- librope - A UTF-8 rope ('heavy' string) library. MIT.
- SDS - Simple Dynamic Strings; a library for handling strings in a
simpler way, but one that is compatible with normal C string
functions. Available via clib. BSD-2-Clause.
- utf8.h - Single-header UTF-8 library, designed to mimic C-style string
functions. Public domain.
- utf8proc - A library for processing UTF-8 data. MIT.
Text Editor Extensions
While practically any decent programmer's text editor supports C, there are some
extensions that make it more pleasant. This is categorized by editor.
- CEDET - Collection of Emacs Development Environment Tools; designed to
provide IDE-like features to Emacs. Built-in. GPL-3.0+.
- Flycheck - Modern syntax checking. For C, it can use either GCC or
Clang as a back-end. GPL-3.0+.
- YASnippet - A template system, with C templates for common code
This is a list of useful programs to help you write and debug C code which are
not editors, libraries or compilers.
- Artistic Style - A fast and small automatic source code formatter that
supports C. LGPL-3.0.
- address-sanitizer - A fast memory error detector. Apache-2.0.
- biicode - A modern dependency manager. MIT.
- c - Compile and execute C "scripts" in one go on the command line. Also
has shebang support. MIT.
- c99sh - Run C files using hash-bang. BSD-2-Clause.
- cdecl - An online service to translate C declarations into English and
vice versa. Public domain.
- cinclude2dot - Graphs include dependencies in a project using
Graphviz. GPL-1.0+ or GPL-2.0+ or GPL-3.0+.
- ClangCheck - A static analysis tool, designed to work with Clang.
- Cppcheck - A static analysis tool. Despite the name, works well with C.
- Glade - A RAD tool to enable quick development of GTK+
- GMSL - GNU Make Standard Library; a collection of additional
functionality for GNU Make. BSD-3-Clause.
- GNU Global - A source code tagging tool. GPL-3.0.
- GPP - A general-purpose preprocessor. More versatile than the C
preprocessor, but more flexible than m4. LGPL-3.0+.
- Highlight - Converts source code to formatted text with nice
- include-what-you-use - Helps find unecessary inclusions and make
suggestions for fixing them. Based on LLVM/Clang (and only works with
- indent - Formats C source code automatically to make it easier to
read. Also converts from one style of source to another. GPL-3.0+.
- qo - A build system that works without a separate config file. MIT.
- SMACK - A modular software verification toolchain and a self-contained
software verifier. Currently only works with programs compiled using Clang.
- unifdef - Removes #ifdef and #if directives with their delimited text
without touching any other part of the file. BSD-3-Clause or BSD-2-Clause.
This is a 'catch-all' category for anything that doesn't fit well anywhere else.
- ApeTagLibs - A library for working with APEv2 tags. MIT.
- argparse - A command-line argument parsing library, inspired by
Python's argparse module. MIT.
- attr - Commands for manipulating filesystem extended
- bfd - A library for manipulating binary object files. Part of GNU
- Caffeine - A library for building daemons and services for Linux and
FreeBSD systems. LGPL-2.1+.
- CException - An implementation of exceptions. MIT.
- CLHash - A library implementing the ridiculously fast CLHash hashing
function. Only works on Intel Haswell or newer. Apache-2.0.
- CommonMark - An implementation of the CommonMark spec.
Variety of licenses, all free.
- CRIU - Checkpoint/Restore In Userspace; a software tool (with a C API)
for 'freezing' a running application to disk, then restoring
it. GPL-2.0 or LGPL-2.1.
- D-Bus - A simple way for applications to talk to one
another. AFL-2.1 or GPL-2.0+.
- Discount - A simple implementation of a Markdown parser. BSD-3-Clause.
- dlx - An implementation of Knuth's Algorithm X, with example
- docopt.c - An implementation of a command-line option parser. MIT.
- dyncall - Another foreign function interface library. MIT.
- Firm - A library that provides a graph-based intermediate
representation, optimizations and assembly code generation suitable for use in
compilers. Comes with an example C front-end under the same
- gjrand - A library of random-number generation
routines. GPL-2.0 or GPL-3.0.
- GNU FreeIPMI - An in-band and out-of-band IPMI
- GNU gperf - A perfect hash function generator, given a list of
strings. Outputs C code. GPL-3.0+.
- GNU Libffcall - A collection of libraries for building foreign function
- Hoedown - A fully-standards-compliant, extension-supporting, UTF-8
aware, fast Markdown parser. MIT.
- iniparser - A parser for .ini files. MIT.
- jwHash - A fast hashtable implementation. Apache-2.0.
- kdtree - A simple library for working with KD-trees. BSD-3-Clause.
- Kitsune - An efficient, general-purpose framework for dynamic software
- libavl - A library containing a range of self-balancing binary
- libbson - A BSON utility library. Apache-2.0.
- libCello - A library introducing higher-level programming to
- libcmark - A library for parsing the CommonMark dialect of
- libcoap - An implementation of the Constrained Application Protocol.
GPL-2.0+ or BSD-2-Clause.
- libconfuse - A small configuration file parser library. ISC.
- libcox - A library which permits cross-platform system calls and
standard utilities across different operating systems. BSD-2-Clause.
- libcsv - A simple, streaming CSV parser. LGPL-2.1+.
- libffi - A portable foreign-function interface library. MIT.
- libgeohash - A pure C implementation of the Geohash algorithm.
- libgit2 - Pure C implementation of Git. GPL-2.0, with a linking exception.
- libgss - Generic Security Service. GPL-3.0+.
- liblfds - A portable lock-free data structure library. Public domain
(more exactly, whatever license you want).
- libimobiledevice - A cross-platform protocol library to communicate
with iThings. LGPL-2.1+.
- libnfc - A platform-independent Near-Field Communication
- libPhenom - An eventing framework for building high-scalability and
high-performance systems. Apache-2.0.
- libpostal - A library for parsing and normalization of street addresses
around the world. Powered by statistical NLP and open geo data. MIT.
- libtrading - An implementation of network protocols for communicating
with exchanges, dark pools and other trading venues. Supports FIX, FIX/FAST
and many proprietary protocols. BSD-2-Clause.
- libucl - A universal configuration library parser. BSD-2-Clause.
- libuv - Cross-platform asynchronous I/O. MIT.
- libYAML - A YAML 1.1 parser and emitter. MIT.
- libxo - Allows an application to generate plain text, XML, JSON and
HTML output using a common set of function calls. The application decides at
runtime what output style should be produced. BSD-2-Clause.
- linenoise - A small, self-contained alternative to readline and
- ncurses - Coloured terminal UI library. MIT.
- netbsd-curses - A simplified and small version of ncurses, with the same
- nope.c - An ultra-light software platform for scalable server-side and
networking applications (think node.js for C programmers). GPL-2.0.
- pbc - A protocol buffers library. MIT.
- progressbar - An easy-to-use library for displaying text progress bars.
- rabbitmq-c - A client library for RabbitMQ. MIT.
- Ragel - A DSL for state machines that compiles to C. GPL-2.0.
- sort - A collection of sorting routines, which type-specialize at
compile-time with a user-defined type. MIT.
- termbox - A library for writing text-based interfaces. MIT.
- tinyexpr - A tiny recursive-descent parser, compiler and evaluation
engine for simple mathematical expressions. BSD-3-Clause.
- Tulip Indicators - A library of functions for technical analysis of
financial data. LGPL-3.0+.
- vector.h - A header library for typed lists. MIT.
- Viola - A simplification of libCello. MIT.
- XLSX I/O - A cross-platform library for reading and writing .xlsx
- zlog - A reliable, pure C logging library. LGPL-2.1.
- zproto - A protocol framework for ZeroMQ. MIT.
This is a list of technologies designed to bring Windows into the 21st century
with respect to support for C.
- Cygwin - Designed to emulate a POSIX-compatible environment extensively
under Windows. Various licenses, all free.
- MinGW-w64 - A minimalist environment for C development on Windows with
64 bit support. Various licenses, all free.
- MSYS2 - Minimal SYStem 2; aims to provide support for a POSIX
environment on Windows, with a package manager based on Arch Linux's
pacman. Packages have individual licenses, otherwise, as MinGW and Cygwin.
"XML is crap. Really. There are no excuses. XML is nasty to parse for humans,
and it's a disaster to parse even for computers. There's just no reason for
that horrible crap to exist." - Linus Torvalds
- Expat - A stream-oriented XML parser. MIT.
- libxml2 - A standards-compliant, portable XML parser. MIT.