Awesome C

A curated list of C good stuff. This list contains only open source code (as defined by the linked Open Source Definition), and sellers who aren't evil for physical resources.

This is released under a Creative Commons-Attribution-ShareAlike license, version 4 (SPDX code CC-BY-SA-4.0 ). 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 CONTRIBUTING.md first.

Contents

AI

Computer vision, neural nets, machine learning, and other similar things. Basically, if your university calls it AI, it lives here.

ccv - C-based/Cached/Core Computer Vision library; modern computer vision. BSD-3-Clause

Cranium - Portable, header-only ANN library in C99. MIT

FANN - Fast Artifical Neural Network library; an implementation of neural networks. GPL-2.0-only

Genann - Simple ANN in C89, without additional dependencies. Zlib

KANN - Two-file ANN library. MIT

LibDEEP - Deep learning library. BSD-3-Clause

Benchmarking

Comparing the performance of various subsystems across different chip/system architectures.

b63 - Light-weight micro-benchmarking tool for C. Apache-2.0

Build Systems

Tools that automate the building and testing of projects in C.

CMake - Cross-platform family of tools designed to build, package and test software. BSD-3-Clause

GNU Make - Tool which controls the generation of executables and other non-source files of a program. GPL-3.0-or-later

Meson - Extremely fast, user-friendly build system. Based on Ninja. Apache-2.0

Premake - 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

SCons - Software construction tool using Python. MIT

xmake - Cross-platform build utility. Apache-2.0

zproject - Project generator and build system support tool. MPL-2.0

Compilers

Compilers, as well as compiler- and compilation-related tooling.

ccache - Compiler cache designed to speed up recompilation. GPL-3.0-or-later

Clang - Compiler for LLVM. Supports C11. NCSA

distcc - Program that allows builds to be distributed among several machines. GPL-2.0-or-later

Firm - 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 license. LGPL-2.1-only

GCC - Provides a C compiler as part of its compiler set. Supports C11. GPL-3.0-or-later

PCC - Venerable compiler. Supports C99. Various licenses, all open source.

Compression

blosc - Extremely fast, multi-threaded, meta-compressor library. Various licenses, all open source.

Brotli - General-purpose lossless compression algorithm library. Has speeds comparable to DEFLATE, but much higher compression ratios. MIT .

. clzip - C version of the high-quality data compressor Lzip (LZMA implementation). GPL-2.0-or-later

CRoaring - C implementation of Roaring bitmaps. Apache-2.0

FiniteStateEntropy - Two highly efficient compression codecs optimized for modern CPUs. BSD-2-Clause

DENSITY - Super-fast compression library. BSD-3-Clause

heatshrink - Data compression/decompression library for embedded and real-time systems. ISC

fast_zlib - Improved zlib, which runs 2 to 10 times faster. BSD-3-Clause

huffandpuff - Minimal Huffman encoder and decoder. Public domain.

libbzip2 - Patent-free, high-quality data compression library. BSD-4-Clause

Lizard - Formerly LZ5; an efficient compressor with fast decompression. Achieves compression ratios comparable with zip and zlib at decompression speeds of 1000MB/s and faster. BSD-2-Clause

lz4 - Library for an extremely fast compression algorithm. BSD-2-Clause

lzo - Fast data compression library. GPL-2.0-or-later

pixz - Parallel, indexed xz compressor. BSD-2-Clause

shoco - Compressor for small text strings. MIT

SIMDComp - Simple library for compressing lists of integers using binary packing. Makes use of SIMD instructions on x86. BSD-3-Clause

smaz - Efficient string compression library. BSD-3-Clause

squash - Compression abstraction library, complete with some utilities. MIT

TurboPFor - Fastest integer compression. GPL-2.0-or-later

TurboRLE - Most efficient run-length encoding. GPL-2.0-or-later

zip - Really really small zip archive processing library. Unlicense

Zlib - Massively spiffy yet delicately unobtrusive compression library. BSD-3-Clause

libarchive - libarchive is a portable, efficient C library that can read and write streaming archives in a variety of formats. BSD-3-Clause

zlib-ng - Zlib replacement with optimizations for 'next-generation' systems. BSD-3-Clause

Zstandard - Fast, lossless compression algorithm, targeting real-time compression scenarios at zlib-level or better compression ratios. BSD-3-Clause

Concurrency and Parallelism

cchan - Small library for channel constructs for inter-thread communication. Public domain.

checkedthreads - 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

FCFS RWLock - First-come first-served Readers/Writers lock for POSIX threads. CC0-1.0

libconcurrent - Concurrent programming library, using coroutines, for C11. BSD-3-Clause

libdill - Library which makes structured concurrent programming easy. MIT

libhl - 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-only

liburcu - Data synchronization library, which scales linearly with the number of cores. LGPL-2.1-or-later

mill - Go-style concurrency. MIT

oclkit - Two-file OpenCL wrapper. GPL-3.0-or-later

OCL-MLA - OpenCL Mid-Level Abstractions. BSD-3-Clause

OpenMP - Set of pragmas designed to allow for easy parallelization of code. Standard (licensing not applicable).

OpenMPI - Message passing interface implementation. BSD-3-Clause

pal - Optimized library for maths, parallel processing and data movement. Apache-2.0

pth - Portable implementation for non-preemptive priority-based scheduling for multiple threads of execution. GPL-3.0-or-later

pthreads - POSIX thread library. Standard (no license applicable).

TinyCThread - Portable, small implementation of the C11 threads API. Zlib

Crypto

Mostly library implementations of well-known cryptographic algorithms or protocols.

Database

Databases and data stores with C APIs.

BerkeleyDB - Library for a high-performance embedded database for key-value data. AGPL-3.0-only

EJDB2 - Embeddable JSON Database engine. MIT

Groonga - Columnar store with full-text search. LGPL-2.1-only

Hiredis - Minimalistic client library for Redis. BSD-3-Clause

libmongoc - High-performance client library for MongoDB. Apache-2.0

LMDB - Ultra-fast, ultra-compact key-value embedded data store. OLDAP-2.8

MySQL - The world's most popular open source database. GPL-2.0-only

PostgreSQL - Powerful object-relational database system. PostgreSQL

Redis - Advanced key-value store. BSD-3-Clause

sophia - Modern, embeddable key-value database. BSD-2-Clause

sparkey - Simple constant key/value storage library. Designed for read-heavy loads with infrequent, large bulk inserts. Apache-2.0

SQLite - Self-contained, serverless, zero-configuration, transactional SQL database engine. Public domain.

UnQLite - Self-contained, serverless, zero-configuration, transactional NoSQL engine. BSD-2-Clause

WhiteDB - Lightweight database library, operating entirely in main memory. GPL-3.0-or-later

Data Structures

C-Macro-Collections - Generate simple and generic data structures using macros. MIT

CLIST - Simple and lightweight dynamic array implementation. BSD-2-Clause

Collections-C - Library of generic data structures. LGPL-3.0-or-later

kdtree - Simple library for working with KD-trees. BSD-3-Clause

libavl - Library containing a range of self-balancing binary trees. GPL-3.0-or-later

ds - Common Data Structures and Algorithms. MIT

igraph - A graph processing library. GPL-2.0-or-later

liblfds - Portable lock-free data structure library. Public domain (more exactly, whatever license you want).

M*LIB - Library for generic, but typesafe C containers. Implemented as header-only. BSD-2-Clause

offbrand - Collection of generic, reference-counted data structures. MIT

libsrt - Soft and hard real-time data structures. BSD-3-Clause .

. list.h - Implementations for singly linked and doubly linked list functions. GPL-3.0-only

PackedArray - Random-access array of tightly packed unsigned integers of any desired width. Has a SIMD-optimized implementation. WTFPL

rb3ptr - Red-Black tree. Exposes almost all implementation primitives, so can be used for scenarios like augmentation, multiple compatible ordering functions, and more. MIT

uthash - Single-file hash table implementation. BSD-1-Clause

vector.h - Header library for typed lists. MIT

Debugging

Because we all have to do it sometimes. Various tools for making debugging easier or better, as well as libraries or code that allows better debugging work.

C-Reduce - 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 code. BSD-3-Clause

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-or-later

Complexity - Tool for measuring the complexity of source code. GPL-3.0-or-later

CScout - Source code analyzer and refactoring browser for C programs. GPL-3.0-only

DDD - Graphical front-end for a range of command-line debuggers. GPL-3.0-or-later

debug - One-header library for easier 'printf debugging'. MIT

ESBMC - Efficient SMT-based Bounded Model Checker; a tool for verification of single and multithread programs, user assertions, overflow, and pointer/memory safety. Apache-2.0

GDB - GNU Project debugger. GPL-3.0-or-later

lldb - LLVM debugger. NCSA

rr - Debugger that records non-deterministic executions to allow for deterministic debugging. BSD-2-Clause

Valgrind - Range of dynamic analysis tools, including a leak checker. GPL-2.0-only

Documentation Generation

Cxref - Generates documentation in either LaTeX, HTML, RTF or SGML. GPL-2.0-only

DocOnce - Modestly tagged markup language that can be used to generate a range of formats. BSD-3-Clause

Doxygen - De-facto standard tool for generating documentation from annotated sources. Can generate a large range of formats. GPL-2.0-only

Editors

Fancier, IDE-type editors. If you want a programmer's text editor, look elsewhere. Besides, whatever you use most likely supports C anyway.

Frameworks

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 functions. Apache-2.0

C Algorithms - Collection of common algorithms and data structures. ISC

CPL - The Common Pipeline Library; a set of libraries designed to be a comprehensive, efficient and robust software toolkit. GPL-2.0-only

EFL - Large collection of useful data structures and functions. Various licenses, all open source.

klib - Small and lightweight implementations of common algorithms and data structures. MIT

libcork - Utility functions and structures, designed for resource-constrained systems. Can be embedded. BSD-3-Clause

libnih - Lightweight library of functions and structures. GPL-2.0-only

libU - Small library of basic utilities, including memory allocation, string manipulation and logging. BSD-3-Clause

PBL - Large library of utilities, featuring data structures, among other things. LGPL-2.1-or-later

qlibc - Simple and powerful library, designed as a replacement for GLib while focusing on being small and light. BSD-2-Clause

TBOX - Multi-platform library with a large number of capabilities. Apache-2.0

Game Programming

Engines, libraries and other helpful things specifically for making games.

Allegro - Cross-platform, video game development and multimedia library. Zlib

AssetKit 🎨 3D asset importer/exporter/util library based on COLLADA/glTF specs MIT

cglm - 📽 Optimized OpenGL/Graphics Math (glm) for C. MIT

Chipmunk2D - Fast and lightweight 2D game physics library. MIT

cmt - 🎮 C Bindings/Wrappers for Apple's METAL Graphics Framework. MIT

Corange - Game engine in pure C. BSD-2-Clause

CSFML - Binding for SFML. Zlib

Darkplaces - Modified version of the Quake2 engine. GPL-2.0-only

Epoxy - Library for handling OpenGL function pointer management. MIT

Flecs - A Multithreaded Entity Component System written for C89 & C99 MIT

Freecell Solver - Set of libraries and command-line programs for automatically solving FreeCell and some similar variants of card Solitaire. MIT

FreeGLUT - Alternative to the OpenGL Utility Toolkit. Allows the creation and management of windows with OpenGL contexts. X11

GLFW - Multi-platform library for creating windows with OpenGL contexts. Zlib

ioquake3 - Quake3 engine, freed at last. GPL-2.0-only

kazmath - Maths library for games. BSD-2-Clause

libao - Cross-platform audio library with a wide variety of outputs. GPL-2.0-or-later

librg - Pure C99 game networking library for building simple and elegant cross-platform multiplayer client-server solutions. Apache-2.0

MATHC - Math library for 2D and 3D programming. ZLib

Orx - Portable, lightweight, plugin-based, data-driven, 2D-oriented game engine. Zlib

Quake - Quake engine. GPL-2.0-only

Quake2 - Quake2 engine. GPL-2.0-only

raylib - Simple and easy-to-use library to learn video game programming. Zlib

RetroArch - Reference frontend for libretro. GPL-3.0-only

SDL2 - Cross-platform library designed to provide low-level access to audio, keyboard, mouse, joystick and graphics hardware via OpenGL. Zlib

sdl-gpu - Library for high-performance, modern 2D graphics. Based on SDL. MIT

SIGIL - Sound, Input and Graphics Integration Library; a simple alternative to other libraries for doing all those things. Various licenses, all open source.

uastar - Minimal A* implementation. ZLib

Graphics

Programmatic manipulation of graphics in C; if you want to make a GUI, the Graphical User Interface section has what you need.

AssetKit 🎨 3D asset importer/exporter/util library based on COLLADA/glTF specs MIT

Cairo - 2D graphics library. LGPL-2.1-only or MPL-1.1 .

or . cmt - 🎮 C Bindings/Wrappers for Apple's METAL Graphics Framework. MIT

giflib - Library for reading and writing gif images. MIT

graphene - Thin layer of graphical data types. MIT

heman - Tiny library of image utilities dealing with height maps, normal maps, distance fields and the like. MIT

libcaca - ASCII renderer for terminal-based interfaces. WTFPL

libgd - 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-or-later

libjpeg-turbo - Faster library for reading and writing JPEG files. Various licences.

libpng - Official PNG reference library. Libpng

libRSVG - Library to render SVG files using Cairo. LGPL-2.1-or-later

libsixel - Library implementing the SIXEL protocol, allowing beautiful graphics in your terminal. MIT

libspng - A simpler interface for reading and writing PNG files. BSD-2-Clause

libvips - Image processing library. LGPL-2.1-or-later

libxmi - Function library for rasterizing 2D vector graphics. GPL-3.0-or-later

lightmapper - Single-file library for lightmap baking, using an existing OpenGL renderer. Public domain.

mozjpeg - Improved JPEG encoder. BSD-3-Clause

nanovg - Anti-aliased 2D vector drawing library on top of OpenGL, for UI and visualizations. Zlib

OpenGL - Industry standard for high-performance graphics, with a native C binding. Various licenses.

Graphical User Interface

Widget toolkits, or things meant to be used in a similar way to them.

GTK+ - Cross-platform widget toolkit. LGPL-2.1-only

IUP - Another cross-platform widget toolkit. MIT

nuklear - Small, C89, single-header widget toolkit. Public domain.

tinyfiledialogs - Single-file library for simple dialogs. Compatible with many other toolkits and OSes. Zlib

Tk - Basic widget toolkit. Part of Tcl/Tk. TCL

XForms Toolkit - Widget toolkit designed for the XWindow system. LGPL-2.1-only

Hashing

Hash function implementations for non-crypto purposes. Cryptographic hashes can be found in the Crypto section.

CLHash - Library implementing the ridiculously fast CLHash hashing function. Only works on Intel Haswell or newer. Apache-2.0

HighwayHash - Fast, strong, SIMD-using hash function. Also contains an implementation of SipHash (although this is slower). Apache-2.0

SpookyHash - Extremely fast hash function. BSD-3-Clause

t1ha - Fast Positive Hash - a portable, fast hash function. BSD-3-Clause

xxHash - Extremely fast hashing algorithm. Comes in 32 and 64-bit varieties. BSD-2-Clause

Learning, Reference and Tutorials

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

Reference books

Beginner books

Intermediate books

21st Century C - Good second programming book on C.

Understanding and Using C Pointers - In-depth resource on pointers in C.

ZeroMQ - Book for using ZeroMQ with C.

Advanced books

Expert C Programming: Deep C Secrets - Interesting, in-depth and entertaining look at the innards of C.

Lexing and Parsing

Libraries specifically for lexical analysis (or lexing) and syntactic analysis (or parsing).

flex - Fast lexical analyzer generator. BSD-2-Clause

GNU Bison - General-purpose parser generator that converts an annotated context-free grammar into a range of parsers. GPL-3.0-or-later

hammer - Parser combinators for binary formats. GPL-2.0-only

mpc - Parser combinator library. BSD-2-Clause

re2c - Lexer generator, producing fast lexers, with access to its internals. Public domain.

Memory Management

Whether a different, faster malloc or outright garbage collection, anything to do with managing C memory lives here.

Multimedia

aubio - Library for audio and music analysis. GPL-3.0-or-later

FFMPEG - Complete, cross-platform solution to record, convert and stream audio and video. LGPL-2.1-or-later

GStreamer - Framework for audio and visual media. LGPL-2.1-or-later

libmpv - Music-playing library. GPL-2.0-or-later

libsndfile - Library for reading and writing sound files. Supports many formats. LGPL-2.1-only or LGPL-3.0-only

or libsoundio - Library for cross-platform, real-time audio input and output. Has a range of back-ends. MIT

libVLC - Complete multimedia library for audio and video encoding, decoding, playing and streaming. GPL-2.0-only

lodepng - Simple PNG image decoder and encoder, requiring no other dependencies. BSD-3-Clause

minimp3 - Lightweight MP3 decoder single header library. CC0-1.0

Soundpipe - Lightweight music DSP library. MIT

Networking and Internet

Low-level networking and internet-related stuff. If you want something more comprehensive and high-level, you may want the Web Frameworks section.

asnlc - Compiler of ASN.1 specifications into C source code. BSD-2-Clause

CHL - C Hypertext Library - A library for writing web applications in C. GPL-3.0-only

czmq - High-level binding for ZeroMQ. MPL-2.0

Dyad.c - Lightweight, easy, asynchronous networking library. MIT

GNU adns - Advanced, easy-to-use, asynch-capable DNS client library and utilities. GPL-3.0-or-later

gumbo-parser - HTML5 parsing library in C99. Apache-2.0

H20 - A new-generation HTTP server. MIT

http-parser - HTTP request/response parser. MIT

ldns - Library to simplify DNS programming. BSD-3-Clause

libcurl - Client-side URL transfer library, supporting a wide range of formats. curl

LibEtPan - Mail library providing an efficient network for IMAP, SMTP, POP and NNTP. BSD-3-Clause

libev - Yet another event loop. BSD-2-Clause

libevent - Event loop replacement for network servers. BSD-3-Clause

libhttpd - Library to add basic web server capabilities to an application or embedded device. GPL-2.0-only

libhv - Cross platform event loop library. BSD-3-Clause

libidn - Implementation of the Stringprep, Punycode and IDNA specifications. GPL-3.0-or-later

libmicrohttpd - Small library that makes it easy to run an HTTP server as part of another application. LGPL-2.1-or-later

libonion - HTTP server library, designed to be easy to use. Apache-2.0

libquickmail - 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-or-later

libsagui - Library for cross-platform HTTP servers. LGPL-3.0-or-later

LibVNCServer - Cross-platform libraries to implement VNC server and/or client functionality. GPL-2.0-or-later

libwebsock - Easy-to-use and powerful web socket library. LGPL-3.0-only

lwan - Experimental, scalable, high-performance HTTP server. GPL-2.0-only

mongoose - Embedded web server. GPL-2.0-only

MQTT-C - A portable MQTT C client for embedded systems and PCs alike. MIT

nanomsg - C-based implementation of ZeroMQ. MIT

NNG - nanomsg-next-generation - lightweight brokerless messaging. MIT

oSip - SIP implementation without additional dependencies. LGPL-2.1-or-later

socket99 - C99 wrapper for the BSD sockets API. ISC

twitc - Mini library for interacting with the Twitter OAuth API. MIT

uriparser - Strictly RFC 3986-compliant URI parsing and handling library. BSD-3-Clause

Wslay - WebSocket library. Implements version 13 of the WebSocket protocol, as described in RFC 6455. MIT

zyre - Framework for proximity-based peer-to-peer applications. MPL-2.0

libpcap - API provides to various kernel packet capture mechanism. BSD-3-Clause

Numerical

Profiling

gperftools - Collection of utilities for measuring and improving performance. BSD-3-Clause

gprof - Performance analysis tool. Part of GNU binutils. GPL-3.0-or-later

OProfile - Statistical profiler for Linux. Can profile any code (including the kernel!) with low overhead and without recompilation. GPL-2.0-only

perf - Linux kernel-based profiler with a lot of functionality. GPL-2.0-only

Regex

Onigmo - Fork of Oniguruma, supporting more advanced regexps. BSD-2-Clause

Oniguruma - Regex library supporting a wide range of encodings, and incorporating many security-oriented fixes. BSD-2-Clause

PCRE - Implementation of regexes identical to that of Perl 5. BSD-3-Clause

SLRE - Super Light Regular Expression library; a small implementation of a subset of Perl regex syntax. GPL-2.0-only

TRE - POSIX-compliant, feature-full regex library. BSD-2-Clause

Serialization

binn - Binary serialization format, meant to be compact, fast and easy-to-use. Apache-2.0

c-capnproto - Implementation of the Cap'n Proto serialization protocol. MIT

cmp - Implementation of the MessagePack serialization protocol. MIT

flatcc - FlatBuffers compiler and library. Apache-2.0

libavro - Implementation of the Avro data serialization system. Apache-2.0

mpack - Another implementation of the MessagePack serialization protocol. MIT

OPIC - Object Persistence in C; a revolutionary serialization framework, with matching on-disk and in-memory representations. GPL-3.0-or-later

protobuf-c - Implementation of Google Protocol Buffer. BSD-2-Clause

tpl - Small binary serialization library. MIT

xdr - External Data Representation; a standard for data serialization. Standard (no license applicable).

pbtools - Google Protocol Buffers C source code generator. MIT

Source Code Collections

Collections of small source code. If you want something big and integrated, check the Frameworks section.

Standard Libraries

Implementations of the (standard-mandated) C standard library.

Bionic - Google's standard library, developed for Android. BSD-3-Clause

cloudlibc - Standard library based on the concept of capability-based security. BSD-2-Clause

dietlibc - Standard library designed for the smallest possible binaries. GPL-2.0-only

glibc - The GNU C Library; an implementation of the standard library. LGPL-2.1-only .

. musl - Standard library, compatible with POSIX 2008 and C11. Designed for static linking. MIT

PDCLib - The Public Domain C Library. Implements most of C99 and some of C11. CC0-1.0

uClibc-ng - Small C library for developing embedded systems. LGPL-2.1-or-later

String Manipulation

Structured File Processing

This includes libraries for things like XML, JSON, CSV, and other similar formats.

CSV

libcsv - Simple, streaming CSV parser. LGPL-2.1-or-later

JSON

Jansson - Library for encoding, decoding and manipulating JSON. MIT

jfes - JSON For Embedded Systems; simple JSON engine without any dependencies. MIT

jsmn - Minimalistic JSON parser. MIT

json - Simple, low-memory-use JSON parser. MIT

json.c - Easily work with JSON in C. Comes with a reference-counted object model, and aims for conformance with RFC 7159. MIT

json.h - Single-file non-streaming JSON parser. Unlicense

parson - Two-file, C89-compatible JSON parser. MIT

WJElement - Advanced JSON manipulation library, with support for JSON Schema. LGPL-2.0-or-later or LGPL-2.1-or-later or LGPL-3.0-or-later

or or YAJL - Fast streaming JSON parser library. ISC

INI

inih - Small and simple INI file parser, good for embedded systems. BSD-3-Clause

iniparser - Parser for .ini files. MIT

libconfini - Yet another INI parser. GPL-3.0-only

minIni - Small and portable INI parser. Apache-2.0

Others

libbson - BSON utility library. Apache-2.0

libconfuse - Small configuration file parser library. ISC

libelf - Simple library for parsing ELF files. MIT

libucl - Universal configuration library parser. BSD-2-Clause

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

XML

Expat - Stream-oriented XML parser. MIT

libxml2 - Standards-compliant, portable XML parser. MIT

xml - Simple, low-memory-use XML parser / tokenizer. MIT

YAML

libYAML - YAML 1.1 parser and emitter. MIT

Testing

CHEAT - Simple unit testing framework. BSD-2-Clause

Check - Unit testing framework. LGPL-2.1-only

ciut - A modern minimal hassle unit test framework. MIT

clar - Clear and simple unit testing framework. MIT

CMock - Mock/stub generator. MIT

cmocka - Unit testing framework with support for mock objects. Apache-2.0

Criterion - KISS, non-intrusive test framework. MIT

ctest - Yet another unit testing framework. Apache-2.0

CUnit - Another unit testing framework. LGPL-2.1-or-later

greatest - Unit testing library in one file, with no memory allocation. ISC

minctest - Unit testing microlibrary. BSD-3-Clause

munit - Small unit testing framework. MIT

Nala - A test framework for C projects. MIT

Rexo - Framework for C89/C++ featuring automatic registration of tests and a polished API. Unlicense

theft - Property-based testing (similar to Quickcheck). MIT

Unity - Simple unit testing framework. MIT

utest - Single-header unit testing library. Unlicense

Text Editor Extensions

While practically any decent programmer's text editor supports C, there are some extensions that make it more pleasant. These are labelled by editor.

CCompletion - Notepad++ autocompletion plugin. Works with all identifiers recognized by Ctags. This is a download link. GPL-2.0-or-later

CEDET - Collection of Emacs Development Environment Tools; designed to provide IDE-like features to Emacs. Built-in. GPL-3.0-or-later

Flycheck - Modern syntax checking for Emacs. For C, it can use either GCC or Clang as a back-end. GPL-3.0-or-later

Neomake - Async :make and linting framework for Neovim/Vim. MIT

Syntastic - Syntax checking and linting for Vim. WTFPL

YASnippet - Emacs code template system, with C templates for common snippets. GPL-3.0-or-later

YouCompleteMe - Code completion engine for Vim. GPL-3.0-only

Tools

Useful programs to help you write and debug C code which are not editors, libraries or compilers.

Artistic Style - Fast and small automatic source code formatter that supports C. LGPL-3.0-only

address-sanitizer - Fast memory error detector. Apache-2.0

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 - 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-later or GPL-2.0-or-later or GPL-3.0-or-later

or ClangCheck - Static analysis tool, designed to work with Clang. NCSA

conan.io - Something of a package manager for C. MIT .

. Cppcheck - Static analysis tool. Despite the name, works well with C. GPL-3.0-or-later

Glade - RAD tool to enable quick development of GTK+ GUIs. GPL-2.0-only

GMSL - GNU Make Standard Library; a collection of additional functionality for GNU Make. BSD-3-Clause

GNU Global - Source code tagging tool. GPL-3.0-only

GPP - General-purpose preprocessor. More versatile than the C preprocessor, but more flexible than m4. LGPL-3.0-or-later

Highlight - Converts source code to formatted text with nice highlighting. GPL-3.0-only

include-what-you-use - Helps find unecessary inclusions and make suggestions for fixing them. Based on LLVM/Clang (and only works with it). NCSA

indent - Formats C source code automatically to make it easier to read. Also converts from one style of source to another. GPL-3.0-or-later

SMACK - Modular software verification toolchain and a self-contained software verifier. Currently only works with programs compiled using Clang. MIT

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

Utilities

A 'catch-all' category for anything that doesn't fit well anywhere else.

Web Frameworks

Comprehensive and integrated solutions for building the next brilliant web application in C.

facil.io - Mini-framework for web applications. Includes a fast HTTP and Websocket server, and also supports custom protocols. MIT

kcgi - CGI and FastCGI library for C ISC .

. KLone - Fully featured, multi-platform, web application development framework, targeted especially at embedded systems and appliances. BSD-3-Clause

Kore - Easy-to-use web application framework for writing scalable web APIs in C. ISC

Windows Environments

Technologies designed to bring Windows into the 21st century with respect to support for C.