Awesome C #

A curated list of C good stuff. This list contains only open source 13 
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 (#ai)
⟡ Benchmarking (#benchmarking)
⟡ Build Systems (#build-systems)
⟡ Compilers (#compilers)
⟡ Compression (#compression)
⟡ Concurrency and Parallelism (#concurrency-and-parallelism)
⟡ Crypto (#crypto)
⟡ Database (#database)
⟡ Data Structures (#data-structures)
⟡ Debugging (#debugging)
⟡ Documentation Generation (#documentation-generation)
⟡ Editors (#editors)
⟡ Embeddable Scripting Engines (#embeddable-scripting-engines)
⟡ Frameworks (#frameworks)
⟡ Game Programming (#game-programming)
⟡ Graphics (#graphics)
⟡ Graphical User Interface (#graphical-user-interface)
⟡ Hashing (#hashing)
⟡ Learning, Reference and Tutorials (#learning-reference-and-tutorials)
  ⟡ Reference resources online (#reference-resources-online)
  ⟡ Beginner resources online (#beginner-resources-online)
  ⟡ Intermediate resources online (#intermediate-resources-online)
  ⟡ Advanced resources online (#advanced-resources-online)
  ⟡ Reference books (#reference-books)
  ⟡ Beginner books (#beginner-books)
  ⟡ Intermediate books (#intermediate-books)
  ⟡ Advanced books (#advanced-books)
⟡ Lexing and Parsing (#lexing-and-parsing)
⟡ Memory Management (#memory-management)
⟡ Multimedia (#multimedia)
⟡ Networking and Internet (#networking-and-internet)
⟡ Numerical (#numerical)
⟡ Profiling (#profiling)
⟡ Regex (#regex)
⟡ Serialization (#serialization)
⟡ Source Code Collections (#source-code-collections)
⟡ Standard Libraries (#standard-libraries)
  ⟡ Template Libraries (#template-libraries)
⟡ String Manipulation (#string-manipulation)
⟡ Structured File Processing (#structured-file-processing)
* **CSV** (#csv)      
* **JSON** (#json)    
* **INI** (#ini)      
* **Others** (#others)
* **XML** (#xml)      
* **YAML** (#yaml)    
⟡ Testing (#testing)
⟡ Text Editor Extensions (#text-editor-extensions)
⟡ Tools (#tools)
⟡ Utilities (#utilities)
⟡ Web Frameworks (#web-frameworks)
⟡ Windows Environments (#windows-environments)

AI ##

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

⟡ ccv 195  - C-based/Cached/Core Computer Vision library; modern computer
  vision. BSD-3-Clause BSD-3-Clause 
⟡ Cranium 525  - Portable, header-only ANN library in C99. MIT MIT 
⟡ FANN 325  - Fast Artifical Neural Network library; an implementation of
  neural networks. GPL-2.0-only GPL-2.0-only 
⟡ Genann 412  - Simple ANN in C89, without additional dependencies. Zlib Zlib 
⟡ KANN 327  - Two-file ANN library. MIT MIT 
⟡ LibDEEP 477  - Deep learning library. BSD-3-Clause BSD-3-Clause 
⟡ m2cgen 610  - A CLI tool to transpile trained classic ML models into a native C code with zero dependencies. MIT MIT 
⟡ sod 611  -  An Embedded Computer Vision & Machine Learning Library GPL-3 GPL-3 

Benchmarking ##

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

⟡ b63 553  - Light-weight micro-benchmarking tool for C. Apache-2.0 Apache-2.0 

Build Systems ##

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

⟡ Autotools 583  - Also known as the GNU build system (automake, autoconf, libtool...)
  is one of the most widely used build systems (configure && make). GPL-1.0-or-later 335 
⟡ Autotools project skeleton 584  - A simple autotools skeleton (template) to quickly bootstrap
  new projects. BSD-2-Clause BSD-2-Clause 
⟡ CMake 329  - Cross-platform family of tools designed to build, package and test
  software. BSD-3-Clause BSD-3-Clause 
⟡ GNU Make 324  - Tool which controls the generation of executables and other
  non-source files of a program. GPL-3.0-or-later GPL-3.0-or-later 
⟡ Meson 368  - Extremely fast, user-friendly build system. Based on Ninja. Apache-2.0 Apache-2.0 
⟡ Premake 435  - 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 BSD-3-Clause 
⟡ SCons 521  - Software construction tool using Python. MIT MIT 
⟡ xmake 271  - Cross-platform build utility. Apache-2.0 Apache-2.0 
⟡ zproject 420  - Project generator and build system support tool. MPL-2.0 MPL-2.0 

Compilers ##

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

⟡ ccache 466  - Compiler cache designed to speed up recompilation. GPL-3.0-or-later GPL-3.0-or-later 
⟡ Clang 38  - Compiler for LLVM. Supports C11. NCSA NCSA 
⟡ cproc 574  - A C11 compiler using QBE as a backend. ISC ISC 
⟡ distcc 452  - Program that allows builds to be distributed among several
  machines. GPL-2.0-or-later GPL-2.0-or-later 
⟡ Firm 361  - 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 LGPL-2.1-only 
⟡ GCC 40  - Provides a C compiler as part of its compiler set. Supports
  C11. GPL-3.0-or-later GPL-3.0-or-later 
⟡ PCC 74  - Venerable compiler. Supports C99. Various licenses 75 , all
  open source.

Compression ##

⟡ blosc 445  - Extremely fast, multi-threaded, meta-compressor library.
  Various licenses, all open source.
⟡ Brotli 24  - General-purpose lossless compression algorithm library. Has
  speeds comparable to DEFLATE, but much higher compression ratios.
  MIT MIT .
⟡ clzip 432  - C version of the high-quality data compressor Lzip 433  (LZMA
  implementation). GPL-2.0-or-later GPL-2.0-or-later 
⟡ CRoaring 481  - C implementation of Roaring bitmaps 482 . Apache-2.0 Apache-2.0 
⟡ FiniteStateEntropy 2  - Two highly efficient compression codecs optimized
  for modern CPUs. BSD-2-Clause BSD-2-Clause 
⟡ DENSITY 506  - Super-fast compression library. BSD-3-Clause BSD-3-Clause 
⟡ heatshrink 514  - Data compression/decompression library for embedded and
  real-time systems. ISC ISC 
⟡ fast\_zlib 533  - Improved zlib, which runs 2 to 10 times faster.
  BSD-3-Clause BSD-3-Clause 
⟡ fastLZ 586  - Lightning-fast lossless compression library (LZ77 type). Embbedable on small target like ARM Cortex-M families. Source code directly embbedable on your project ( a pair of h/c files), no dynamic 
memory allocation. MIT MIT 
⟡ huffandpuff 214  - Minimal Huffman encoder and decoder. Public domain.
⟡ libzip 587  - C library for reading, creating and modifying zip archives.
  BSD-3-Clause BSD-3-Clause 
⟡ libbzip2 427  - Patent-free, high-quality data compression
  library. BSD-4-Clause BSD-4-Clause 
⟡ Lizard 489  - 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 BSD-2-Clause 
⟡ lz4 508  - Library for an extremely fast compression algorithm.
  BSD-2-Clause BSD-2-Clause 
⟡ lzo 338  - Fast data compression library.
  GPL-2.0-or-later GPL-2.0-or-later 
⟡ pixz 49  - Parallel, indexed xz compressor. BSD-2-Clause BSD-2-Clause 
⟡ shoco 363  - Compressor for small text strings. MIT MIT 
⟡ SIMDComp 519  - Simple library for compressing lists of integers using
  binary packing. Makes use of SIMD instructions on x86.
  BSD-3-Clause BSD-3-Clause 
⟡ smaz 364  - Efficient string compression library.
  BSD-3-Clause BSD-3-Clause 
⟡ squash 393  - Compression abstraction library, complete with some
  utilities. MIT MIT 
⟡ TurboPFor 471  - Fastest integer compression.
  GPL-2.0-or-later GPL-2.0-or-later 
⟡ TurboRLE 484  - Most efficient run-length encoding. GPL-2.0-or-later GPL-2.0-or-later 
⟡ zip 520  - Really really small zip archive processing library.
  Unlicense Unlicense 
⟡ Zlib 230  - Massively spiffy yet delicately unobtrusive compression
  library. BSD-3-Clause BSD-3-Clause 
⟡ libarchive 548  - libarchive is a portable, efficient C library that can read and write streaming archives in a variety of formats.
  BSD-3-Clause BSD-3-Clause 
⟡ zlib-ng 1  - Zlib replacement with optimizations for 'next-generation'
  systems. BSD-3-Clause BSD-3-Clause 
⟡ Zstandard 510  - Fast, lossless compression algorithm, targeting real-time
  compression scenarios at zlib-level or better compression ratios.
  BSD-3-Clause BSD-3-Clause 

Concurrency and Parallelism ##

⟡ cchan 243  - Small library for channel constructs for inter-thread
  communication. Public domain.
⟡ checkedthreads 465  - A simple library for
  parallelism, with built-in checking for race conditions. BSD-2-Clause BSD-2-Clause 
⟡ ck 242  - Concurrency primitives, safe memory reclamation mechanisms and
  non-blocking data structures. BSD-2-Clause BSD-2-Clause 
⟡ FCFS RWLock 540  - First-come first-served Readers/Writers lock for POSIX threads. CC0-1.0 CC0-1.0 
⟡ Libaco 599  - A blazing fast and lightweight C asymmetric coroutine library. Apache-2.0 Apache-2.0 
⟡ libconcurrent 390  - Concurrent programming library, using coroutines, for
  C11. BSD-3-Clause BSD-3-Clause 
⟡ libcsp 572  - High performance concurrency C library influenced by the CSP model. MIT MIT 
⟡ libdill 442  - Library which makes structured concurrent programming
  easy. MIT MIT 
⟡ libhl 478  - 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 LGPL-3.0-only 
⟡ liburcu 474  - Data synchronization library, which scales linearly with the
  number of cores. LGPL-2.1-or-later LGPL-2.1-or-later 
⟡ mill 352  - Go-style concurrency. MIT MIT 
⟡ oclkit 311  - Two-file OpenCL wrapper. GPL-3.0-or-later GPL-3.0-or-later 
⟡ OCL-MLA 312  - OpenCL Mid-Level Abstractions. BSD-3-Clause BSD-3-Clause 
⟡ OpenMP 37  - Set of pragmas designed to allow for easy parallelization of
  code. Standard (licensing not applicable).
⟡ Open MPI 284  - Message passing interface implementation. BSD-3-Clause BSD-3-Clause 
⟡ pal 459  - Optimized library for maths, parallel processing and data
  movement. Apache-2.0 Apache-2.0 
⟡ pth 180  - Portable implementation for non-preemptive priority-based
  scheduling for multiple threads of execution.
  GPL-3.0-or-later GPL-3.0-or-later 
⟡ pthreads 146  - POSIX thread library. Standard (no license applicable).
⟡ TinyCThread 115  - Portable, small implementation of the C11 threads
  API. Zlib Zlib 

Crypto ##

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

⟡ GNU SASL 160  - Implementation of the Simple Authentication and Security
  Layer and a few common SASL mechanism. GPL-3.0-or-later GPL-3.0-or-later 
⟡ GnuTLS 112  - Secure communication library, implementing SSL, TLS and
  DTLS. LGPL-2.1-or-later LGPL-2.1-or-later 
⟡ libgcrypt 142  - General-purpose cryptography library, with a range of
  available ciphers. LGPL-2.1-or-later LGPL-2.1-or-later 
⟡ OpenSSL 110  - Implementation of the SSL and TLS protocols. Also includes a
  cryptography library. Dual Licensed under the OpenSSL License and the SSLeay License 111 .
⟡ liboqs 493  - Library for quantum-resistant cryptographicl algorithms.
  MIT MIT 
⟡ libsodium 198  - Modern and easy-to-use crypto library. MIT MIT 
⟡ libtomcrypt 299  - Fairly comprehensive, modular and portable
  cryptographic toolkit. Public domain.
⟡ mbed TLS 291  - Another crypto implementation. Apache-2.0 Apache-2.0 
⟡ MIRACL 480  - Multiprecision Integer and Rational Arithmetic Cryptographic
  Library; an SDK for elliptic curve cryptography.
  AGPL-3.0-or-later AGPL-3.0-or-later 
⟡ retter 507  - Collection of hash functions, ciphers, tools, libraries and
  materials related to cryptography and security. Public domain.
⟡ s2n 359  - C99 implementation of the TLS/SSL protocols, designed to be
  simple, fast and with security as a priority. Apache-2.0 Apache-2.0 
⟡ sphlib 526  - Set of implementations of various hash functions, including
  several cryptographic ones. MIT MIT 
⟡ trezor-crypto 485  - Heavily optimized crypto algorithms for embedded
  devices. MIT MIT 
⟡ bfish 598  - A single include ANSI-C Blowfish ECB crypto library. Public
  domain.

Database ##

Databases and data stores with C APIs.

⟡ BerkeleyDB 380  - Library for a high-performance embedded database for
  key-value data. AGPL-3.0-only AGPL-3.0-only 
⟡ DuckDB 702  - Fast in-process analytical database, with C API. MIT MIT   
⟡ EJDB2 568  - Embeddable JSON Database engine. MIT MIT 
⟡ Groonga 524  - Columnar store with full-text search. LGPL-2.1-only LGPL-2.1-only 
⟡ Hiredis 201  - Minimalistic client library for Redis.
  BSD-3-Clause BSD-3-Clause 
⟡ libmongoc 233  - High-performance client library for MongoDB 234 . Apache-2.0 Apache-2.0 
⟡ LMDB 105  - Ultra-fast, ultra-compact key-value embedded data store. OLDAP-2.8 OLDAP-2.8 
⟡ MySQL 551  - The world's most popular open source database. GPL-2.0-only GPL-2.0-only 
⟡ PostgreSQL 121  - Powerful object-relational database system. PostgreSQL PostgreSQL 
⟡ Redis 51  - Advanced key-value store. BSD-3-Clause BSD-3-Clause 
⟡ sophia 244  - Modern, embeddable key-value database.
  BSD-2-Clause BSD-2-Clause 
⟡ sparkey 509  - Simple constant key/value storage library. Designed for
  read-heavy loads with infrequent, large bulk inserts.
  Apache-2.0 Apache-2.0 
⟡ SQLite 22  - Self-contained, serverless, zero-configuration, transactional
  SQL database engine. Public domain.
⟡ UnQLite 23  - Self-contained, serverless, zero-configuration,
  transactional NoSQL engine. BSD-2-Clause BSD-2-Clause 
⟡ WhiteDB 512  - Lightweight database library, operating entirely in main
  memory. GPL-3.0-or-later GPL-3.0-or-later 

Data Structures ##

⟡ C-Macro-Collections 550  - Generate simple and generic data structures using macros. MIT MIT 
⟡ CLIST 371  - Simple and lightweight dynamic array 25  implementation.
  BSD-2-Clause BSD-2-Clause 
⟡ Collections-C 406  - Library of generic data structures. LGPL-3.0-or-later LGPL-3.0-or-later 
⟡ ds 541  - Common Data Structures and Algorithms. MIT MIT 
⟡ igraph 544  - A graph processing library.
  GPL-2.0-or-later GPL-2.0-or-later 
⟡ kdtree 337  - Simple library for working with KD-trees. BSD-3-Clause BSD-3-Clause 
⟡ libavl 156  - Library containing a range of self-balancing binary
  trees. GPL-3.0-or-later GPL-3.0-or-later 
⟡ libcdada 585  - A small, portable, MACRO-less library for basic data structures
  (list, set, map, queue...) in C (C++ backend). BSD-2-Clause BSD-2-Clause 
⟡ liblfds 411  - Portable lock-free data structure library. Public domain
  (more exactly, whatever license you want).
⟡ libsrt 305  - Soft and hard real-time data structures.
  BSD-3-Clause BSD-3-Clause .
⟡ list.h 538  - Implementations for singly linked and doubly linked list functions.
  GPL-3.0-only GPL-3.0-only 
⟡ M*LIB 350  - Library for generic, but typesafe C containers. Implemented as
  header-only. BSD-2-Clause BSD-2-Clause 
⟡ offbrand 498  - Collection of generic, reference-counted data structures.
  MIT MIT 
⟡ PackedArray 241  - Random-access array of tightly packed unsigned integers of
  any desired width. Has a SIMD-optimized implementation. WTFPL WTFPL 
⟡ rb3ptr 561  - Red-Black tree. Exposes almost all implementation primitives, so can be used for
  scenarios like augmentation, multiple compatible ordering functions, and more. MIT MIT 
⟡ uthash 273  - Single-file hash table implementation. BSD-1-Clause BSD-1-Clause 
⟡ vector.h 154  - Header library for typed lists. MIT 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 403  - 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 BSD-3-Clause 
⟡ CBMC 309  - C Bounded Model Checker; a tool for verification of array
  bounds, pointer safety and user-specified assertions.
  BSD-4-Clause BSD-4-Clause 
⟡ cflow 404  - Analyzes a collection of source files and prints a graph
  charting control flow in the program. GPL-3.0-or-later GPL-3.0-or-later 
⟡ Complexity 307  - Tool for measuring the complexity of source
  code. GPL-3.0-or-later GPL-3.0-or-later 
⟡ CScout 410  - Source code analyzer and refactoring browser for C
  programs. GPL-3.0-only GPL-3.0-only 
⟡ DDD 320  - Graphical front-end for a range of command-line
  debuggers. GPL-3.0-or-later GPL-3.0-or-later 
⟡ debug 467  - One-header library for easier 'printf debugging'.
  MIT MIT 
⟡ ESBMC 567  - 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 Apache-2.0 
⟡ GDB 87  - GNU Project debugger. GPL-3.0-or-later GPL-3.0-or-later 
⟡ lldb 468  - LLVM debugger. NCSA NCSA 
⟡ rr 95  - Debugger that records non-deterministic executions to allow for
  deterministic debugging. BSD-2-Clause BSD-2-Clause 
⟡ Valgrind 85  - Range of dynamic analysis tools, including a leak
  checker. GPL-2.0-only GPL-2.0-only 

Documentation Generation ##

⟡ Cxref 317  - Generates documentation in either LaTeX, HTML, RTF or
  SGML. GPL-2.0-only GPL-2.0-only 
⟡ DocOnce 322  - Modestly tagged markup language that can be used to
  generate a range of formats. BSD-3-Clause BSD-3-Clause 
⟡ Doxygen 318  - De-facto standard tool for generating documentation from
  annotated sources. Can generate a large range of formats. GPL-2.0-only 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.

⟡ Anjuta DevStudio 42  - GNOME IDE. GPL-2.0-only GPL-2.0-only 
⟡ Code::Blocks 249  - Extendable, configurable IDE supporting
  C. GPL-3.0-only GPL-3.0-only 
⟡ CodeLite 45  - Cross-platform IDE. GPL-2.0-only GPL-2.0-only 
⟡ Geany 43  - Small and fast IDE. GPL-2.0-or-later GPL-2.0-or-later 
⟡ KDevelop 44  - KDE IDE. GPL-2.0-only GPL-2.0-only 
⟡ zinjaI 578  - Simple, lightweight and feature-rich IDE. GPL-3.0-only GPL-3.0-only 

Embeddable Scripting Engines

When C isn't the right solution, or when you need a more dynamic configration engine:

⟡ Duktape 591  - Embeddable Javascript engine with a focus on portability and compact footprint MIT MIT .
⟡ MetaCall 607  - Cross-platform Polyglot Runtime which supports NodeJS, JavaScript, TypeScript, Python, Ruby, C#, Wasm, Java, Cobol and more. Apache-2.0 Apache-2.0 

Frameworks ##

Big libraries that provide data structures and other stuff you expect of a
'modern' standard library.

⟡ APR 78  - Apache Portable Runtime; another library of cross-platform utility
  functions. Apache-2.0 Apache-2.0 
⟡ C Algorithms 88  - Collection of common algorithms and data structures. ISC ISC 
⟡ CPL 308  - The Common Pipeline Library; a set of libraries designed to be a
  comprehensive, efficient and robust software toolkit.
  GPL-2.0-only GPL-2.0-only 
⟡ EFL 119  - Large collection of useful data structures and
  functions. Various licenses, all open source.
⟡ GLib 701  - Library of utility functions and structures, designed to be
  portable, efficient and powerful. LGPL-2.1-only LGPL-2.1-only 
⟡ klib 76  - Small and lightweight implementations of common algorithms and
  data structures. MIT MIT 
⟡ libcork 476  - Utility functions and structures, designed for
  resource-constrained systems. Can be embedded. BSD-3-Clause BSD-3-Clause 
⟡ libnih 93  - Lightweight library of functions and
  structures. GPL-2.0-only GPL-2.0-only 
⟡ libU 28  - Small library of basic utilities, including memory allocation,
  string manipulation and logging. BSD-3-Clause BSD-3-Clause 
⟡ PBL 346  - Large library of utilities, featuring data structures, among
  other things. LGPL-2.1-or-later LGPL-2.1-or-later 
⟡ plibsys 588  - Cross-platform system C library. Zero third-party dependencies, uses only native system calls. MIT MIT 
⟡ qlibc 277  - Simple and powerful library, designed as a replacement for
  GLib while focusing on being small and light. BSD-2-Clause BSD-2-Clause 
⟡ sc 595  - Common libraries and data structures for C. MIT MIT 
⟡ TBOX 398  - Multi-platform library with a large number of
  capabilities. Apache-2.0 Apache-2.0 
⟡ pspsdk 620  - An open-source SDK for PSP homebrew development. Various licences 621 .

Game Programming ##

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

⟡ Allegro 48  - Cross-platform, video game development and multimedia
  library. Zlib Zlib 
⟡ AssetKit 571  🎨 3D asset importer/exporter/util library based on COLLADA/glTF specs MIT MIT 
⟡ astera 594  - C99 Cross Platform 2D Game Library  MIT MIT 
⟡ cglm 542  - 📽 Optimized OpenGL/Graphics Math (glm) for C. MIT MIT 
⟡ Chipmunk2D 303  - Fast and lightweight 2D game physics library. MIT MIT 
⟡ cmt 570  - 🎮 C Bindings/Wrappers for Apple's METAL Graphics Framework. MIT MIT 
⟡ Corange 101  - Game engine in pure C. BSD-2-Clause BSD-2-Clause 
⟡ CSFML 90  - Binding for SFML 91 . Zlib Zlib 
⟡ Darkplaces 369  - Modified version of the Quake2 engine. GPL-2.0-only GPL-2.0-only 
⟡ Epoxy 414  - Library for handling OpenGL function pointer management. MIT MIT 
⟡ exengine 618  - 3D game engine in C99 with a starting template. MIT MIT 
⟡ Flecs 557  - A Multithreaded Entity Component System written for C89 & C99 MIT MIT 
⟡ Freecell Solver 539  - Set of libraries and command-line programs for
  automatically solving FreeCell and some similar variants of card Solitaire. MIT MIT 
⟡ FreeGLUT 99  - Alternative to the OpenGL Utility Toolkit. Allows the
  creation and management of windows with OpenGL contexts. X11 X11 
⟡ GLFW 98  - Multi-platform library for creating windows with OpenGL
  contexts. Zlib Zlib 
⟡ ioquake3 107  - Quake3 engine, freed at last.
  GPL-2.0-only GPL-2.0-only 
⟡ kazmath 446  - Maths library for games. BSD-2-Clause BSD-2-Clause 
⟡ libao 376  - Cross-platform audio library with a wide variety of
  outputs. GPL-2.0-or-later GPL-2.0-or-later 
⟡ librg 558  - Pure C99 game networking library for building simple and elegant cross-platform multiplayer client-server solutions. Apache-2.0 Apache-2.0 
⟡ MATHC 534  - Math library for 2D and 3D programming. ZLib Zlib 
⟡ Orx 370  - Portable, lightweight, plugin-based, data-driven, 2D-oriented
  game engine. Zlib Zlib 
⟡ Quake 225  - Quake engine. GPL-2.0-only GPL-2.0-only 
⟡ Quake2 221  - Quake2 engine. GPL-2.0-only GPL-2.0-only 
⟡ raylib 516  - Simple and easy-to-use library to learn video game
  programming. Zlib Zlib 
⟡ RetroArch 231  - Reference frontend for libretro 232 . GPL-3.0-only GPL-3.0-only 
⟡ SDL2 50  - Cross-platform library designed to provide low-level access to
  audio, keyboard, mouse, joystick and graphics hardware via OpenGL. Zlib Zlib 
⟡ sdl-gpu 457  - Library for high-performance, modern 2D graphics. Based on
  SDL. MIT MIT 
⟡ SIGIL 429  - Sound, Input and Graphics Integration Library; a simple
  alternative to other libraries for doing all those things. Various licenses,
  all open source.
⟡ uastar 535  - Minimal A* implementation. ZLib 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 571  🎨 3D asset importer/exporter/util library based on COLLADA/glTF specs MIT MIT 
⟡ Cairo 384  - 2D graphics library. LGPL-2.1-only LGPL-2.1-only  or MPL-1.1 385 .
⟡ cmt 570  - 🎮 C Bindings/Wrappers for Apple's METAL Graphics Framework. MIT MIT 
⟡ giflib 401  - Library for reading and writing gif images. MIT MIT 
⟡ graphene 515  - Thin layer of graphical data types. MIT MIT 
⟡ heman 365  - Tiny library of image utilities dealing with height maps,
  normal maps, distance fields and the like. MIT MIT 
⟡ libcaca 366  - ASCII renderer for terminal-based interfaces. WTFPL WTFPL 
⟡ libgd 402  - Library for the dynamic creation of images by programmers. MIT MIT 
⟡ libimagequant 300  - Small, portable library for high-quality conversion of
  RGBA images to 8-bit indexed colour images. GPL-3.0-or-later GPL-3.0-or-later 
⟡ libjpeg-turbo 193  - Faster library for reading and writing JPEG files.
  Various licences 194 .
⟡ libpng 382  - Official PNG reference library. Libpng Libpng 
⟡ libRSVG 417  - Library to render SVG files using Cairo. LGPL-2.1-or-later LGPL-2.1-or-later 
⟡ libsixel 17  - Library implementing the SIXEL protocol, allowing beautiful
  graphics in your terminal. MIT MIT 
⟡ libspng 68  - A simpler interface for reading and writing PNG files.
  BSD-2-Clause BSD-2-Clause 
⟡ libvips 511  - Image processing library. LGPL-2.1-or-later LGPL-2.1-or-later 
⟡ libxmi 174  - Function library for rasterizing 2D vector
  graphics. GPL-3.0-or-later GPL-3.0-or-later 
⟡ lightmapper 444  - Single-file library for lightmap baking, using an
  existing OpenGL renderer. Public domain.
⟡ little CMS 600  - A Color Management System. It provides fast transforms between ICC profiles.  MIT MIT 
⟡ mozjpeg 200  - Improved JPEG encoder. BSD-3-Clause BSD-3-Clause 
⟡ nanovg 505  - Anti-aliased 2D vector drawing library on top of OpenGL, for
  UI and visualizations. Zlib Zlib 
⟡ OpenGL 147  - Industry standard for high-performance graphics, with a
  native C binding. Various licenses 148 .
⟡ PlutoVG 590  - A standalone 2D vector graphics library in C MIT MIT 
⟡ SAIL 601  - ⛵ The missing small and fast image decoding library for humans (not for machines) MIT MIT 

Graphical User Interface ##

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

⟡ GTK+ 14  - Cross-platform widget toolkit. LGPL-2.1-only LGPL-2.1-only 
⟡ IUP 16  - Another cross-platform widget toolkit. MIT MIT 
⟡ microui 616  - Tiny immediate-mode UI library written in portable ANSI C. MIT MIT 
⟡ nuklear 408  - Small, C89, single-header widget toolkit. Public domain.
⟡ tinyfiledialogs 426  - Single-file library for simple dialogs. Compatible
  with many other toolkits and OSes. Zlib Zlib 
⟡ Tk 19  - Basic widget toolkit. Part of Tcl/Tk. TCL TCL 
⟡ XForms Toolkit 21  - Widget toolkit designed for the XWindow
  system. LGPL-2.1-only LGPL-2.1-only 
⟡ LVGL 575  - embedded GUI with easy-to-use graphical elements, beautiful visuals and
  a low memory footprint. MIT MIT 
⟡ luigi 614  - A barebones single-header GUI library for Win32, X11 and Essence. MIT MIT 

Hashing ##

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

⟡ CLHash 495  - Library implementing the ridiculously fast CLHash hashing
  function. Only works on Intel Haswell or newer. Apache-2.0 Apache-2.0 
⟡ HighwayHash 527  - Fast, strong, SIMD-using hash function. Also contains
  an implementation of SipHash (although this is slower).
  Apache-2.0 Apache-2.0 
⟡ SpookyHash 326  - Extremely fast hash function.
  BSD-3-Clause BSD-3-Clause 
⟡ t1ha 530  - Fast Positive Hash - a portable, fast hash function.
  BSD-3-Clause BSD-3-Clause 
⟡ xxHash 522  - Extremely fast hashing algorithm. Comes in 32 and 64-bit
  varieties. BSD-2-Clause BSD-2-Clause 

Learning, Reference and Tutorials ##

Resources for learning C programming in general, or something useful relating
to C programming.

Reference resources online ###

⟡ Benchmarks of the Lockless Memory Allocator 450 
⟡ C FAQ - comp.lang.c Frequently Asked Questions 262 
⟡ Comparison of C/POSIX standard library implementations for Linux 362 
⟡ Draft C89 standard 6 
⟡ Draft C99 standard 258 
⟡ Draft C11 standard 247 
⟡ Finding the best 64-bit simulation PRNG 529 
⟡ SEI CERT C Coding Standard 266 
⟡ tinyc.game 559  - Tiny C games you can compile and run RIGHT NOW http://tinyc.games MIT MIT 

Beginner resources online ###

⟡ A tutorial on pointers 213 
⟡ A tutorial on portable Makefiles 528 
⟡ Building C Projects 208 
⟡ C Programming Wikibook 248 
⟡ Introduction to `fun' C 279 
⟡ Learning C with GDB 349 
⟡ memcpy vs memmove 205 
⟡ POSIX Threads Programming tutorial 263  (a little dated, but most of it is
  still valid and useful)
⟡ The GNU C Programming Tutorial 212  (online PDF)
⟡ Templating in C 267 
⟡ What a C programmer should know about memory 227 
⟡ CodeforWin: Learn C Programming, Data Structures Tutorials and Exercises online 605 
⟡ Learn C: Free and Open-Source Interactive C Tutorial 606 
⟡ How to program a text adventure in C 615 

Intermediate resources online ###

⟡ 8 gdb tricks you should know 206 
⟡ 10 C99 tricks 257 
⟡ A comprehensive MPI tutorial resource 454 
⟡ Build Your Own Text Editor 700 
⟡ Diving into concurrency: trying out mutexes and atomics 202 
⟡ Generic C reference counting 443 
⟡ How to write portable C without complicating your build 490 
⟡ Introduction to OpenMP 207  (video)
⟡ OpenMP tutorial 264  (for the OpenMP3 standard)
⟡ MPI tutorial 265 
⟡ Scalable C - Writing Large-Scale Distributed C 391 
⟡ Some unknown features or tricks in C language 374 
⟡ What every C programmer should know about undefined behaviour 275 

Advanced resources online ###

⟡ Advanced metaprogramming in C 357 
⟡ A quick tutorial on implementing and debugging malloc, free, calloc, and realloc 204 
⟡ Bit twiddling hacks 73 
⟡ Implementing smart pointers for the C programming language 240 
⟡ Inline functions in C 245 
⟡ Metaprogramming custom control structures in C 343 
⟡ Solving the temporary storage problem of C macros 358 
⟡ Some dark corners of C 210 
⟡ Writing efficient C and C code optimization 33 
⟡ Compiling Algebraic Data Types in Pure C99 608 

Reference books ###

⟡ C: A Reference Manual 5E 181  - Full reference book for C99.
⟡ C in a Nutshell 2E 418  - Concise reference book for C11.
⟡ C Pocket Reference 182  - Concise reference book for C99.
⟡ The C Programming Language 2E 7  - Original book on C, by its creators.

Beginner books ###

⟡ C Primer Plus 6E 184  - Complete tutorial on programming in C11.
⟡ C Programming: A Modern Approach 64  - Excellent book to learn the basics
  of C.
⟡ Head First C 102  - 'Head-first' style book for learning C.

Intermediate books ###

⟡ 21st Century C 35  - Good _second_ programming book on C.
⟡ Understanding and Using C Pointers 36  - In-depth resource on pointers in
  C.
⟡ ZeroMQ 183  - Book for using ZeroMQ with C.

Advanced books ###

⟡ Expert C Programming: Deep C Secrets 55  - Interesting, in-depth and
  entertaining look at the innards of C.
⟡ Modern C, Third Edition: Covers the C23 standard 425  - In Modern C, Third Edition you’ll learn to harness C’s full potential using the latest tools and techniques.

Lexing and Parsing ##

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

⟡ flex 491  - Fast lexical analyzer generator. BSD-2-Clause BSD-2-Clause 
⟡ GNU Bison 492  - General-purpose parser generator that converts an
  annotated context-free grammar into a range of parsers. GPL-3.0-or-later GPL-3.0-or-later 
⟡ hammer 356  - Parser combinators for binary formats.
  GPL-2.0-only GPL-2.0-only 
⟡ mpc 238  - Parser combinator library. BSD-2-Clause BSD-2-Clause 
⟡ owl 576  - A parser generator for visibly pushdown languages. MIT MIT 
⟡ re2c 34  - 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.

⟡ Boehm GC 125  - Garbage collection for C. Various
  licenses, all open source.
⟡ jemalloc 293  - Malloc implementation that emphasizes avoidance of
  fragmentation and scalable concurrency support.
  BSD-2-Clause BSD-2-Clause 
⟡ Lockless Memory Allocator 451  - Efficient memory allocator.
  GPL-3.0-or-later GPL-3.0-or-later 
⟡ libcsptr 66  - Smart pointers for C. MIT MIT 
⟡ rpmalloc 126  - Thread-caching, fast memory allocator, naturally aligned on
  32-byte boundaries. Public domain.
⟡ talloc 353  - Hierarchical, reference-counted memory pool system with
  destructors. LGPL-3.0-or-later LGPL-3.0-or-later 
⟡ tlsf 531  - Two-Level Segregated Fit allocator; a general-purpose, dynamic
  memory allocator designed to meet real-time requirements. Up-to-date
  implementation 532 . BSD-3-Clause BSD-3-Clause 

Multimedia ##

⟡ aubio 523  - Library for audio and music analysis. GPL-3.0-or-later GPL-3.0-or-later 
⟡ FFMPEG 63  - Complete, cross-platform solution to record, convert and
  stream audio and video. LGPL-2.1-or-later LGPL-2.1-or-later 
⟡ GStreamer 123  - Framework for audio and visual media. LGPL-2.1-or-later LGPL-2.1-or-later 
⟡ libmpv 348  - Music-playing library. GPL-2.0-or-later GPL-2.0-or-later 
⟡ libsndfile 458  - Library for reading and writing sound files. Supports
  many formats. LGPL-2.1-only LGPL-2.1-only  or
  LGPL-3.0-only LGPL-3.0-only 
⟡ libsoundio 372  - Library for cross-platform, real-time audio input and
  output. Has a range of back-ends. MIT MIT 
⟡ libVLC 556  - Complete multimedia library for audio and video
  encoding, decoding, playing and streaming. GPL-2.0-only GPL-2.0-only 
⟡ lodepng 69  - Simple PNG image decoder and encoder, requiring no other
  dependencies. BSD-3-Clause BSD-3-Clause 
⟡ minimp3 536  - Lightweight MP3 decoder single header library. CC0-1.0 CC0-1.0 
⟡ Soundpipe 513  - Lightweight music DSP library. MIT 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 138  - Compiler of ASN.1 specifications into C source code. BSD-2-Clause BSD-2-Clause 
⟡ CHL 422  - C Hypertext Library - A library for writing web applications in
  C. GPL-3.0-only GPL-3.0-only 
⟡ czmq 226  - High-level binding for ZeroMQ. MPL-2.0 MPL-2.0 
⟡ Dyad.c 554  - Lightweight, easy, asynchronous networking library. MIT MIT 
⟡ GNU adns 155  - Advanced, easy-to-use, asynch-capable DNS client library
  and utilities. GPL-3.0-or-later GPL-3.0-or-later 
⟡ gumbo-parser 196  - HTML5 parsing library in C99.
  Apache-2.0 Apache-2.0 
⟡ H20 127  - A new-generation HTTP server. MIT MIT 
⟡ llhttp 197  - HTTP request/response parser. MIT MIT 
⟡ ldns 339  - Library to simplify DNS programming.
  BSD-3-Clause BSD-3-Clause 
⟡ libcurl 65  - Client-side URL transfer library, supporting a wide range of
  formats. curl curl 
⟡ LibEtPan 222  - Mail library providing an efficient network for IMAP,
  SMTP, POP and NNTP. BSD-3-Clause BSD-3-Clause 
⟡ libev 144  - Yet another event loop. BSD-2-Clause BSD-2-Clause 
⟡ libevent 124  - Event loop replacement for network servers. BSD-3-Clause BSD-3-Clause 
⟡ libhttpd 166  - Library to add basic web server capabilities to an
  application or embedded device. GPL-2.0-only GPL-2.0-only 
⟡ libhv 564  - Cross platform event loop library. BSD-3-Clause BSD-3-Clause 
⟡ libidn 164  - Implementation of the Stringprep, Punycode and IDNA
  specifications. GPL-3.0-or-later GPL-3.0-or-later 
⟡ libmicrohttpd 165  - Small library that makes it easy to run an HTTP
  server as part of another application. LGPL-2.1-or-later LGPL-2.1-or-later 
⟡ libnl 582  - libnl is a collection of libraries to provie APIs to the
  Netlink protocol (replacement for ioctl). It's primary use is to communicate
  with the Linux kernel, to modify networking state (interfaces, routing etc...).
  LGPL-2.1-only LGPL-2.1-only 
⟡ libonion 170  - HTTP server library, designed to be easy to
  use. Apache-2.0 Apache-2.0 
⟡ libpcap 566  - API provides to various kernel packet capture mechanism. BSD-3-Clause BSD-3-Clause 
⟡ libquickmail 399  - 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 GPL-3.0-or-later 
⟡ libsagui 172  - Library for cross-platform HTTP servers. LGPL-3.0-or-later LGPL-3.0-or-later 
⟡ libuhttpd 577  - A very flexible, lightweight and fully asynchronous HTTP server
  library based on libev and http-parser for Embedded Linux. MIT MIT 
⟡ LibVNCServer 464  - Cross-platform libraries to implement VNC server and/or
  client functionality. GPL-2.0-or-later GPL-2.0-or-later 
⟡ libwebsock 261  - Easy-to-use and powerful web socket library.
  LGPL-3.0-only LGPL-3.0-only 
⟡ libzmq 581  - Core ZeroMQ library, a high-performance asynchronous
  messaging library, aimed at use in distributed or concurrent applications.
  C API (backend C++) GPL-3.0-or-later GPL-3.0-or-later  with static
  linking exception
⟡ lwan 199  - Experimental, scalable, high-performance HTTP
  server. GPL-2.0-only GPL-2.0-only 
⟡ mongoose 171  - Embedded web server. GPL-2.0-only GPL-2.0-only 
⟡ MQTT-C 549  - A portable MQTT C client for embedded systems and PCs alike. MIT MIT 
⟡ nanomsg 139  - C-based implementation of ZeroMQ. MIT MIT 
⟡ NNG 106  - nanomsg-next-generation - lightweight brokerless messaging.
  MIT MIT 
⟡ oSip 179  - SIP implementation without additional
  dependencies. LGPL-2.1-or-later LGPL-2.1-or-later 
⟡ silgy 579  - Asynchronous HTTP(S) engine for C/C++ projects. MIT MIT 
⟡ socket99 203  - C99 wrapper for the BSD sockets API. ISC ISC 
⟡ twitc 237  - Mini library for interacting with the Twitter OAuth API. MIT MIT 
⟡ uriparser 100  - Strictly RFC 3986-compliant URI parsing and handling library.
  BSD-3-Clause BSD-3-Clause 
⟡ Wslay 460  - WebSocket library. Implements version 13 of the WebSocket
  protocol, as described in RFC 6455. MIT MIT 
⟡ zyre 419  - Framework for proximity-based peer-to-peer applications. MPL-2.0 MPL-2.0 

Numerical ##

⟡ apophenia 188  - Library for statistical and scientific computing. GPL-2.0-only GPL-2.0-only 
⟡ Arb 497  - Library for arbitrary-precision interval arithmetic.
  LGPL-2.1-or-later LGPL-2.1-or-later 
⟡ ATLAS 137  - Automatically Tuned Linear Algebra Software. BSD-3-Clause BSD-3-Clause 
⟡ clBLAS 439  - BLAS functions written in OpenCL. Apache-2.0 Apache-2.0 
⟡ cmathl 546  - Math library with a great variety of mathematical functions with CMake build support. Seeks to be close to C89/C90 compliant for portability. MIT MIT 
⟡ Cuba 316  - Library for multidimensional numerical integration. LGPL-3.0-only LGPL-3.0-only 
⟡ fft-c 537  - A high-performance Fourier Transform from netlib's fftpack; wrapped in a user-friendly format MIT  MIT 
⟡ FFTW 70  - The Fastest Fourier Transform in the West; a highly optimized
  fast Fourier transform routine. GPL-2.0-or-later GPL-2.0-or-later 
⟡ FLINT 255  - Fast Library for Number Theory; a library supporting arithmetic
  with numbers, polynomials, power series and matrices, among
  others. GPL-2.0-or-later GPL-2.0-or-later 
⟡ GLPK 159  - GNU Linear Programming Kit; a package designed for solving
  large-scale linear programming, mixed integer programming and other related
  problems. GPL-3.0-or-later GPL-3.0-or-later 
⟡ GMP 79  - GNU Multple Precision Arithmetic Library; a library for
  arbitrary-precision arithmetic. GPL-2.0-only GPL-2.0-only  or LGPL-3.0-only LGPL-3.0-only 
⟡ GNU MPC 175  - Library for complex number arithmetic. LGPL-3.0-or-later LGPL-3.0-or-later 
⟡ GNU MPFR 176  - Library for arbitrary-precision floating-point
  arithmetic. LGPL-3.0-or-later LGPL-3.0-or-later 
⟡ GNU MPRIA 177  - Portable mathematics library for multi-precision rational
  interval arithmetic. GPL-3.0-or-later GPL-3.0-or-later 
⟡ GSL 47  - The GNU Scientific Library; a sophisticated numerical
  library. GPL-3.0-only GPL-3.0-only .
⟡ KISS FFT 71  - Simple fast Fourier transform library. BSD-3-Clause BSD-3-Clause 
⟡ LAPACKE 133  - Interface to LAPACK 134 . BSD-3-Clause BSD-3-Clause 
⟡ LibTomMath 461  - Portable, number-theoretic, multiple-precision integer
  library. Supports algebra, digit manipulation, modular reductions, and various
  number-theoretic routines. Public domain.
⟡ LibTomPoly 463  - Polynomial-related maths library. Public domain.
⟡ PARI/GP 256  - Computer algebra system for number theory; includes a
  compiler to C. GPL-2.0-or-later GPL-2.0-or-later 
⟡ PETSc 282  - Suite of data structures and routines for scalable parallel
  solution of scientific applications modelled by partial differential
  equations. BSD-2-Clause BSD-2-Clause 
⟡ SCS 483  - Splitting Conic Solver; a numerical optimization package for
  solving large-scale convex cone problems. MIT MIT 
⟡ SLEPc 283  - Library for the solution of large, sparse eigenvalue
  problems on parallel computers. LGPL-3.0-only LGPL-3.0-only 
⟡ TomsFastMath 462  - Set of optimized maths operations (in assembly),
  suitable for cryptographic use. Public domain.
⟡ Yeppp! 72  - Fast, SIMD-optimized mathematical library. BSD-3-Clause BSD-3-Clause 

Profiling ##

⟡ gperftools 295  - Collection of utilities for measuring and improving
  performance. BSD-3-Clause BSD-3-Clause 
⟡ gprof 86  - Performance analysis tool. Part of GNU binutils.
  GPL-3.0-or-later GPL-3.0-or-later 
⟡ OProfile 475  - Statistical profiler for Linux. Can profile any code
  (including the kernel!) with low overhead and without recompilation. GPL-2.0-only GPL-2.0-only 
⟡ perf 375  - Linux kernel-based profiler with a lot of functionality.
  GPL-2.0-only GPL-2.0-only 

PDF ##

⟡ pdfio 612  - PDFio is a simple C library for reading and writing PDF files.Apache-2.0 Apache-2.0 

Regex ##

⟡ Onigmo 518  - Fork of Oniguruma, supporting more advanced regexps.
  BSD-2-Clause BSD-2-Clause 
⟡ Oniguruma 517  - Regex library supporting a wide range of encodings, and
  incorporating many security-oriented fixes. BSD-2-Clause BSD-2-Clause 
⟡ PCRE 83  - Implementation of regexes identical to that of
  Perl 5. BSD-3-Clause BSD-3-Clause 
⟡ SLRE 80  - Super Light Regular Expression library; a small
  implementation of a subset of Perl regex syntax.
  GPL-2.0-only GPL-2.0-only 
⟡ TRE 82  - POSIX-compliant, feature-full regex library. BSD-2-Clause BSD-2-Clause 

Serialization ##

⟡ binn 400  - Binary serialization format, meant to be compact, fast and
  easy-to-use. Apache-2.0 Apache-2.0 
⟡ c-capnproto 130  - Implementation of the Cap'n Proto serialization
  protocol. MIT MIT 
⟡ cmp 377  - Implementation of the MessagePack 379  serialization
  protocol. MIT MIT 
⟡ flatcc 187  - FlatBuffers 145  compiler and library.
  Apache-2.0 Apache-2.0 
⟡ libavro 140  - Implementation of the Avro data serialization system. Apache-2.0 Apache-2.0 
⟡ mpack 378  - Another implementation of the MessagePack 379  serialization
  protocol. MIT MIT 
⟡ OPIC 397  - Object Persistence in C; a revolutionary serialization framework,
  with matching on-disk and in-memory representations. GPL-3.0-or-later GPL-3.0-or-later 
⟡ protobuf-c 129  - Implementation of Google Protocol Buffer. BSD-2-Clause BSD-2-Clause 
⟡ tpl 473  - Small binary serialization library. MIT MIT 
⟡ xdr 131  - External Data Representation; a standard for data
  serialization. Standard (no license applicable).
⟡ pbtools 555  - Google Protocol Buffers C source code generator. MIT MIT 

Source Code Collections ##

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

⟡ CCAN 103  - Modelled after Perl's CPAN, this is a big collection of code
  that does stuff. The full list is here 104 . Various licenses, all
  open source.
⟡ clib 26  - Something of a package manager. Comes with
  a bunch of libraries of its own 27 . MIT MIT 
⟡ gnulib 46  - Collection of common GNU code. Various licenses, all
  open source.
⟡ libdjb 292  - Collection of libraries doing various things. (Apparently)
  public domain.
⟡ mmx 448  - Collection of single-header libraries. Various licenses, all
  open source.
⟡ par 456  - Bunch of single-file libraries. MIT MIT 
⟡ Snippets 220  - Useful code snippets and header-only libraries.
  Public domain.
⟡ stb 114  - Range of single-file libraries. Public domain.
⟡ tinyheaders 108  - Collection of header-only libraries, primarily oriented
  toward game development. Zlib Zlib 
⟡ zpl 602  - C99 cross-platform header-only library with many goodies. BSD-3-Clause, Unlicense BSD-3-Clause, Unlicense 

Standard Libraries ##

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

⟡ Bionic 4  - Google's standard library, developed for Android. BSD-3-Clause BSD-3-Clause 
⟡ cloudlibc 486  - Standard library based on the concept of
  capability-based security 487 . BSD-2-Clause BSD-2-Clause 
⟡ dietlibc 9  - Standard library designed for the smallest possible
  binaries. GPL-2.0-only GPL-2.0-only 
⟡ glibc 57  - The GNU C Library; an implementation of the standard
  library. LGPL-2.1-only LGPL-2.1-only .
⟡ musl 10  - Standard library, compatible with POSIX 2008 and C11. Designed
  for static linking. MIT MIT 
⟡ PDCLib 447  - The Public Domain C Library. Implements most of C99 and some of
  C11. CC0-1.0 CC0-1.0 
⟡ uClibc-ng 12  - Small C library for developing embedded systems.
  LGPL-2.1-or-later LGPL-2.1-or-later 

Template libraries

⟡ CTL 613  - C CONTAINER TEMPLATE LIBRARY (CTL) MIT MIT 

String Manipulation ##

⟡ bstring 116  - The Better String Library. BSD-3-Clause BSD-3-Clause 
⟡ ICU 67  - International Components for Unicode; a library for Unicode
  support. ICU ICU 
⟡ levenstein.c 360  - Levenstein distance 334  algorithm implementation.
  MIT MIT .
⟡ libunistring 173  - Library for manipulating Unicode
  strings. LGPL-3.0-only LGPL-3.0-only 
⟡ libgiconv 163  - Text conversion library. LGPL-2.1-only LGPL-2.1-only 
⟡ librope 479  - UTF-8 rope ('heavy' string) library. MIT MIT 
⟡ SDS 29  - 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 26 . BSD-2-Clause BSD-2-Clause 
⟡ stmr.c 383  - Porter Stemmer 367  algorithm implementation. MIT MIT 
⟡ str 587  - Yet another string library for C language. BSD-3-Clause BSD-3-Clause 
⟡ StringZilla 623  - Up to 10x faster SIMD and SWAR-accelerated string search, sort, hashes, edit distances, alignments, and generators. Apache-2.0 Apache-2.0 
⟡ utf8.h 472  - Single-header UTF-8 library, designed to mimic C-style string
  functions. Public domain.
⟡ utf8proc 469  - Library for processing UTF-8 data. MIT MIT 

Structured File Processing ##

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

CSV ###

⟡ libcsv 387  - Simple, streaming CSV parser. LGPL-2.1-or-later LGPL-2.1-or-later 

JSON ###

⟡ Jansson 53  - Library for encoding, decoding and manipulating JSON. MIT MIT 
⟡ jfes 488  - JSON For Embedded Systems; simple JSON engine without any
  dependencies. MIT MIT 
⟡ jsmn 120  - Minimalistic JSON parser. MIT MIT 
⟡ json 39  - Simple, low-memory-use JSON parser. MIT MIT 
⟡ json-c 8  - Easily work with JSON in C. Comes with a reference-counted object
  model, and aims for conformance with RFC 7159 11 . MIT MIT 
⟡ json.h 431  - Single-file non-streaming JSON parser. Unlicense Unlicense 
⟡ parson 32  - Two-file, C89-compatible JSON parser. MIT MIT 
⟡ WJElement 77  - Advanced JSON manipulation library, with support for JSON
  Schema. LGPL-2.0-or-later LGPL-2.0-or-later  or
  LGPL-2.1-or-later LGPL-2.1-or-later  or LGPL-3.0-or-later LGPL-3.0-or-later 
⟡ YAJL 60  - Fast streaming JSON parser library. ISC ISC 

INI ###

⟡ inih 547  - Small and simple INI file parser, good for embedded systems. BSD-3-Clause BSD-3-Clause 
⟡ iniparser 336  - Parser for .ini files. MIT MIT 
⟡ libconfini 122  - Yet another INI parser. GPL-3.0-only GPL-3.0-only 
⟡ minIni 109  - Small and portable INI parser. Apache-2.0 Apache-2.0 

Others ###

⟡ libbson 235  - BSON utility library. Apache-2.0 Apache-2.0 
⟡ libcbor 573 : CBOR protocol implementation for C and others. MIT MIT 
⟡ libconfuse 135  - Small configuration file parser library. ISC ISC 
⟡ libelf 310  - Simple library for parsing ELF files. MIT MIT 
⟡ libucl 239  - Universal configuration library parser. BSD-2-Clause BSD-2-Clause 
⟡ libxo 407  - 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 BSD-2-Clause 

XML ###

⟡ Expat 89  - Stream-oriented XML parser. MIT MIT 
⟡ libxml2 62  - Standards-compliant, portable XML parser. MIT MIT 
⟡ xml 569  - Simple, low-memory-use XML parser / tokenizer. MIT MIT 

YAML ###

⟡ libYAML 341  - YAML 1.1 parser and emitter. MIT MIT 

Signal Processing ##

⟡ libsigrok 601  -  signal analysis software suite that supports various
device types (such as logic analyzers, oscilloscopes, multimeters, and more). GPL GPL 

Testing ##

⟡ CHEAT 84  - Simple unit testing framework. BSD-2-Clause BSD-2-Clause 
⟡ Check 59  - Unit testing framework. LGPL-2.1-only LGPL-2.1-only 
⟡ ciut 5  - A modern minimal hassle unit test framework. MIT MIT 
⟡ clar 470  - Clear and simple unit testing framework. MIT MIT 
⟡ CMock 297  - Mock/stub generator. MIT MIT 
⟡ cmocka 141  - Unit testing framework with support for mock objects. Apache-2.0 Apache-2.0 
⟡ Criterion 246  - KISS, non-intrusive test framework. MIT MIT 
⟡ ctest 503  - Yet another unit testing framework. Apache-2.0 Apache-2.0 
⟡ CUnit 94  - Another unit testing framework.
  LGPL-2.1-or-later LGPL-2.1-or-later 
⟡ greatest 58  - Unit testing library in one file, with no memory
  allocation. ISC ISC 
⟡ minctest 394  - Unit testing microlibrary. BSD-3-Clause BSD-3-Clause 
⟡ munit 392  - Small unit testing framework. MIT MIT 
⟡ Nala 560  - A test framework for C projects. MIT MIT 
⟡ Rexo 563  - Framework for C89/C++ featuring automatic registration of tests and a polished API. Unlicense Unlicense 
⟡ Tau 609  -  A Micro Unit testing framework for C/C++ (~1k lines of code). Includes a rich set of assertion macros, supports automatic test 
registration and can output to multiple formats, like the TAP format or JUnit XML. Supported on Linux, macOS, FreeBSD, and Windows. MIT MIT 
⟡ theft 302  - Property-based testing (similar to Quickcheck 301 ). MIT MIT 
⟡ Unity 296  - Simple unit testing framework. MIT MIT 
⟡ utest 386  - Single-header unit testing library. Unlicense 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 92  - Notepad++ autocompletion plugin. Works with all
  identifiers recognized by Ctags. This is a download link. GPL-2.0-or-later GPL-2.0-or-later 
⟡ CEDET 250  - Collection of Emacs Development Environment Tools; designed to
  provide IDE-like features to Emacs. Built-in.
  GPL-3.0-or-later GPL-3.0-or-later 
⟡ Flycheck 149  - Modern syntax checking for Emacs. For C, it can use either
  GCC or Clang as a back-end. GPL-3.0-or-later GPL-3.0-or-later 
⟡ Neomake 441  - Async :make and linting framework for Neovim/Vim. MIT MIT 
⟡ Syntastic 186  - Syntax checking and linting for Vim. WTFPL WTFPL 
⟡ YASnippet 150  - Emacs code template system, with C templates for common
  snippets. GPL-3.0-or-later GPL-3.0-or-later 
⟡ YouCompleteMe 151  - Code completion engine for Vim.
  GPL-3.0-only GPL-3.0-only 

Tools ##

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

⟡ Artistic Style 314  - Fast and small automatic source code formatter that
  supports C. LGPL-3.0-only LGPL-3.0-only 
⟡ address-sanitizer 288  - Fast memory error detector.
  Apache-2.0 Apache-2.0 
⟡ bcc 619  - A byte array generator to import binary files directy from C in
  the spirit of xxd. ISC ISC 
⟡ c 276  - Compile and execute C "scripts" in one go on the command line. Also
  has shebang support. MIT MIT 
⟡ c99sh 113  - Run C files using hash-bang. BSD-2-Clause BSD-2-Clause 
⟡ cdecl 347  - Online service to translate C declarations into English and
  vice versa. Public domain.
⟡ cinclude2dot 280  - Graphs include dependencies in a project using
  Graphviz. GPL-1.0-or-later 335  or GPL-2.0-or-later GPL-2.0-or-later  or
  GPL-3.0-or-later GPL-3.0-or-later 
⟡ ClangCheck 502  - Static analysis tool, designed to work with Clang.
  NCSA NCSA 
⟡ conan.io 304  - Something of a package manager for C. MIT MIT .
⟡ Cppcheck 501  - Static analysis tool. Despite the name, works well with C.
  GPL-3.0-or-later GPL-3.0-or-later 
⟡ Glade 328  - RAD tool to enable quick development of GTK+
  GUIs. GPL-2.0-only GPL-2.0-only 
⟡ GMSL 331  - GNU Make Standard Library; a collection of additional
  functionality for GNU Make. BSD-3-Clause BSD-3-Clause 
⟡ GNU Global 330  - Source code tagging tool. GPL-3.0-only GPL-3.0-only 
⟡ GPP 269  - General-purpose preprocessor. More versatile than the C
  preprocessor, but more flexible than m4.
  LGPL-3.0-or-later LGPL-3.0-or-later 
⟡ Highlight 333  - Converts source code to formatted text with nice
  highlighting. GPL-3.0-only GPL-3.0-only 
⟡ include-what-you-use 289  - Helps find unecessary inclusions and make
  suggestions for fixing them. Based on LLVM/Clang (and only works with
  it). NCSA NCSA 
⟡ incbin 592  - Include binary files in your C/C++ applications with ease Unlicense Unlicense 
⟡ indent 315  - 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 GPL-3.0-or-later 
⟡ SMACK 500  - Modular software verification toolchain and a self-contained
  software verifier. Currently only works with programs compiled using Clang.
  MIT MIT 
⟡ unifdef 290  - Removes #ifdef and #if directives with their delimited text
  without touching any other part of the file. BSD-3-Clause BSD-3-Clause  or
  BSD-2-Clause BSD-2-Clause 

Utilities ##

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

⟡ ApeTagLibs 345  - Library for working with APEv2 tags. MIT MIT 
⟡ argparse 413  - Command-line argument parsing library, inspired by
  Python's argparse module. MIT MIT 
⟡ attr 425  - Commands for manipulating filesystem extended
  attributes. GPL-2.0-or-later GPL-2.0-or-later 
⟡ bfd 157  - Library for manipulating binary object files. Part of GNU
  binutils. GPL-3.0-or-later GPL-3.0-or-later 
⟡ Caffeine 496  - Library for building daemons and services for Linux and
  FreeBSD systems. LGPL-2.1-or-later LGPL-2.1-or-later 
⟡ CException 298  - Implementation of exceptions. MIT MIT 
⟡ CommonMark 223  - Implementation of the CommonMark spec.
⟡ cosmopolitan 597  - fast portable static native textmode containers (build C programs for Linux\Mac\Windows in one go)
  Variety of licenses, all open source 224 .
⟡ cpu\_features 319  - Get CPU features at runtime. Apache-2.0 Apache-2.0 .
⟡ CRIU 440  - Checkpoint/Restore In Userspace; a software tool (with a C API)
  for 'freezing' a running application to disk, then restoring
  it. GPL-2.0-only GPL-2.0-only  or LGPL-2.1-only LGPL-2.1-only 
⟡ D-Bus 430  - Simple way for applications to talk to one
  another. AFL-2.1 AFL-2.1  or GPL-2.0-or-later GPL-2.0-or-later 
⟡ Discount 438  - Simple implementation of a Markdown parser. BSD-3-Clause BSD-3-Clause 
⟡ dlx 388  - Implementation of Knuth's Algorithm X 389 , with example
  solvers. GPL-3.0-or-later GPL-3.0-or-later 
⟡ docopt.c 270  - Implementation of a command-line option parser. MIT MIT 
⟡ dyncall 281  - Another foreign function interface library. MIT MIT 
⟡ GNU FreeIPMI 158  - In-band and out-of-band IPMI
  implementation. GPL-3.0-only GPL-3.0-only 
⟡ GNU gperf 351  - Perfect hash function generator, given a list of
  strings. Outputs C code. GPL-3.0-or-later GPL-3.0-or-later 
⟡ GNU Libffcall 162  - Collection of libraries for building foreign function
  interfaces. GPL-3.0-or-later GPL-3.0-or-later 
⟡ Hoedown 405  - Fully standards-compliant, extension-supporting, UTF-8
  aware, fast Markdown parser. MIT MIT 
⟡ Kitsune 355  - Efficient, general-purpose framework for dynamic software
  updating. LGPL-3.0-or-later LGPL-3.0-or-later 
⟡ libCello 96  - Library introducing higher-level programming to
  C. BSD-3-Clause BSD-3-Clause 
⟡ libcmark 436  - Library for parsing the CommonMark dialect of
  Markdown. BSD-2-Clause BSD-2-Clause 
⟡ libcoap 136  - Implementation of the Constrained Application Protocol 117 .
  GPL-2.0-or-later GPL-2.0-or-later  or BSD-2-Clause BSD-2-Clause 
⟡ libcox 373  - Library which permits cross-platform system calls and
  standard utilities across different operating systems.
  BSD-2-Clause BSD-2-Clause 
⟡ libffi 128  - Portable foreign-function interface library. MIT MIT 
⟡ libgeohash 499  - Pure C implementation of the Geohash algorithm.
  BSD-3-Clause BSD-3-Clause 
⟡ libgit2 61  - Portable implementation of the Git core methods, provided as a
  re-entrant linkable library. Custom license 41 .
⟡ libgss 161  - Generic Security Service.
  GPL-3.0-or-later GPL-3.0-or-later 
⟡ libimobiledevice 354  - Cross-platform protocol library to communicate
  with iThings. LGPL-2.1-or-later LGPL-2.1-or-later 
⟡ libnfc 332  - Platform-independent Near-Field Communication
  library. LGPL-3.0-only LGPL-3.0-only 
⟡ libpostal 434  - Library for parsing and normalization of street addresses
  around the world. Powered by statistical NLP and open geo data. MIT MIT 
⟡ libtrading 455  - 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 BSD-2-Clause 
⟡ libusb 306  - Provides generic access to USB devices.
  LGPL-2.1-or-later LGPL-2.1-or-later 
⟡ libuv 56  - Cross-platform asynchronous I/O. MIT MIT 
⟡ libvldmail 3  - Your friendly email validation library. No external
  dependencies (not even regexps). WTFPL WTFPL 
⟡ linenoise 504  - Small, self-contained alternative to readline and
  libedit. BSD-2-Clause BSD-2-Clause 
⟡ libXDGdirs 589  - An implementation of XDG Base Directory Specification
  MIT MIT 
⟡ MegaMimes 31  - Library for getting the MIME 30  types of a file.
  MIT MIT 
⟡ ncurses 178  - Coloured terminal UI library. MIT MIT 
⟡ netbsd-curses 494  - Simplified and small version of ncurses, with the same
  interface. BSD-3-Clause BSD-3-Clause 
⟡ nope.c 209  - Ultra-light software platform for scalable server-side and
  networking applications (think node.js for C programmers). GPL-2.0-only GPL-2.0-only 
⟡ obj.h 580  - A single-header supports OOP in pure C. MIT MIT 
⟡ parg 274  - A single-file reimplementation of getopt with better defaults.
  CC0-1.0 CC0-1.0 
⟡ pbc 236  - Protocol buffers library. MIT MIT 
⟡ progressbar 453  - Easy-to-use library for displaying text progress bars.
  BSD-3-Clause BSD-3-Clause 
⟡ rabbitmq-c 228  - Client library for RabbitMQ 229 . MIT MIT 
⟡ Ragel 54  - DSL for state machines that compiles to C. GPL-2.0-only GPL-2.0-only 
⟡ rmw 622  - safe-remove utility for the command line that can purge items from your waste directories after x number of days. GPL-3.0-or-later GPL-3.0-or-later 
⟡ Rogueutil 565  - Cross-platform library for creating text-based user
  interfaces (TUI) Apache-2.0 Apache-2.0 
⟡ sort 190  - Collection of sorting routines, which type-specialize at
  compile-time with a user-defined type. MIT MIT 
⟡ termbox 396  - Library for writing text-based interfaces. MIT MIT 
⟡ tinyexpr 395  - Tiny recursive-descent parser, compiler and evaluation
  engine for simple mathematical expressions. BSD-3-Clause BSD-3-Clause 
⟡ tm 543  - ⏱ Timer and Timeline Utils for C. MIT MIT 
⟡ Tulip Indicators 449  - Library of functions for technical analysis of
  financial data. LGPL-3.0-or-later LGPL-3.0-or-later 
⟡ whereami 167  - One-file library for locating the current executable on the
  file system. WTFPL WTFPL 
⟡ XLSX I/O 344  - Cross-platform library for reading and writing .xlsx
  files. MIT MIT 
⟡ xlsx_drone 596  - Fast Microsoft Excel's .xlsx reader. MIT MIT   
⟡ zlog 437  - Reliable, pure C logging library.
  LGPL-2.1-only LGPL-2.1-only 
⟡ zproto 421  - Protocol framework for ZeroMQ. MIT MIT 
⟡ Metalang99 603  - Full-blown preprocessor metaprogramming. MIT MIT 
⟡ Datatype99 604  - Algebraic data types for C99. MIT MIT 

Web Frameworks ##

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

⟡ Concord 617  - A Discord API wrapper library written in C. MIT MIT 
⟡ facil.io 118  - Mini-framework for web applications. Includes a fast HTTP and
  Websocket server, and also supports custom protocols. MIT MIT 
⟡ kcgi 562  - CGI and FastCGI library for C ISC ISC .
⟡ KLone 423  - Fully featured, multi-platform, web application development
  framework, targeted especially at embedded systems and
  appliances. BSD-3-Clause BSD-3-Clause 
⟡ Kore 415  - Easy-to-use web application framework for writing scalable
  web APIs in C. ISC ISC 

Windows Environments ##

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

⟡ Cygwin 253  - Designed to emulate a POSIX-compatible environment extensively
  under Windows. Various licenses, all open source 254 .
⟡ MinGW-w64 287  - Minimalist environment for C development on Windows with
  64 bit support. Various licenses, all open source 252 .
⟡ MSYS2 428  - 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.


AFL-2.1 : https://spdx.org/licenses/AFL-2.1.html
AGPL-3.0-only : https://spdx.org/licenses/AGPL-3.0-only.html
AGPL-3.0-or-later : https://spdx.org/licenses/AGPL-3.0-or-later.html
Apache-2.0 : https://spdx.org/licenses/Apache-2.0.html
BSD-1-Clause : https://spdx.org/licenses/BSD-1-Clause.html
BSD-2-Clause : https://spdx.org/licenses/BSD-2-Clause.html
BSD-3-Clause : https://spdx.org/licenses/BSD-3-Clause.html
BSD-4-Clause : https://spdx.org/licenses/BSD-4-Clause.html
CC0-1.0 : https://spdx.org/licenses/CC0-1.0.html
curl : https://spdx.org/licenses/curl.html
GPL-2.0-only : https://spdx.org/licenses/GPL-2.0-only.html
GPL-2.0-or-later : https://spdx.org/licenses/GPL-2.0-or-later.html
GPL-3.0-only : https://spdx.org/licenses/GPL-3.0-only.html
GPL-3.0-or-later : https://spdx.org/licenses/GPL-3.0-or-later.html
ICU : https://spdx.org/licenses/ICU.html
ISC : https://spdx.org/licenses/ISC.html
LGPL-2.0-or-later : https://spdx.org/licenses/LGPL-2.0-or-later.html
LGPL-2.1-only : https://spdx.org/licenses/LGPL-2.1-only.html
LGPL-2.1-or-later : https://spdx.org/licenses/LGPL-2.1-or-later.html
LGPL-3.0-only : https://spdx.org/licenses/LGPL-3.0-only.html
LGPL-3.0-or-later : https://spdx.org/licenses/LGPL-3.0-or-later.html
Libpng : https://spdx.org/licenses/Libpng.html
MIT : https://spdx.org/licenses/MIT.html
MPL-2.0 : https://spdx.org/licenses/MPL-2.0.html
NCSA : https://spdx.org/licenses/NCSA.html
OLDAP-2.8 : https://spdx.org/licenses/OLDAP-2.8.html
PostgreSQL : https://spdx.org/licenses/PostgreSQL.html
TCL : https://spdx.org/licenses/TCL.html
Unlicense : https://spdx.org/licenses/Unlicense.html
WTFPL : https://spdx.org/licenses/WTFPL.html
X11 : https://spdx.org/licenses/X11.html
Zlib : https://spdx.org/licenses/Zlib.html

1 : https://github.com/Dead2/zlib-ng
2 : https://github.com/Cyan4973/FiniteStateEntropy
3 : https://github.com/dertuxmalwieder/libvldmail
4 : https://github.com/aosp-mirror/platform_bionic
5 : https://github.com/yhfudev/cpp-ci-unit-test.git
6 : https://port70.net/~nsz/c/c89/c89-draft.html
7 : https://en.wikipedia.org/wiki/The_C_Programming_Language
8 : https://github.com/json-c/json-c
9 : https://www.fefe.de/dietlibc/
10 : https://musl.libc.org/
11 : https://tools.ietf.org/html/rfc7159
12 : https://uclibc-ng.org/
13 : https://opensource.org/osd
14 : https://www.gtk.org/

16 : http://webserver2.tecgraf.puc-rio.br/iup/
17 : https://github.com/saitoha/libsixel
18 : https://www.enlightenment.org?p=about%252Flibs
19 : http://www.tcl.tk/

21 : http://xforms-toolkit.org/
22 : https://www.sqlite.org/
23 : https://unqlite.org/
24 : https://github.com/google/brotli
25 : https://en.wikipedia.org/wiki/Dynamic_array
26 : https://github.com/clibs/clib
27 : https://github.com/clibs/clib/wiki/Packages
28 : http://www.koanlogic.com/libu/
29 : https://github.com/antirez/sds
30 : https://en.wikipedia.org/wiki/MIME
31 : https://trumpowen.github.io/MegaMimes
32 : https://github.com/kgabis/parson
33 : https://www.codeproject.com/Articles/6154/Writing-Efficient-C-and-C-Code-Optimization
34 : http://re2c.org/index.html
35 : http://shop.oreilly.com/product/0636920033677.do
36 : http://shop.oreilly.com/product/0636920028000.do
37 : https://www.openmp.org/
38 : https://clang.llvm.org/
39 : https://github.com/recp/json
40 : https://gcc.gnu.org/
41 : https://github.com/libgit2/libgit2/blob/master/COPYING
42 : http://anjuta.org/
43 : https://www.geany.org/
44 : https://www.kdevelop.org/
45 : https://www.codelite.org/
46 : https://www.gnu.org/software/gnulib/
47 : https://www.gnu.org/software/gsl/
48 : https://liballeg.org
49 : https://github.com/vasi/pixz
50 : https://www.libsdl.org/
51 : https://redis.io/
52 : http://zeromq.org/
53 : http://www.digip.org/jansson/
54 : http://www.colm.net/open-source/ragel/
55 : https://dl.acm.org/citation.cfm?id=179241
56 : http://libuv.org
57 : https://www.gnu.org/software/libc/
58 : https://github.com/silentbicycle/greatest
59 : https://libcheck.github.io/check
60 : https://lloyd.github.io/yajl/
61 : https://libgit2.org/
62 : http://xmlsoft.org/
63 : https://www.ffmpeg.org/
64 : http://knking.com/books/c2/index.html
65 : https://curl.haxx.se/libcurl/
66 : https://github.com/Snaipe/libcsptr
67 : http://site.icu-project.org/
68 : https://libspng.org/
69 : https://lodev.org/lodepng/
70 : http://www.fftw.org/
71 : https://sourceforge.net/projects/kissfft/
72 : https://bitbucket.org/MDukhan/yeppp
73 : https://graphics.stanford.edu/~seander/bithacks.html
74 : http://pcc.ludd.ltu.se/
75 : http://pcc.ludd.ltu.se/licenses/
76 : http://attractivechaos.github.io/klib/#About
77 : https://github.com/netmail-open/wjelement/
78 : http://apr.apache.org/
79 : https://gmplib.org/
80 : https://github.com/cesanta/slre
81 : http://tiny-rex.sourceforge.net/
82 : https://github.com/laurikari/tre/
83 : http://www.pcre.org/
84 : https://github.com/Tuplanolla/cheat
85 : http://www.valgrind.org/
86 : https://www.gnu.org/software/binutils/
87 : https://www.gnu.org/software/gdb/
88 : https://fragglet.github.io/c-algorithms
89 : http://expat.sourceforge.net/
90 : https://www.sfml-dev.org/download/csfml/
91 : https://www.sfml-dev.org/index.php
92 : http://freeweb.siol.net/rmihor/NppCCompletionPlugin.zip
93 : https://github.com/keybuk/libnih
94 : http://cunit.sourceforge.net/
95 : https://rr-project.org/
96 : http://libcello.org/
97 : http://nethack4.org/projects/aimake/
98 : https://www.glfw.org/
99 : http://freeglut.sourceforge.net
100 : https://uriparser.github.io
101 : https://github.com/orangeduck/Corange
102 : http://shop.oreilly.com/product/0636920015482.do
103 : http://ccodearchive.net/
104 : http://ccodearchive.net/list.html
105 : https://www.symas.com/lmdb
106 : https://nanomsg.github.io/nng/
107 : https://ioquake3.org
108 : https://github.com/RandyGaul/tinyheaders
109 : https://github.com/compuphase/minIni
110 : https://www.openssl.org/
111 : https://www.openssl.org/source/license.html
112 : http://www.gnutls.org/
113 : https://github.com/RhysU/c99sh
114 : https://github.com/nothings/stb
115 : https://tinycthread.github.io/
116 : http://mike.steinert.ca/bstring/
117 : http://coap.technology/
118 : http://facil.io/
119 : https://www.enlightenment.org
120 : https://zserge.com/jsmn.html
121 : https://www.postgresql.org/
122 : https://madmurphy.github.io/libconfini/html/index.html
123 : https://gstreamer.freedesktop.org/
124 : http://libevent.org/
125 : https://www.hboehm.info/gc/
126 : https://github.com/rampantpixels/rpmalloc
127 : https://h2o.examp1e.net/
128 : https://github.com/atgreen/libffi
129 : https://github.com/protobuf-c/protobuf-c
130 : https://github.com/jmckaskill/c-capnproto
131 : https://en.wikipedia.org/wiki/External_Data_Representation
132 : https://bitbucket.org/martijnj/msgpackalt
133 : http://www.netlib.org/lapack/lapacke.html
134 : http://www.netlib.org/lapack/
135 : https://github.com/martinh/libconfuse
136 : https://github.com/obgm/libcoap
137 : http://math-atlas.sourceforge.net/
138 : http://lionet.info/asn1c/compiler.html
139 : https://github.com/nanomsg/nanomsg
140 : http://avro.apache.org/docs/current/api/c/index.html#_introduction_to_avro_c
141 : https://cmocka.org/
142 : https://gnupg.org/related_software/libgcrypt
143 : https://github.com/libressl-portable/
144 : http://software.schmorp.de/pkg/libev.html
145 : https://google.github.io/flatbuffers/
146 : https://en.wikipedia.org/wiki/POSIX_Threads
147 : https://www.opengl.org/
148 : http://www.sgi.com/tech/opengl/?/license.html
149 : https://github.com/flycheck/flycheck
150 : http://joaotavora.github.io/yasnippet/
151 : https://github.com/ycm-core/YouCompleteMe
152 : https://sites.google.com/site/lccretargetablecompiler/
153 : https://github.com/drh/lcc/blob/master/CPYRIGHT
154 : https://github.com/swenson/vector.h
155 : https://www.gnu.org/software/adns/
156 : http://adtinfo.org/libavl.html/index.html
157 : http://sourceware.org/binutils/docs/bfd/
158 : https://gnu.org/software/freeipmi/index.html
159 : https://gnu.org/software/glpk/
160 : https://gnu.org/software/gsasl/
161 : https://gnu.org/software/gss/
162 : https://gnu.org/software/libffcall/
163 : https://gnu.org/software/libiconv/
164 : https://gnu.org/software/libidn/
165 : https://gnu.org/software/libmicrohttpd/
166 : https://www.hughes.com.au/products/libhttpd/
167 : https://github.com/gpakosz/whereami
168 : http://www.webdav.org/neon/
169 : http://mihl.sourceforge.net/
170 : https://www.coralbits.com/libonion/
171 : https://cesanta.com
172 : https://risoflora.github.io/libsagui/
173 : https://gnu.org/software/libunistring/
174 : https://gnu.org/software/libxmi/
175 : http://www.multiprecision.org/mpc/
176 : http://mpfr.loria.fr/index.html
177 : https://gnu.org/software/mpria/
178 : https://gnu.org/software/ncurses/
179 : https://gnu.org/software/osip/
180 : https://gnu.org/software/pth/
181 : https://savedparadigms.files.wordpress.com/2014/09/harbison-s-p-steele-g-l-c-a-reference-manual-5th-ed.pdf
182 : http://shop.oreilly.com/product/9780596004361.do
183 : http://shop.oreilly.com/product/0636920026136.do
184 : https://www.pearson.com/us/higher-education/program/Prata-C-Primer-Plus-6th-Edition/PGM4399.html
185 : http://www.planetpdf.com/codecuts/pdfs/ooc.pdf
186 : https://github.com/vim-syntastic/syntastic
187 : https://github.com/dvidelabs/flatcc
188 : http://apophenia.info
189 : https://github.com/b-k/apophenia/blob/master/install/COPYING
190 : https://github.com/swenson/sort
191 : http://steve-yegge.blogspot.co.nz/2008/10/universal-design-pattern.html
192 : http://libjpeg.sourceforge.net/
193 : https://libjpeg-turbo.virtualgl.org/
194 : https://www.libjpeg-turbo.org/About/License
195 : http://libccv.org/
196 : https://github.com/google/gumbo-parser
197 : https://llhttp.org
198 : https://download.libsodium.org/doc
199 : https://lwan.ws
200 : https://github.com/mozilla/mozjpeg
201 : https://github.com/redis/hiredis
202 : https://jvns.ca/blog/2014/12/14/fun-with-threads/
203 : https://github.com/silentbicycle/socket99
204 : http://danluu.com/malloc-tutorial/
205 : https://web.archive.org/web/20170620131430/https://www.tedunangst.com/flak/post/memcpy-vs-memmove
206 : https://blogs.oracle.com/linux/8-gdb-tricks-you-should-know-v2
207 : https://www.youtube.com/playlist?list=PLLX-Q6B8xqZ8n8bwjGdzBJ25X2utwnoEG
208 : http://nethack4.org/blog/building-c.html
209 : https://github.com/riolet/WAFer
210 : https://docs.google.com/presentation/d/1h49gY3TSiayLMXYmRMaAEMl05FaJ-Z6jDOWOz3EsqqQ/edit?pli=1#slide=id.gaf50702c_0153
212 : http://www.crasseux.com/books/ctut.pdf
213 : https://pdos.csail.mit.edu/6.828/2017/readings/pointers.pdf
214 : https://github.com/adamierymenko/huffandpuff
215 : https://sourceforge.net/projects/vtd-xml/
216 : https://michaelrsweet.github.io?Z3
217 : http://svn.msweet.org/mxml/trunk/COPYING
218 : http://ezxml.sourceforge.net/
219 : https://github.com/blunderer/libroxml
220 : https://github.com/DanielGibson/Snippets/
221 : https://github.com/id-Software/Quake-2
222 : http://www.etpan.org
223 : https://github.com/commonmark/commonmark-spec
224 : https://github.com/commonmark/commonmark-spec/blob/master/LICENSE
225 : https://github.com/id-Software/Quake
226 : http://czmq.zeromq.org
227 : https://marek.vavrusa.com/memory/
228 : https://github.com/alanxz/rabbitmq-c
229 : http://www.rabbitmq.com/
230 : http://zlib.net
231 : https://github.com/libretro/RetroArch
232 : https://www.libretro.com/
233 : http://mongoc.org/
234 : https://www.mongodb.org/
235 : https://github.com/mongodb/libbson
236 : https://github.com/cloudwu/pbc
237 : https://github.com/sinemetu1/twitc
238 : https://github.com/orangeduck/mpc
239 : https://github.com/vstakhov/libucl
240 : http://snaipe.me/c/c-smart-pointers/
241 : https://github.com/gpakosz/PackedArray
242 : http://concurrencykit.org
243 : http://repo.hu/projects/cchan/
244 : http://sophia.systems
245 : http://www.greenend.org.uk/rjk/tech/inline.html
246 : https://criterion.readthedocs.io/en/master
247 : https://port70.net/~nsz/c/c11/n1570.html
248 : https://en.wikibooks.org/wiki/C_Programming
249 : http://www.codeblocks.org/
250 : http://cedet.sourceforge.net/
251 : http://mingw.org/
252 : http://mingw.org/license
253 : https://cygwin.com/
254 : https://cygwin.com/licensing.html
255 : http://flintlib.org/
256 : http://pari.math.u-bordeaux.fr/
257 : http://blog.noctua-software.com/c-tricks.html
258 : https://port70.net/~nsz/c/c99/n1256.html
259 : https://spdx.org/licenses/EPL-1.0.html
260 : https://netbeans.org/
261 : https://github.com/JonnyWhatshisface/libwebsock
262 : http://c-faq.com/
263 : https://computing.llnl.gov/tutorials/pthreads/
264 : https://computing.llnl.gov/tutorials/openMP/
265 : https://computing.llnl.gov/tutorials/mpi/
266 : https://wiki.sei.cmu.edu/confluence/display/c/SEI+CERT+C+Coding+Standard
267 : http://blog.pkh.me/p/20-templating-in-c.html
268 : http://lipforge.ens-lyon.fr/www/crlibm/index.html
269 : https://logological.org/gpp
270 : https://github.com/docopt/docopt.c
271 : https://xmake.io/
273 : http://troydhanson.github.io/uthash/
274 : https://github.com/jibsen/parg
275 : http://blog.llvm.org/2011/05/what-every-c-programmer-should-know.html
276 : https://github.com/ryanmjacobs/c
277 : http://wolkykim.github.io/qlibc
278 : https://github.com/wolkykim/qlibc/blob/master/LICENSE
279 : https://gist.github.com/eatonphil/21b3d6569f24ad164365
280 : https://www.flourish.org/cinclude2dot/
281 : http://www.dyncall.org/
282 : http://www.mcs.anl.gov/petsc/
283 : http://slepc.upv.es/
284 : https://github.com/open-mpi/ompi
285 : http://www.mpich.org/
286 : http://git.mpich.org/mpich.git/blob_plain/6aab201f58d71fc97f2c044d250389ba86ac1e3c:/COPYRIGHT
287 : http://mingw-w64.yaxm.org/doku.php/start
288 : https://github.com/google/sanitizers
289 : https://github.com/include-what-you-use/include-what-you-use
290 : http://dotat.at/prog/unifdef/
291 : https://tls.mbed.org/
292 : http://www.fefe.de/djb/
293 : http://jemalloc.net
295 : https://github.com/gperftools/gperftools
296 : http://www.throwtheswitch.org/unity
297 : http://www.throwtheswitch.org/cmock
298 : http://www.throwtheswitch.org/cexception
299 : https://www.libtom.net
300 : https://pngquant.org/lib/
301 : https://wiki.haskell.org/Introduction_to_QuickCheck2
302 : https://github.com/silentbicycle/theft
303 : http://chipmunk-physics.net
304 : https://conan.io/
305 : https://faragon.github.io/libsrt.html
306 : https://libusb.info/
307 : https://www.gnu.org/software/complexity/
308 : http://www.eso.org/sci/software/cpl/
309 : https://www.cprover.org/cbmc/
310 : https://github.com/0intro/libelf
311 : https://github.com/matze/oclkit
312 : http://tuxfan.github.io/ocl-mla/
313 : http://c2html.sourceforge.net/whatisc2html.html
314 : http://astyle.sourceforge.net/
315 : https://www.gnu.org/software/indent/
316 : http://www.feynarts.de/cuba/
317 : http://www.gedanken.org.uk/software/cxref/
318 : http://www.doxygen.nl/
319 : https://github.com/google/cpu_features
320 : https://www.gnu.org/software/ddd/ddd.html
321 : http://docutils.sourceforge.net/
322 : https://hplgit.github.io/doconce/doc/web/index.html
323 : http://fabutil.org/
324 : https://www.gnu.org/software/make/
325 : https://github.com/libfann/fann
326 : https://github.com/centaurean/spookyhash
327 : https://github.com/attractivechaos/kann
328 : https://glade.gnome.org/
329 : https://cmake.org/
330 : https://www.gnu.org/software/global/
331 : https://gmsl.sourceforge.net/
332 : https://github.com/nfc-tools/libnfc
333 : http://www.andre-simon.de/index.php
334 : https://en.wikipedia.org/wiki/Levenshtein_distance
335 : https://spdx.org/licenses/GPL-1.0.html
336 : https://github.com/ndevilla/iniparser
337 : https://github.com/jtsiomb/kdtree
338 : http://www.oberhumer.com/opensource/lzo/
339 : http://www.nlnetlabs.nl/projects/ldns/index.html
340 : https://wiki.gnome.org/Projects/LibRsvg
341 : https://www.pyyaml.org/wiki/LibYAML
342 : https://www.xiph.org/ao/
343 : https://www.chiark.greenend.org.uk/~sgtatham/mp/
344 : https://brechtsanders.github.io/xlsxio/
345 : https://github.com/jeremyevans/ape_tag_libs/tree/master/c
346 : http://www.mission-base.com/peter/source/
347 : https://cdecl.org/
348 : https://mpv.io
349 : https://www.recurse.com/blog/5-learning-c-with-gdb
350 : https://github.com/P-p-H-d/mlib
351 : https://www.gnu.org/software/gperf/
352 : http://libmill.org/
353 : https://talloc.samba.org/talloc/doc/html/index.html
354 : https://github.com/libimobiledevice/libimobiledevice
355 : http://kitsune-dsu.com/
356 : https://github.com/abiggerhammer/hammer
357 : http://250bpm.com/blog:56
358 : https://web.archive.org/web/20170429175803/http://www.samnip.ps/thought/macro-storage-for-inverse-comma
359 : https://github.com/awslabs/s2n
360 : https://github.com/wooorm/levenshtein.c
361 : https://pp.ipd.kit.edu/firm/
362 : http://www.etalabs.net/compare_libcs.html
363 : http://ed-von-schleck.github.io/shoco
364 : https://github.com/antirez/smaz
365 : https://github.com/prideout/heman
366 : https://github.com/cacalabs/libcaca
367 : http://tartarus.org/martin/PorterStemmer/
368 : https://mesonbuild.com/
369 : https://icculus.org/twilight/darkplaces/
370 : http://orx-project.org
371 : https://github.com/AlexanderAgd/CLIST
372 : http://libsound.io
373 : http://libcox.symisc.net/
374 : https://proprogramming.org/some-unknown-features-or-tricks-in-c-language/
375 : https://perf.wiki.kernel.org/index.php/Main_Page
376 : https://xiph.org/ao/
377 : https://github.com/camgunz/cmp
378 : https://github.com/ludocode/mpack
379 : https://msgpack.org/
380 : http://www.oracle.com/us/products/database/berkeley-db
381 : https://spdx.org/licenses/AGPL-1.0.html
382 : http://www.libpng.org/
383 : https://github.com/wooorm/stmr.c
384 : http://cairographics.org/
385 : https://spdx.org/licenses/MPL-1.1.html
386 : https://github.com/evolutional/utest
387 : https://github.com/rgamble/libcsv
388 : https://github.com/blynn/dlx
389 : https://en.wikipedia.org/wiki/Knuth's_Algorithm_X
390 : https://github.com/sharow/libconcurrent
391 : https://hintjens.gitbooks.io/scalable-c/content/index.html
392 : https://nemequ.github.io/munit
393 : https://github.com/quixdb/squash
394 : https://github.com/codeplea/minctest
395 : https://github.com/codeplea/tinyexpr
396 : https://github.com/nsf/termbox
397 : http://opic.rocks/
398 : https://github.com/waruqi/tbox
399 : http://sourceforge.net/projects/libquickmail/
400 : https://github.com/liteserver/binn
401 : https://sourceforge.net/projects/giflib/
402 : https://github.com/libgd/libgd
403 : https://embed.cs.utah.edu/creduce/
404 : http://www.gnu.org/software/cflow/
405 : https://github.com/hoedown/hoedown
406 : https://github.com/srdja/Collections-C
407 : https://github.com/Juniper/libxo
408 : https://github.com/Immediate-Mode-UI/Nuklear
409 : https://github.com/blunderer/libroxml
410 : https://www.spinellis.gr/cscout/
411 : https://liblfds.org/
412 : https://codeplea.com/genann
413 : https://github.com/cofyc/argparse
414 : https://github.com/anholt/libepoxy
415 : https://kore.io/
416 : http://zeromq.org/
417 : https://wiki.gnome.org/action/show/Projects/LibRsvg?action=show&redirect=LibRsvg
418 : http://shop.oreilly.com/product/0636920033844.do
419 : https://github.com/zeromq/zyre
420 : https://github.com/zeromq/zproject
421 : https://github.com/zeromq/zproto
422 : https://github.com/it4e/CHL
423 : http://www.koanlogic.com/klone/
425 : http://savannah.nongnu.org/projects/attr/
426 : https://sourceforge.net/projects/tinyfiledialogs/
427 : http://www.bzip.org/
428 : http://msys2.github.io/
429 : http://www.libsigil.com/
430 : https://www.freedesktop.org/wiki/Software/dbus/
431 : https://github.com/sheredom/json.h
432 : http://lzip.nongnu.org/clzip.html
433 : http://lzip.nongnu.org/lzip.html
434 : https://github.com/openvenues/libpostal
435 : https://premake.github.io/
436 : https://github.com/jgm/cmark
437 : http://hardysimpson.github.io/zlog/
438 : http://www.pell.portland.or.us/~orc/Code/discount/
439 : https://github.com/clMathLibraries/clBLAS
440 : https://criu.org/Main_Page
441 : https://github.com/neomake/neomake
442 : http://libdill.org/
443 : https://nullprogram.com/blog/2015/02/17
444 : https://github.com/ands/lightmapper
445 : http://blosc.org/pages/blosc-in-depth
446 : https://github.com/Kazade/kazmath
447 : http://pdclib.e43.eu/
448 : https://github.com/vurtun/mmx
449 : https://tulipindicators.org/
450 : https://locklessinc.com/benchmarks_allocator.shtml
451 : https://locklessinc.com/
452 : https://github.com/distcc/distcc
453 : https://github.com/doches/progressbar
454 : http://mpitutorial.com/
455 : http://libtrading.org/
456 : https://github.com/prideout/par
457 : https://github.com/grimfang4/sdl-gpu
458 : http://www.mega-nerd.com/libsndfile/
459 : https://github.com/parallella/pal
460 : https://tatsuhiro-t.github.io/wslay/
461 : http://www.libtom.net/LibTomMath/
462 : http://www.libtom.net/TomsFastMath/
463 : http://www.libtom.net/LibTomPoly/
464 : https://github.com/LibVNC/libvncserver
465 : https://github.com/yosefk/checkedthreads
466 : https://ccache.dev/
467 : https://github.com/esneider/debug
468 : https://lldb.llvm.org/
469 : https://github.com/JuliaLang/utf8proc
470 : https://github.com/vmg/clar
471 : https://github.com/powturbo/TurboPFor
472 : https://github.com/sheredom/utf8.h
473 : https://github.com/troydhanson/tpl
474 : http://liburcu.org/
475 : http://oprofile.sourceforge.net/news/
476 : http://libcork.readthedocs.io/en/0.14.0/
477 : https://github.com/jppbsi/LibDEEP
478 : https://github.com/xant/libhl
479 : https://github.com/josephg/librope
480 : https://github.com/miracl/MIRACL
481 : https://github.com/RoaringBitmap/CRoaring
482 : http://roaringbitmap.org/
483 : https://github.com/cvxgrp/scs
484 : https://github.com/powturbo/TurboRLE
485 : https://github.com/trezor/trezor-crypto
486 : https://github.com/NuxiNL/cloudlibc
487 : https://en.wikipedia.org/wiki/Capability-based_security
488 : https://github.com/NeonMercury/jfes
489 : https://github.com/inikep/lizard
490 : https://nullprogram.com/blog/2017/03/30
491 : https://github.com/westes/flex
492 : https://www.gnu.org/software/bison/
493 : https://openquantumsafe.org/
494 : https://github.com/sabotage-linux/netbsd-curses
495 : https://github.com/lemire/clhash
496 : https://github.com/dmw/caffeine
497 : https://github.com/fredrik-johansson/arb
498 : https://github.com/theck01/offbrand_lib
499 : https://github.com/simplegeo/libgeohash
500 : https://github.com/smackers/smack
501 : http://cppcheck.sourceforge.net/
502 : https://clang.llvm.org/docs/ClangCheck.html
503 : https://github.com/bvdberg/ctest
504 : https://github.com/antirez/linenoise
505 : https://github.com/memononen/nanovg
506 : https://github.com/centaurean/density
507 : https://maciejczyzewski.github.io/retter
508 : http://lz4.github.io/lz4/
509 : https://github.com/spotify/sparkey
510 : http://facebook.github.io/zstd/
511 : https://libvips.github.io/libvips/
512 : https://github.com/priitj/whitedb
513 : http://paulbatchelor.github.io/proj/soundpipe.html
514 : https://github.com/atomicobject/heatshrink
515 : http://ebassi.github.io/graphene/
516 : https://www.raylib.com
517 : https://github.com/kkos/oniguruma
518 : https://github.com/k-takata/Onigmo
519 : https://github.com/lemire/simdcomp
520 : https://github.com/kuba--/zip
521 : https://www.scons.org/
522 : http://cyan4973.github.io/xxHash
523 : https://github.com/aubio/aubio
524 : https://github.com/groonga/groonga
525 : https://100.github.io/Cranium/
526 : http://www.saphir2.com/sphlib/
527 : https://github.com/google/highwayhash
528 : http://nullprogram.com/blog/2017/08/20/
529 : http://nullprogram.com/blog/2017/09/21/
530 : https://github.com/leo-yuriev/t1ha
531 : http://www.gii.upv.es/tlsf/
532 : https://github.com/minad/tlsf
533 : https://github.com/gildor2/fast_zlib
534 : https://github.com/ferreiradaselva/mathc
535 : https://github.com/ferreiradaselva/uastar
536 : https://github.com/lieff/minimp3
537 : https://github.com/adis300/fft-c
538 : https://github.com/nbulischeck/list.h
539 : https://github.com/shlomif/fc-solve
540 : http://www.shlomifish.org/rwlock/
541 : https://github.com/recp/ds
542 : https://github.com/recp/cglm
543 : https://github.com/recp/tm
544 : https://igraph.org/
546 : https://scientificc.github.io/cmathl/
547 : https://github.com/benhoyt/inih
548 : https://github.com/libarchive/libarchive
549 : https://github.com/LiamBindle/MQTT-C
550 : https://github.com/LeoVen/C-Macro-Collections
551 : https://github.com/mysql/mysql-server
553 : https://github.com/okuvshynov/b63
554 : https://github.com/rxi/dyad
555 : https://github.com/eerimoq/pbtools
556 : https://wiki.videolan.org/LibVLC
557 : https://github.com/SanderMertens/flecs
558 : https://github.com/librg/librg
559 : https://github.com/superjer/tinyc.games
560 : https://github.com/eerimoq/nala
561 : http://jstimpfle.de/projects/rb3ptr/rb3ptr.html
562 : https://kristaps.bsd.lv/kcgi
563 : https://github.com/christophercrouzet/rexo
564 : https://github.com/ithewei/libhv
565 : https://github.com/sakhmatd/rogueutil
566 : https://github.com/the-tcpdump-group/libpcap
567 : http://esbmc.org/
568 : https://ejdb.org/
569 : https://github.com/recp/xml
570 : https://github.com/recp/cmt
571 : https://github.com/recp/AssetKit
572 : https://github.com/shiyanhui/libcsp
573 : https://github.com/PJK/libcbor
574 : https://git.sr.ht/~mcf/cproc
575 : https://lvgl.io/
576 : https://github.com/ianh/owl
577 : https://github.com/zhaojh329/libuhttpd
578 : http://zinjai.sourceforge.net/
579 : https://github.com/silgy/silgy
580 : https://github.com/small-c/obj.h
581 : https://github.com/zeromq/libzmq
582 : https://www.infradead.org/~tgr/libnl/
583 : https://www.gnu.org/software/automake/manual/html_node/GNU-Build-System.html
584 : https://github.com/msune/autotools-skeleton
585 : https://msune.github.io/libcdada/
586 : https://github.com/ariya/fastlz
587 : https://github.com/maxim2266/str
588 : https://github.com/saprykin/plibsys
589 : https://github.com/Jorengarenar/libXDGdirs
590 : https://github.com/sammycage/plutovg
591 : https://duktape.org/
592 : https://github.com/graphitemaster/incbin
593 : https://libzip.org
594 : https://github.com/tek256/astera
595 : https://github.com/tezc/sc
596 : https://github.com/damian-m-g/xlsx_drone
597 : https://github.com/jart/cosmopolitan
598 : https://github.com/cjwagenius/bfish
599 : https://github.com/hnes/libaco
600 : www.littlecms.com
601 : https://github.com/smoked-herring/sail
601 : https://sigrok.org/wiki/Libsigrok
602 : https://github.com/zpl-c/zpl
603 : https://github.com/Hirrolot/metalang99
604 : https://github.com/Hirrolot/datatype99
605 : https://codeforwin.org/2015/09/singly-linked-list-data-structure-in-c.html
606 : https://www.learn-c.org
607 : https://github.com/metacall/core
608 : https://hirrolot.github.io/posts/compiling-algebraic-data-types-in-pure-c99.html
609 : https://github.com/jasmcaus/tau
610 : https://github.com/BayesWitnesses/m2cgen
611 : https://sod.pixlab.io/
612 : https://github.com/michaelrsweet/pdfio
613 : https://github.com/rurban/ctl
614 : https://github.com/nakst/luigi
615 : https://github.com/helderman/htpataic
616 : https://github.com/rxi/microui
617 : https://github.com/Cogmasters/concord
618 : https://github.com/solenum/exengine
619 : https://projects.malikania.fr/bcc
620 : https://github.com/pspdev/pspsdk
621 : https://github.com/pspdev/pspsdk/blob/master/LICENSE
622 : https://remove-to-waste.info
623 : https://github.com/ashvardanian/StringZilla
700 : https://viewsourcecode.org/snaptoken/kilo/
701 : https://wiki.gnome.org/Projects/GLib
702 : https://duckdb.org/