Awesome C

A curated list of C good stuff. Contributions are welcome.

An important note: first and foremost linked resources are for C, therefore C++ is an afterthought.

Note: there are several awesome-c lists already, but they are having somewhat different sets of libraries in them. This list tries to incorporate them all, and many more other resources. Consider it my personal cheat sheet and index for easier search instead of github stars. Also, original list categories are a mess.

Note: all licenses after project descriptions are leading to actual license text or declaration, if any provided. Source code with no license attached is considered as automatically copyrighted by law or it is falling under the case of terms of service of provided source code publication and hosting service, so keep this in mind. Also, probably sometimes license can be provided or mentioned, but I've failed to find it.

I am not an attorney btw.

Incorporated lists:

https://github.com/aleksandar-todorovic/awesome-c (rare updates, too vague and sometimes mismatched categories, not very wide selection of content)
https://github.com/kozross/awesome-c (updated regularly, but has even less content than one above)
https://github.com/uhub/awesome-c (regular updates, much more content than previous two, but much more of it doesn't even belong to C list. Also, no structure at all)

Index

Meta

AI
Algoritm Implementations
Argument Parsing
Calculations
Compression
Concurrency and Parallelism
Crypto
Databases
Data Structures
Events
FFI
Filetype Targets
- Binaries
- CSV
- JSON
- INI
- XML
- Other Filetypes
Flow Control and Language Extension
Game Development
- Engines
- Graphics Rendering
- Helping Libraries
Geography
GUI
Hardware Oriented
Hashing
Image Processing and Computer Vision
Integrated Debugging
I/O
Lexing and Parsing
Memory Management
Multimedia
Multiple Purpose Libraries
Networking
- DNS
- HTTP
- Mail
- Messaging
- Remote Desktops
- RPC
- TCP, UDP and Sockets
- Web Servers
- Web Service APIs
- Websockets
- Uncategorized Networking
OpenCL
OS Specifics
Procedural Generation
Processes and IPC
Regex and Search
Serialization
Source Code Collections
Special Purpose Libraries
Standard Libraries
String Manipulation
Testing
TUI

Uncategorized

`^` AI

Neural nets, machine learning, pattern recognition etc.

cjac/cmusphinx - CMU Sphinx - Speech Recognition Toolkit. Licenses
100/Cranium - A portable, header-only, artificial neural network library written in C99. MIT
pjreddie/darknet - Convolutional Neural Networks. License
TheWeatherChannel/dClass - Device Classification Engine. Apache 2
2hanson/DecisionTree - Decision Tree. MIT
yusugomori/DeepLearning - Deep Learning (several languages, C included). MIT
encog/encog-c - C implementation of Encog - machine learning framework for Java/C#. No license
codeplea/genann - simple neural network library in ANSI C. Zlib
attractivechaos/kann - Two-file ANN library. MIT
Blei-Lab/lda-c - This is a C implementation of variational EM for latent Dirichlet allocation (LDA), a topic model for text or other discrete data. LGPL 2.1
jppbsi/LibDEEP - Deep learning library. No license
H2CO3/libsprec - C library for speech recognition using the Google Speech API. License
robwhess/opensift - Open-Source SIFT Library. License
dake/openVP - Voice Print Recognition in C language. No license
cmusphinx/pocketsphinx - Lightweight speech recognition engine, specifically tuned for handheld and mobile devices, though it works equally well on the desktop. BSD 2-Clause
HIPS/Probabilistic-Backpropagation - Implementation in C and Theano of the method Probabilistic Backpropagation for scalable Bayesian inference in deep neural networks. BSD 3-Clause
GHamrouni/Recommender - A C library for product recommendations/suggestions using collaborative filtering (CF). BSD 2-Clause
ufoym/recursive-bf - A lightweight library for recursive bilateral filtering. MIT
xiph/rnnoise - Recurrent neural network for audio noise reduction. License
antirez/shapeme - Evolve images using simulated annealing. BSD 2-Clause
symisc/sod - An Embedded Computer Vision & Machine Learning Library (CPU Optimized & IoT Capable). GPL 3
iunderstand/SWE - Learning Semantic Word Embeddings based on Ordinal Knowledge Constraints. Apache 2
glouw/tinn - The tiny neural network library. MIT
canyalniz/CNN-Inference-Didactic - A readable CNN Inference implementation in C. GPL 3

Algoritm Implementations

`^` Algoritm Implementations

Some generic agoritms or ones with no specific attachments.

dhuertas/AES - AES algorithm implementation in C. No license
mischasan/aho-corasick - A-C implementation in "C". Tight-packed (interleaved) state-transition matrix. LGPL 3
davidreynolds/algorithms - A repository of assorted algorithms and data structures. No license
BigZaphod/AStar - C Implementation of the A* Pathfinding Algorithm. License
citiususc/BigBWA - Approaching the Burrows-Wheeler Aligner to Big Data Technologies. GPL 3
TheAlgorithms/C - All Algorithms implemented in C No license
chaoslawful/ccard-lib - C library for estimating cardinality in streams for which it is infeasible to store all events in memory. No license
agl/curve25519-donna - Implementations of a fast Elliptic-curve Diffie-Hellman primitive. License
aimxhaisse/des - C implementation of DES. License
tarequeh/DES - Implementation of Data Encryption Standard in C. MIT
blynn/dlx - Implementation of Knuth's Algorithm X, with example solvers. GPL 3
oap/ekf-angles - Extended Kalman Filter for Accelerometer and Gyro data. No license
Cyan4973/FiniteStateEntropy - Finite State Entropy and Huff0. BSD 2-Clause
BlackLight/fkmeans - A tiny library in C for managing kmeans clusterization algorithm over arbitrary data sets, both by manually specifying the number k of clusters and computing it automatically using Schwarz criterion. GPL 3
kljensen/Gemoda - A generic motif discovery algorithm for sequential data. GPL 2
lacker/ikalman - An iPhone-friendly Kalman filter written in C. MIT
tsuraan/Jerasure - C Implementation of Reed-Solomon coding. License
jmcejuela/Levenshtein-MySQL-UDF - General Levenshtein algorithm and k-bounded levenshtein distance in linear time and constant space. LGPL 3
CVLearner/Mixture-of-Gaussians - Fit a Gaussian mixture model given a set of data. MIT
richarddurbin/pbwt - Implementation of Positional Burrows-Wheeler Transform for genetic data. License
ntamas/plfit - Fitting power-law distributions to empirical data, according to the method of Clauset, Shalizi and Newman. License
Kevincav/Radix-Sort - Radix Sort with different data types. MIT
duckythescientist/obfuscatedLife - Conway's Game of Life in 9 lines of C. No license
kokke/tiny-AES-c - Small portable AES128/192/256 in C. Unlicense
kroitor/gjk.c - Gilbert-Johnson-Keerthi (GJK) collision detection algorithm in 200 lines of clean plain C. WTFPL
ai-ku/scode - Sphere embedding (s-code) is a variation of Euclidean embedding of co-occurence data (code). MIT
swenson/sort - Collection of sorting routines, which type-specialize at compile-time with a user-defined type. MIT
msteinbeck/tinyspline - ANSI C library for NURBS, B-Splines, and Bézier curves with interfaces for C++, C#, D, Java, Lua, Octave, PHP, Python, R, and Ruby. MIT
ferreiradaselva/uastar - Minimal A* implementation. Zlib
madler/crcany - CRC calculation library. Zlib

Argument Parsing

`^` Argument Parsing

cofyc/argparse - Command-line arguments parsing library. MIT
clibs/commander - Commander option parser ported to C - simple API, auto-generated --help. MIT
docopt/docopt.c - Implementation of a command-line option parser. MIT
clibs/flag - Go-style flag parsing for C. MIT
jibsen/parg - A single-file reimplementation of getopt with better defaults. License

Calculations and Math

`^` Calculations and Math

b-k/apophenia - Library for statistical and scientific computing. GPL 2
fredrik-johansson/arb - Library for arbitrary-precision interval arithmetic. LGPL 2.1
ATLAS - Automatically Tuned Linear Algebra Software. License
BLAS - Basic Linear Algebra Subprograms; a set of routines that provide vector and matrix operations. License
Lichtso/CCWT - Complex Continuous Wavelet Transformation. MIT
CDFLIB - Library with routines to evaluate cumulative density functions for a variety of standard probability distributions. Also can compute one parameter of the CDF given the others. No license
ScientificC/cmathl - Pure-C Math library with a great variety of mathematical functions and CMake build support. Seeks to be close to C89/C90 compliant for portability. MIT
Cuba - Library for multidimensional numerical integration. LGPL
adis300/fft-c - A high-performance Fourier Transform from netlib's fftpack; wrapped in a user-friendly format. MIT
FFTW - The Fastest Fourier Transform in the West; a highly-optimized fast Fourier transform routine. GPL 2
FLINT - Fast Library for Number Theory; a library supporting arithmetic with numbers, polynomials, power series and matrices, among others. LGPL 2.1
gjrand - Library of random-number generation routines. GPL 2
GLPK - GNU Linear Programming Kit; a package designed for solving large-scale linear programming, mixed integer programming and other related problems. GPL 3
GMP - GNU Multple Precision Arithmetic Library; a library for arbitrary-precision arithmetic. Licenses
GNU MPC - Library for complex number arithmetic. LGPL 3
GNU MPFR - Library for arbitrary-precision floating-point arithmetic. LGPL 3
GNU MPRIA - Portable mathematics library for multi-precision rational interval arithmetic. GPL 3
GSL - The GNU Scientific Library; a sophisticated numerical library. GPL3
HdrHistogram/HdrHistogram_c - C port of the HdrHistogram. License
igraph- Library for creating and manipulating large graphs. GPL2
KISS FFT - Very simple fast Fourier transform library. BSD
LAPACKE - C interface to LAPACK. License
PARI/GP - Computer algebra system for number theory; includes a compiler to C. GLP
PETSc - Suite of data structures and routines for scalable parallel solution of scientific applications modelled by partial differential equations. License
PROB - Library that handles various discrete and continuous probability density functions. LGPL 3
PetteriAimonen/libfixmatrix - C library for fixed point matrix, quaternion and vector calculations. MIT
canonizer/libgpuvm - library which simplifies host-GPU data transfer using userspace pagefault handling. No license
libtom/libtommath - LibTomMath is a free open source portable number theoretic multiple-precision integer library written entirely in C. Unlicense
JuliaMath/openlibm - High quality system independent, portable, open source libm implementation. License
imneme/pcg-c - PCG — C Implementation. Apache 2
imneme/pcg-c-basic - PCG — Minimal C Implementation. Apache 2
libtom/tomsfastmath - TomsFastMath is a fast public domain, open source, large integer arithmetic library written in portable ISO C. Licenses
cvxgrp/scs - C package that solves convex cone problems via operator splitting. MIT
SLEPc - Library for the solution of large, sparse eigenvalue problems on parallel computers. BSD 2-Clause
slim-curve/slim-curve - SLIM Curve: a package for exponential curve fitting of combined spectral lifetime image data. GPL 3
tinyexpr - Tiny recursive-descent parser, compiler and evaluation engine for simple mathematical expressions. Zlib
Yeppp! - Very fast, SIMD-optimized mathematical library. License
PetteriAimonen/libfixmath - Cross Platform Fixed Point Maths Library.MIT
datenwolf/linmath.h - Linear math as required for computer graphics. WTFPL

Compression

`^` Compression

Blosc/bcolz - Fast, multi-threaded, meta-compressor library. Licenses
kiyo-masui/bitshuffle - Filter for improving compression of typed binary data. License
google/brotli - Generic lossless compression algorithm based on LZ77, Huffman coding and 2nd order context modelling. MIT
bzip2 - Patent-free, high-quality data compression library. BSD 4-Clause
Blosc/c-blosc - A blocking, shuffling and loss-less compression library that can be faster than memcpy(). Licenses
clzip - C lzip implementation. GPL 2
richox/comprox - An experimental lossless data compression program with high compression ratio. BSD 3-Clause
RoaringBitmap/CRoaring - Roaring bitmaps in C (and C++). Apache 2
adnanozsoy/CUDA_Compression - A GPU-based LZSS compression algorithm, highly tuned for NVIDIA GPGPUs and for streaming data, leveraging the respective strengths of CPUs and GPUs together. Apache 2
centaurean/density - Superfast compression library. BSD 3-Clause
gildor2/fast_zlib - Improved zlib, which runs 2 to 10 times faster. BSD 3-Clause
Cyan4973/FiniteStateEntropy - Two efficient compression codecs optimized for modern CPUs. BSD 2-Clause
rjsikarwar/gpu_compression - Nine Light weight Schemes to Compress and Decompress the data of Database Using GPU and also a planer. No license
atomicobject/heatshrink - data compression library for embedded/real-time systems. ISC
adamierymenko/huffandpuff - Minimal Huffman encoder and decoder. Public domain
libarchive/libarchive - Multi-format archive and compression library. Licenses
nih-at/libzip - A C library for reading, creating, and modifying zip archives. BSD 3-Clause
inikep/lizard - Formerly LZ5. Achieves compression ratios comparable with zip and zlib at decompression speeds of 1000MB/s and faster. Licenses
lz4/lz4 - Extremely Fast Compression algorithm. Licenses
lzo - Very fast data compression library. GPL 2
richgel999/miniz - Single C source file zlib-replacement library. License
moinakg/pcompress - A Parallelized Data Deduplication and Compression utility. LGPL 3
vasi/pixz - Parallel, indexed xz compressor. BSD 2-Clause
mist64/pucrunch - pucrunch, an Optimizing Hybrid LZ77 RLE Data Compression Program for C64/C128/VIC-20/Plus4. LGPL 2.1
quicklz - Fast compression library. Licenses
Ed-von-Schleck/shoco - Compressor for small text strings. MIT
lemire/simdcomp - Simple library for compressing lists of integers using binary packing. Makes use of SIMD instructions on x86. BSD 3-Clause
antirez/smaz - Small strings compression library. BSD 3-Clause
andikleen/snappy-c - C port of the snappy compressor. License
quixdb/squash - Compression abstraction library, complete with utilities. MIT
powturbo/TurboPFor - Fast integer compression. GPL 2
powturbo/TurboRLE - Fastest Run Length Encoding. GPL 2
kuba--/zip - A portable, simple zip library written in C. Unlicense
madler/zlib - Massively-spiffy yet delicately-unobtrusive compression library. Zlib
zlib-ng/zlib-ng - zlib replacement with optimizations for "next generation" systems. Zlib
facebook/zstd - Fast real-time compression algorithm. BSD 3-Clause
jsvennevid/filearchive - File archive library allowing for easy creation and access to data stored inside a container through a simple API. MIT
ariya/FastLZ - Byte-aligned LZ77 compression. License

Concurrency and Parallelism

`^` Concurrency and Parallelism

yosefk/checkedthreads - A simple library for parallelism, with built-in checking for race conditions. BSD 2-Clause
FCFS RWLock - First-come first-served Readers/Writers lock for POSIX threads. Licenses
sharow/libconcurrent - Concurrent programming library, using coroutines, for C11. Zlib
liburcu - Data synchronization library, which scales linearly with the number of cores. LGPL 2.1
cchan - Small library for channel constructs for inter-thread communication. Public Domain
pmodels/mpich - Another implementation of MPI. License
open-mpi/ompi - Message passing interface implementation. License
GNU pth - Portable implementation for non-preemptive priority-based scheduling for multiple threads of execution. LGPL 2.1
POSIX threads - The POSIX thread library. No license
tinycthread/tinycthread - Portable, small implementation of the C11 threads API. License
Pithikos/C-Thread-Pool - A minimal but powerful thread pool in ANSI C. MIT
baruch/libwire - User space threading (aka coroutines) library for C resembling GoLang and goroutines. MIT
bjoernknafla/amp - C portable low-level assemblies for parallelism and threading. BSD 3-Clause
bjoernknafla/peak - Parallelism exploration assembly kit. C toolkit to experiment with task- and data-parallelism. BSD 3-Clause
cloudwu/coroutine - A asymmetric coroutine library for C. MIT
concurrencykit/ck - Concurrency primitives, safe memory reclamation mechanisms and non-blocking (including lock-free) data structures designed to aid in the research, design and implementation of high performance concurrent systems developed in C99+. Licenses
etmc/lemon - Lemon is an MPI parallel I/O library that is intended to allow for efficient parallel I/O of both binary and metadata on massively parallel architectures. Data is stored in the SciDAC Lattice QCD Interchange Message Encapsulation format, that allows for storing large blocks of binary data and corresponding metadata in the same file. GPL 3
geertj/cgreenlet - Coroutines for C/C++. MIT
halayli/lthread - lthread, a multicore enabled coroutine library written in C. BSD 2-Clause
hnes/libaco - A blazing fast and lightweight C asymmetric coroutine library. Apache 2
jtsiomb/c11threads - Trivial C11 threads.h implementation over POSIX threads. Public domain
matianfu/FUNK - a c continuation library inspired by Adam Dunkel's ProtoThread. Apache 2
mbrossard/threadpool - A simple C Thread pool implementation. BSD 2-Clause
oneoo/alilua-coevent-module - epoll base coroutine module. MIT
ramonza/libcoro - Lightweight C coroutines. BSD 2-Clause
sustrik/libdill - Structured concurrency in C. MIT
sustrik/libmill - Go-style concurrency in C. MIT
stevedekorte/coroutine - C multiplatform coroutine implementation via ucontext, fibers or setjmp. No license
parallella/pal - An optimized C library for math, parallel processing and data movement. Apache 2
danluu/setjmp-longjmp-ucontext-snippets - Implementing coroutines, channels, message passing, etc.Apache 2
Precisamento/cpthreads - Cross Platform (e.g. Windows) support for C11 threads. MIT
shiyanhui/libcsp - Concurrency C library influenced by the CSP model. MIT

Cryptography

`^` Cryptography

GNU SASL - Implementation of the Simple Authentication and Security Layer and few common SASL mechanisms. Licenses
aidansteele/sphlib - Set of implementations of various hash functions, including several cryptographic ones. MIT
GnuTLS - Secure communication library, implementing SSL, TLS and DTLS. LGPL 2.1
libgcrypt - General-purpose cryptography library, with a range of available ciphers. Licenses
OpenSSL - Implementation of the SSL and TLS protocols, and also includes a cryptography library. Licenses
jedisct1/libsodium - A modern, portable and easy to use crypto library. ISC
ARMmbed/mbedtls - An open source, portable, easy to use, readable and flexible SSL library. License
B-Con/crypto-algorithms - Basic implementations of standard cryptography algorithms, like AES and SHA-1. No license
WickrInc/wickr-crypto-c - An implementation of the Wickr Secure Messaging Protocol in C. License
ashwinraghav/Parallel_Open_SSL - Use your idle GPU to encrypt your data. Give your CPU some breathing time! Licenses
awslabs/s2n - s2n : an implementation of the TLS/SSL protocols. Apache 2
bitcoin-core/secp256k1 - Optimized C library for EC operations on curve secp256k1. MIT
cloudflare/keyless - CloudFlare's Keyless SSL Server Reference Implementation. Agreement
ctz/cifra - A collection of cryptographic primitives targeted at embedded use. License
cyassl/cyassl - Small, fast, portable implementation of TLS/SSL for embedded devices to the cloud. GPL 2
eduardsui/tlse - Single C file TLS 1.2/1.3 implementation, using tomcrypt as crypto library. BSD 2-Clause
h2o/picotls - TLS 1.3 implementation in C (master supports RFC8446 as well as draft-26, -27, -28). License
jedisct1/libhydrogen - A lightweight, secure, easy-to-use crypto library suitable for constrained environments. ISC
libressl-portable/openbsd - LibreSSL source code. Licenses
libtom/libtomcrypt - LibTomCrypt is a fairly comprehensive, modular and portable cryptographic toolkit that provides developers with a vast array of well known published block ciphers, one-way hash functions, chaining modes, pseudo-random number generators, public key cryptography and a plethora of other routines. Licenses
maciejczyzewski/retter - A collection of hash functions, ciphers, tools, libraries, and materials related to cryptography. No license
mikeryan/crackle - Crack and decrypt BLE encryption. BSD 2-Clause
open-quantum-safe/liboqs - C library for quantum-resistant cryptographic algorithms. MIT
tbuktu/libntru - C Implementation of NTRUEncrypt. Licenses
trezor/trezor-crypto - Heavily optimized cryptography algorithms for embedded devices. MIT
droe/sslsplit - Transparent SSL/TLS interception. BSD 2-Clause
orlp/ed25519 - Portable C implementation of Ed25519, a high-speed high-security public-key signature system. Zlib
wolfSSL/wolfssl - wolfSSL (formerly CyaSSL) is a small, fast, portable implementation of TLS/SSL for embedded devices to the cloud. GPL 2
rg3/bcrypt - bcrypt password hash C library. License
LoupVaillant/Monocypher - An easy to use, easy to deploy crypto library. Licenses
tombonner/blowfish-api - Blowfish block cipher implementation. License

Databases

`^` Databases

priitj/whitedb - Lightweight database library, operating entirely in main memory. GPL 3
mongodb/mongo-c-driver - High-performance client library for MongoDB. Apache 2
SQLite - Self-contained, serverless, zero-configuration, transactional SQL database engine with a C interface. Public domain
symisc/unqlite - Self-contained, serverless, zero-configuration, transactional NoSQL engine with a C interface. License
Akash91/CoSQL - A Co-Relational Key-Value Data Store. No license
GNOME/libgda - Libgda is a (relatively small) database access library. GPL 2
Softmotions/ejdb - EJDB — Embeddable JSON Database engine. MIT
aerospike/aerospike-client-c - Aerospike C Client. License
bcmpinc/dagdb - small database for storing semi-structured data. GPL 3
maciejczyzewski/hashbase - A fast, efficient on-disk/in-memory database with many different kind of data structures. MIT
maxmind/libmaxminddb - C library for the MaxMind DB file format. Apache 2
pmwkaa/sophia - modern emeddable key-value database. License
redis/hiredis - Minimalistic C client for Redis. BSD 3-Clause
seppo0010/rlite - self-contained, serverless, zero-configuration, transactional redis-compatible database engine. rlite is to Redis what SQLite is to SQL. BSD 2-Clause
sqlcipher/sqlcipher - SQLCipher is an SQLite extension that provides 256 bit AES encryption of database files. License
tglman/orientdb-c - The C client of OrientDB. No license
spotify/sparkey - Simple constant key/value storage library, for read-heavy systems with infrequent large bulk inserts. Apache 2
vrogier/ocilib - Open source C and C++ library for accessing Oracle databases. Apache 2
symisc/vedis - An Embedded Implementation of Redis. License
orca-zhang/influxdb-c - C write client for InfluxDB. MIT
t3rm1n4l/lightkv - Key-value data storage. No license

Data Structures and Types

`^` Data Structures and Types

recp/ds - Common Data Structures and Algorithms. MIT
P-p-H-d/mlib - Library for generic, but typesafe C containers. Implemented as header-only. BSD 2-Clause
libsrt - Soft and hard real-time data structures. BSD 3-Clause
nbulischeck/list.h - Implementations for single- and double-linked list functions. GPL 3
gpakosz/PackedArray - Random-access array of tightly packed unsigned integers of any desired width. Has a SIMD-optimized implementation. WTFPL
swenson/vector.h - Header library for typed lists. MIT
20centaurifux/datatypes - A collection of various datatypes in C (linked lists, stack, queue, red-black tree and hash table). GPL 3
ClickerMonkey/CDSL - A data structure library written in C. License
Incarnation-p-lee/libds - Unified data structure implementation library of C. GPL 2
LPD-EPFL/ASCYLIB - Concurrent-search data-structure library with over 30 implementantions of linked lists, hash tables, skip lists, and binary search trees. GPL 2
MichaelJWelsh/cdsa - A library of generic intrusive data structures and algorithms in ANSI C. ISC
ZSShen/C-Common-Data-Structures - Uniform C APIs for data structure manipulation. No license
agl/critbit - Critbit trees in C. No license
antirez/rax - A radix tree implementation in ANSI C. BSD 2-Clause
armon/libart - Adaptive Radix Trees implemented in C. BSD 3-Clause
ashinkarov/trie - Simple implementation of trie data structure. License
bcopeland/em_misc - External memory data structure playground. No license
begeekmyfriend/bplustree - A minimal but extreme fast B+ tree indexing structure demo for billions of key-value storage. MIT
chrismoos/hash-ring - C hash ring library. Apache 2
chriso/bitset - A compressed bitset with supporting data structures and algorithms. LGPL
codeprepper/data-structures - Arrays, linked lists, stacks and queues. MIT
dminor/skip-quadtree - Implementation of the skip quadtree and compressed quadtree data structures. License
douglascrockford/DEC64 - Decimal floating point. No license
fmela/libdict - C library of key-value data structures with an object-oriented interface. BSD 2-Clause
fragglet/c-algorithms - A library of common data structures and algorithms written in C. ISC
gnudennis/ds_c - Data Structure In C. No license
graphitemaster/libintrusive - Intrusive data structures for C. Unlicense
grundprinzip/bitcompressedvector - Provide a container for integral data types that applies light-weight bit compression. License
hacatu/haclib - A utility library providing data types C should have been made with such as vectors and sequences, mostly as macros. MPL 2
hyPiRion/c-rrb - RRB-tree implemented as a library in C. MIT
hyPiRion/roulette-tree - Data structure for efficient fitness-proportionate selection. MIT
jarun/dslib - A library of handy data structures. GPL 3
johnj/llds - Low-Level Data Structure - efficient data structures, and fast data access in the 2.6/3.0 kernel. License
jtsiomb/kdtree - A simple C library for working with KD-Trees. License
jvirkki/libbloom - A simple and small bloom filter implementation in plain C. BSD 2-Clause
ksheedlo/kmdata - Data structures for C programmers, by C programmers. No license
louiswins/RB-Tree - An implementation of the Red-Black Tree data structure. No license
livioso/datastructures-in-C - Implementation of a some data structures in C for educational purposes. No license
malbrain/Btree-source-code - A working project for High-concurrency B-tree source code in C. License
michaeltyson/TPCircularBuffer - A simple, fast circular buffer implementation. License
mikedlowis/data-structures - A collection of data structures implemented in C to be included in multiple projects. BSD 2-Clause
naraing/dsLib - An algorithm library with core data-sttructures and common algortihm implementations on those data structures. GPL 3
noporpoise/BitArray - C bit array structs and methods. License
orangejulius/cs_fundamentals - simple implementations of common data structures/algorithms. GPL 3
paulasmuth/libsmatrix - thread-safe sparse matrix data structure. MIT
pcdavid/data-structures - Sample implementations of classical data structures in C. WTFPL
petewarden/c_hashmap - A simple string hashmap in C. Public domain
rxi/map - A type-safe hash map implementation for C. MIT
rxi/vec - A type-safe dynamic array implementation for C. MIT
siganakis/tny - Tiny data structures that pack a punch! License
srdja/Collections-C - A library of generic data structures. LGPL 3
steven-schronk/C-Data-Structures - Collection of basic data structures in C. GPL 3
wasabiz/xrope - rope data structure. No license
torch/tds - Torch C data structures. License
watmough/jwHash - Simple hash table implementation for C. Apache 2
zhemao/libds - Simple, memory-safe data-structures in C. MIT
willemt/cbuffer - A circular buffer written in C using Posix calls to create a contiguously mapped memory space. License
xant/libhl - Simple and fast C library implementing a thread-safe API to manage hash-tables, linked lists, lock-free ring buffers and queues. LGPL 3
yuyuyu101/C-Buffered-tree - A buffered-tree implemented in dictionary type and more. MIT
MagerValp/AsmHeap - Heap data structure in 6502 assembler. No license
Snaipe/libcsptr - Smart pointers in C. MIT
C-Macro-Collections - Generate simple and generic data structures using macros. MIT
troydhanson/uthash - C macros for hash tables and more. License
begeekmyfriend/CuckooFilter - Substitute for bloom filter. License
bitly/dablooms - Scaling, counting, bloom filter library. MIT
krglaws/KyleStructs - Simple data structures written for educational purposes. No license
armon/c-minheap-array - Implements a Min-Heap / Priority Queue in C using a simple array. BSD 3-Clause
jstimpfle/rb3ptr - Red-black tree in C. License

Events

`^` Events

libev - Yet another event loop. BSD 2-Clause
libevent - Event loop replacement for network servers. BSD 3-Clause
Lupus/libevfibers - Small C fiber library that uses libev based event loop and libcoro based coroutine context switching. Apache 2
facebook/libphenom - An eventing framework for building high performance and high scalability systems in C. Apache 2
libuv/libuv - Cross-platform asychronous I/O. Licenses
ithewei/libhv - Event-loop with non-blocking IO and timer. BSD 3-Clause

Foreign Function Interfaces

`^` Foreign Function Interfaces

GNU Libffcall - Collection of libraries for building foreign function interfaces. GPL 3
dyncall - Another foreign function interface library. License
atgreen/libffi - A portable foreign-function interface library. License
dyu/ffi-overhead - comparing the c ffi overhead on various programming languages. Apache 2
jmckaskill/luaffi - Standalone FFI library for calling C functions from lua. Compatible with the luajit FFI interface. License
taviso/ctypes.sh - A foreign function interface for bash. MIT

Filetype Targets

Libraries for working with specific filetypes or classes of filetypes.

╠════ Binaries

`^` Binaries

bfd - Library for manipulating binary object files. Part of GNU binutils. Licenses
0intro/libelf - Simple library for parsing ELF files. MIT
fuzxxl/memf - Portable scanf/printf-like functions to marshal binary data. BSD 2-Clause
nicklockwood/FastCoding - A faster and more flexible binary file format replacement for NSCoding, Property Lists and JSON. License
abiggerhammer/hammer - Parser combinators for binary formats. GPL 2

╠════ CSV

`^` CSV

rgamble/libcsv - Simple, streaming CSV parser. LGPL 2.1
tadasv/csv_parser - Callback based (SAX like) CSV Parser for C. MIT

╠════ HTML

`^` HTML

lexborisov/Modest - Modest is a fast HTML renderer implemented as a pure C99 library with no outside dependencies. LGPL 2.1
lexborisov/myhtml - Fast C/C++ HTML 5 Parser. Using threads. LGPL 2.1
htacg/tidy-html5 - The granddaddy of HTML tools, with support for modern standards. License
google/gumbo-parser - HTML5 parsing library in C99. Apache 2

╠════ JSON

`^` JSON

NeonMercury/jfes - JSON For Embedded Systems; simple JSON engine without any dependencies. MIT
zserge/jsmn - Minimalistic JSON parser. MIT
netmail-open/wjelement - Advanced JSON manipulation library, with support for JSON Schema. Licenses
DaveGamble/cJSON - Ultralightweight JSON parser in ANSI C. MIT
akheron/jansson - C library for encoding, decoding and manipulating JSON data. MIT
armink/struct2json - A fast convert library between the JSON and C structure. Implement structure serialization and deserialization for C. MIT
cesanta/frozen - JSON parser and generator for C/C++ with scanf/printf like interface. Targeting embedded systems. Apache 2
cloudflare/lua-resty-json - JSON library for Lua and C. BSD 2-Clause
json-c/json-c - Official code repository for json-c. License
keenerd/jshon - JSON parser designed for maximum convenience within the shell. MIT
kgabis/parson - Lightweight JSON library written in C. MIT
kevinbirch/kanabo - Query JSON/YAML data with JSONPath. License
lloyd/yajl - A fast streaming JSON parsing library in C. ISC
orangeduck/json2c - Convert JSON to C data literals. BSD 3-Clause
quartzjer/js0n - Flexible Zero-Footprint JSON Parser in C. Unlicense
sheredom/json.h - JSON parser for C and C++. Unlicense
vincenthz/libjson - JSON parser and printer library in C. Easy to integrate with any model. License
udp/json-parser - Very low footprint JSON parser written in portable ANSI. License
garnetius/jsong - Faster than light streaming JSON & USON parser and writer with rich and trivial to use API plus SSE optimizations. BSD 2-Clause
recp/json - Parses JSON files into DOM-like data structures. MIT
mjansson/json - Single header JSON/SJSON parser. Unlicense

╠════ INI

`^` INI

ndevilla/iniparser - Parser for .ini files. MIT
madmurphy/libconfini - Yet another INI parser. GPL 3
benhoyt/inih - Simple .INI file parser in C, good for embedded systems. License
LloydLabs/librini - Tiny, non-libc dependant, .ini file parser programmed from scratch in C99. MIT
compuphase/minIni - A small and portable INI file library with read/write support. Apache 2

╠════ Markdown

`^` Markdown

hoedown/hoedown - Fully standards-compliant, extension-supporting, UTF-8 aware, fast Markdown parser. ISC
commonmark/cmark - Library for parsing the CommonMark dialect of Markdown. License
Orc/discount- My C implementation of John Gruber's Markdown markup language. License
commonsguy/cwac-anddown - CWAC AndDown: Markdown Utility Library. Apache 2
fletcher/MultiMarkdown-6 - Lightweight markup processor to produce HTML, LaTeX, and more. License
jgm/peg-markdown - An implementation of markdown in C, using a PEG grammar. Licenses
vmg/sundown - Standards compliant, fast, secure markdown processing library in C. License

╠════ XML

`^` XML

libexpat/libexpat - Stream-oriented XML parser. License
libxml2 - Standards-compliant, portable XML parser. MIT
michaelrsweet/mxml - Small XML reading and writing library. No dependencies aside from C standard library. Apache 2
ooxi/xml.c - Simple XML subset parser comparable to glib's Markup parser. License
bakulf/libmrss - C library for parsing, writing and creating RSS files or streams. LGPL 2.1
mmuszkow/librss - RSS and ATOM parsing library. No license
bakulf/libnxml - Library for parsing, writing and creating XML 1.0 and 1.1 documents. LGPL 2.1
anton/rss_aggregator - Feed reader lib written in C with use of libxml2 and utlist. No license

╚════ Other Filetypes

`^` Other Filetypes

yaml/libyaml - Canonical source repository for LibYAML. MIT
mongodb/libbson - BSON utility library. Apache 2
martinh/libconfuse - Small configuration file parser library. ISC
vstakhov/libucl - Universal configuration library parser. BSD 2-Clause
Juniper/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
brechtsanders/xlsxio - Cross-platform library for reading and writing .xlsx files. MIT
arrbee/diff-match-patch-c - C language port of google-diff-match-patch library. License
hyperrealm/libconfig - C/C++ library for processing configuration files. LGPL 2.1
jedwing/CHMLib - Library for reading Microsoft ITSS/CHM format files. LGPL 2.1
jmcnamara/libxlsxwriter - A C library for creating Excel XLSX files. License
libharu/libharu - Free PDF library. Zlib
samtools/htslib - C library for high-throughput sequencing data formats. License
vmg/houdini - API for escaping text for the web. MIT
trumpowen/MegaMimes - A C mime type library MIT

Flow Control and Language Extension

`^` Flow Control and Language Extension

orangeduck/Cello - Library introducing higher-level programming to C. BSD 2-Clause
Ragel - DSL for state machines that compiles to C. License
kitsune-dsu/kitsune-core - Efficient, general-purpose framework for dynamic software updating. License
P99 - Suite of macros to implement advanced features like default function arguments, scope-bound resources, etc. License
CObjectSystem/COS - C Object System. Apache 2
H2CO3/Sparkling - Lightweight extension language. BSD 2-Clause
lua/lua - Embeddable scripting programming language. License
Zeex/subhook - Simple hooking library for C/C++ (x86 only, 32/64-bit, no dependencies). BSD 2-Clause
arnaudbrejeon/cspec - Behavior driven development in C. GPL 3
comex/substitute - A free runtime modification library. License
elua/elua - Highly portable version of Lua. License
eudoxia0/magma - Extending C with cmacro. License
graphitemaster/lambdapp - Anonymous functions in C. Unlicense
guillermocalvo/exceptions4c - Exception handling framework for C. LGPL 3
orangeduck/LuaAutoC - Automagically use C Functions and Structs with the Lua API. License
pfultz2/Cloak - A mini-preprocessor library to demostrate the recursive capabilites of the preprocessor. Boost
skeeto/interactive-c-demo - Demonstration of interactive C programming. Unlicense
symisc/PH7 - An Embedded Implementation of PHP (C Library). License
yasm/yasm - Provides libyasm - embeddable YASM engine. License
zserge/partcl - Micro Tcl implementation. MIT
cesanta/mjs - Embedded JavaScript engine for C/C++. License
graphitemaster/incbin - Include binary files in C/C++. Unlicense
pkrumins/bithacks.h - bithacks.h is a C header file containing useful bit manipulation macros. MIT
breckinloggins/ngtemplate - A template engine written in C designed to be syntax-compatible with Google CTemplate. MIT
ccxvii/mujs - An embeddable Javascript interpreter in C. ISC
Microsoft/checkedc - Extension to C that adds checking to detect or prevent common programming errors such as buffer overruns and out-of-bounds memory accesses. MIT
hexspeakerg/ONLY_ONCE - ONLY_ONCE macro makes it so that the block of code is only run once across threads. MIT
SanderMertens/flecs - An Entity Component System with a dashboard. MIT
akeep/scheme-to-c - A small nanopass compiler from a subset of Scheme to C. MIT
takanuva/ANSI-ISO-C-Exception-Handling - Exceptions in C. LGPL 3
small-c/obj.h - A single-header support for OOP in pure C. MIT
Hirrolot/poica - Features of modern programming languages in plain C11 implemented via macro system. MIT

Game Development

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

╠════ Game Engines

`^` Game Engines

xonotic/darkplaces - Modified version of the Quake2 engine. GPL 2
ioquake/ioq3 - The Quake3 engine, freed at last. GPL 2
orx/orx - Portable, lightweight, plugin-based, data-driven, 2D-oriented game engine. License
zturtleman/spearmint - Engine designed for FPS games. GPL 3
Gigoteur/UnicornConsole - Unicorn Console: create quick game! MIT
MarilynDafa/Bulllord-Engine - lightspeed lightweight elegant game engine in pure c. MIT
HerculesWS/Hercules - Creation of a robust massively multiplayer online role playing game (MMORPG) server package. GPL 3
Olde-Skuul/doom3do - The complete archive for DOOM for the 3DO. MIT
RandyGaul/AsciiEngine - Game engine written in C to create Ascii art games within the Windows console. MIT
littlewolf - The tiny software graphics and game engine. MIT
eduard-permyakov/permafrost-engine - An OpenGL 3.3 RTS game engine written in C. GPL 3
ejoy/ejoy2d - A 2D Graphics Engine for Mobile Game. MIT
etlegacy/etlegacy - ET: Legacy is based on the source code of the Wolfenstein: Enemy Territory which was released under the GPLv3 license. GPL 3
fabiensanglard/chocolate_duke3D - chocolate Duke Nukem 3D. License
a-nikolaev/curseofwar - A Real Time Strategy game for Linux. GPL 3
chocolate-doom/chocolate-doom - Chocolate Doom is a Doom source port that is minimalist and historically accurate. GPL 2
cxong/cdogs-sdl - Classic overhead run-and-gun game. GPL 2
fogleman/Craft - A simple Minecraft clone written in C using modern OpenGL (shaders). MIT
id-Software/DOOM - DOOM Open Source Release. License
id-Software/Quake-2 - Quake 2 GPL Source Release. GPL 2
id-Software/Quake-III-Arena - Quake III Arena GPL Source Release. GPL 2
id-Software/Quake - Quake GPL Source Release. GPL 2
keendreams/keen - Keen Dreams on Greenlight! GPL 2
linleyh/liberation-circuit - Trapped in a hostile computer system, you must make a way out - RTS/coding game. GPL 3
martincohen/Punity - A tiny game engine in C. MIT
orangeduck/Corange - Pure C Game Engine. License
naev/naev - Naev is a 2d action/rpg space game that combines elements from the action, rpg and simulation genres. GPL 3
nikki93/cgame - some ideas involving games and C. No license
scottcgi/Mojoc - A cross-platform, open-source, pure C game engine for mobile game. MIT
septag/darkhammer - darkHAMMER is a lightweight, open-source, multiplatform game engine. written in C (C99) language, supports python and C# bindings and lua scripts. License
taylor001/crown - The flexible game engine. MIT
theunamedguy/market-sim - A retro stock-trading game utilizing live market data. GPL 2
tpoindex/crobots - CROBOTS is a programming game, for programmers (or aspiring programmers). GPL 2
andwn/cave-story-md - A fan port of Cave Story for the Sega Mega Drive. License
angband/angband - A free, single-player roguelike dungeon exploration game. License
nesbox/tic.computer - Public TIC-80 issues tracker. MIT
cschied/q2vkpt - Real-time path tracer VKPT integrated into q2pro Quake 2 client. GPL 2
ec-/Quake3e - Improved Quake III Arena engine. GPL 2
skullernet/q2pro - Enhanced Quake 2 client and server focused on multiplayer. GPL 2
jdolan/quake2 - Classic Quake II for Mac and Linux. GPL 2
nothings/obbg - Block/voxel-based game. Public domain
bvschaik/julius - An open source re-implementation of Caesar III. AGPL 3
simple2d/simple2d - Simple, open-source 2D graphics for everyone. MIT
exezin/exengine - A C99 3D game engine. MIT
NightDiveStudios/shockmac - System Shock (PowerMac version Official GPL Release). GPL 3
blinry/gish - Open Source version of the award-winning physics platformer. Licenses
ambethia/aposelene - Experimental 2D Engine in C. MIT
klaussilveira/qengine - Retro game engine for developers that enjoy creating games like it's 1997. GPL 2
sebbekarlsson/coelum - Game engine for 2d and 3d written in C. GPL 3
bjornbytes/lovr - Virtual Reality Engine. MIT
EvilPudding/candle - Game engine based on GLEW and SDL. MIT
zauonlok/renderer - Shader-based software renderer in C89 with minimal dependencies. MIT
cdev-tux/q3lite - Quake 3 engine rendered in OpenGL ES. GPL 3
kondrak/vkQuake2 - Vulkan Quake 2 implementation. LGPL 2

╠════ Graphics Rendering

`^` Graphics Rendering

Everything related to video rendering only. Also visit awesome-opengl and awesome-vulkan.

grimfang4/sdl-gpu - Library for high-performance, modern 2D graphics. Based on SDL. MIT
dcnieho/FreeGLUT - Alternative to the OpenGL Utility Toolkit. Allows the creation and management of windows with OpenGL contexts. License
MauriceGit/Cloth_Simulation - Cloth-Visualization via particle-simulation. ISC
MauriceGit/Partikel_accelleration_on_GPU - Particle accelleration with OpenGL 4.3, using the compute shader to calculate particle movement on graphics hardware. ISC
ands/lightmapper - A C/C++ single-file library for drop-in lightmap baking. Just use your existing OpenGL renderer to bounce light! Public domain
ands/seamoptimizer - A C/C++ single-file library that minimizes the hard transition errors of disjoint edges in lightmaps. Public domain
ebassi/graphene - A thin layer of graphic data types. MIT
cacalabs/libcaca - ASCII renderer for terminal-based interfaces. WTFPL
OpenGL - Industry adopted 2D and 3D graphics API. Graphics API
OpenGL ES - Industry adopted 2D and 3D graphics API for mobile and embedded devices. Graphics API
OpenGL SC - Graphic and compute standard for industry requiring system safety certification. Graphics API
Vulkan - Explicit graphic and compute API for modern cross-platform development. Graphics API
Cairo -2D graphics library. Licenses
Cogl - GPU graphics and utilities API. License
glfw/glfw - A multi-platform library for OpenGL, OpenGL ES, Vulkan, window and input. Zlib
nigels-com/glew - The OpenGL Extension Wrangler Library. License
anoek/ex-sdl-cairo-freetype-harfbuzz - Example code which uses SDL, cairo, freetype, and harfbuzz to do ttf/otf text layout and rendering. No license
ashima/webgl-noise - Procedural Noise Shader Routines compatible with WebGL. MIT
grz0zrg/fbg - Lightweight C 2D graphics API agnostic library with parallelism support. BSD 3-Clause
ileben/ShivaVG - OpenGL based ANSI C implementation of the OpenVG standard. LGPL 2.1
jpbruyere/vkvg - Vulkan vector drawing, try to stay close to cairo api. MIT
memononen/nanovg - Antialiased 2D vector drawing library on top of OpenGL for UI and visualizations. Zlib
micahpearlman/MonkVG - OpenVG 1.1 like vector graphics API implementation optimized for game use currently using an OpenGL ES backend that should be compatible with any HW that supports OpenGL ES 2.0 which includes most iOS and Android devices. License
minusinf/opengl_dataviewer - A simple OpenGL xyzw dataviewer. GPL 3
rougier/freetype-gl - OpenGL text using one vertex buffer, one texture and FreeType. License
simple2d/simple2d - Simple, open-source 2D graphics for everyone. MIT
jakogut/tinyflock - A simple, high-performance, threaded, and interactive flocking demo written in C with GLFW. No license
anholt/libepoxy - Library for handling OpenGL function pointer management. License
felselva/gfw - Pure C Minimal Graphics Framework (OpenGL). Zlib
karimnaaji/voxelizer - Header only mesh voxelizer in c99. MIT
kbernholm/leloup - All the C functions needed for drawing solid 3D vector graphics. MIT
dr-soft/glbind - Single file OpenGL API loader. Licenses
dr-soft/vkbind - Single file Vulkan API loader. Licenses
dr-soft/minidraw - Single file 2D graphics library written in C. Licenses
glouw/gel - N64-like software renderer. MIT

╚════ Gamedev Helping Libraries

`^` Gamedev Helping Libraries

sigil - Sound, Input and Graphics Integration Library; a simple alternative to other libraries for doing all those things. Various licenses, all open source. Licenses
SFML/CSFML - Binding for SFML in C. License
SDL - Cross-platform development library designed to provide low-level access to audio, keyboard, mouse, joystick and graphics hardware via OpenGL. SDL2 is the most current version. Zlib
HBehrens/obj2opengl - script to convert 3D models of OBJ files to C/C++ float arrays (vertices, faces, texture) compatible with OpenGL ES glDrawArrays compatible with iPhone/iPad. GPL 3
Kazade/kazmath - A C math library targeted at games. BSD 2-Clause
R4stl1n/cAudio - 3D Audio Engine Based on Openal. Zlib
Tangent128/luasdl2 - A pure C binding of SDL 2.0 for Lua 5.1, Lua 5.2, and LuaJIT. ISC
ccore/ccore_rewrite - A cross platform low level game development library. BSD 3-Clause
cloudwu/skynet - A lightweight online game framework. MIT
felselva/mathc - Pure C math library for 2D and 3D programming. Zlib
gabomdq/SDL_GameControllerDB - A community sourced database of game controller mappings to be used with SDL2 Game Controller functionality. License
geon/gloss - A bidirectional path tracer written in C. MIT
jarikomppa/soloud - Free, easy, portable audio engine for games. License
liballeg/allegro5 - The official Allegro 5 git repository. License
recp/cglm - Highly Optimized Graphics Math (glm) for C. MIT
raysan5/raylib - A simple and easy-to-use library to enjoy videogames programming. Zlib
rxi/lovedos - A framework for making 2D DOS games in Lua. MIT
slembcke/Chipmunk2D - A fast and lightweight 2D game physics library. MIT
shaunlebron/blinky - Exploring peripheral vision in games (using Quake). MIT
nem0/OpenFBX - Lightweight open source FBX importer. MIT
librg/librg - Library for building simple and elegant cross-platform mmo client-server solutions. Apache 2
Srekel/phyxed-2d - 2d physics engine with fixed-point support. Licenses
recp/AssetKit - 3D asset importer/exporter/util library based on COLLADA/glTF specs. MIT
olofson/audiality2 - A realtime scripted modular audio engine for video games and musical applications. Zlib
dr-soft/miniobj - Simple library for loading OBJ mesh files. Public Domain
dr-soft/mintaro - Framework for making simple, retro style games. Public Domain
SasLuca/rayfork - raylib fork introducing some changes. No license
jkuhlmann/cgltf - Single-file glTF 2.0 loader/writer in C99. MIT

Geography

`^` Geography

Geodata, street maps, navigation and so on

Unidata/gempak - Analysis, display, and product generation package for meteorological data. BSD 3-Clause
evanmiller/ProjCL - Crazy-fast map projections and geodesic calculations. License
olofsj/GLMap - An OpenGL ES 2.0 renderer for Openstreetmap data. LGPL 3
olofsj/Whichway - C library for flexible (bike, foot, car) routing in road networks from Openstreetmap data. No license
maxmind/geoip-api-c - GeoIP Legacy C API. License
navit-gps/navit - The open source (GPL v2) turn-by-turn navigation software for many OS. License
lionsoul2014/ip2region - Offline IP location library with accuracy rate of 99.9% and 0.0x millseconds searching performance. DB file is less then 5Mb with all ip address stored. binding for Java, PHP, C, Python, Nodejs, Golang, C#, lua. Binary, B-tree, Memory searching algorithm. Apache 2
openvenues/libpostal - A C library for parsing/normalizing street addresses around the world. Powered by statistical NLP and open geo data. MIT
propublica/simple-tiles - Simple tile generation for maps. MIT
simplegeo/libgeohash - A pure C implementation of the Geohash algorithm. BSD 3-Clause
kosma/minmea - Lightweight GPS NMEA 0183 parser library in pure C. WTFPL
geocommons/geocoder - Modular Street Address Geocoder. LGPL 3
bauerca/gridfloat - Slice and dice USGS elevation data from the command line. MIT

GUI

`^` GUI

tinyfiledialogs - Single-file library for simple dialogs. Compatible with many other toolkits and OSes. Zlib
vurtun/nuklear - A single-header ANSI C gui library. Licenses
andlabs/libui - Simple and portable (but not inflexible) GUI library in C that uses the native GUI technologies of each platform it supports. License
lc-soft/LCUI - A small C library for building user interfaces with C, XML and CSS. MIT
littlevgl/lvgl - Graphics library to create an embedded GUI with easy-to-use graphical elements, beautiful visual effects and low memory footprint. It offers anti-aliasing, opacity, and animations using only one frame buffer. MIT
ocornut/imgui_club - Nice things to use along dear imgui. No license
GTK+ - Cross-platform widget toolkit. License
IUP - Another cross-platform widget toolkit. License
Tk - Basic widget toolkit. Part of Tcl/Tk. License
XForms Toolkit - Widget toolkit designed for the XWindow system. LGPL 2.1
Clutter - UI library based on OpenGL. LGPL 2.1
randrew/layout - Single-file library for calculating 2D UI layouts using stacking boxes. Compiles as C99 or C++. License
cimgui/cimgui - c-api for imgui. MIT
elvismt/slope - A library to create charts from raw data using cairo. Can be shown in GtkDrawingArea LGPL 3
DeXP/nuklear_cross - Nuklear+ (read as "Nuklear cross") is a front-end overlay for Nuklear GUI library. Licenses
xkbcommon/libxkbcommon - Keymap handling library for toolkits and window systems. License
raysan5/raygui - Immediate GUI library from raylib author. Zlib
rxi/microui - Immediate-mode UI ANSI C library. MIT
VincentWei/minigui - Crossplatform windowing and GUI library targeted for embed usage. GPL 3
achimdoebler/UGUI - Graphic library for embedded systems. License

Hardware Oriented

`^` Hardware Oriented

obgm/libcoap - Implementation of the Constrained Application Protocol. License
Genymobile/scrcpy - Display and control your Android device. Apache 2
Azure/azure-iot-sdk-c - A C99 SDK for connecting devices to Microsoft Azure IoT services. MIT
FoxelSA/libfastcal - Fast calibration data access. AGPL 3
Stephane-D/SGDK - SGDK: A small, open and free development kit for the Sega Megadrive. MIT
andygock/avr-uart - AVR UART C Library. License
anrieff/libcpuid - a small C library for x86 CPU detection and feature extraction. BSD 2-Clause
coocox/cox - CoX is an peripherals library with a unified standard interface specially for ARM Cortex M. BSD 3-Clause
edorfaus/TEMPered - C library and program for reading the TEMPer family of thermometer and hygrometer devices. BSD 2-Clause
google/cpu_features - A cross platform C99 library to get cpu features at runtime. Apache 2
jackmitch/libsoc - C library for interfacing with common SoC peripherals through generic kernel interfaces. LGPL 2.1
joan2937/pigpio - C library for the Raspberry which allows control of the General Purpose Input Outputs (GPIO). Unlicense
libimobiledevice/libimobiledevice - A cross-platform protocol library to communicate with iOS devices. LGPL 2.1
libopencm3/libopencm3 - Open Source ARM cortex m microcontroller library. GPL 3
libusb/libusb - A cross-platform library to access USB devices. LGPL 2.1
micronucleus/micronucleus - ATTiny usb bootloader with a strong emphasis on bootloader compactness. License
nfc-tools/libnfc - Platform independent Near Field Communication library. LGPL 3
signal11/hidapi - A Simple library for communicating with USB and Bluetooth HID devices on Linux, Mac, and Windows. Licenses
wiiudev/libwiiu - Build system and examples for running C code on the Wii U. No license
floooh/chips - 8-bit chip and system emulators in standalone C headers. Zlib
rofl0r/endianness.h - Endianness detection and conversion. Licenses

Hashing

`^` Hashing

Hash function implementations for non-cryptographic purposes.

centaurean/spookyhash - Fast hash function. BSD 3-Clause
leo-yuriev/t1ha - Fast Positive Hash - a portable, fast hash function. BSD 3-Clause
Cyan4973/xxHash - Extremely fast non-cryptographic hash algorithm. BSD 2-Clause
PeterScott/murmur3 - Murmur3 hash in C. Public domain
RJ/ketama - C library for consistent hashing, and langauge bindings. BSD 2-Clause
cr-marcstevens/sha1collisiondetection - Library and command line tool to detect SHA-1 collision in a file. MIT
clibs/hash - C hash implementation based on khash. MIT
lemire/clhash - C library implementing fast CLHash function. Apache 2
mattsta/crcspeed - This make CRC be fast. Included implementations: CRC-64-Jones and CRC-16-CCITT. BSD 3-Clause
plashchynski/str2hex - Data formats convertion utility. Apache 2
tzvetkoff/hashids.c - Port of the Hashids library. MIT

Image Processing and Computer Vision

`^` Image Processing and Computer Vision

libgd/libgd - Library for the dynamic creation of images by programmers. License
giflib - Library for reading and writing gif images. License
libjpeg-turbo/libjpeg-turbo - Faster library for reading and writing JPEG files. Licenses
libpng - The official PNG reference library. License
liuliu/ccv - C-based/Cached/Core Computer Vision Library, A Modern Computer Vision Library. License
Phildo/pixQL - SQL for image processing. No license
XadillaX/byakuren - A theme color extracting library. MIT
ansilove/ansilove - ANSi / ASCII art to PNG converter. BSD 2-Clause
bluesmoon/pngtocss - Read in a gradient from a png file and spit out CSS for it. BSD
brendangregg/Dump2PNG - Visualize file data as a PNG. License
buaazp/zimg - A lightweight and high performance image storage and processing system. BSD 3-Clause
dbohdan/s2png - Store data of any kind inside PNG images. GPL 2
ginsweater/gif-h - Simple C++ one-header library for the creation of animated GIFs from image data. Unlicense
libvips/libvips - A fast image processing library with low memory needs. LGPL 2.1
mozilla/mozjpeg - Improved JPEG encoder. Licenses
openslide/openslide - C library for reading virtual slide images. License
pornel/giflossy - Lossy GIF compressor. GPL 2
pornel/pngquant - Lossy PNG compressor. License
rflynn/imgmin - Lossy image optimization. MIT
uclouvain/openjpeg - Official repository of the OpenJPEG project. BSD 2-Clause
vlfeat/vlfeat - An open library of computer vision algorithms. BSD 2-Clause
libspng - Secure PNG reading/writing. BSD 2-Clause
ImageMagick/ImageMagick - Image processing suite with C interface. License
saitoha/libsixel - Library implementing the SIXEL protocol, allowing beautiful graphics in your terminal. License
jedisct1/libpuzzle - A library to quickly find visually similar images. ISC
mattes/epeg - Fast JPEG/ JPG thumbnail scaling with the minimum fuss and CPU overhead. It makes use of libjpeg features of being able to load an image by only decoding the DCT coefficients needed to reconstruct an image of the size desired. License
dr-soft/dr_pcx - Single file PCX image loader. Public Domain
cbraudo/qdbmp - Cross-platform C library for handling BMP files. MIT
lecram/gifdec - GIF decoder. Public Domain
gfxprim/gfxprim - Library for processing and drawing images in variety of formats. LGPL 2.1

Integrated Debugging and Logging

`^` Integrated Debugging and Logging

gpakosz/whereami - One-file library for locating the current executable on the file system. MIT
HardySimpson/zlog - Reliable, pure C logging library. LGPL 2.1
esneider/debug - One-header library for easier 'printf debugging'. MIT
ThrowTheSwitch/CException - Implementation of exceptions. License
google/pblog - Small, low overhead, structured logging library intended for logging formware events. Apache 2
0xmalloc/c-log - a fast ,stable and thread-safe log lib(logger) for C/C++ language. Apache 2
Celtoys/Remotery - Single C file, Realtime CPU/GPU Profiler with Remote Web Viewer. Apache 2
armink/EasyLogger - A ultra-lightweight(ROM<1.6K, RAM<0.3k), high-performance C/C++ log library. MIT
cyrus-and/prof - Self-contained C/C++ profiler library for Linux. License
facebook/liblogfaf - A library that logs messages using non-blocking UDP datagrams. BSD 3-Clause
kmcallister/embedded-breakpoints - Embed GDB breakpoints in C source code. BSD 3-Clause
ntpeters/SimpleLogger - Basic logger for C and C++ projects. MIT
openjudge/sandbox - Open-source suite of software components for C/C++ and Python developers to create automated profiling tools and watchdog programs. BSD 3-Clause
rxi/log.c - A simple logging library implemented in C99. MIT
yosefk/checkedthreads - checkedthreads: no race condition goes unnoticed! Simple API, automatic load balancing, Valgrind-based checking. BSD 2-Clause
libFirm - 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. GPL 2
daddinuz/watchdog - Memory tracer, leaks hunter. MIT
okuvshynov/b63 - Lightweight benchmarking tool for C. Apache 2
stephenrkell/trap-syscalls - Monitor, rewrite and/or otherwise trap system calls. Licenses
immunityinc/libptrace - An event driven multi-core process debugging, tracing, and manipulation framework. LGPL 2.1

I/O

`^` I/O

Lajnold/falloc - falloc creates files of a user-specified size. It uses the posix_fallocate syscall for allocating the right size directly, instead of copying data like the commonly used dd tool does. GPL 3
cgaebel/pipe - A simple thread-safe FIFO in C. MIT
cxong/tinydir - Lightweight, portable and easy to integrate C directory and file reader. License
reverbrain/eblob - Eblob is an append-only low-level IO library, which saves data in blob files. Created as low-level backend for elliptics. LGPL 3
tronkko/dirent - C/C++ library for retrieving information on files and directories. MIT
jwerle/fs.c - File system API much like Node's fs module. MIT
zevv/duc - Library and suite of tools for inspecting disk usage. LGPL 3
kwhat/libuiohook - A multi-platform C library to provide global keyboard and mouse hooks from userland.GPL 3
dr-soft/dr_fs - Single file libraries for working with file system. Public Domain
mpaland/printf - Standalone printf, sprintf and (v)snprintf implementation. MIT

Lexing and Parsing

`^` Lexing and Parsing

GNU Bison - General-purpose parser generator that converts an annotated context-free grammar into a range of parsers. GPL 3
bbu/simple-interpreter - A hackable and extensible lexer, parser and interpreter for a minimalistic, imperative, C-like language. No license
dcreager/libpush - An arrow-based parser combinator library for C. BSD 3-Clause
kmussel/Moment - Natural Language Date Parser Using Lex/Yacc/C. MIT
skvadrik/re2c - lexer generator for C/C++. License
westes/flex - The Fast Lexical Analyzer - scanner generator for lexing in C and C++. License
orangeduck/mpc - Parser combinator library. BSD 2-Clause
transceptor-technology/libcleri - Libcleri is a powerful tool to build languages. From a built language, libcleri can automatically create parse trees, which are data structures representing how a grammar matches input. It also provides feedback in case the input does not match the language. This can be useful for auto-completion, suggestions or error handling. MIT
dr-soft/url - URL parsing in C. BSD 2-Clause

Memory Management

`^` Memory Management

Boehm GC - Garbage collection for C. Various licenses, all open source. License
Lockless Memory Allocator - Efficient memory allocator. GPL 3
talloc - Hierarchical, reference-counted memory pool system with destructors. LGPL 3
mattconte/tlsf - Two-Level Segregated Fit allocator; a general-purpose, dynamic memory allocator designed to meet real-time requirements. BSD 3-Clause
jemalloc/jemalloc - General purpose malloc(3) implementation that emphasizes fragmentation avoidance and scalable concurrency support, commonly used in production systems. License
dlmalloc - Doug Lea's malloc(3) implementation, useful for academic and research purposes. Public domain
CCareaga/heap_allocator - A simple heap memory allocator in ~200 lines. MIT
ivmai/bdwgc - The Boehm-Demers-Weiser conservative C/C++ Garbage Collector (libgc, bdwgc, boehm-gc). License
mulle-nat/mulle-allocator - Flexible C memory allocation scheme with leak checking. BSD 3-Clause
munificent/mark-sweep - A simple mark-sweep garbage collector in C. MIT
ned14/nedmalloc - Fast portable thread caching malloc implementation written in C for multiple threads without lock contention based on dlmalloc. Optimised for x86 and x64. Compatible with C++. Can patch itself into existing binaries on Windows. Boost
orangeduck/tgc - A Tiny Garbage Collector for C. BSD 2-Clause
rampantpixels/rpmalloc - Public domain cross platform lock free thread caching 32-byte aligned memory allocator implemented in C. License
stevedekorte/garbagecollector - Incrementall garbage collector library in C for use by high level language implementions. BSD 3-Clause
Simon-Swenson-8351/tralloc - A binary tree based memory allocator. BSD 3-Clause
Qqwy/raii_with - A simple library to provide RAII in standard-compliant C99. MIT
emeryberger/Malloc-Implementations - A collection of memory allocators. No license
microsoft/mimalloc - Compact general purpose allocator by Microsoft. MIT
mjansson/rpmalloc - Cross platform lock free thread caching 16-byte aligned memory allocator. License
yvan-sraka/malloc - malloc implementation with reduced dependencies. GPL 3
AlxHnr/CRegion - Region-based memory management library. License

Multimedia

`^` Multimedia

Audio and video processing.

jeremyevans/ape_tag_libs - Library for working with APEv2 tags. MIT
lieff/minimp3 - Lightweight MP3 decoder single header library. License
FFMPEG - Complete, cross-platform solution to record, convert and stream audio and video. LGPL 2.1
GStreamer - Framework for audio and visual media. LGPL 2
mpv-player/mpv - Media player MPV with provided library libmpv. Compile with ./waf configure --disable-cplayer --enable-libmpv-shared to not have the music player. License
andrewrk/libsoundio - Library for cross-platform, real-time audio input and output. Has a range of back-ends. MIT
AVbin/AVbin - Thin, cross-platform wrapper around Libav’s video- and audio-decoding functionality, providing long-term binary compatibility for applications and languages that need it. LGPL 3
PaulBatchelor/Soundpipe - A lightweight music DSP library. MIT
Themaister/libfmsynth - A C library which implements an FM synthesizer. MIT
UniversalPrimer/flv-analyzer - Loads an FLV file into sane C data structures and outputs fields as human readable. GPL 3
Vidvox/hap-qt-codec - A QuickTime codec for Hap video. License
acrisci/playerctl - mpris command-line controller and library for spotify, vlc, audacious, bmp, cmus, and others. LGPL 3
aubio/aubio - a library for audio and music analysis. GPL 3
cmatsuoka/libxmp - Libxmp is a library that renders module files to PCM data. License
cnlohr/colorchord - Chromatic Sound to Light Conversion System. BSD 3-Clause
csound/csound - A sound and music computing system. LGPL 2.1
dxjia/ffmpeg-commands-executor-library - execute ffmpeg commands through a jni shared library. Apache 2
erikd/libsndfile - A C library for reading and writing sound files containing sampled audio data. LGPL 2.1
kfish/libfishsound - A simple programming interface for decoding and encoding audio data using Xiph.org codecs (FLAC, Speex and Vorbis). BSD 3-Clause
libass/libass - libass is a portable subtitle renderer for the ASS/SSA (Advanced Substation Alpha/Substation Alpha) subtitle format. ISC
libav/libav - Collection of libraries and tools to process multimedia content such as audio, video, subtitles and related metadata. License
mltframework/mlt - MLT Multimedia Framework. LGPL 2.1
sahib/glyr - Glyr is a music related metadata searchengine, both with commandline interface and C API. LGPL 3
simonyiszk/csdr - A simple DSP library and command-line tool for Software Defined Radio. License
xiph/flac - Free Lossless Audio Codec. License
xiph/opus - Modern audio compression for the internet. License
mhroth/tinyosc - A minimal Open Sound Control (OSC) library written in vanilla C. ISC
libao - Cross-platform audio library with a wide variety of outputs. GPL 2
libvlc - VLC player library. Licenses
raysan5/raudio - A simple and easy-to-use audio library based on miniaudio. Zlib
dr-soft/miniaudio - Single file audio playback and capture library written in C. Licenses

Multiple Purpose Libraries

`^` Multiple Purpose Libraries

parallella/pal - Optimized library for maths, parallel processing and data movement. Apache 2
APR - Apache Portable Runtime; another library of cross-platform utility functions. Apache 2
GLib - Library of utility functions and structures, designed to be portable, efficient and powerful. LGPL 2.1
keybuk/libnih - Lightweight library of C functions and structures. GPL 2
wolkykim/qlibc - Simple and powerful C library, designed as a replacement for GLib while focusing on being small and light. License
chutsu/cog - C common library containing common data structures, sorting algorithms and utility functions. MIT
cs50/libcs50 - CS50 Library for C. MIT
dcreager/libcork - A simple, easily embeddable cross-platform C library. BSD 3-Clause
faragon/libsrt - C library for writing fast and safe C code, faster. It provides string, vector, bit set, set, map, hash set, and hash map handling. Suitable for soft and hard real-time. Allows both heap and stack allocation. BSD 3-Clause
koanlogic/libu - LibU is a multiplatform utility library written in C, with APIs for handling memory allocation, networking and URI parsing, string manipulation, debugging, and logging in a very compact way, plus many other miscellaneous tasks. License
letoram/arcan - Display Server, Multimedia Framework, Game Engine-> "Desktop Engine". Licenses
saprykin/plibsys - Highly portable C system library: threads and synchronization primitives, sockets (TCP, UDP, SCTP), IPv4 and IPv6, IPC, hash functions (MD5, SHA-1, SHA-2, SHA-3, GOST), binary trees (RB, AVL) and more. Native code performance. MIT
tboox/tbox - A glib-like multi-platform c library. Apache 2
zpl-c/zpl - Your C99 Powerkit. Licenses
dmw/caffeine - C Application Framework. LGPL 2.1
breckinloggins/libuseful - A collection of useful data structures, algorithms, and utilities for C programming. MIT
erimatnor/libckit - A kit of C-based utilities and data structures. Apache 2
pforemski/libpjf - A C library of data structures with tools (based on libasn). GPL 3
stevedekorte/basekit - C based OO portable data structure library. BSD 3-Clause
mjansson/foundation_lib - Cross-platform foundation library in C providing basic support data types and functions to write applications and games in a platform-independent fashion. Unlicense
happyfish100/libfastcommon - Functions including: string, logger, chain, hash, socket, ini file reader, base64 encode / decode, url encode / decode, fast timer, skiplist, object pool etc. detail info please see the c header files. LGPL
sabit/libcprops - C prototyping tools. LGPL 2.1

Networking

╠════ DNS

`^` DNS

GNU adns - Advanced, easy-to-use, asynch-capable DNS client library and utilities. GPL 3
ldns - Library to simplify DNS programming. BSD 3-Clause
bagder/c-ares - Library for asynchronous DNS requests. License
farsightsec/dnstable - encoding format, library, and utilities for passive DNS data. Apache 2
wahern/dns - Single file non-blocking DNS C library without callbacks or external dependencies. MIT
libidn - Implementation of the Stringprep, Punycode and IDNA specifications. Licenses
mjansson/mdns - mDNS/DNS-SD library. Unlicense

╠════ HTTP

`^` HTTP

nodejs/http-parser - HTTP request/response parser for c. MIT
h2o/picohttpparser - Tiny HTTP parser. MIT
iafonov/multipart-parser-c - Http multipart parser implemented in C. MIT
solusipse/ureq - Micro C library for handling HTTP requests on low resource systems. MIT
nghttp2/nghttp2 - HTTP/2 C Library. MIT
wg/wrk - Modern HTTP benchmarking tool. License

╠════ Mail

`^` Mail

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
dinhviethoa/libetpan - Mail Framework for C Language. License
dertuxmalwieder/libvldmail - Your friendly e-mail address validation library. WTFPL

╠════ Messaging and Brokers

`^` Messaging and Brokers

nanomsg/nng - Lightweight brokerless messaging. MIT
alanxz/rabbitmq-c - Client library for RabbitMQ. License
antirez/disque - Disque is a distributed message broker. BSD 3-Clause
circonus-labs/fq - F@#$*&%Q (Message queue that is fast, brokered, in C and gets out of your way). MIT
zeromq/czmq - High-level C binding for ØMQ. License
nanomsg/nanomsg - C-based implementation of ZeroMQ. License
LiamBindle/MQTT-C - MQTT protocol implementation. MIT

╠════ Remote Desktops

`^` Remote Desktops

FreeRDP/FreeRDP - FreeRDP is a free remote desktop protocol library and clients. Apache 2
LibVNC/libvncserver - LibVNCServer/LibVNCClient are cross-platform C libraries that allow you to easily implement VNC server or client functionality in your program. GPL 2

╠════ RPC

`^` RPC

hmng/jsonrpc-c - JSON-RPC in C. MIT
lopter/lightsd - A daemon with a JSON-RPC API to control your light bulbs. GPL 3
laruence/yar - RPC for C and PHP. License
protobuf-c/protobuf-c-rpc - Using protobuf-c for RPC. License

╠════ TCP, UDP, Sockets

`^` TCP, UDP, Sockets

bovine/datapipe - Network TCP port forwarding. Public domain
sch3m4/libntoh - User-friendly C Library to perform TCP streams reassembly and IPv4/6 defragmentation. License
tass-belgium/picotcp - PicoTCP is a free TCP/IP stack implementation. Licenses
opendp/dpdk-odp - Open data plane on dpdk, TCP/IP stack for dpdk. BSD
lsalzman/enet - ENet reliable UDP networking library. MIT
hoxnox/rawsock_recv_example - SOCK_RAW IPPROTO_UDP socket data transmission example. BSD 3-Clause
silentbicycle/socket99 - C99 wrapper for the BSD sockets API. ISC
fastos/fastsocket - Fastsocket is a highly scalable socket and its underlying networking implementation of Linux kernel. GPL 2
sustrik/msg_control - Helper functions for dealing with socket ancillary data. MIT

╠════ Web Servers

`^` Web Servers

taf2/libebb - Lightweight high-performance HTTP server library for C. MIT
libhttpd - Library to add basic web server capabilities to an application or embedded device. LGPL
libmicrohttpd - Small C library that makes it easy to run an HTTP server as part of another application. Licenses
risoflora/libsagui - Cross-platform C library which helps to develop web servers or frameworks. LGPL 3
h2o/h2o - Optimized HTTP/1, HTTP/2 high performance server/library. MIT
mongrel2/mongrel2 - The Mongrel2 Web Server Project. BSD 3-Clause
shenfeng/tiny-web-server - a tiny web server in C, for daily use. MIT
zyearn/zaver - Yet another fast and efficient HTTP server. MIT
libsoup - GNOME HTTP client/server library. Uses GObject. LGPL 2
criticalstack/libevhtp - Create extremely-fast and secure embedded HTTP servers with ease. BSD 3-Clause
civetweb/civetweb - Embedded C/C++ web server. Licenses
lpereira/lwan - Experimental, scalable, high-performance HTTP server. GPL 2
cesanta/mongoose - Embedded web server for C/C++. License
oneoo/alilua - epoll/kqueue+lua based web server. MIT
haywire/haywire - Haywire is an asynchronous HTTP server framework written in C that's built using the event loop based libuv platform layer that node.js is built on top of. Apache 2
davidmoreno/onion - C library to create simple HTTP servers and Web Applications. Licenses
wolkykim/libasyncd - Embeddable Event-based Asynchronous Message/HTTP Server library for C/C++. BSD 2-Clause
balde/balde - Microframework for C based on GLib. LGPL 2.1
bitly/simplehttp - A family of libraries and daemons for building scalable web infrastructure. MIT
boazsegev/facil.io - Your high performance web application C framework. MIT
iafonov/cosmonaut - Fast web server & micro framework implemented in C. Just for fun. MIT
riolet/WAFer - WAFer is a C language-based software platform for scalable server-side and networking applications. Think node.js for C programmers. GPL 2
jeremycw/httpserver.h - Single header library for writing non-blocking HTTP servers in C. MIT
lammertb/libhttp - Crossplatform HTTP and HTTPS library. MIT
zhaojh329/libuhttpd - Fully asynchronous HTTP server library based on libev and http-parser for embedded Linux. MIT
silgy/silgy - Multipurpose asynchronous web application backend engine. MIT

╠════ Web Service APIs

`^` Web Service APIs

sinemetu1/twitc - Mini library for interacting with the Twitter OAuth API. MIT
dajobe/flickcurl - Flickr C API library. GPL 2
Cotix/cReddit - CLI Reddit client written in C. Includes separated library. License
HalosGhost/shaman - A small, native C library and utility to fetch weather. GPL 2
PromyLOPh/pianobar - Console-based pandora.com player. License
Yubico/yubico-c-client - Yubico C client library. BSD 2-Clause
adobkin/libcapn - A simple C Library for interact with the Apple Push Notification Service (APNs). MIT
aws/aws-iot-device-sdk-embedded-C - SDK for connecting to AWS IoT from a device using embedded C. Apache 2
domsson/libtwirc - Twitch IRC library for Linux. License

╠════ Websockets

`^` Websockets

tatsuhiro-t/wslay - WebSocket library. Implements version 13 of the WebSocket protocol, as described in RFC 6455. MIT
JonnyWhatshisface/libwebsock - Easy-to-use and powerful web socket library. LGPL 3
m8rge/cwebsocket - Lightweight websocket server library. MIT
zhaojh329/libuwsc - A Lightweight and fully asynchronous WebSocket client C library based on libubox for Embedded Linux. LGPL 2.1
warmcat/libwebsockets - Canonical websocket library. `License
wbudd/RingSocket - Lockless multi-threaded C11 Linux WebSocket server. MIT
clemenskresser/ezwebsocket - Websocket server library in C. MIT

╚════ Uncategorized Networking

`^` Uncategorized Networking

libcurl - Client-side URL transfer library, supporting a wide range of formats. License
oSip - SIP implementation in C without additional dependencies. LGPL
rxi/dyad - Asynchronous networking library. MIT
51Degrees/Device-Detection - Device detection for C / PHP / Perl / Python and Node.js - professionally maintained device data. License
uriparser/uriparser - Strictly RFC 3986-compliant URI parsing and handling library. BSD 3-Clause
c9s/r3 - High-performance path dispatching library. It compiles your route paths into a prefix tree (trie). By using the constructed prefix trie in the start-up time, you may dispatch your routes with efficiency. MIT
versatica/OverSIP- OverSIP: the SIP framework you dreamed about. MIT
libssh2/libssh2 - the SSH library. BSD 3-Clause
rockdaboot/mget - Multithreaded metalink/file/website downloader (like Wget) and C library. LGPL 3
seanmiddleditch/libtelnet - Simple RFC-complient TELNET implementation as a C library. Public domain
shadeslayer/libnice - Implementation of the IETF's Interactive Connectivity Establishment (ICE) standard (RFC 5245) and the Session Traversal Utilities for NAT (STUN) standard (RFC 5389). Licenses
udp/lacewing - Cross-platform network I/O library for C/C++. License
verse/verse - Network protocol for real-time sharing between graphical applications. Licenses
the-tcpdump-group/libpcap - the LIBpcap interface to various kernel packet capture mechanism. BSD 3-Clause
the-tcpdump-group/tcpdump - the TCPdump network dissector. BSD 3-Clause
luohaha/CSpider - A scalable and convenient crawler framework. MIT
nitrogenlogic/cliserver - A sample libevent-based network socket server that presents a simple command line interface to multiple connecting clients. BSD 2-Clause
babelouest/ulfius - Web Framework to build REST APIs, Webservices or any HTTP endpoint in C language. Can stream large amount of data, integrate JSON data with Jansson, and create websocket services. LGPL 2.1
haiwen/ccnet - Ccnet is a framework for writing networked applications in C. GPL 2
it4e/CHL - C Hypertext Library - A library for writing web applications in C. LGPL 3
jorisvink/kore - An easy to use, scalable and secure web application framework for writing web APIs in C. License
monkey/duda - Duda I/O is an event-driven and high performant web services framework which exposes a friendly C API. Apache 2
zeromq/zyre - Framework for proximity-based peer-to-peer applications. License
Maxime2/dataparksearch - Open source, feature rich search engine. License
kristapsdz/kcgi - Minimal CGI and FastCGI library for C/C++. ISC

OpenCL

`^` OpenCL

OpenCL, CUDA, OpenMP and other similar APIs.

cf4ocl - The C Framework for OpenCL. LGPL 3
clMathLibraries/clRNG - an OpenCL based software library containing random number generation functions. License
tuxfan/ocl-mla - OpenCL Mid-Level Abstractions. License
matze/oclkit - Two-file OpenCL wrapper. GPL 3
emrainey/OpenCL-Environment - A series of utilities aimed at making OpenCL easier to use. Apache 2

OS Specifics

`^` OS Specifics

symisc/libcox - Library which permits cross-platform system calls and standard utilities across different operating systems. BSD 2-Clause
checkpoint-restore/criu - Checkpoint/Restore In Userspace; a software tool (with a C API) for 'freezing' a running application to disk, then restoring it. Targeted for Linux. Licenses
alsa-lib - Userspace library to interact with ALSA. LGPL 2.1
Leandros/WindowsHModular - A modular Windows.h Header. License
a0rtega/pafish - Pafish is a demonstration tool that employs several techniques to detect sandboxes and analysis environments in the same way as malware families do. GPL 3
antirez/linenoise - A small self-contained alternative to readline and libedit. BSD 2-Clause
fancycode/MemoryModule - Library to load a DLL from memory. License
jimon/osx_app_in_plain_c - A simple showcase how to create a simple OS X app in plain C without any Objective-C. No license
rvoicilas/inotify-tools - Library and a set of command-line programs for Linux providing a simple interface to inotify. GPL 2
tinyalsa/tinyalsa - Tiny library to interface with ALSA in the Linux kernel. BSD 3-Clause
wengkai/ACLLib - A bunch of C functions covers Win32API and provides simpler API to beginners for programming Windows GUI applications. GPL 3
zardus/preeny - Some helpful preload libraries for pwning stuff. BSD 2-Clause

Procedural Generation

`^` Procedural Generation

prideout/heman - Tiny library of image utilities dealing with height maps, normal maps, distance fields and the like. MIT
JCash/voronoi - A C implementation for creating 2D voronoi diagrams. MIT
Srekel/the-worldinator - Procedural world generation experiment. Licenses
saxbophone/libsxbp - Experimental generation of 2D spiralling lines based on input binary data. License
ajxs/pbp - Procedural Block Painter. Experiments in procedural art generation. MIT
Tastyep/ProceduralNoise - Useful functions for procedural generation. No license

Processes and IPC

`^` Processes and IPC

D-Bus - Interprocess communications bus. Licenses
bus1/dbus-broker - Linux D-Bus Message Broker. Apache 2
signalapp/libsignal-protocol-c - Signal Protocol C Library. GPL 3
sharvil/flingfd - A tiny library to send file descriptors across processes. Apache 2
sheredom/process.h - A simple one header solution to launching processes and interacting with them for C and C++. Unlicense
troydhanson/kvspool - A library to support streaming data applications. MIT
xroche/coffeecatch - Tiny native POSIX signal catcher (especially useful for JNI code on Android/Dalvik). BSD 2-Clause
samuellab/InterProcess - A compact C library to share data between processes on Windows. GPL 3

Regex and Search

`^` Regex and Search

kkos/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. License
nasciiboy/RecursiveRegexpRaptor-4 - Simple and complete implementation of regular expressions with its own sintax. GPL 3
laurikari/tre - POSIX-compliant, feature-full regex library. License
cesanta/slre - Super Light Regexp engine for C/C++. License
k-takata/Onigmo - Regular expressions library forked from Oniguruma. License
openresty/sregex - A non-backtracking NFA/DFA-based Perl-compatible regex engine matching on large data streams. BSD 3-Clause

Serialization

`^` Serialization

dvidelabs/flatcc - FlatBuffers compiler and library. Apache 2
liteserver/binn - Binary serialization format meant to be compact, fast and easy-to-use. Apache 2
jmckaskill/c-capnproto - Implementation of the Cap'n Proto serialization protocol. MIT
apache/avro - Avro data serialization system for several languages, including C. Apache 2
liteserver/netstring-c - Netstring encoder and decoder. Public domain
protobuf-c - Implementation of Google Protocol Buffer in C. License
ErikDubbelboer/c-pack - Simple data packing/unpacking in C. No license
acg/lwpb - Lightweight Protocol Buffers for C and Python. Apache 2
camgunz/cmp - An implementation of the MessagePack serialization format in C. MIT
cloudwu/pbc - A protocol buffers library for C. MIT
cloudwu/sproto - Yet another protocol library like google protocol buffers ,but simple and fast. MIT
dryman/opic - Fast serialization framework for C. LGPL 3
google/upb - Small protobuf implementation in C. BSD 3-Clause
greghaynes/Afproto - Serial data framing protocol. License
ludocode/mpack - Encoder/decoder for the MessagePack serialization format. MIT
nanopb/nanopb - Protocol Buffers with small code size. Zlib
troydhanson/tpl - Small binary serialization library for C. License
clibs/dumpasn1 - Display the contents of ASN.1 encoded data. License
vlm/asn1c - The ASN.1 Compiler. BSD 2-Clause
eerimoq/pbtools - Google protobuf tools. MIT

Source Code Collections

`^` Source Code Collections

DanielGibson/Snippets - Useful code snippets and header-only libraries. Public domain
CCAN - Modelled after Perl's CPAN, this is a big collection of C code. No license
libdjb - Collection of libraries doing various things. License
BurntSushi/clibs - A smattering of miscellaneous C libraries. Includes sane argument parsing, a thread-safe multi-producer/multi-consumer queue, and implementation of common data structures (hashmaps, vectors and linked lists). WTFPL
RandyGaul/cute_headers - Collection of cross-platform one-file C/C++ libraries with no dependencies, primarily used for games. Licenses
chadjoan/C-Survival-Kit - A set of useful functions, data structures, and macros aimed at allowing more expressive and reliable C code. Portability targets are OpenVMS and Linux. Boost
floooh/sokol - Minimal cross-platform standalone C headers. Zlib
gingerBill/gb - Single-file public domain libraries for C & C++. Public domain
gozfree/libraries - Basic libraries all written in c by gozfree, including network, event, config, log, hash, ipc, rpc, mem, and so on. MIT
mackron/dr_libs - A collection of public domain single-file libraries for C/C++. Public domain
mattiasgustavsson/libs - Single-file public domain libraries for C/C++. Public domain
matteobertozzi/carthage - Pure C Data Structure and Utils. BSD
napsy/libhelper - General functions and data structures for C. BSD 3-Clause
niklasfrykholm/nflibs - A collection of interoperable minimalistic C libraries. `Public domain
nothings/stb - Single-file public domain libraries for C/C++. Licenses
prideout/par - Single-file C libraries from Philip Allan Rideout. MIT
rmitton/rjm - Various single-file C libraries. Public domain
vurtun/mmx - single header libraries for C/C++. No license
yl790/algorithms-and-data-structures - Different algorithms & data structures. No license
rofl0r/libulz - a collection of useful functions and data structures to create C apps faster. focus on simplicity, ability to statically link and minimal binary size. LGPL 2.1
sdroege/snippets - Some algorithms and data structures. LGPL 3
lbrito1/cstuff - Algorithms & data structures in C. GPL 2
angelortega/mpdm - Minimum Profit Data Manager. Public domain
attractivechaos/klib - Small and lightweight implementations of common algorithms and data structures. MIT
f1nalspace/final_game_tech - Game related libraries. MIT
QwertyQaz414/anv - Collection of header-only utility libraries. MIT

Scientific

`^` Scientific

Math mostly located in Calculations category

GuillaumeHolley/BloomFilterTrie - A data structure for pan-genome storage. MIT
noporpoise/seq_file - Library for Reading Bioinformatic Sequence Data in C. Public domain
r0nk/corvus - Genetic BF programming. No license
XenonofArcticus/DynamicTrack - Access sources of dynamically-updated data about discrete entities like GPSes, INSes, ADS-B sources. MIT
ericmandel/funtools - A "minimal buy-in" FITS library and utility package for astronomical data analysis. LGPL 2.1

Special Purpose

`^` Special Purpose

Libraries with very narrow non-generic purpose.

TulipCharts/tulipindicators - Library of functions for technical analysis of financial data. LGPL 3
MatthewLM/cbitcoin - Low-level bitcoin library written in C. MIT
RhysU/ESIO - Provides simple, high throughput input and output of structured data sets using parallel HDF5. ESIO is designed to support reading and writing turbulence simulation restart files within C, C++, and modern Fortran applications. LGPL 2.1
Unidata/netcdf-c - Official GitHub repository for netCDF-C libraries and utilities. BSD 3-Clause
jgarzik/picocoin - A bitcoin library in C, SPV wallet & more. License
libtrading/libtrading - Ultra low-latency trading connectivity library for C and C++. BSD 2-Clause
nayuki/QR-Code-generator - High-quality QR Code generator library in Java, JavaScript, Python, C++, C. MIT
qiq/Czech-morphology - Czech morphology library, using data files compatible with PDT 2.0 License
sleuthkit/sleuthkit - The Sleuth Kit® (TSK) is a library and collection of command line digital forensics tools that allow you to investigate volume and file system data. The library can be incorporated into larger digital forensics tools and the command line tools can be directly used to find evidence. Licenses
hroptatyr/uterus - universal tick encoder library to efficiently transport huge amounts of tick data. BSD 3-Clause
luke-jr/bfgminer - Modular ASIC/FPGA miner written in C, featuring overclocking, monitoring, fan speed control and remote interface capabilities. GPL 3

Standard Libraries

`^` Standard Libraries

Implementations of the C standards

PDCLib - The Public Domain C Library. Implements most of C99 and some of C11. License
uClibc-ng - Small C library for developing embedded systems. LGPL 2.1
dietlibc - C standard library designed for the smallest possible binaries. GPL 2
glibc - The GNU C Library; an implementation of the C standard library. Licenses
musl - Standard C library, compatible with POSIX 2008 and C11. Designed for static linking. MIT
NuxiNL/cloudlibc - CloudABI's standard C library. BSD 2-Clause
marssaxman/startc - Minimal freestanding C library for bare-metal i386 development. License
olibc/olibc - Another C Library optimized for Embedded Linux. BSD
lpsantil/rt0 - A minimal C runtime for Linux i386 & x86_64. BSD 2-Clause
keith-packard/picolibc - Standard C library APIs that targets small embedded systems with limited RAM. Licenses

String Manipulation

`^` String Manipulation

wooorm/levenstein.c - Levenstein distance algorithm implementation. MIT
wooorm/stmr.c - Porter Stemmer algorithm implementation. MIT
websnarf/bstrlib- The Better String Library. BSD 3-Clause
ICU - International Components for Unicode; a library for Unicode support. License
libunistring - Library for manipulating Unicode strings in C. Licenses
libgiconv - Text conversion library. LGPL
JuliaStrings/utf8proc - Small, clean library for processing UTF-8 Unicode data. License
antirez/sds - Simple Dynamic Strings library for C. BSD 2-Clause
boyerjohn/rapidstring - Maybe the fastest string library ever. MIT
clibs/buffer - Tiny C string library. MIT
chrisjmccormick/word2vec_commented - Commented (but unaltered) version of original word2vec C implementation. Apache 2
fontforge/libuninameslist - A library with a large (sparse) array mapping each unicode code point to the annotation data for it. BSD 3-Clause
jasonmaclafferty/String - Dynamic string data type implementation. MIT
josephg/librope - UTF-8 rope library for C. MIT
sheredom/utf8.h - Single header utf8 string functions for C and C++. Unlicense
branchless-utf8 - Branchless UTF-8 decoder. Unlicense
g-berthiaume/strsepf - Single header string parsing function with memory safety of strsep and the convenience of a sscanf-like interface. MIT
karlmcguire/sing - String ring buffer library. MIT

Testing

`^` Testing

yhfudev/cpp-ci-unit-test - A modern minimal hassle unit test framework. MIT
codeplea/minctest - Unit testing microlibrary. Zlib
evolutional/utest - Single-header unit testing library. Unlicense
Tuplanolla/cheat - Very simple unit testing framework. BSD 2-Clause
libcheck/check - Unit testing framework for C. LGPL 2.1
ThrowTheSwitch/CMock - Mock/stub generator for C. MIT
cmocka - Unit testing framework with support for mock objects. Apache 2
rafael-santiago/cutest - Library for unit testing with memory leak detection (Linux, FreeBSD and Windows). GPL 2
nemequ/munit - Small but full-featured unit testing framework for C with no dependencies. MIT
zorgnax/libtap - Write tests in C. LGPL 3
Snaipe/Criterion - A cross-platform C and C++ unit testing framework for the 21th century. MIT
ThrowTheSwitch/Unity - Simple Unit Testing for C. MIT
bvdberg/ctest - Unit test framework for software written in C. Apache 2
clear-code/cutter - An easy to write and debug unit testing framework for C and C++. Licenses
compiler-dept/speck - A small unit testing framework for C. MIT
joewalnes/tinytest - A tiny unit-testing framework for C. No license
lpabon/cmockery2 - Reviving cmockery unit test framework from Google. Apache 2
mcandre/qc - C port of the QuickCheck unit test framework. BSD 2-Clause
mchochlov/Gnucash - Data model unit testing - GSoC 2011. Licenses
mortie/snow - A testing library for C. MIT
orangeduck/ptest - DRY Microtesting Framework for C. BSD 3-Clause
silentbicycle/greatest - A C testing library in 1 file. No dependencies, no dynamic allocation. ISC
silentbicycle/theft - property-based testing for C: generate input to find obscure bugs, then reduce to minimal failing input. ISC
siu/minunit - Minimal unit testing framework for C. MIT
stephenmathieson/describe.h - Simple BDD describe test. MIT
vmg/clar - What tests are made of. ISC
CuTest - C Unit Testing Framework. Licenses
eerimoq/nala - Test framework for C projects. Based on narwhal and narmock. MIT
vberlier/narwhal - Framework for writing readable and maintainable tests for C programs and libraries. MIT
vberlier/narmock - Finds the functions mocked in your tests and generates mocks. MIT
sheredom/utest.h - Single header unit testing framework. [Unlicense][80-61]
Koldar/crashc - Automatic C source code testing framework. MIT
christophercrouzet/rexo - Unit testing framework for C and C++. Unlicense

TUI

`^` TUI

Textual User Interface

sabotage-linux/netbsd-curses - Simplified and small version of curses, with the same interface. Licenses
ncurses - Coloured terminal UI library. Licenses
doches/progressbar - An easy-to-use C library for displaying text progress bars. BSD 3-Clause
jwerle/progress.c - Progress display lib for c. MIT
nsf/termbox - Library for writing text-based user interfaces. MIT
alandekok/recli - A re-imagined CLI. Customizable syntax, help, permissions, data types. BSD 2-Clause
matthiasbock/ucurses - Very small and simple text-based user interface (TUI) library for microcontrollers. GPL 3
serameo/TUI - Text User Interface using curses for UNIX. GPL 3
jakubfi/emui - Text user interface toolkit. License
nejohnson/stui - Simple Text User Interface. BSD 3-Clause
tboox/ltui - A cross-platform terminal ui library based on Lua. Apache 2
okbob/ncurses-st-menu - ncurses based library for CUA look menu. BSD 2-Clause
LionyxML/nocurses - A terminal screen manipulation library. GPL 2
seleznevae/libfort - Crossplatform library for formatted text tables creation. MIT
LiquidityC/termesc - ANSI escape TUI library. No license
tryggth/newt - TUI library made by RedHat. License
serameo/TUI2 - TUI fox Unix. No license

Uncategorized

`^` Uncategorized

recp/tm - Timer and Timeline Utils for C. MIT
libgit2/libgit2 - Pure C implementation of Git. License
ThomasHabets/monotonic_clock - Portable C library for getting monotonic time. BSD 3-Clause
graphviz - Graph Visualization Tools. License
h2non/semver.c - semantic version parser and serializer written in ANSI C. MIT
libical/libical - Libical is an Open Source implementation of the iCalendar protocols and protocol data units. Licenses
jonpe960/ufsm - UML Statechart library in C and XMI importer. BSD 3-Clause
locasto/libdisorder - A simple C library for entropy measurement of byte streams and other data. GPL 2
lucasb-eyer/heatmap - High performance C heatmap generation library. Supposed to be wrapped by higher-level languages. MIT
tailhook/objpath - A library that allows to traverse data structures by path. MIT
pornin/CTTK - Constant-Time Toolkit. MIT
juliettef/IconFontCppHeaders - C, C++ headers and C# classes for icon fonts: Font Awesome, Fork Awesome, Material Design, Material Design icons, Kenney game icons and Ionicons. Zlib
eam/libcrange - Range parsing library for managing sets of ostnames, ips, clusters, roles and other operational data. BSD 3-Clause

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CODE_OF_CONDUCT.md		CODE_OF_CONDUCT.md
CONTRIBUTING.md		CONTRIBUTING.md
LICENSE		LICENSE
README.md		README.md

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Awesome C

Index

Meta

^ Standards

Tooling

^ Build Systems

^ Compilers

^ Debugging and Analysis

^ Documentation Generation

^ Editors

^ Microsoft Windows Environment

^ Profiling

^ Text Editor Extensions

^ Utilities

Reading Material

^ Books

Reference Books

Beginner Books

Intermediate Books

Advanced Books

Articles and Other Resources

^ Benchmarks

^ Beginner Level

^ Intermediate Level

^ Advanced Level

Code Examples

^ Operating Systems

^ Emulators, VMs

^ UI, Windowing, Graphics

^ Language Implementations

^ Challenges

^ Other Examples

^ AI

^ Algoritm Implementations

^ Argument Parsing

^ Calculations and Math

^ Compression

^ Concurrency and Parallelism

^ Cryptography

^ Databases

^ Data Structures and Types

^ Events

^ Foreign Function Interfaces

Filetype Targets

^ Binaries

^ CSV

^ HTML

^ JSON

^ INI

^ Markdown

^ XML

^ Other Filetypes

^ Flow Control and Language Extension

Game Development

^ Game Engines

^ Graphics Rendering

^ Gamedev Helping Libraries

^ Geography

^ GUI

^ Hardware Oriented

^ Hashing

^ Image Processing and Computer Vision

^ Integrated Debugging and Logging

^ I/O

^ Lexing and Parsing

^ Memory Management

^ Multimedia

^ Multiple Purpose Libraries

Networking

^ DNS

^ HTTP

^ Mail

^ Messaging and Brokers

^ Remote Desktops

`^` Standards

`^` Build Systems

`^` Compilers

`^` Debugging and Analysis

`^` Documentation Generation

`^` Editors

`^` Microsoft Windows Environment

`^` Profiling

`^` Text Editor Extensions

`^` Utilities

`^` Books

`^` Benchmarks

`^` Beginner Level

`^` Intermediate Level

`^` Advanced Level

`^` Operating Systems

`^` Emulators, VMs

`^` UI, Windowing, Graphics

`^` Language Implementations

`^` Challenges

`^` Other Examples