C

Build script generator for toolsets like Visual Studio, Xcode, or GNU Make. 3-clause BSD

Small, simple build system with a focus on speed. Apache 2.0

Cross-platform build utility based on lua. Apache 2.0

Build system for various operating systems and targets. Apache 2.0

Build system created and used by Facebook. Apache 2.0

Fast compression library (implementation in C++, native bindings to C).

Generic lossless compression algorithm based on LZ77, Huffman coding and 2nd order context modelling

Pixz (pronounced pixie) is a parallel, indexing version of xz.

Minimalistic client library for Redis.

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

Cross-platform IDE written with C++ and Qt, part of the Qt SDK. Supports Clang Code Model.

Header only, macro generated, generic and type-safe Collections in C. MIT

Lightweight library of C functions and structures. GNU GPL2.1

Range of single-file libraries for C. Public Domain

GPU graphics and utilities API. Expat

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

ASCII renderer for terminal-based interfaces. WTFPLv2

Improved JPEG encoder. 3-clause BSD

Single-header ANSI C gui library. Public Domain

Simple and portable (but not inflexible) GUI library. MIT

Small C library for building user interfaces with C, XML and CSS. MIT

Fast hashtable implementation. Apache 2.0

Multi platform CRC library. MIT

C implementation of MurMur Hashing. Public Domain

Fast Positive Hash library. zlib

Library for working with JSON. Expat

Lightweight JSON library written in C. MIT

Advanced JSON manipulation library, with support for JSON Schema. LGPL, any version

Cross platform, lock-free memory allocator. Public Domain

HTML5 parsing library in C99. Apache 2.0

HTTP request/response parser. Expat

Sagui is a cross-platform C library which helps to develop web servers or frameworks. GNU LGPL3

Your friendly e-mail address validation library. WTFPLv2

Portable MQTT C client for embedded systems and PCs alike. MIT

C-based implementation of ZeroMQ. Expat

C99 implementation of the TLS/SSL protocols, designed to be simple, fast and with security as a priority. Apache 2.0

C99 wrapper for the BSD sockets API. ISC

Mini C library for interacting with the Twitter OAuth API. Expat

Library for building simple and elegant cross-platform mmo client-server solutions. Apache 2.0

Asynchronous networking library. MIT

Optimized HTTP/1, HTTP/2 high performance server/library. MIT

Linux packet crafting tool. GPL2

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

Suite of data structures and routines for scalable parallel solution of scientific applications modelled by partial differential equations. FreeBSD

Very fast, SIMD-optimized mathematical library. 3-clause BSD

Message passing interface implementation. 3-clause BSD

Parser combinators for binary formats. GNU GPL2.1

Parser for .ini files. Expat

Yet another INI parser. GNU GPL3 or later

Parser combinator library. FreeBSD

Universal configuration library parser. FreeBSD

Simple and complete implementation of regular expressions with its own sintax. GNU GPL3 or later

Super Light Regular Expression library; a very small implementation of a subset of Perl regex syntax. GNU GPL2.1

Non-backtracking NFA/DFA-based Perl-compatible regex engine library. 3-clause BSD

POSIX-compliant, feature-full regex library.

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

Implementation of the Cap'n Proto serialization protocol. Expat

Implementation of the MessagePack serialization protocol. Expat

Another implementation of the MessagePack serialization protocol. Expat

Netstring encoder and decoder. Public Domain

Implementation of Google Protocol Buffer in C. FreeBSD

Something of a package manager for C. Comes with a bunch of libraries of its own. Expat

Google's C standard library, developed for Android. 3-clause BSD

Simple Dynamic Strings; a library for handling C strings in a simpler way, but one that is compatible with normal C string functions. Available via clib. FreeBSD

Efficient string compression library. 3-clause BSD

Single header utf8 string functions. Unlicense

Small, clean library for processing UTF-8 Unicode data. License

Library for unit testing with memory leak detection (Linux, freeBSD and Windows). GPL2

Minimal unit testing framework for C. Expat

Small but full-featured unit testing framework for C with no dependencies. MIT

Fast memory error detector. Apache 2.0

Compile and execute C "scripts" in one go on the command line. Also has shebang support. Expat

Run C files using hash-bang. FreeBSD

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

C library for working with APEv2 tags. Expat

C implementation of the CommonMark spec. Various Licenses

C implementation of exceptions. Expat

C implementation of a command-line option parser. Expat

Simple neural network library in C. Zlib

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

Minimal Huffman encoder and decoder. Public Domain

Simple library for working with KD-trees. 3-clause BSD

BSON utility library. Apache 2.0

Portable foreign-function interface library. Expat

Cross-platform protocol library to communicate with iThings. GNU LGPLv2.1 or later (library) or GNU GPL2.1 or later (tools)

Platform-independent Near-Field Communication library. GNU LGPL3

Deprecated, here for archival purposes. Eventing framework for building high-scalability and high-performance systems. Apache 2.0

C-language-based, ultra-light software platform for scalable server-side and networking applications (think node.js for C programmers). GNU GPL2.1

Protocol buffers library. Expat

Client library for RabbitMQ. Expat

Tiny recursive-descent parser, compiler and evaluation engine for simple mathematical expressions. zlib

A cross platform C99 library to get cpu features at runtime. Apache 2.0

Small, low overhead, structured logging library intended for logging formware events.Apache 2.0

ELF object file access library in C. GNU GPL2.1

Dissasembly/disassembler framework. BSD 3-clause

Small XML reading and writing library. No dependencies aside from C standard library. Apache 2.0 with exceptions