QBE is a small compiler backend using an SSA-based intermediate language as input.

The Permuted Congruential Generator (PCG) extends the Linear Congruential Generator (LCG) with a permutation function to increase output randomness while retaining speed, simplicity, and conciseness.

The UDUNITS-2 package provides support for units of physical quantities. Its three main components are:

1. udunits2lib, a C library for units of physical quantities;

2. udunits2prog, a utility for obtaining the definition of a unit and for converting numeric values between compatible units; and

3. an extensive database of units.

Grand Central Dispatch (GCD or libdispatch) implements a concurrency model wherein program tasks are divided into work items. These can be run sequentially or in parallel, with optional synchronization in between, and GCD will take care of dispatching tasks to available cores.

Relaxed Radix Balanced Trees are an immutable vector-like data structure with good performance characteristics for concatenation and slicing.

This library provides a C99 client implementation of the Simple Storage Service (S3) protocol for object storage.

This C library contains some essential string manipulation functions and more, like escaping special characters.

This library provides a C99 implementation of compression algorithms, currently limited to Huffman encoding and decoding.

TCC, also referred to as "TinyCC", is a small and fast C compiler written in C. It supports ANSI C with GNU and extensions and most of the C99 standard.

This package provides a C99 preprocessor written in pure Python.

PCC is a portable C compiler. The project goal is to write a C99 compiler while still keeping it small, simple, fast and understandable.

ISPC is a compiler for a variant of the C programming language, with extensions for single program, multiple data programming. Under the SPMD model, the programmer writes a program that generally appears to be a regular serial program, though the execution model is actually that a number of program instances execute in parallel on the hardware.

This library provides a C99 implementation for AWS client-side authentication.

tinydir is a header-only C wrapper for listing directory contents.

This library is a C99 implementation for AWS event stream encoding, a binary format for bidirectional client-server communication.

This library provides a C99 framework for constructing event-driven, asynchronous network application protocols.

cproc is a C compiler using QBE as a backend, supporting most of C11 along with some GCC and C2x extensions.

A simple one header solution to supporting UTF-8 strings in C and C++. The functions it provides are like those from the C header string.h, but with a utf8* prefix instead of the str* prefix.

libfastjson is a fork from json-c aiming to provide: a small library with essential JSON handling functions, sufficiently good JSON support (not 100% standards compliant), and very fast processing.

Berkeley Yacc is an LALR(1) parser generator. Yacc reads the grammar specification from a file and generates an LALR(1) parser for it. The parsers consist of a set of LALR(1) parsing tables and a driver routine written in the C programming language.

Liblogging is an easy to use library for logging. It offers an enhanced replacement for the syslog() call, but retains its ease of use.

This package provides a header-only unit testing library for C/C++.

Sparse is a semantic parser for C and is required for Linux development. It provides a compiler frontend capable of parsing most of ANSI C as well as many GCC extensions, and a collection of sample compiler backends, including a static analyzer also called sparse. Sparse provides a set of annotations designed to convey semantic information about types, such as what address space pointers point to, or what locks a function acquires or releases.

sfsexp is a C/C++ library to read, parse, modify, and create symbolic expressions.