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 unifdef utility selectively processes conditional C preprocessor #if and #ifdef directives. It removes from a file both the directives and the additional text that they delimit, while otherwise leaving the file alone. It can be useful for avoiding distractions when studying code that uses #ifdef heavily for portability.

Concurrency Kit (ck) provides 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+.

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

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

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

The aml library provides a portable event loop for C, with the following features:

1. file descriptor event handlers

2. timers and tickers

3. signal handlers

4. idle dispatch callbacks

5. thread pool support

This library provides a C99 wrapper for hash, HMAC, and ECC cryptographic primitives for the AWS SDK.

This package provides support macros and auxiliary functions around the functionality of common C standard libraries. This includes helpers for the ISO C Standard Library, but also other common specifications like POSIX or common extended features of widespread compilers like gcc and clang.

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

The libsais library provides fast linear-time construction of suffix array (SA), generalized suffix array (GSA), longest common prefix (LCP) array, permuted LCP (PLCP) array, Burrows-Wheeler transform (BWT) and inverse BWT based on the induced sorting algorithm with OpenMP support for multi-core parallel construction.

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

The c-siphash project is a standalone implementation of SipHash in Standard ISO-C11. It provides a streaming-capable API to compute data hashes according to the SipHash algorithm. For API documentation, see the c-siphash.h header file, as well as the docbook comments for each function.

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 library provides common C99 primitives, configuration, data structures, and error handling for the AWS SDK.

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

simdutf is a C++ library providing Unicode routines (UTF8, UTF16, UTF32). These routines are optimized for many specific architectures using SIMD (Single Instruction, Multiple Data) instructions.

This manual explains the C language for use with the GNU Compiler Collection (GCC) on the GNU/Linux system and other systems. We refer to this dialect as GNU C. If you already know C, you can use this as a reference manual.

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

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.

Calcurse is a text-based calendar and scheduling application. It helps keep track of events, appointments and everyday tasks. A configurable notification system reminds user of upcoming deadlines, and the curses based interface can be customized to suit user needs. All of the commands are documented within an online help system.

Khal is a standards based console calendar program, able to synchronize with CalDAV servers through vdirsyncer. It includes both a CLI and a TUI named 'ikhal'.

adl-submit is a tool that can be used to submit events to any instance of the Agenda Du Libre (a web calendar originally meant for free software events). Users can set fields through the command line or create an XML that can be submitted with the adl-submit tool. While the Agenda Du Libre web application is available in multiple languages, most of the events on https://www.agendadulibre.org are in French and the adl-submit tool is only available in French.

ccal is a command line program which writes a Gregorian calendar together with Chinese calendar to standard output. Its usage is similar to the cal program. In addition to console output, it can also generate Encapsulated Postscript and HTML table outputs for use in do-it-yourself calendars and web pages. It supports both simplified and traditional Chinese characters.