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

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+.

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

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.

This library provides cross-Platform hardware accelerated CRC32c and CRC32 with fallback to efficient C99 software implementations.

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

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.

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.

Hebcal is a program for converting between Hebrew and Gregorian dates, and generating lists of Jewish holidays for a given year. Shabbat, holiday candle lighting, and havdalah times are approximated using your location.

It can also show daily prayer times, the weekly Torah reading, and the daily leaf of Talmud. The program can help with counting of the Omer or with calculation of Hebrew yahrzeits, birthdays, or anniversaries.

By default, date2name gets the modification time of matching files and directories and adds a datestamp in standard ISO 8601+ format YYYY-MM-DD at the beginning of the file or directory name.

gsimplecal is a lightweight calendar application written in C++ using GTK. Launched once, it pops up a small calendar applet, launched again it closes the running instance. It can additionally be configured to show the current time in different timezones.

Gcal is a program to calculate and print calendars on the command-line. Calendars can be printed in 1-month, 3-month or whole-year views. In addition, eternal holiday lists can be generated for many countries, which can be complemented by user-made lists of fixed dates to make an agenda. Gcal can also calculate astronomical data, such as the phases of the moon, and supports alternative calendar formats: Julian, Gregorian, Islamic, Chinese and more.

LibHdate is a small library for the Hebrew calendar and times of day, written in C, and including bindings for C++, pascal, perl, php, python, and ruby. It includes two illustrative command-line programs, hcal and hdate, and some snippets and scripts written in the binding languages.

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.

Date is a header only C++ library that extends the chrono date algorithms library for calendar dates and durations. It also provides the <tz.h> library for handling time zones and leap seconds.

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'.

ConfClerk is an application written in Qt, which makes conference schedules available offline. It displays the conference schedule from various views, support searches on various items (speaker, speech topic, location, etc.) and enables you to select favorite events and create your own schedule.

At the moment ConfClerk is able to import schedules in XML format created by the PentaBarf conference management system (or frab) used by e.g. FOSDEM, DebConf, FrOSCon, Grazer LinuxTage, and the CCC congresses.

ConfClerk is targeted at mobile devices but works on any system running Qt.

Libical is an implementation of the iCalendar protocols and protocol data units.

Remind allows you to remind yourself of upcoming events and appointments. Each reminder or alarm can consist of a message sent to standard output, or a program to be executed. It also features: sophisticated date calculation, moon phases, sunrise/sunset, Hebrew calendar, alarms, PostScript output and proper handling of holidays.

Ccache is a compiler cache. It speeds up recompilation by caching previous compilations and detecting when the same compilation is being done again. Supported languages are C, C++, Objective-C and Objective-C++.

The GNU Compact Disc Input and Control Library (libcdio) is a library for CD-ROM and CD image file access. It allows the developer to add CD access to an application without having to worry about the OS- and device-dependent properties of CD-ROM or the specific details of CD image formats. It includes pycdio, a Python interface to libcdio, and libcdio-paranoia, a library providing jitter-free and error-free audio extraction from CDs.

libcdio-paranoia is an implementation of CD paranoia libraries based on libcdio.

cd-discid is a command-line tool to retrieve CDDB discid information from an audio CD.