Library for playing audio CDs

http://libcdaudio.sourceforge.net/

Library to access data on a CDDB server

http://libcddb.sourceforge.net/

Compact Disc Input and Control Library

http://www.gnu.org/software/libcdio/

Read audio from the CDROM directly as data

http://www.gnu.org/software/libcdio/

C library aimed to provide a Gtk+ widget to display rasterized maps and markers

http://projects.gnome.org/libchamplain/

Unit test framework for C

http://check.sourceforge.net/

Alternative configuration system for Compiz

Configuration file parsing library

http://savannah.nongnu.org/projects/confuse/

CSS2 parsing library

http://www.freespiders.org/projects/libcroco/

GNOME application for managing encryption keys (PGP, SSH)

https://gitlab.gnome.org/GNOME/libcryptui

CUE Sheet Parser Library

https://github.com/lipnitsk/libcue

Implementation of the Code Sourcery C++ ABI

https://github.com/pathscale/libcxxrt

Lightweight C library that eases the writing of UNIX daemons

http://0pointer.de/lennart/projects/libdaemon/

Double-array trie implementation library

https://linux.thai.net/projects/datrie/

Qt5 implementation of the DBusMenu protocol

https://launchpad.net/libdbusmenu-qt

Free DTS Coherent Acoustics decoder

https://www.videolan.org/developers/libdca.html

Generic Device Query and Monitor interface

https://github.com/freebsd/libdevq

Library for creating MusicBrainz DiscIDs

http://musicbrainz.org/doc/libdiscid

Grand Central Dispatch API support library

http://libdispatch.macosforge.org/

Library for reading and writing Data Matrix barcodes

http://libdmtx.sourceforge.net/

DMX extension library

http://www.freedesktop.org/Software/xorg

Simple interface to low level networking routines

https://github.com/5u623l20/libdnet/

Standard library for Window Maker dock apps

http://solfertje.student.utwente.nl/~dalroi/libdockapp/

Userspace interface to kernel Direct Rendering Module services

https://dri.freedesktop.org/

Alsa compatibility library to build DSSI

http://www.smbolton.com/linux.html

Quasar DV codec (libdv): software codec for DV video encoding format

http://libdv.sourceforge.net/

Portable abstraction library for DVD decryption

https://www.videolan.org/developers/libdvdcss.html

Videolan version of the libdvdnav project

https://www.videolan.org/developers/libdvdnav.html

MPlayer version of the libdvdread project

https://www.videolan.org/developers/libdvdnav.html

Command line editor library

http://thrysoee.dk/editline/

Enhanced Metafile Library

http://libemf.sourceforge.net/

Library to handle OpenGL function pointer management

https://github.com/anholt/libepoxy

Liberation fonts from Red Hat to replace MS TTF fonts

https://github.com/liberationfonts/liberation-fonts

Full-featured and high-performance event loop library

http://software.schmorp.de/pkg/libev.html

API for executing callback functions on events or timeouts

http://libevent.org/

Library for inspecting program's backtrace

http://www.gnu.org/software/libc/manual/html_node/Backtraces.html

Library to read digital camera file meta-data

https://libexif.github.io/

Application library for the Xfce desktop environment

https://www.xfce.org/

Video encoding library

http://fame.sourceforge.net/

Foreign Function Interface

https://sourceware.org/libffi/

The fontenc Library

https://www.x.org/

Library routines for working with Flashpix images

https://www.i3a.org/

General purpose crypto library based on code used in GnuPG

https://www.gnupg.org/software/libgcrypt/index.html

Provides uniform access to different kinds of data sources

http://www.gnome-db.org/

GObject collection library

https://wiki.gnome.org/Projects/Libgee

The GGZ Gaming Zone - Base Library

http://www.ggzgamingzone.org/

Portable, pure C implementation of the Git core

https://libgit2.github.com/

Glib wrapper library around the libgit2 git access library

https://git.gnome.org/browse/libgit2-glib

GNOME glade library

Common GL api library used by Mesa based ports

http://www.freedesktop.org/Software/xorg