C (programming language) libraries

general-purpose programming language

GTK (formerly GIMP ToolKit and GTK+) is a free open-source widget toolkit for creating graphical user interfaces (GUIs) targeted at Linux and specifically GNOME (though with some use in other desktop environments). It is licensed under the terms of the GNU LGPL, allowing both free and proprietary software to use it.

SQLite ( "S-Q-L-ite", "sequel-ite") is a free and open-source relational database engine written in the C programming language. It is not a standalone application; rather, it is a library that software developers embed in their applications. As such, it belongs to the family of embedded databases. According to its developers, SQLite is the most widely deployed database engine, as it is used by several of the top web browsers, operating systems, mobile phones, and other embedded systems.

OpenSSL is a software library for applications that provide secure communications over computer networks against eavesdropping, and identify the party at the other end. It is widely used by Internet servers, including the majority of HTTPS websites.

cURL (pronounced like "curl", ) is a free and open source CLI app for uploading and downloading individual files. It can download a URL from a web server over HTTP, and supports a variety of other network protocols, URI schemes, multiple versions of HTTP, and proxying. The project consists of a library (libcurl) and command-line tool (curl), which have been widely ported to different computing platforms. It was created by Daniel Stenberg, who is still the lead developer of the project.

FFmpeg is a free and open-source software project consisting of a suite of libraries and programs for handling video, audio, and other multimedia files and streams. At its core is the command-line ffmpeg tool itself, designed for processing video and audio files. It is widely used for format transcoding, basic editing (trimming and concatenation), video scaling, video post-production effects, and standards compliance (SMPTE, ITU).

free software multimedia library

authoritative programming book by Brian Kernighan and Dennis Ritchie, the developers of the C programming language

Pango (stylized as Παν語) is a text (i.e. glyph) layout engine library which works with the HarfBuzz shaping engine for displaying multi-language text.

ncurses (new curses) is a programming library for creating textual user interfaces (TUIs) that work across a wide variety of terminals. It is written in a way that attempts to optimize the commands that are sent to the terminal, to reduce the latency experienced when updating the displayed content.

zlib ( or "zeta-lib", ) is a data format and a lossless data compression software library created by Jean-loup Gailly and Mark Adler. The library implements the Deflate algorithm and supports compressing and decompressing data using the zlib data format, the gzip file format, or simply as a Deflate stream.

x264 is a free and open-source software library and a command-line utility developed by VideoLAN for encoding video streams into the H.264/MPEG-4 AVC video coding format. It is released under the terms of the GNU General Public License.

library for numerical analysis in C and C++

FreeType is a software development library used to render text onto bitmaps, and which provides support for other font-related operations. The FreeType font rasterization engine is free and open-source software with the source code dual-licensed under a BSD-like license and the GPL. FreeType supports a number of font formats, including TrueType, Type 1, and OpenType.

software library for video game development

thumb|Simplified software architecture of GTK, [[Pango, GDK, ATK, GIO, Cairo and GLib.]] GLib is a bundle of three (formerly five) low-level system libraries written in C and developed mainly by GNOME. GLib's code was separated from GTK, so it can be used by software other than GNOME and has been developed in parallel ever since.

software library for interpreting regular expressions

thumb|X11-clients use xlib to communicate with the display server.

Zstandard is a lossless data compression algorithm developed by Yann Collet at Facebook. Zstd is the corresponding reference implementation in C, released as open-source software on 31 August 2016.

library for arbitrary precision arithmetic, operating on signed integers, rational numbers and floating point numbers

LibreSSL is an open-source implementation of the Transport Layer Security (TLS) protocol. The implementation is named after Secure Sockets Layer (SSL), the deprecated predecessor of TLS, for which support was removed in release 2.3.0. The OpenBSD project forked LibreSSL from OpenSSL 1.0.1g in April 2014 as a response to the Heartbleed security vulnerability, with the goals of modernizing the codebase, improving security, and applying development best practices.

libxml2 is a software library for parsing XML documents. It is also the basis for the libxslt library which processes XSLT-1.0 stylesheets.

libavcodec is a free and open-source library of codecs for encoding and decoding video and audio data.

Compression algorithm

libpng is the official Portable Network Graphics (PNG) reference library (originally called pnglib). It is a platform-independent library that contains C functions for handling PNG images. It supports almost all of PNG's features, is extensible, and has been widely used and tested for over 28 years. libpng is dependent on zlib for data compression and decompression routines.

The Generic Graphics Library (GEGL) is a programming library under development for image processing applications. It is mainly developed for GIMP in order to add support for higher bit depth images, and non-destructive editing. It was partially implemented in GIMP 2.6, with more added in 2.8, and is now a central part in 2.10. Many Filters are ready, but also much work in progress. Target is full support of all important filters in roadmap in Version 3.0. It is also used by GNOME's Photos and gedl.

Family of file formats

The GLib Object System, or GObject, is a free software library providing a portable object system and transparent cross-language interoperability. GObject is designed for use both directly in C programs to provide object-oriented C-based APIs and through bindings to other languages to provide transparent cross-language interoperability, e.g. PyGObject.

libjpeg is a free library with functions for handling the JPEG image data format. It implements a JPEG codec (encoding and decoding) alongside various utilities for handling JPEG data. It is written in C and distributed as free software together with its source code under the terms of a custom permissive (BSD-like) free software license, which demands attribution. The original variant is maintained and published by the Independent JPEG Group (IJG). Meanwhile, there are several forks with additional features.

wolfSSL is a small, portable, embedded SSL/TLS library targeted for use by embedded systems developers. It is an open source implementation of TLS (SSL 3.0, TLS 1.0, 1.1, 1.2, 1.3, and DTLS 1.0, 1.2, and 1.3) written in the C programming language. It includes SSL/TLS client libraries and an SSL/TLS server implementation as well as support for multiple APIs, including those defined by SSL and TLS. wolfSSL also includes an OpenSSL compatibility interface with the most commonly used OpenSSL functions.

supporting library for the Apache web server

Lempel–Ziv–Oberhumer (LZO) is a lossless data compression algorithm that is focused on decompression speed.

GLFW (Graphics Library Framework) is a lightweight utility library for use with OpenGL, OpenGL ES and Vulkan. It provides programmers with the ability to create and manage windows as well as OpenGL and Vulkan contexts, as well as handle joystick, keyboard and mouse input.

libdvdcss (or libdvdcss2 in some repositories) is a free and open-source software library for accessing DVDs encrypted with Content Scramble System (CSS). libdvdcss is part of the VideoLAN project and is used by VLC media player and other media player software, such as Ogle, xine-based players, and MPlayer.

librsvg, (occasionally stylized as LibRsvg) is a free software SVG rendering library written as part of the GNOME project, intended to be lightweight and portable. The Linux command-line program rsvg-convert uses the library to turn SVG files into raster images.

X11 XToolkit Intrinsics library used to manage resources and events

Libwww is an early World Wide Web software library providing core functions for web browsers, implementing HTML, HTTP, and other technologies. Tim Berners-Lee, at the European Organization for Nuclear Research (CERN), released libwww (then also called the Common Library) in late 1992, comprising reusable code from the first browsers (WorldWideWeb and Line Mode Browser).

thumb|X11-clients use XCB to communicate with the display server|X server. thumb|A more complete view of the Linux graphics stack thumb|Programs often use GTK or [[FLTK or Qt for their GUI widgets.]] thumb|A more complete view of the components of an operating system for home computers.

graphics library included with many Borland compiler products in the 1990s

Mathomatic is a free, portable, general-purpose computer algebra system (CAS) that can symbolically solve, simplify, combine and compare algebraic equations, and can perform complex number, modular, and polynomial arithmetic, along with standard arithmetic. It can perform symbolic calculus (derivative, extrema, Taylor series, and polynomial integration and Laplace transforms), numerical integration, and can handle all elementary algebra except logarithms. Trigonometric functions can be entered and manipulated using complex exponentials, with the GNU m4 preprocessor. Not currently implemented a

mpg123 is a free and open-source audio player. It supports MPEG audio formats, including MP3.

thumb|upright=1.5|The Linux API is composed out of the System Call Interface of the Linux kernel, the [[GNU C Library, libcgroup, libdrm, libalsa and libevdev (by freedesktop.org).]]

PARI/GP is a computer algebra system with the main aim of facilitating number theory computations. Versions 2.1.0 and higher are distributed under the GNU General Public License. It runs on most common operating systems.

C library for arbitrary-precision floating-point arithmetic

libuv is a multi-platform C library that provides support for asynchronous I/O based on event loops. It supports epoll(4), kqueue(2), Windows IOCP, Solaris event ports and Linux io_uring. It is primarily designed for use in Node.js but is also used by other software projects. It was originally an abstraction around libev or Windows IOCP, as libev does not support IOCP. In node-v0.9.0's version of libuv, the dependency on libev was removed.

Raylib (stylized as raylib) is a cross-platform open-source software development library. The library was made to create graphical applications and games.

software library for computing discrete Fourier transforms

library

an object file library used by the GNU debugger, assembler, linker, and the binary utilities

is a source code header file that Microsoft provides for the development of programs that access the Windows API (WinAPI) via C language. It declares the WinAPI functions, associated data types and common macros.

OpenJPEG is an open-source library to encode and decode JPEG 2000 images. As of version 2.1 released in April 2014, it is officially conformant with the JPEG 2000 Part-1 standard. It was subsequently adopted by ImageMagick instead of JasPer in 6.8.8-2 and approved as new reference software for this standard in July 2015. OpenJPEG is a fork of libj2k, a JPEG-2000 codec library written by David Janssens during his master thesis at University of Louvain (UCLouvain) in 2001. In April 2016 Grok was forked from libopenjp2 by Aaron Boxer under the more restrictive AGPL. He was aiming to close up to t

'''Developer's Image Library or DevIL''', started by Denton Woods, is a cross-platform image library which aims to provide a common API for different image file formats. It consists of three parts: the main library (IL), the utility library (ILU) and the utility toolkit (ILUT), mirroring the corresponding parts of OpenGL (although the OpenGL Utility Toolkit is not part of the OpenGL specification).

free software library implementing TLS

software library

garbage collector software library for C and C++

XML parser library