The Schrödinger Project
- Project supported by BBC R&D and Fluendo to develop open source libraries for the Dirac video codec. Include developer information and frequently asked questions.
- http://schrodinger.sourceforge.net/

Sglib
- A generic library for C. It extensively uses the preprocessor for generic implementation of sorting algorithms on arrays, lists, sorted lists, red-black trees. The library operates on user types and does not depend on a particular memory management system
- http://sglib.sourceforge.net

Standard Function Library: SFL
- By iMatix Corp., portable function library for C/C++ programs; many years development; written in ANSI C; ports: DOS, OpenVMS, OS/2, most Unix, Windows; full sources and documentation (HTML); given as Open Source software for the benefit of Internet commu
- http://legacy.imatix.com/html/sfl/

liberror
- A library for C and C++ that solves the allegedly simply task of printing messages. Thus, it is essentially a feature-rich substitute for fprintf(stderr,...).
- http://www.theiling.de/projects/liberror.html

Levenberg-Marquardt non-linear least squares algorithms in C/C++
- Package containing double and single precision flavors of the Levenberg-Marquardt algorithm. Included are versions with analytic and finite difference approximated jacobians. [Open source, GPL]
- http://www.ics.forth.gr/~lourakis/levmar/

Embedded File System for Secure Digital (SD) Media
- FAT12 and FAT16 ANSI C API libraries to implement file storage on SD removable media disks for Freescale embedded microcontrollers. The development environment is implemented for both Metrowerks Code Warrior and ImageCraft ANSI C compilers. [Commercial]
- http://www.inmotiondesign.ca

Gopt
- An ANSI C library, for parsing command line arguments and options according to GNU standards. [Open source, GPL]
- http://gopt.sourceforge.net/

Flux
- A library for integrated data storage and indexing, marshalling, transfer and encryption. It also features a slew of utility functions for various purposes. It is written in C, using the GLib paradigm. [Open source]
- http://www.fluxlib.org/

ForbiSoft
- ForbiSoft DIB Library provides platform independent bitmap loading. ForbiSoft ToolTip Library provides platform independent tooltip display. Target Win32 or Windows CE with the same code. Shipped as source code and will compile with Microsoft eMbedded 3.0
- http://www.forbisoft.com/

Math a la Carte
- Collections of mathematical software in Fortan and C. Software is free for some uses and can be purchased for others. Much of the software was developed at the Jet Propulsion Laboratory.
- http://mathalacarte.com

jclassinfo
- Information extractor and disassembler for Java classes. Backend code available as a C library. [Open source, GPL]
- http://jclassinfo.sourceforge.net/

GNU Scientific Library
- A free numerical library for C programmers. [Open source, GPL]
- http://www.gnu.org/software/gsl/

Crusher Data Compression Toolkits
- Cross-platform compression libraries. [Open source, Commercial]
- http://www.dcmicro.com/crusher/

Fingerprint Verification System
- An easy to use library that allows programmers to integrate fingerprint technology into their software without specific know-how. Fast, easy to use, and small; great for embedded systems. [Open source, MPL]
- http://fvs.sourceforge.net/

Better String Library
- A safe and fast string library. It's buffer overflow and aliasing safe, high performance. The library includes a robust C++ wrapper that uses overloaded operators and rich constructors to make the CBstring struct a natural and powerful string abstraction
- http://bstring.sourceforge.net/

IRCG
- A library for dispatching messages to huge groups of users over an arbitrary number of separate communication channels in real-time using IRC protocol. [Open source]
- http://schumann.cx/ircg/

libZI
- A portable configuration file API that utilizes XML for data storage and retrieval. libZI provides a typesafe way of serializing configuration data into a file in a manner consistent to XML standards. [Open source, GPL]
- http://libzi.sourceforge.net/

LZO
- Portable high-speed lossless data compression library written in ANSI C.
- http://www.oberhumer.com/opensource/lzo/

Template2doc
- Library that allow generation of html page using templates. A template contain specific keywords that tell the routines where to insert data. Support insertion of table data.
- http://www.algonet.se/~thunberg/template2doc/

Matrix2D
- A library implements a set of functions allowing to manage bi-dimensional matrix with languages C and C++. Matrix2D contains also several functions of images processing. [Free for personal use]
- http://dev.tplanet.net/Matrix2D/

xnprintf() family functions for C/C++
- A small source file for 16/32/64-bit compilers. Provides snprintf() and others. [GPL or modified BSD license]
- http://domainename.com/software/xnprintf.html

libESMTP
- Library for Posting Electronic Mail: manages posting email using SMTP to a preconfigured MTA. Can be used as part of a Mail User Agent or other program that must post email. Free: GNU LGPL.
- http://www.stafford.uklinux.net/libesmtp/

MAlib
- C library for Media Analysis, Motion Analizing, Movie Architecture, and Media Authoring. [Open source, LGPL]
- http://www.malib.net/

WM_MOTIF
- C library allows developers to port code from Windows to Unix or Linux systems. By Software Uno.
- http://softwareuno.com/

The Endpoint Library
- Library for winsock applications.Currently only compatible with winsock v1.1.
- http://tangentsoft.net/endpoint/

DateLib
- A portable library for all kinds of date and time calculations, provides auto-analyzing date and time parsers.
- http://www.datelib.de/index.shtml.en

MyLibC
- A glibc clon for windows.
- http://mylibc.sourceforge.net/

a386
- C programming library providing a virtual i386 running in protected mode.
- http://a386.nocrew.org/

Vermont Views Plus
- A C programming library for creating cross platform user interfaces across Unix, Linux, Posix, VMS, DOS and Windows.
- http://www.vtsoft.com/products/vviews4.html

W3C Sample Code Library
- A general-purpose Web API written in C
- http://www.w3.org/Library/

UniquE RAR File Library
- The URARFileLib is a platform-independent, small and fast static library for decompressing RAR files (RAR archives are created with WinRAR). Full RAR v2.0 file format support of all compression methods, including multimedia compression and encoding.
- http://www.unrarlib.org/

uClibc
- C library optimized for embedded systems. Free: GNU LGPL.
- http://www.uclibc.org/

FFTW Home Page
- Fast free C FFT library; includes multi-dimensional, real-complex, and parallel transforms.
- http://www.fftw.org/

diet libc
- A small, static libc optimized for small size.
- http://www.fefe.de/dietlibc/

Cheap Threads
- Open source C library implementing synchronous multithreading with prioritized scheduling and message passing.
- http://home.swbell.net/mck9/ct/

SoftC Database Library
- A library of programming tools for programmers who want to develop their xBASE applications in C without the limitations of using one xBASE language. Provides functions to access data, index and memo files for dBASE, Clipper and FoxPro. Supports multi-use
- http://www.amr-usa.com/

djblib
- Source-file library derived from the many fine software packages written by D.J. Bernstein; collects files from various packages into a central repository from which code is easy to use in new programs.
- http://www.superscript.com/djblib/intro.html

ubiqx
- A free and open source library of simple programming utilities (written in C), including linked lists, AVL and Splay balanced binary trees, a simple caching system, Sparse Arrays. [Open source, LGPL]
- http://ubiqx.org/