LibU is a multiplatform C library that comes under a BSD-style license. It includes many interdependent modules for accomplishing several tasks: memory allocation, networking and URI parsing, string manipulation, debugging, and logging in a very compact way, plus many other miscellaneous tasks. It has a small footprint (about 70KB for the default configuration), it is modular, and it has a multiplatform nature, making it an ideal candidate for embedded systems. KLone is an example of such usage.
The Tinyserial library is a space-saving alternative to the Arduino software distribution's libraries for reading and writing characters and strings to the USART0 serial port on the Atmel ATmega168 and ATmega328p MCUs found on Arduino Diecimilla and Duemilanove boards. While the Arduino software distribution's libraries provide interrupt-driven serial I/O with far more features and support more MCUs, the Tinyserial library provides only the most basic polling-based serial I/O. However, the Tinyserial library uses far less Flash and SRAM, thereby giving you room to implement larger and more complicated applications on your boards. The Tinyserial library respects the GNU libc ABI, so you can call into it from C and C++ programs.
LibAPCNIS is a PHP library for accessing the NIS port of the Apcupsd UPS Monitoring daemon. It allows you to access realtime UPS stats from a PHP script without having Apcupsd installed. It does not require the apcaccess application included with an Apcupsd installation, and there are no external dependencies.
EO is a template-based, ANSI-C++ evolutionary computation library that helps you to write your own stochastic optimization algorithms quickly. Evolutionary algorithms form a family of algorithms inspired by the theory of evolution, and solve various problems. They evolve a set of solutions to a given problem in order to produce the best results. These are stochastic algorithms because they iteratively use random processes. The vast majority of these methods are used to solve optimization problems, and may be also called "metaheuristics". They are also ranked among computational intelligence methods, a domain close to artificial intelligence. With the help of EO, you can easily design evolutionary algorithms that will find solutions to virtually all kind of hard optimization problems, from continuous to combinatorial ones.
MMLi is a simple Music Macro Language interpreter written in ISO C99. The Music Macro Language originated in 8-bit BASIC implementations (as part of the “PLAY” command), and can still be found in modern BASICs (like QB64) and in system software (like FreeBSD's spkr.c driver.) This interpreter features an example "mmlitest" program which can be used to translate MML sequences into beep(1) commandline arguments.