The C++ Portable Types Library (PTypes) is a simple alternative to the STL that includes multithreading and networking. It defines dynamic strings, character sets, variants, lists and other basic data types along with threads, synchronization primitives and IP sockets. It is portable across modern Unix and Windows systems and includes a sample HTTP daemon showing the full power of the library.
AntTweakBar is a small and easy-to-use C/C++ library that allows programmers to quickly add a light and intuitive GUI into OpenGL or DirectX based graphic programs to interactively tweak them. Program variables can be linked to a graphical control that allows users to modify them. Programmers are not required to design the graphical interface by providing coordinates or by using a visual UI editor. Controls are automatically organized following an optional given hierarchy.
EGSL is a small interpreter which can execute Lua scripts. It includes some functions for fast and easy game development. These are image manipulation functions, functions for 2D drawing, sound and music, input via mouse, keyboard, and joypad, and some helper functions. The engine is based on SDL, SDL_gfx, and SDL_mixer, and additionally on SDL_image on Haiku-OS.