CrissCross is a small cross-platform C++ library for console and file I/O, CPU identification (CPUID), hashing (MD2, MD4, MD5, SHA-1, SHA-256, SHA-512, Tiger), sockets (TCP and UDP only currently), and data structures (LList, DArray, RedBlackTree, AVLTree, SplayTree, etc). It is designed to run on Windows, Linux, FreeBSD, OpenBSD, NetBSD, Mac OS X, and even the Nintendo DS. Other platforms may become supported upon request. The main idea is to provide the ability to write a program using identical calls on the major platforms without needing to rewrite code.
LibGC is a small, fast, portable, multi-threaded garbage collection library for C++. It is highly customizable, as it can be multithreaded or single threaded, and the memory size to use for the collector may be changed at compile time. It is precise, as it only scans pointers that exist as members on the stack or as global variables. It's very easy to use, since it has only two classes, Object (the base class for garbage-collected objects) and Pointer (for garbage-collected pointers).
The Visual Component Framework is a cross platform C++ application framework that offers a modern, clean architecture. It is divided into three major libraries. The FoundationKit provides services such as file access, streams, threads, synchronization primitives, and advanced RTTI features. The GraphicsKit includes classes for working with both image and vector graphics, and has built in support for the Anti-Grain Graphics library. The ApplicationKit provides GUI controls, use of the Model-View-Control pattern, property and component editors, undo/redo support, drag-and-drop, clipboard services, application resources, and UI metrics and policy managers.
U++ is a C++ cross-platform rapid application development suite focused on programmers' productivity without sacrificing runtime performance. Based on strictly deterministic design, it provides a viable alternative to garbage-collected platforms, even for business logic oriented problems.
MUSCLE (Multi User Server Client Linking Environment) is an N-way messaging server and networking API. It includes client-side networking APIs for various languages, including C, C++, C#, Delphi, Java, and Python. MUSCLE lets programs communicate over a network via streams of serialized Message objects. The included server program ("muscled") lets its clients message each other and store information in its server-side hierarchical database. The database supports flexible queries via hierarchical wildcarding, and "live" updates via a subscription mechanism.