The libQtSerialization library is a Qt extension that makes it easy to serialize your data in a forward and backward compatible way. The library is composed of QWriter and QReader. The writer is straightforward - all you have to do is call a writeTag() function and the data is serialized. The reader is a little more complex as it supports special cases, such as sub-classes (so you can save a tree of classes) and arrays of classes (your tree may be composed of multiple instances of a given object).
The YB.ORM library aims to simplify writing C++ code that has to deal with SQL databases. The goal is to provide a convenient interface like SQLAlchemy (Python) or Hibernate (Java). The library itself is cross-platform and supports a variety of SQL dialects: SQLite3, MySQL, Postgres, Oracle, and Firebird. Integration with Boost, Qt4, and wxWidgets is built-in. In a typical usage scenario, you would describe your database schema and table relationships in a simple XML-based format, generate SQL code to populate database schema with tables, generate C++ classes, add application-specific logic to the classes, and use these classes in cooperation with the Session object to query objects from the database, create new or modify/delete existing objects, or link and unlink objects using relations. Simple serialization to XML is supported along with connection pooling.
libKISSlog is a trivial lightweight C++ template library designed and written according to the KISS (Keep It Simple and Straightforward) principle. It leans heavily on STL for keeping its implementation as simple as its usage, and tries to provide C++ developers with a lightweight, paradigm-pure, and flexible alternative to logging libraries which use design and/or implementation decisions which at least the author of libKISSlog believes to be questionable. Its easiest to explain why libKISSlog would be suitable for your needs by listing the things which libKISSlog does not choose to use or do: no singletons or other forms of mutable global state, no macros, no attempt to fit the Java runtime everything model onto a C++ library, no attempt to be a Java-style (bloated) framework, no attempt to make the choice for you of whether you need thread safety, and no compromise on simplicity in order to facilitate questionable inner-loop logging practices.
libLunchbox facilitates the development and deployment of multi-threaded applications. It provides OS Abstraction, using utility classes abstracting common operating system features (such as threads, locks, memory maps, shared library loading, and condition variables), high-performance primitives (including thread-safe utilities tuned for performance, such as atomic variables, spin locks, and lock-free containers), and utility classes (including helper primitives which are not in the standard library, such as logging, pools, and random number generation).
uma::bson is a DOM-style C++ API for reading/writing BSON data. Unlike the MongoDB C++ API, which exposes a read-only interface with a separate interface for creating a BSON representation, this API allows reading/writing on the existing data. The API is designed primarily for serialising/deserialising BSON data to/from streams (files, socket connections, etc.).
libjmmcg is a basic, low-level library with pretensions to implementing features above and beyond (but not necessarily better than!) those implemented within the Standard C++ Library and the Boost Library. It features a library for multi-core or multi-chip SMP parallelism, a suite of hashing algorithms, functions for raising numbers to integer powers, a generic factory wrapper and a generic, multi-threaded, read-only cache (which uses PPD), arguably the world's worst sorting technique, trace output, exceptions that have the file, line, revision, function, and argument details, string utilities, logging, simple command line processing, and much more.