an Open Source Probabilistic Information Retrieval library, a highly adaptable toolkit to allow developers to easily add advanced indexing and search facilities to their own applications.
a class library that provides some features that are usually common for object oriented programming languages like Java or Python, but not for C++ (mark-sweep garbage collector...)
provides free peer-reviewed portable C++ source libraries. The emphasis is on libraries which work well with the C++ Standard Library. The libraries are intended to be widely useful, and are in regular use by thousands of programmers across a broad spectr
an event-driven networking framework supports TCP, UDP, SSL/TLS, multicast, Unix sockets, a large number of protocols (including HTTP, NNTP, IMAP, SSH, IRC, FTP, and others)
a Free C++/Python GIS Toolkit for developing mapping applications. Above all Mapnik is about making beautiful maps. It is easily extensible and suitable for both desktop and web development.