OpenXAdES enables people to work with legally-binding digital signatures (primarily giving and verifying them). Legislation often defines a set of requirements that legal digital signature technologies and infrastructures must be compliant with, and OpenXAdES aims at meeting many, if not all, such requirements from different legislations.
JX is a full-featured C++ application framework and GUI widget library for use with the X Window System. It provides support for all facets of application development, including distributed applications, and aims to combine the best of MacOS and NeXTSTEP. It is built directly on top of Xlib and has been carefully optimized for performance.
Itzam/C++ wraps the Itzam database engine with C++ templates for both simple and complex database classes. It supports B-tree, hash table, and sparse matrix indexes with unique or duplicate keys, and includes multithreaded resource locking and atomic file transactions. Complete class documentation is embedded in the source code, and available online and in the distribution archive.
BX/XIK automates the integration of Sitraka's (formerly KL Group) Motif based XRT widgets into Builder Xcessory PRO. After installing the XRT Integration Kit, the XRT widgets will appear on the BX PRO palette and can be "dragged-and-dropped" to create a sophisticated Motif-based user interface.
The Mithral Client Server Software Development Kit (part of the Cosm project) allows developers to quickly and easily write large scale client-server applications including "distributed computing" and peer-to-peer types. Examples of what this will allow you to build with this technology are distributed.net, SETI@Home, Napster, Gnutella, etc.