PascalSCADA is a framework for Delphi and Lazarus to quick development of HMI/SCADA applications. The platforms supported by PascalSCADA are Windows, Linux, and FreeBSD under 32 and 64 bits (FreeBSD only in 32 bits). You can communicate with CLP's, create interfaces, store values and alarms of process, and control users of the application.
libsysactivity is a lightweight library that retrieves statistics of the system's activity in a portable and thread safe way. In each OS that it supports, it offers the same API for retrieving the activity of Hard disks, CPUs memory, Processes, Network interfaces, Memory, and Swaps.
The stx::CBTreeDB is a collection of C++ classes with which read-only key-value database files can be created and read. A database efficiently maps a large number of integral fixed-length keys to opaque binary value blobs. Variable-length or duplicate keys are currently not supported. Keys are organized into a highly compact index structure, which is very similar to a B-tree and allows very fast key lookups. Both keys and values are stored in order and thus queries in a local proximity can benefit from caching effects. All applications mapping a large number of constant, integral keys to string or data blobs can benefit from this library.
Mapnik is a toolkit for developing GIS applications. At the core is a C++ shared library providing algorithms/patterns for spatial data access and visualization. Essentially a collection of geographic objects (map, layer, datasource, feature, and geometry), the library doesn't rely on "windowing systems" and can be deployed in any server environment. It is intended to play fair in a multi-threaded environment and is aimed primarily, but not exclusively, at Web-based development. High-level Python bindings (boost.python) facilitate rapid application development, targeting zope3, django, etc.