LibU is a multiplatform C library that comes under a BSD-style license. It includes many interdependent modules for accomplishing several tasks: memory allocation, networking and URI parsing, string manipulation, debugging, and logging in a very compact way, plus many other miscellaneous tasks. It has a small footprint (about 70KB for the default configuration), it is modular, and it has a multiplatform nature, making it an ideal candidate for embedded systems. KLone is an example of such usage.
Armadillo is a C++ linear algebra library (matrix maths) aiming towards a good balance between speed and ease of use. The API is deliberately similar to Matlab's. Integer, floating point, and complex numbers are supported, as well as a subset of trigonometric and statistics functions. Various matrix decompositions are provided through optional integration with LAPACK and ATLAS numerics libraries. A delayed evaluation approach, based on template meta-programming, is used (during compile time) to combine several operations into one and reduce or eliminate the need for temporaries.
wxFreeChart is powerful charting library based on wxWidgets. It is designed with flexibility in mind, and supports many types of charts with many different configurations. These include line/histogram charts base on x/y coordinates, bar charts (vertical or horizontal), stacked bar charts, layered bar charts, OHLC financial charts (bars or candlesticks), pie charts, bubble charts, and Gantt charts.
Assimp is a portable and extensible library designed for reading various well-known 3D file formats. It provides APIs for C and C++ and several wrappers for other languages. It reads more than 20 different 3D file formats (including Collada, 3DS, OBJ, LWO, and X) into a straightforward, hierarchical in-memory data structure that can easily be read and processed by applications. Several post processing steps can be applied, such as normal and tangent computations, index buffer, and vertex cache optimization. The library supports complex multi-layer materials and skinned meshes with multiple animations. A Windows-based viewer utility is provided as an implementation reference.
The Parsing Expression Grammar Template Library (PEGTL) is a C++0x library for creating parsers according to a Parsing Expression Grammar (PEG). Grammars are embedded as regular C++ code, created with template programming (not template meta programming). These hierarchies naturally correspond to the inductive definition of PEGs. The library extends on the subject of PEGs with new expression types, actions that can be attached to grammar rules, and mechanisms to ensure helpful diagnostics in case of parsing errors. PEGs are superficially similar to Context-Free Grammars (CFGs).