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.
MeteoIO is a C++ library whose main design goals are: providing meteorological data format/protocol independent data access; providing safe and robust I/O; making I/O code as unobtrusive and simple as possible for the user; providing ready to use data to the user (transparent caching, filtering, resampling, and spatial interpolation); enabling unattended use from an I/O point of view; offering high modularity so that individual elements of the library can easily be replaced/expanded/added; and by its modularity, help interdisciplinary development, each module being targeted at a specific developer profile.
The OATH Toolkit makes it easy to build one-time password authentication systems. It contains shared libraries, commandline tools, and a PAM module. Supported technologies include the event-based HOTP algorithm (RFC4226) and the time-based TOTP algorithm (RFC6238). OATH stands for Open AuTHentication, which is the organization which specifies the algorithms. For managing secret key files, the Portable Symmetric Key Container (PSKC) format described in RFC6030 is supported.
libusbx is a library which provides generic access to USB devices. As a library, it is meant to facilitate the development of applications which communicate with USB hardware. Its main features are portability (a single cross-platform API for Linux, OS X, Windows, and *BSD), user-mode (no special privileges required), and USB version-agnosticism (all versions of the protocol supported, including USB 3.0).
libquickmail is a library intended to give C/C++ developers a quick and easy way to send email from their applications. It supports multiple To/Cc/Bcc recipients and multiple MIME attachments without size limitation. It uses libcurl for SMTP communication, but a light version is also included without the libcurl dependancy. The library can also be used to just create a multipart MIME message body. It also comes with a command line application for sending mail (with optional attachments).
PolarSSL is a light-weight cryptographic and SSL/TLS library written in C. PolarSSL makes it easy for developers to include cryptographic and SSL/TLS capabilities in their (embedded) applications with as little hassle as possible. Loose coupling of the components inside the library means that it is easy to separate the parts that are needed, without needing to include the total library. PolarSSL is written with embedded systems in mind and has been ported on a number of architectures, including ARM, PowerPC, MIPS, and Motorola 68000. The source is written to have very loose coupling, enabling easy integration of parts in other software projects. Very loosely coupled cryptographic algorithms for MD2, MD4, MD5, SHA1, SHA-256, SHA-512, AES, Camellia, DES, Triple DES, ARC3, and RSA are included.
sqlpp11 is an embedded domain-specific language which allows programming SQL very naturally in modern C++. It also enables the compiler to detect syntax errors, type errors, name errors, and even some semantic errors before they ever hit unit tests or production. Queries can be constructed at compile time or run time, offering varying levels of safety and flexibility.