libdwarf reads and/or writes DWARF debugging information in Elf object files. dwarfdump uses libdwarf to read object files and print the DWARF content in a readable fashion. libdwarf implements the DWARF2 (and later) standard by providing function interfaces that abstract away many DWARF implementation details (the writer code only emits DWARF2 so far). The source also includes implementations of a few tree search (tsearch) algorithms (balanced, red-black, and binary).
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).
CLOGS is a library for higher-level operations on top of the OpenCL C++ API. It is designed to integrate with other OpenCL code, including synchronization using OpenCL events. Currently only two operations are supported: radix sorting and exclusive scan. Radix sort supports all the unsigned integral types as keys, and all the built-in scalar and vector types suitable for storage in buffers as values. Scan supports all the integral types. It also supports vector types, which allows limited multi-scan capabilities.
libKISSlog is a trivial lightweight C++ template library designed and written according to the KISS (Keep It Simple and Straightforward) principle. It leans heavily on STL for keeping its implementation as simple as its usage, and tries to provide C++ developers with a lightweight, paradigm-pure, and flexible alternative to logging libraries which use design and/or implementation decisions which at least the author of libKISSlog believes to be questionable. Its easiest to explain why libKISSlog would be suitable for your needs by listing the things which libKISSlog does not choose to use or do: no singletons or other forms of mutable global state, no macros, no attempt to fit the Java runtime everything model onto a C++ library, no attempt to be a Java-style (bloated) framework, no attempt to make the choice for you of whether you need thread safety, and no compromise on simplicity in order to facilitate questionable inner-loop logging practices.
Agnos is a cross-language, cross-platform, lightweight RPC framework with support for passing objects by value or by reference. Agnos is meant to allow programs written in different languages to easily interoperate, by providing the needed bindings (glue-code) and hiding all the details from the programmer. The project essentially serves the same purpose as existing technologies like SOAP, WSDL, CORBA, and others, but takes a minimalistic approach to the issue at hand. Unlike the aforementioned technologies, which tend to require integration with Web servers, using verbose XML-based protocols on top of textual transports (HTTP), often also requiring complex topologies (such as name servers for registering objects, etc.). Agnos is designed to be simple, efficient, and straightforward, allowing for direct communication between two ends using a compact binary protocol.
EO is a templates-based, ANSI-C++ compliant evolutionary computation library. It contains classes for any kind of evolutionary computation (specially genetic algorithms) you might come up to. It is component-based, so that if you don't find the class you need in it, it is very easy to subclass existing abstract or concrete class.