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GNU uCommon C++ is meant as a very light-weight C++ library to facilitate using C++ design patterns even for very deeply embedded applications, such as for systems using uclibc along with posix threading support. For this reason, uCommon disables language features that consume memory or introduce runtime overhead, such as rtti and exception handling, and assumes one will mostly be linking applications with other pure C based libraries rather than using the overhead of the standard C++ library and other class frameworks. GNU uCommon C++ by default does build with support for the bloated ansi standard c++ library unless this is changed at configure time with the --disable-stdcpp option. This is to assure maximum portability and will be used to merge UCommon with GNU Common C++ to form GNU Common C++ 2.0. Some specific features are tested for when stdc++ is enabled, and these will be used to add back in GNU Common C++ classes such as TCP Stream and serialization. GNU uCommon C++ introduces some Objective-C based design patterns, such as reference counted objects, memory pools, smart pointers, and offers dynamic typing through very light use of inline templates for pure type translation that are then tied to concrete base classes to avoid template instantiation issues. C++ auto-variable automation is also used to enable referenced objects to be deleted and threading locks to be released that are acquired automatically when methods return rather than requiring one to explicitly code for these things. GNU uCommon C++ depends on and when necessary will introduce some portable C replacement functions, especially for sockets, such as adding getaddrinfo for platforms which do not have it, or when threadsafe versions of existing C library functions are needed. Basic socket support for connecting to named destinations and multicast addresses, and binding to interfaces with IPV4 and IPV6 addresses is directly supported. Support for high resolution timing and Posix realtime clocks are also used when available. While GNU uCommon C++ has been influenced by GNU Common C++, it introduces some new concepts for handling of thread locking and synchronization. GNU uCommon C++ also builds all higher level thread synchronization objects directly from conditionals. Hence, on platforms which for example do not have rwlocks, barriers, or semaphores, these are still found in uCommon. A common and consistent call methodology is used for all locks, whether mutex, rw, or semaphore, based on whether used for exclusive or "shared" locking. GNU uCommon C++ requires some knowledge of compiler switches and options to disable language features, the C++ runtime and stdlibs, and associated C++ headers. The current version supports compiling with GCC, which is commonly found on GNU/Linux, OS/X, BSD based systems, and many other platforms; and the Sun Workshop compiler, which is offered as an example how to adapt UCommon for additional compilers. GNU uCommon C++ may also be built with GCC cross compiling for mingw32 to build Microsoft Windows targets natively. The cmake build system can also be used, to create project files for various platforms including xcode for OS/X and various Microsoft Visual Studio project file formats. The minimum platform support for uCommon is a modern and working posix pthread threading library. I use a subset of posix threads to assure wider portability by avoiding more specialized features like process shared synchronization objects, pthread rwlocks and pthread semaphores, as these are not implemented on all platforms that I have found. I also eliminate the practice and dependency on pthread automatic cancellation behavior, which otherwise introduces much greater complexity to user applications and can often lead to defective coding practices. The first three releases of uCommon were introduced in 1999-2000 as a pure "C" library for embedded targets, and had not seen an update in 7 years. Hence I have had the package name in use for a very long time. Work on what became uCommon C++ 0.4 was originally intended as a refactoring effort for GNU Common C++ to better support IPV6, and became something different as entirely new code was written in 2006. I originally hoped to release GNU uCommon C++ in March of 2007 as a new package under the GNU GPL V3, but the license was unavoidably delayed. GNU uCommon C++ will merge code from and replace GNU Common C++ in future releases. GNU uCommon C++ is a linkable library distributed under the GNU General Public License, Version 3 or later. As of version 2.0, we are now using the GNU Lesser General Public License, Version 3 or later, to remain consistent and compatible with past GNU Common C++ licensing. A new release series of GNU uCommon C++ is 2.1 involved refactoring the abi release from prior 2.0.x releases, offering greater clarity, consistency of use, and some new features that were migrated from Common C++. To better focus on standardizing secure and runtime services, uCommon was somewhat simplified in release 3.4. ccscript is now part of GNU Bayonne, and ccaudio has been separated again.