| 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. |
| |