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“...one of the most highly regarded and expertly designed C++ library projects in the world.” — Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

# Welcome to Boost.org!

Boost provides free peer-reviewed portable C++ source libraries.

We emphasize libraries that work well with the C++ Standard Library. Boost libraries are intended to be widely useful, and usable across a broad spectrum of applications. The Boost license encourages both commercial and non-commercial use.

We aim to establish "existing practice" and provide reference implementations so that Boost libraries are suitable for eventual standardization. Ten Boost libraries are already included in the C++ Standards Committee's Library Technical Report ( TR1) as a step toward becoming part of a future C++ Standard. More Boost libraries are proposed for the upcoming TR2.

Getting started: Boost works on almost any modern operating system, including UNIX and Windows variants. Follow the Getting Started Guide to download and install Boost. Popular Linux and Unix distributions such as Fedora, Debian, and NetBSD include pre-built Boost packages. Boost may also already be available on your organization's internal web server.

Background: The Background Information page has introductory material to help those educating their organization about Boost.

## Participation

Although Boost was begun by members of the C++ Standards Committee Library Working Group, participation has expanded to include thousands of programmers from the C++ community at large.

If you are interested in participating in Boost, please join our main developers mailing list. Discussions are highly technical, and list members are encouraged to participate in formal reviews of proposed libraries. There is also a users mailing list, and several project specific lists.

Both the main Boost developers list and the users list are also accessible as newsgroups.

## Latest News

### May 12, 2007 - Version 1.34.0

#### New Libraries

- Foreach Library: `BOOST_FOREACH` macro for easily iterating over the elements of a sequence, from Eric Niebler.
- Statechart Library: Arbitrarily complex finite state machines can be implemented in easily readable and maintainable C++ code, from Andreas Huber.
- TR1 Library: An implementation of the C++ Technical Report on Standard Library Extensions, from John Maddock. This library does not itself implement the TR1 components, rather it's a thin wrapper that will include your standard library's TR1 implementation (if it has one), otherwise it will include the Boost Library equivalents, and import them into namespace `std::tr1`. Highlights include: Reference Wrappers, Smart Pointers, result_of, Function Object Binders, Polymorphic function wrappers, Type Traits, Random Number Generators and Distributions, Tuples, Fixed Size Array, Hash Function Objects, Regular Expressions, and Complex Number Additional Algorithms.
- Typeof Library: Typeof operator emulation, from Arkadiy Vertleyb and Peder Holt.
- Xpressive Library: Regular expressions that can be written as strings or as expression templates, and that can refer to each other and themselves recursively with the power of context-free grammars, from Eric Niebler.

#### Updated Libraries

- Assign Library:
  - Support for `ptr_map<key,T>` via the new function `ptr_map_insert()`
  - Support for initialization of Pointer Containers when the containers hold pointers to an abstract base class.
- Date_time library:
  - Support for new US/Canada timezone rules and other bug fixes. See Change History for details.
- Filesystem Library: Major upgrade in preparation for submission to the C++ Standards Committee for TR2. Changes include:
  - Internationalization, provided by class templates basic_path, basic_filesystem_error, basic_directory_iterator, and basic_directory_entry.
  - Simplification of the path interface by eliminating special constructors to identify native formats.
  - Rationalization of predicate function design, including the addition of several new functions.
  - Clearer specification by reference to POSIX, the ISO/IEEE Single Unix Standard, with provisions for Windows and other operating systems.
  - Preservation of existing user code whenever possible.
  - More efficient directory iteration.
  - Addition of a recursive directory iterator.
- Function Library: Boost.Function now implements a small buffer optimization, which can drastically improve the performance when copying or constructing Boost.Function objects storing small function objects. For instance, `bind(&X:foo, &x, _1, _2)` requires no heap allocation when placed into a Boost.Function object.
- Functional/Hash Library
  - Use declarations for standard classes, so that the library doesn't need to include all of their headers
  - Deprecated the `<boost/functional/hash/*.hpp>` headers.
  - Add support for the `BOOST_HASH_NO_EXTENSIONS` macro, which disables the extensions to TR1
  - Minor improvements to the hash functions for floating point numbers.
- Graph Library:
  - `edmonds_maximum_cardinality_matching`, from Aaron Windsor.
  - `lengauer_tarjan_dominator_tree`, from JongSoo Park.
  - `compressed_sparse_row_graph`, from Jeremiah Willcock and Douglas Gregor of Indiana University.
  - `sorted_erdos_renyi_iterator`, from Jeremiah Willcock of Indiana University.
  - `biconnected_components` now supports a visitor and named parameters, from Janusz Piwowarski.
  - `adjacency_matrix` now models the Bidirectional Graph concept.
  - `dijkstra_shortest_paths` now calls `vis.initialize_vertex` for each vertex during initialization.
  - Note: the name of the compiled library for the GraphViz reader has changed to `boost_graph` (from `bgl-viz`) to match Boost conventions.
  - See the complete revision history for more information.
- MultiArray Library: Boost.MultiArray now by default provides range-checking for `operator[]`. Range checking can be disabled by defining the macro `BOOST_DISABLE_ASSERTS` before including `multi_array.hpp`. A bug in `multi_array::resize()` related to storage orders was fixed.
- Multi-index Containers Library:
  - New random access indices.
  - Non key-based indices feature new rearrange facilities.
  - This version also includes a number of optimizations and usage improvements. For a complete list of changes, see the library release notes.
- Optional Library:
  - `boost::none_t and boost::none` now added to Optional's documentation
  - Relational operators now directly support arguments of type `'T'` and `'none_t'`
  - operator->() now also works with reference types.
  - Helper functions `make_optional(val), make_optional(cond,val) and get_optional_value_or(opt,alternative_value)` added.
  - Constructor taking a boolean condition (as well as a value) added.
  - Member function `get_value_or(alternative_value)` added.
  - Incompatbility bug with mpl::apply<> fixed.
  - Converting assignment bug with uninitialized lvalues fixed.
- Parameter Library:
  - Every ArgumentPack is now a valid MPL Forward Sequence.
  - Support for unnamed arguments (those whose keyword is deduced from their types) is added.
  - Support for named and unnamed template arguments is added.
  - New overload generation macros solve the forwarding problem directly.
  - See also the Python library changes, below.
- Pointer Container Library:
  - Support for serialization via Boost.Serialization.
  - Exceptions can be disabled by defining the macro BOOST_PTR_CONTAINER_NO_EXCEPTIONS before including any header. This macro is defined by default if BOOST_NO_EXCEPTIONS is defined.
  - Additional `std::auto_ptr<T>` overloads added s.t. one can also pass `std::auto_ptr<T>` instead of only `T*` arguments to member functions.
  - `transfer()` now has weaker requirements s.t. one can transfer objects from `ptr_container<Derived>` to `ptr_container<Base>`,
- Python Library:
  - Boost.Python now automatically appends C++ signatures to docstrings. The new `docstring_options.hpp` header is available to control the content of docstrings.
  - `stl_input_iterator`, for turning a Python iterable object into an STL input iterator, from Eric Niebler.
  - Support for `void*` conversions is added.
  - Integrated support for wrapping C++ functions built with the parameter library; keyword names are automatically known to docsstrings.
  - Enhancements to the API for better embedding support (`boost::python::import()`, `boost::python::exec()`, and `boost::python::exec_file()`).
- Signals Library: More improvements to signal invocation performance from Robert Zeh.
- Smart Pointers Library:
  - Allocator support as proposed in N1851 (162 Kb PDF).
  - `pointer_cast` and `pointer_to_other` utilities to allow pointer-independent code, from Ion Gaztanaga.
- String Algorithm Library:
  - `lexicographical_compare`
  - `join`
  - New comparison predicates `is_less`, `is_not_greater`.
  - Negative indexes support (like Perl) in various algorihtms (`*_head/tail`, `*_nth`).
- Wave Library:
  - Wave now correctly recognizes pp-number tokens as mandated by the C++ Standard, which are converted to C++ tokens right before they are returned from the library.
  - Several new preprocessing hooks have been added. For a complete description please refer to the related documentation page: The Context Policy.
  - Shared library (dll) support has been added for the generated Wave libraries.
  - The overall error handling has been improved. It is now possible to recover and continue after an error or a warning was issued.
  - Support for optional comment and/or full whitespace preservation in the generated output stream has been added.
  - The Wave library now performs automatic include guard detection to avoid accessing header files more than once, if appropriate.
  - Full interactive mode has been added to the Wave tool. Now the Wave tool can be used just like Python or Perl for instance to interactively try out your BOOST_PP macros. Additionally it is now possible to load and save the current state of an interactive session (macro tables et.al.).
  - The overall performance has been improved by upto 40-60%, depending on the concrete files to process.
  - Support for new pragmas has been added allowing to control certain library features from inside the preprocessed sources (partial output redirection, control of generated whitespace and #line directives).
  - Optional support for #pragma message "..." has been added.
  - This version also includes a number of bug fixes and usage improvements. For a complete list of changes, see the libraries change log.

#### Supported Compilers

Boost is tested on a wide range of compilers and platforms. Since Boost libraries rely on modern C++ features not available in all compilers, not all Boost libraries will work with every compiler. The following compilers and platforms have been extensively tested with Boost, although many other compilers and platforms will work as well. For more information, see the regression test results.

- Apple GCC 4.0.1 on Mac OS X.
- Borland C++ 5.8.2 on Windows.
- GNU C++
  - 3.2.x., 3.3.x, 3.4.x, 4.0.x, 4.1.x on Linux
  - 4.1.x on Solaris
  - 3.4.x on Windows
- HP aC++ A.06.14.
- Intel C++ 9.1 on Windows, 9.0 on Linux.
- Metrowerks CodeWarrior 9.4 on Windows.
- Microsoft Visual C++ 6.0 (sp5, with and without STLport), 7.0, 7.1, 8.0. Note: Boost does not support the non-standard "Safe" C++ Library shipping with Visual C++ 8.0, which may result in many spurious warnings from Boost headers and other standards-conforming C++ code. To suppress these warnings, define the macro `_SCL_SECURE_NO_DEPRECATE`.
- Sun Studio 11 on Solaris.

#### Acknowledgements

Thomas Witt managed this release.

A great number of people contributed their time and expertise to make this release possible. Special thanks go to Vladimir Prus for making Boost.Build version 2 a reality, David Abrahams for authoring a new Getting Started guide, Rene Rivera for general build and installation support and Greg D. for answering countless questions.