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[DynamicAny] Feedback
by Daniel Larimer 05 Mar '11

05 Mar '11

I recently ran into a problem where I wanted to retrieve the value stored in a boost::any by casting to a base class. Unfortunately, boost::any requires you cast out the exact type as that held. Boost.DynamicAny is a vairant on Boost.Any which provides more flexible dynamic casting of the underlying type. Whereas retreiving a value from Boost.Any requires that you know the exact type stored within the Any, Boost.DynamicAny allows you to dynamically cast to either a base or derived class of the held type. Boost.DynamicAny passes all of the same unit tests as Boost.Any, but additionally supports the following test: #include <boost/dynamic_any.hpp> using boost::dynamic_any_cast; struct base { int a; }; struct base1 { int a1; }; struct derived : base, base1 { int b; }; struct other {}; void test_dynamic_cast() { derived d; dynamic_any a(d); derived & ra = dynamic_any_cast<derived&>(a); base & b = dynamic_any_cast<base&>(a); base1 & b1 = dynamic_any_cast<base1&>(a); const base1 & cb1 = dynamic_any_cast<const base1&>(a); TEST_CHECK_THROW( dynamic_any_cast<other&>(a), bad_dynamic_any_cast, "dynamic_any_cast to incorrect reference type"); For scalar types, Boost.DynamicAny works just like Boost.Any. This means that it currently does not support dynamic casting of pointers stored within the any, but that should not be too hard to add. https://github.com/bytemaster/Boost.DynamicAny

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[PATCH v2] [exception] Replace C cast with static_cast for Metrowerks C++
by Joshua Juran 05 Mar '11

05 Mar '11

Metrowerks C++ 2.4.1 thinks the type of (T*)0 is T, rather than T*. But static_cast works fine. --- This patch doesn't affect the compilation of g++ 4.0.1. diff --git boost/exception/exception.hpp boost/exception/exception.hpp index adaac68..afb2008 100644 --- boost/exception/exception.hpp +++ boost/exception/exception.hpp @@ -334,7 +334,7 @@ boost struct enable_error_info_return_type { - typedef typename enable_error_info_helper <T,sizeof(exception_detail::dispatch_boost_exception((T*)0))>::type type; + typedef typename enable_error_info_helper < T ,sizeof (exception_detail ::dispatch_boost_exception(static_cast<T*>(0)))>::type type; }; }

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[PATCH] [exception] Replace C cast with reinterpret_cast for Metrowerks C++
by Joshua Juran 05 Mar '11

05 Mar '11

Metrowerks C++ 2.4.1 thinks the type of (T*)0 is T, rather than T*. But reinterpret_cast works fine. --- This patch doesn't affect the compilation of g++ 4.0.1. diff --git boost/exception/exception.hpp boost/exception/exception.hpp index fd516dd..87063af 100644 --- boost/exception/exception.hpp +++ boost/exception/exception.hpp @@ -334,7 +334,7 @@ boost struct enable_error_info_return_type { - typedef typename enable_error_info_helper <T,sizeof(exception_detail::dispatch_boost_exception((T*)0))>::type type; + typedef typename enable_error_info_helper < T ,sizeof (exception_detail ::dispatch_boost_exception(reinterpret_cast<T*>(0)))>::type type; }; }

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[chrono] [thread] Incorporating Chrono into Boost.Thread implementation
by David Deakins 05 Mar '11

05 Mar '11

During the review of the Boost.Chrono library and earlier, there was some discussion about how Boost.Thread might adopt the Chrono-based interfaces once Chrono was formally accepted and merged into the trunk. I believe that Vicente even had proposed code for some of the possible changes. Now that Ratio and Chrono are officially part of Boost, is there still an intention to do this? If so, is there any timeline for when these Boost.Thread changes might begin appearing in the trunk? I know this depends on Anthony and others' availability, but I was just curious. Thanks, -Dave

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[general] mingw.org site was hacked
by Jim Bell 04 Mar '11

04 Mar '11

Of interest to MinGW users: It seems that the mingw.org site was hacked a couple days ago: <http://sourceforge.net/mailarchive/message.php?msg_id=27147169>

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Review Wizard Report for March 2011
by Ronald Garcia 04 Mar '11

04 Mar '11

============================================== Review Wizard Status Report for March 2011 ============================================== News ==== 1. Move Library Accepted 2. Ratio Library Accepted 3. Chrono Library Accepted 4. GIL.IO Library Accepted 5. Boost 1.46 Released New Libraries: Interval Containers Revised Libraries: Array, Asio, Bind, Concepts, Filesystem, Fusion, Graph, Hash, Iterator, Math, Meta State Machine, Optional, Pool, Program Options, Proto, Signals, Spirit, Tokenizer, Unordered, Wave Revised Tools: Boostbook, Inspect, Quickbook Open Issues =========== The following libraries have been reviewed and await reports from their review managers: * Process - reviewed February 2011; review manager: Marshall Clow. * Phoenix - reviewed March 2011; review manager: Hartmut Kaiser. The following libraries have been accepted to Boost, but have not yet been submitted to SVN: * GIL.IO - accepted January 2011; author: Christian Henning. * Move - accepted February 2011; author: Ion Gaztanaga. The following libraries have been accepted and submitted to SVN, but have not yet appeared in a release: * Geometry Library - accepted November 2009; author: Barend Gehreis et al. * Ratio - accepted October 2010; author: Vicente Botet. * GIL.IO - accepted January 2011; author: Christian Henning. * Chrono - accepted January 2011; author: Vicente Botet. The following libraries have been accepted provisionally to Boost, but have not been submitted for mini-review and full acceptance: * Switch - accepted provisionally January 2008; author: Steven Watanabe. * Log - accepted provisionally March 2010; author: Andrey Semashev. General Announcements ===================== As always, we need experienced review managers. The review schedule has grown substantially but we have few volunteers, so manage reviews if possible and if not please make sure to watch the review schedule and participate. Please take a look at the list of libraries in need of managers and check out their descriptions. In general review managers are active boost participants, including library contributors, infrastructure contributors, and other mailing list participants with a substantial track record of constructive participation. If you can serve as review manager for any of them, email Ron Garcia or John Phillips, "rxg at cs dot cmu dot edu" and "phillips at mps dot ohio-state dot edu" respectively. We are also suffering from a lack of reviewers. While we all understand time pressures and the need to complete paying work, the strength of Boost is based on the detailed and informed reviews submitted by you. If you are interested in reviewing a library but won't have time during the review period, you can always prepare your review ahead of time. No rule says you can only work on a review during the review period. A link to this report will be posted to www.boost.org. If you would like us to make any modifications or additions to this report before we do that, please email Ron or John. The review schedule is an unordered list of the libraries awaiting review. As such, any library on the schedule can be reviewed once the developer is ready, a review manager has been secured, and the manager, developer, and wizards agree on a date to schedule the review. Review Schedule =============== * Join (M) * Pimpl (M) * Endian * Conversion (M) * Sorting (M) * AutoBuffer (M) * Convert * Containers * Type Traits Extensions * Lockfree (M) * Fiber (M) * Quaternions, Vectors, Matrices (M) * Locale * Context * Stopwatches * Autoindex * Variadic Macro Data (M) ``(M)`` marks libraries that need review managers. -------------------- Join ---- :Author: Yigong Liu :Review Manager: Needed :Download: http://channel.sourceforge.net/ :Description: Join is an asynchronous, message based C++ concurrency library based on join calculus. It is applicable both to multi-threaded applications and to the orchestration of asynchronous, event-based applications. It follows Comega's design and implementation and builds with Boost facilities. It provides a high level concurrency API with asynchronous methods, synchronous methods, and chords which are "join-patterns" defining the synchronization, asynchrony, and concurrency. Pimpl ----- :Author: Vladimir Batov :Review Manager: Needed :Download: | `Boost Vault <http://www.boost-consulting.com/vault/index.php?action=downloadfile&fil…>`__ | http://www.ddj.com/cpp/205918714 (documentation) :Description: The Pimpl idiom is a simple yet robust technique to minimize coupling via the separation of interface and implementation and then implementation hiding. This library provides a convenient yet flexible and generic deployment technique for the Pimpl idiom. It's seemingly complete and broadly applicable, yet minimal, simple and pleasant to use. Endian ------ :Author: Beman Dawes :Review Manager: Joel Falcou :Download: http://svn.boost.org/svn/boost/sandbox/endian/ :Description: Conversion ---------- :Author: Vicente Botet :Review Manager: Needed :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=co…>`__ :Description: Generic explicit conversion between unrelated types. Boost.Conversion provides: * a generic ``convert_to`` function which can be specialized by the user to make explicit conversion between unrelated types. * a generic ``assign_to`` function which can be specialized by the user to make explicit assignation between unrelated types. * conversion between ``std::complex`` of explicitly convertible types. * conversion between ``std::pair`` of explicitly convertible types. * conversion between ``boost::optional`` of explicitly convertible types. * conversion between ``boost::rational`` of explicitly convertible types. * conversion between ``boost::interval`` of explicitly convertible types. * conversion between ``boost::chrono::time_point`` and ``boost::ptime``. * conversion between ``boost::chrono::duration`` and ``boost::time_duration``. Sorting ------- :Author: Steven Ross :Review Manager: Needed :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=al…>`__ :Description: A grouping of 3 templated hybrid radix/comparison-based sorting algorithms that provide superior worst-case and average-case performance to std::sort: integer_sort, which sorts fixed-size data types that support a rightshift (default of >>) and a comparison (default of <) operator. float_sort, which sorts standard floating-point numbers by safely casting them to integers. string_sort, which sorts variable-length data types, and is optimized for 8-bit character strings. All 3 algorithms have O(n(k/s + s)) runtime where k is the number of bits in the data type and s is a constant, and limited memory overhead (in the kB for realistic inputs). In testing, integer_sort varies from 35% faster to 2X as fast as std::sort, depending on processor, compiler optimizations, and data distribution. float_sort is roughly 70% faster than std::sort. string_sort is roughly 2X as fast as std::sort. AutoBuffer ---------- :Author: Thorsten Ottosen :Review Manager: Robert Stewart :Download: http://www.cs.aau.dk/~nesotto/boost/auto_buffer.zip :Description: Boost.AutoBuffer provides a container for efficient dynamic, local buffers. Furthermore, the container may be used as an alternative to std::vector, offering greater flexibility and sometimes better performance. Convert -------------- :Author: Vladimir Batov :Review Manager: Edward Diener :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=bo…>`__ :Description: The Convert library takes the approach of boost::lexical_cast in the area of string-to-type and type-to-string conversions, builds on the past boost::lexical_cast experience and advances that conversion functionality further to additionally provide: * throwing and non-throwing conversion-failure behavior; * support for the default value to be returned when conversion fails; * two types of the conversion-failure check -- basic and better/safe; * formatting support based on the standard I/O Streams and the standard (or user-defined) I/O Stream-based manipulators (like std::hex, std::scientific, etc.); * locale support; * support for boost::range-compliant char and wchar_t-based string containers; * no DefaultConstructibility requirement for the Target type; * consistent framework to uniformly incorporate any type-to-type conversions. It is an essential tool with applications making extensive use of configuration files or having to process/prepare considerable amounts of data in, say, XML, etc. Containers ---------- :Author: Ion Gaztanaga :Review Manager: John Maddock :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=bo…>`__ :Documentation: `Boost Sandbox <http://svn.boost.org/svn/boost/sandbox/move/libs/container/doc/html/index.h…>`__ :Description: Boost.Container library implements several well-known containers, including STL containers. The aim of the library is to offers advanced features not present in standard containers or to offer the latest standard draft features for compilers that comply with C++03. Type Traits Extensions -------------------------- :Author: Frederic Bron :Review Manager: Joel Falcou :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=ty…>`__ :Description: The purpose of the addition is to add type traits to detect if types T and U are comparable in the sense of <, <=, >, >=, == or != operators, i.e. if t<u has a sens when t is of type T and u of type U (same for <=, >, >=, ==, !=). The following traits are added: is_equal_to_comparable<T,U> is_greater_comparable<T,U> is_greater_equal_comparable<T,U> is_less_comparable<T,U> is_less_equal_comparable<T,U> is_not_equal_to_comparable<T,U> The names are based on the corresponding names of the standard template library (<functional> header, section 20.3.3 of the standard). The code has the following properties: * returns true if t<u is meaningful and returns a value convertible to bool * returns false if t<u is meaningless. * fails with compile time error if t<u is meaningful and returns void (a possibility to avoid compile time error would be to return true with an operator, trick but this has little sens as returning false would be better) Lockfree ------------------ :Author: Tim Blechmann :Review Manager: Needed :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=bo…>`__ :Documentation: http://tim.klingt.org/boost_lockfree/ :Description: Lockfree provides implementations of lock-free data structures. Lock-free data structures can be accessed by multiple threads without the necessity of blocking synchronization primitives such as guards. Lock-free data structures can be used in real-time systems, where blocking algorithms may lead to high worst-case execution times, to avoid priority inversion, or to increase the scalability for multi-processor machines. Lockfree provides: * boost::lockfree::fifo, a lock-free fifo queue * boost::lockfree::stack, a lock-free stack Fiber ----- :Author: Oliver Kowalke :Review Manager: Needed :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=bo…>`__ :Description: C++ Library for launching fibers (micro-threads) and synchronizing data between the fibers. Quaternions, Vectors, Matrices ------------------------------ :Author: Emil Dotchevski :Review Manager: Needed :Download: http://www.revergestudios.com/boost-qvm/ :Description: QVM defines a set of generic functions and operator overloads for working with quaternions, vectors and matrices of static size. The library also defines vector and matrix data types, however it allows users to introduce their own types by specializing the q_traits, v_traits and m_traits templates. Locale ------ :Author: Artyom Beilis :Review Manager: Chad Nelson :Download: https://sourceforge.net/projects/cppcms/files/boost_locale/boost_locale_for… :Description: The Locale library provides powerful tools that extend existing built-in C++ localization facilities in a Unicode-aware way. Context ------- :Author: Oliver Kowalke :Review Manager: Vicente Botet :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=bo…>`__ :Description: Context provides the ability to switch between different user-level context and is intended to be the basis for a higher abstraction like coroutine and fiber. A user-level context represents the current execution state, including all registers and CPU flags, the instruction pointer, the stack pointer. boost::context encapsulates such a user-level context and is able to store/restore its associated user-level context. This allows multiple execution paths running on a single thread using a sort of cooperative scheduling (in contrast a thread is preemptively scheduled) - the running boost::context decides explicitly when its yields to allow another boost::context to run (user-level context switching). A context can only run on a single thread at any point in time but may be migrated between thread. Stopwatches ----------- :Author: Vicente Botet :Review Manager: Anthony Williams :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=st…>`__ :Description: On top of the standard facilities of Boost.Chrono, Stopwatches provides: * Stopwatches: A facility to measure elapsed time with the ability to start, stop, suspend, or resume measurement. * Stopwatch concept * Scoped helper classes allowing to pairwise start/stop operations, suspend/resume and resume/suspend a Stopwatch. * stopwatch, model of Stopwatch capturing elapsed Clock times. * stopwatch_accumulator, model of Stopwatch capturing accumulated elapsed Clock times. * Stopclocks: a complete time reporting package that can be invoked in a single line of code. * stopwatch_reporter, convenient reporting to an output stream (including wide char streams) of the elapsed time of models of Stopwatch results. * stopclock<Clock> shortcut of stopwatch_reporter<stopwatch<Clock>> AutoIndex (Tool) ---------------- :Author: John Maddock :Review Manager: Daniel James :Download: `Boost Vault <http://www.boostpro.com/vault/index.php?action=downloadfile&filename=au…>`__ :Documentation: `Boost Sandbox <http://svn.boost.org/svn/boost/sandbox/tools/auto_index/doc/html/index.html>`__ :Description: AutoIndex is a tool for taking the grunt work out of indexing a Boostbook/Docbook document (perhaps generated by your Quickbook file mylibrary.qbk, and perhaps using also Doxygen autodoc) that describes C/C++ code. Traditionally, in order to index a Docbook document you would have to manually add a large amount of <indexterm> markup: in fact one <indexterm> for each occurrence of each term to be indexed. Instead AutoIndex will automatically scan one or more C/C++ header files and extract all the function, class, macro and typedef names that are defined by those headers, and then insert the <indexterm>s into the Docbook XML document for you. Variadic Macro Data ------------------- :Author: Edward Diener :Review Manager: Needed :Download: `Boost Sandbox <http://svn.boost.org/svn/boost/sandbox/variadic_macro_data/>`__ :Description: The variadic_macro_data library adds support and functionality for variadic macros to Boost as well as integrating variadic macros with the Boost PP library without changing the latter library in any way. Libraries under development =========================== See http://svn.boost.org/trac/boost/wiki/LibrariesUnderConstruction for a current listing of libraries under development.

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[ASIO] async_accept : Error m_val 1.
by Cyprien DIOT 04 Mar '11

04 Mar '11

Hello, I'm currently developping a tcp server with boost asio with vs2010 on win 7. My server class: Header file: class Server { private: boost::asio::io_service &_io; boost::asio::ip::tcp::acceptor *acceptor; bool connected; boost::asio::ip::tcp::socket *_client; }; Source file: Server::Server(boost::asio::io_service& io) : _io(io) { connected = false; } void Server::receiving() { boost::system::error_code error; acceptor = new tcp::acceptor(_io, tcp::endpoint(tcp::v4(), 14242)); _client = new tcp::socket(_io); connected = false; try { acceptor->async_accept(*_client, boost::bind(&Server::handle_accept, this, boost::asio::placeholders::error)); } catch(...) { } } void Server::handle_accept(const boost::system::error_code& error) { // problem appears here } In main function, i'm running io.run(); Moreover, i'm using in another class boost asio as a tcp client (which work properly) with the same io_service. When a tcp client connect to boost asio tcp server (Class Server), handle_accept is called. error has the following values: m_val = 1; m_cat = 0x00ab8d00 instance; | [boost::asio::error::detail::misc_category] = {...} | boost::noncopyable_::noncopyable = {...} | __vfptr = 0x00a8bf18 const boost::asio::error::detail::misc_category::`vftable' | [0] = 0x0098aaaa boost::asio::error::detail::misc_category::`scalar deleting destructor'(unsigned int) | [1] = 0x0098b4e1 boost::asio::error::detail::misc_category::name(void) | [2] = 0x0098b603 boost::asio::error::detail::misc_category::message(int) | [3] = 0x0098e39e boost::system::error_category::default_error_condition(int) | [4] = 0x0098bef0 boost::system::error_category::equivalent(class boost::system::error_code const &,int) | [5] = 0x0098cb61 boost::system::error_category::equivalent(int,class boost::system::error_condition const &) Do anyone know what does it mean? Can you help me to fix it? Thank you ! Cyprien DIOT France

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[date_time] Concurrent posix_time streaming crashes under MinGW-32
by Jim Bell 04 Mar '11

04 Mar '11

The attached program crashes under MinGW-32 (gcc-4.4), but works under VC8. It does concurrent streaming of posix_time::ptime values to independent std::ostringstream's. Mutexing the ostringstream from construction to destruction keeps it from crashing, but that shouldn't have to be done for independent streams. Mutexing just the ptime insertions makes it run longer, but it still crashes. I made it a Trac ticket, but wondered if anyone here had any input on it. Could it be a GCC or MinGW bug? Are other platforms escaping a crash just by luck? Building: MinGW: g++ -DBOOST_THREAD_USE_LIB DTConcur.cpp -IC:\Software\Open\lib\boost_1_45_0\ -DWIN32 -D_WINDOWS -LC:\Software\Open\lib\boost_1_45_0\mgw44\lib -mthreads -g -frtti -fexceptions -mthreads -Wall -lstdc++ -lmingw32 -o DTConcur -lboost_thread-mgw44-mt-s-1_45 VC8: cl DTConcur.cpp /IC:\Software\Open\lib\boost_1_45_0\ /MT /D BOOST_THREAD_USE_LIB /GR /EHsc /D "WIN32" /D "_WINDOWS" /FeDTConcur.exe /link /LIBPATH:C:\Software\Open\lib\boost_1_45_0\msvc8\lib

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[phoenix 3] Review
by Michael Caisse 04 Mar '11

04 Mar '11

I have been anticipating this mini-review since the Phoenix V2 review results were first announced. I am a heavy user of Phoenix and am excited to see it take it's place as a first class citizen. Thomas has done an excellent job at surpassing the requirements for the review and making Phoenix an extensible FP tool. Executive Summary: Phoenix 3 has meet the requirements and should be moved to the trunk for integration. ----- The initial review concluded with the following main points needing to be addressed in the mini-review. - the breaking interface changes from v2 - the migration path from boost::bind and lambda to Phoenix - how the interoperability with std::bind is solved (result_of semantics) - C++0x features such as rvalue references and variadic templates - the new extensibility mechanism - unified placeholders and interoperability issues with other Proto-based DSELs (such as Spirit.Qi, Spirit.Karma, and Xpressive) - compile times Thomas has addressed all of the above points; however, I would like to see two of them "documented" differently. o The Phoenix documentation should have a "What's New" section such as Spirit does. It can tersely represent the improvements, changes and most of all breaking-changes. o Compile time is often a concern with libraries that make heavy use of expression templates. While I personal don't care much about the subject, I also don't see an objective way to determine if it is better or worse with subsequent releases. Adding a compile time test would be ideal. This should be easily invoked and results from various compilers reported within the documentation. ----- Not on the list of items to review: o At some point there should be a runtime benchmark added. o Minor doc diffs attached o function.qbk : factorial.cpp is missing o BOOST_PHOENIX_DEFINE_EXPRESSION_EXT_VARARG bottom of page has TBD for the Example Thank you Thomas and the Phoenix team for such a wonderful library! michael -- Michael Caisse Object Modeling Designs www.objectmodelingdesigns.com

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detect an enum type in template arguments
by Aston 03 Mar '11

03 Mar '11

Hi, consider the example below, is there a way to detect an enum type and non-enum type ? thus if there were a way to do it, assume it to be "is_enum<T>::value" then the output of example below would have been output: Generic Type Enumeration Type **************************** example begins *************************** // all types except enumeration come here template T> class Foo { void identify() { std::cout << "Generic"; } }; // all enumerations types come here <template T> class Foo<is_enum<T>::value> { void identify() { std::cout << "Enumeration"; } }; enum BarEnum { Mon, Tue, Wed }; int main( int argc, char* argv[]) { std::cout << Foo<int> << " Type" << std::endl; std::cout << Foo<BarEnum> << " Type" << std::endl; return 0; } **************************** example ends *************************** Aston

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