January 2012 - Boost - lists.preview.boost.org

Latest Boost.Process ?
by Mathias Gaunard 29 Jan '12

29 Jan '12

I wanted to use Boost.Process, and the latest I could fine is from June at <https://github.com/JeffFlinn/boost-process>. Including the main file is enough to get lots of errors, and after fixing them (and there are quite a lot), it appears the functions from the documentation are not there (stdout_to etc.) Is there any recent usable version somewhere?

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[1.49.0] Beta 1 available
by Beman Dawes 28 Jan '12

28 Jan '12

Boost release 1.49.0 beta 1 is now available from SourceForge See http://sourceforge.net/projects/boost/files/ This release contains a new library, Boost.Heap priority queues, and numerous enhancements and bug fixes for existing libraries. For details of what's in the release, see http://beta.boost.org/users/news/version_1_49_0. Note that the links to files on this web page are for the final release - use the SourceForge link above to get the beta files. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

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[phoenix] msvc 8.0 errors
by Lorenzo Caminiti 27 Jan '12

27 Jan '12

Hello all, Why doesn't this Phoenix 3.0 code compile? (I'm sure, I'm doing something wrong... but I can't see what...) #include <boost/spirit/include/phoenix.hpp> #define BOOST_TEST_MODULE AddPhoenix #include <boost/test/unit_test.hpp> #include <algorithm> #include <iostream> BOOST_AUTO_TEST_CASE( add_phoenix ) //[add_phoenix { using boost::phoenix::let; using boost::phoenix::local_names::_f; using boost::phoenix::cref; using boost::phoenix::ref; using boost::phoenix::arg_names::_1; int sum = 0, factor = 10; int nums[] = {1, 2, 3}; // Passed to template, `factor` by constant, and defined in expression. std::for_each(nums, nums + 3, let(_f = cref(factor))[ // Unfortunately, body cannot use C++ statement syntax. ref(sum) += _f * _1 // Access `sum` by reference. ]); BOOST_CHECK( sum == 60 ); } //] On MSVC 8.0: ...patience... ...patience... ...found 3219 targets... ...updating 114 targets... compile-c-c++ bin\add_phoenix.test\msvc-8.0\debug\threading-multi\add_phoenix.obj add_phoenix.cpp C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/spirit/home/phoenix/operator/arithmetic.hpp(54) : error C2784: 'boost::phoenix::actor<as_composite<boost::phoenix::multiplies_eval,T0,boost::phoenix::actor<BaseT1>>::type> boost::phoenix::operator *(const T0 &,const boost::phoenix::actor<BaseT1> &)' : could not deduce template argument for 'const boost::phoenix::actor<BaseT1> &' from 'boost::mpl::void_' C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/spirit/home/phoenix/operator/arithmetic.hpp(107) : see declaration of 'boost::phoenix::operator *' C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/mpl/eval_if.hpp(41) : see reference to class template instantiation 'boost::phoenix::result_of_multiplies<X,Y>' being compiled with [ X=const int &, Y=boost::mpl::void_ & ] C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/spirit/home/phoenix/operator/arithmetic.hpp(76) : see reference to class template instantiation 'boost::mpl::eval_if<C,F1,F2>' being compiled with [ C=boost::mpl::or_<boost::phoenix::is_actor<const int &>,boost::phoenix::is_actor<boost::mpl::void_ &>>, F1=boost::phoenix::re_curry<boost::phoenix::multiplies_eval,const int &,boost::mpl::void_ &>, F2=boost::phoenix::result_of_multiplies<const int &,boost::mpl::void_ &> ] C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/spirit/home/phoenix/core/detail/composite_eval.hpp(88) : see reference to class template instantiation 'boost::phoenix::multiplies_eval::result<Env,A0,A1>' being compiled with [ Env=boost::phoenix::scoped_environment<boost::phoenix::basic_environment<>,boost::phoenix::basic_environment<>,boost::fusion::vector1<const int &>,boost::phoenix::detail::map_local_index_to_tuple<boost::phoenix::local_names::_f_key,boost::phoenix::detail::unused<1>,boost::phoenix::detail::unused<2>,boost::phoenix::detail::unused<3>,boost::phoenix::detail::unused<4>,boost::phoenix::detail::unused<5>,boost::phoenix::detail::unused<6>,boost::phoenix::detail::unused<7>,boost::phoenix::detail::unused<8>,boost::phoenix::detail::unused<9>>>, A0=boost::phoenix::local_variable<boost::phoenix::local_names::_f_key>, A1=boost::phoenix::argument<0> ] C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/spirit/home/phoenix/core/composite.hpp(60) : see reference to class template instantiation 'boost::phoenix::detail::composite_eval<2>::result<Composite,Env>' being compiled with [ Composite=boost::phoenix::composite<boost::phoenix::multiplies_eval,boost::fusion::vector<boost::phoenix::local_variable<boost::phoenix::local_names::_f_key>,boost::phoenix::argument<0>,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_>>, Env=boost::phoenix::scoped_environment<boost::phoenix::basic_environment<>,boost::phoenix::basic_environment<>,boost::fusion::vector1<const int &>,boost::phoenix::detail::map_local_index_to_tuple<boost::phoenix::local_names::_f_key,boost::phoenix::detail::unused<1>,boost::phoenix::detail::unused<2>,boost::phoenix::detail::unused<3>,boost::phoenix::detail::unused<4>,boost::phoenix::detail::unused<5>,boost::phoenix::detail::unused<6>,boost::phoenix::detail::unused<7>,boost::phoenix::detail::unused<8>,boost::phoenix::detail::unused<9>>> ] C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/spirit/home/phoenix/operator/arithmetic.hpp(68) : see reference to class template instantiation 'boost::phoenix::composite<EvalPolicy,EvalTuple>::result<Env>' being compiled with [ EvalPolicy=boost::phoenix::multiplies_eval, EvalTuple=boost::fusion::vector<boost::phoenix::local_variable<boost::phoenix::local_names::_f_key>,boost::phoenix::argument<0>,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_>, Env=boost::phoenix::scoped_environment<boost::phoenix::basic_environment<>,boost::phoenix::basic_environment<>,boost::fusion::vector1<const int &>,boost::phoenix::detail::map_local_index_to_tuple<boost::phoenix::local_names::_f_key,boost::phoenix::detail::unused<1>,boost::phoenix::detail::unused<2>,boost::phoenix::detail::unused<3>,boost::phoenix::detail::unused<4>,boost::phoenix::detail::unused<5>,boost::phoenix::detail::unused<6>,boost::phoenix::detail::unused<7>,boost::phoenix::detail::unused<8>,boost::phoenix::detail::unused<9>>> ] C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/spirit/home/phoenix/core/detail/composite_eval.hpp(88) : see reference to class template instantiation 'boost::phoenix::plus_assign_eval::result<Env,A0,A1>' being compiled with [ Env=boost::phoenix::scoped_environment<boost::phoenix::basic_environment<>,boost::phoenix::basic_environment<>,boost::fusion::vector1<const int &>,boost::phoenix::detail::map_local_index_to_tuple<boost::phoenix::local_names::_f_key,boost::phoenix::detail::unused<1>,boost::phoenix::detail::unused<2>,boost::phoenix::detail::unused<3>,boost::phoenix::detail::unused<4>,boost::phoenix::detail::unused<5>,boost::phoenix::detail::unused<6>,boost::phoenix::detail::unused<7>,boost::phoenix::detail::unused<8>,boost::phoenix::detail::unused<9>>>, A0=boost::phoenix::reference<int>, A1=boost::phoenix::composite<boost::phoenix::multiplies_eval,boost::fusion::vector<boost::phoenix::local_variable<boost::phoenix::local_names::_f_key>,boost::phoenix::argument<0>,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_>> ] C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/spirit/home/phoenix/core/composite.hpp(60) : see reference to class template instantiation 'boost::phoenix::detail::composite_eval<2>::result<Composite,Env>' being compiled with [ Composite=boost::phoenix::composite<boost::phoenix::plus_assign_eval,boost::fusion::vector<boost::phoenix::reference<int>,boost::phoenix::composite<boost::phoenix::multiplies_eval,boost::fusion::vector<boost::phoenix::local_variable<boost::phoenix::local_names::_f_key>,boost::phoenix::argument<0>,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_>>,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_>>, Env=boost::phoenix::scoped_environment<boost::phoenix::basic_environment<>,boost::phoenix::basic_environment<>,boost::fusion::vector1<const int &>,boost::phoenix::detail::map_local_index_to_tuple<boost::phoenix::local_names::_f_key,boost::phoenix::detail::unused<1>,boost::phoenix::detail::unused<2>,boost::phoenix::detail::unused<3>,boost::phoenix::detail::unused<4>,boost::phoenix::detail::unused<5>,boost::phoenix::detail::unused<6>,boost::phoenix::detail::unused<7>,boost::phoenix::detail::unused<8>,boost::phoenix::detail::unused<9>>> ] C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/spirit/home/phoenix/scope/let.hpp(48) : see reference to class template instantiation 'boost::phoenix::composite<EvalPolicy,EvalTuple>::result<Env>' being compiled with [ EvalPolicy=boost::phoenix::plus_assign_eval, EvalTuple=boost::fusion::vector<boost::phoenix::reference<int>,boost::phoenix::composite<boost::phoenix::multiplies_eval,boost::fusion::vector<boost::phoenix::local_variable<boost::phoenix::local_names::_f_key>,boost::phoenix::argument<0>,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_>>,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_>, Env=boost::phoenix::scoped_environment<boost::phoenix::basic_environment<>,boost::phoenix::basic_environment<>,boost::fusion::vector1<const int &>,boost::phoenix::detail::map_local_index_to_tuple<boost::phoenix::local_names::_f_key,boost::phoenix::detail::unused<1>,boost::phoenix::detail::unused<2>,boost::phoenix::detail::unused<3>,boost::phoenix::detail::unused<4>,boost::phoenix::detail::unused<5>,boost::phoenix::detail::unused<6>,boost::phoenix::detail::unused<7>,boost::phoenix::detail::unused<8>,boost::phoenix::detail::unused<9>>> ] C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/spirit/home/phoenix/core/actor.hpp(56) : see reference to class template instantiation 'boost::phoenix::let_actor<Base,Vars,Map>::result<Env>' being compiled with [ Base=boost::phoenix::composite<boost::phoenix::plus_assign_eval,boost::fusion::vector<boost::phoenix::reference<int>,boost::phoenix::composite<boost::phoenix::multiplies_eval,boost::fusion::vector<boost::phoenix::local_variable<boost::phoenix::local_names::_f_key>,boost::phoenix::argument<0>,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_>>,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_>>, Vars=boost::fusion::vector<boost::phoenix::reference<const int>,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_>, Map=boost::phoenix::detail::map_local_index_to_tuple<boost::phoenix::local_names::_f_key,boost::phoenix::detail::unused<1>,boost::phoenix::detail::unused<2>,boost::phoenix::detail::unused<3>,boost::phoenix::detail::unused<4>,boost::phoenix::detail::unused<5>,boost::phoenix::detail::unused<6>,boost::phoenix::detail::unused<7>,boost::phoenix::detail::unused<8>,boost::phoenix::detail::unused<9>>, Env=boost::phoenix::basic_environment<> ] C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/mpl/eval_if.hpp(41) : see reference to class template instantiation 'boost::phoenix::eval_result<Eval,Env>' being compiled with [ Eval=boost::phoenix::let_actor<boost::phoenix::composite<boost::phoenix::plus_assign_eval,boost::fusion::vector<boost::phoenix::reference<int>,boost::phoenix::composite<boost::phoenix::multiplies_eval,boost::fusion::vector<boost::phoenix::local_variable<boost::phoenix::local_names::_f_key>,boost::phoenix::argument<0>,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_>>,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_>>,boost::fusion::vector<boost::phoenix::reference<const int>,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_>,boost::phoenix::detail::map_local_index_to_tuple<boost::phoenix::local_names::_f_key,boost::phoenix::detail::unused<1>,boost::phoenix::detail::unused<2>,boost::phoenix::detail::unused<3>,boost::phoenix::detail::unused<4>,boost::phoenix::detail::unused<5>,boost::phoenix::detail::unused<6>,boost::phoenix::detail::unused<7>,boost::phoenix::detail::unused<8>,boost::phoenix::detail::unused<9>>>, Env=boost::phoenix::basic_environment<> ] C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/spirit/home/phoenix/core/actor.hpp(91) : see reference to class template instantiation 'boost::mpl::eval_if<C,F1,F2>' being compiled with [ C=boost::mpl::bool_<false>, F1=boost::mpl::identity<boost::phoenix::detail::error_expecting_arguments>, F2=boost::phoenix::eval_result<boost::phoenix::let_actor<boost::phoenix::composite<boost::phoenix::plus_assign_eval,boost::fusion::vector<boost::phoenix::reference<int>,boost::phoenix::composite<boost::phoenix::multiplies_eval,boost::fusion::vector<boost::phoenix::local_variable<boost::phoenix::local_names::_f_key>,boost::phoenix::argument<0>,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_>>,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_>>,boost::fusion::vector<boost::phoenix::reference<const int>,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_>,boost::phoenix::detail::map_local_index_to_tuple<boost::phoenix::local_names::_f_key,boost::phoenix::detail::unused<1>,boost::phoenix::detail::unused<2>,boost::phoenix::detail::unused<3>,boost::phoenix::detail::unused<4>,boost::phoenix::detail::unused<5>,boost::phoenix::detail::unused<6>,boost::phoenix::detail::unused<7>,boost::phoenix::detail::unused<8>,boost::phoenix::detail::unused<9>>>,boost::phoenix::basic_environment<>> ] add_phoenix.cpp(29) : see reference to class template instantiation 'boost::phoenix::actor<Eval>' being compiled with [ Eval=boost::phoenix::let_actor<boost::phoenix::composite<boost::phoenix::plus_assign_eval,boost::fusion::vector<boost::phoenix::reference<int>,boost::phoenix::composite<boost::phoenix::multiplies_eval,boost::fusion::vector<boost::phoenix::local_variable<boost::phoenix::local_names::_f_key>,boost::phoenix::argument<0>,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_>>,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_>>,boost::fusion::vector<boost::phoenix::reference<const int>,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_,boost::fusion::void_>,boost::phoenix::detail::map_local_index_to_tuple<boost::phoenix::local_names::_f_key,boost::phoenix::detail::unused<1>,boost::phoenix::detail::unused<2>,boost::phoenix::detail::unused<3>,boost::phoenix::detail::unused<4>,boost::phoenix::detail::unused<5>,boost::phoenix::detail::unused<6>,boost::phoenix::detail::unused<7>,boost::phoenix::detail::unused<8>,boost::phoenix::detail::unused<9>>> ] C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/spirit/home/phoenix/operator/arithmetic.hpp(54) : error C2784: 'boost::phoenix::actor<as_composite<boost::phoenix::multiplies_eval,boost::phoenix::actor<Eval>,T1>::type> boost::phoenix::operator *(const boost::phoenix::actor<Eval> &,const T1 &)' : could not deduce template argument for 'const boost::phoenix::actor<Eval> &' from 'const int' C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/spirit/home/phoenix/operator/arithmetic.hpp(107) : see declaration of 'boost::phoenix::operator *' C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/spirit/home/phoenix/operator/arithmetic.hpp(54) : error C2784: 'boost::phoenix::actor<as_composite<boost::phoenix::multiplies_eval,boost::phoenix::actor<Eval>,boost::phoenix::actor<BaseT1>>::type> boost::phoenix::operator *(const boost::phoenix::actor<Eval> &,const boost::phoenix::actor<BaseT1> &)' : could not deduce template argument for 'const boost::phoenix::actor<Eval> &' from 'const int' C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/spirit/home/phoenix/operator/arithmetic.hpp(107) : see declaration of 'boost::phoenix::operator *' C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/spirit/home/phoenix/operator/arithmetic.hpp(54) : error C2677: binary '*' : no global operator found which takes type 'boost::mpl::void_' (or there is no acceptable conversion) C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/spirit/home/phoenix/operator/arithmetic.hpp(54) : error C2866: 'boost::phoenix::result_of_multiplies<X,Y>::size' : a const static data member of a managed type must be initialized at the point of declaration with [ X=const int &, Y=boost::mpl::void_ & ] C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/spirit/home/phoenix/operator/arithmetic.hpp(54) : error C2057: expected constant expression C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/spirit/home/phoenix/operator/arithmetic.hpp(54) : error C2975: 'N' : invalid template argument for 'boost::mpl::at_c', expected compile-time constant expression C:\Users\lorcam\Desktop\code\boost\trunk.windows\boost/mpl/at.hpp(41) : see declaration of 'N' call "C:\Program Files (x86)\Microsoft Visual Studio 8\VC\vcvarsall.bat" x86 >nul cl /Zm800 -nologo @"bin\add_phoenix.test\msvc-8.0\debug\threading-multi\add_phoenix.obj.rsp" ...failed compile-c-c++ bin\add_phoenix.test\msvc-8.0\debug\threading-multi\add_phoenix.obj... ...failed updating 1 target... Thanks a lot! --Lorenzo

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multi_index problems
by brook＠biology.nmsu.edu 26 Jan '12

26 Jan '12

I am trying to use boost.MultiIndex as a class data member and am having difficulty because it seems that calling get<>() will not compile on a NetBSD box (gcc version 4.1.3). The code below illustrates a simple test case. Am I missing something obvious or doing something clearly mistaken? Any help is greatly appreciated. Thanks alot. Cheers, Brook =========================================================================== #include <boost/multi_index_container.hpp> #include <boost/multi_index/sequenced_index.hpp> namespace mi = boost::multi_index; template < typename T > struct container { typedef mi::multi_index_container< T, mi::indexed_by< mi::sequenced< > > > type; }; template < typename T > struct S { typedef typename container< T >::type container_type; void operator () () const { c_.get<0>(); // XXX - will not compile } private: container_type c_; }; int main () { return 0; }

2 1

[codecvt] UTF-8 codecvt
by Artyom Beilis 26 Jan '12

26 Jan '12

Hello, There is an implementation of UTF-8 codecvt facet for various purposes. Unfortunately it has two problems: 1. It does not implement UTF-16 properly (only UCS-2) 2. It requires linking with some library. Boost.Locale provides codecvt facets and I'm planning to add some template for codecvt converter in header files basically Boost.Locale will have header only version of utf-8 codecvt facet and actually very simple pattern to implement any codecvt facet for stateless encoding. I thought about two options: 1. Put it in boost::locale namespace as part of Boost.Locale library 2. Create some small "codecvt" boost library that would provide a simple framework for generation of codecvt facets for boost in general and it would include utf8 codecvt as well. Generally it would look like this: Converter concept: class Converter { public: // copyable Converter(Converter const &); // Max MB length for single Unicode code point int max_length() const; // convert a single mb sequence to code point // returing constants illegal or incomplete in case // if invalid sequence to incomplete sequence uint32_t to_unicode(char const *&begin,char const *end) const; // Convert codepoint u to [begin,end) returning mb length // or returning illegal if it is impossible to convert u to mb sequence // or U is invalid or incomplete if [begin,end) has not enough space uint32_t from_unicode(uint32_t u,char *begin,char const *end) const; }; Note, the converter works only for stateless encodings (which are 99% of all used encodings) And the basic facet would be defined as following: template<typename CharType,typename EncoderType,int size = sizeof(CharType)> class code_converter; Such that for converter concept utf8_converter I can create a utf8_codecvt facet as code_converter<wchar_t,utf8_converter> - is a facet that can be imbued to the locale object. The biggest "trick" is actually implementing codecvt facet to handle UTF-16 properly and it is implemented in Boost.Locale. So Boosters: Do You Want It Boost.Codecvt or it is fine to have it as part of Boost.Locale. In either case it would be header only "codecvt" framework. Artyom Beilis -------------- CppCMS - C++ Web Framework: http://cppcms.sf.net/ CppDB - C++ SQL Connectivity: http://cppcms.sf.net/sql/cppdb/

2 2

Scoped Enum Emulation
by Joshua Boyce 26 Jan '12

26 Jan '12

I'm currently updating some of my code to take advantage of C++0x features where available, but I also want to retain backwards compatibility with C++03. I was looking at scoped enums and noticed a thread on the mailing list by Beman Dawes discussing a scoped enum emulation implementation for Boost. I see that it's currently being used by Boost, and resides in /boost/detail/scoped_enum_emulation.hpp. My question is, why is this an implementation detail? Would it be possible for it to be moved to Boost.Config with the other 'helper' macros like BOOST_CONSTEXPR? Obviously it's not hard to reimplement, but I figured that it would be useful to other library users, so it would be best (imo) if it were moved somewhere public, rather than being hidden away. Thanks.

4 10

Re: [boost] [lexical_cast] Fast conversion from boost::iterator_range<std::string::iterator>?
by Matthew Chambers 26 Jan '12

26 Jan '12

On Oct 13, 2011 Michel Morin wrote: > lexical_cast made optimizations for some types (such as `std::string`) > to achieve better performance. But, from my experience, > it seems that lexical_cast does not make any optimization for > `boost::iterator_range<std::string::iterator>`. > > Is there any plan to add optimization for such iterator ranges? > Currently, > - `lexical_cast<int>(std::string(iter_rng.begin(), iter_rng.end()))` > is faster > than `lexical_cast<int>(iter_rng)`. > - Assuming it is safe to use `std::atoi`, > `std::atoi(&iter_rng.front())` is faster > than both of the above two methods. > (`iter_rng` is an instance of `boost::iterator_range<std::string::iterator>`.) > > Regards, > Michel This post was on the boost users list but never got a reply. I figure it might be a better fit on the developer list. I too would like to see optimized conversions work on string ranges; what's the point in doing a fast conversion if you have to do a string copy first? :) -Matt

8 16

Attribute names with underscores for GCC
by Michel Morin 26 Jan '12

26 Jan '12

Recently, Petr Machata created several trac tickets for requesting the use of attribute names with underscores for GCC. Since there is no link to the GCC's documentation in the tickets, I'd like to put a link to the documentation. In the GCC's manuals --> "Extensions to the C Language Family" --> "Declaring Attributes of Functions", "Specifying Attributes of Variables", and "Specifying Attributes of Types", there is description about attributes with preceding and following `__`: You may also specify attributes with `__' preceding and following each keyword. This allows you to use them in header files without being concerned about a possible macro of the same name. For example, you may use __noreturn__ instead of noreturn. Here are links to the gcc-2.9.5's documentation: http://gcc.gnu.org/onlinedocs/gcc-2.95.3/gcc_4.html#SEC84 http://gcc.gnu.org/onlinedocs/gcc-2.95.3/gcc_4.html#SEC90 http://gcc.gnu.org/onlinedocs/gcc-2.95.3/gcc_4.html#SEC91 I also checked manuals of gcc-3.0.4 and 4.0.4, and found the same description. Hope this helps, Michel

2 2

[assert] [exception] Fast output binary file size growth
by Antony Polukhin 26 Jan '12

26 Jan '12

Greetings, When BOOST_ENABLE_ASSERT_HANDLER is defined or BOOST_THROW_EXCEPTION used, compiler generates a string with function name. If a function is templated, compiler will generate a string for each function template. That leads to a huge binary files. Consider the following example: #define BOOST_ENABLE_ASSERT_HANDLER #include <boost/assert.hpp> template <class MplVectorT> void do_something(bool v) { BOOST_ASSERT(v); } void do_something<boost::mpl::vector<int, double>>(v); void do_something<boost::mpl::vector<int, int>>(v); This two functions will generate strings like "void do_something<MplVectorT>(bool v) [with MplVectorT = boost::mpl::vector<int, double> ]" and "void do_something<MplVectorT>(bool v) [with MplVectorT = boost::mpl::vector<int, int> ]". When there is more mataprogramming, one such string can have a size of a few kilobytes. In one of my binaries, such strings take more than 50 megabytes of binary size (total size of binary is 70 megabytes). I`ve got a patch and documentation update for Boost.Assert and Boost.Exception, that allow to disable construction of such strings or to use different macro for current function name (for example macro that prints ONLY function name). Is there interest in this feature/patches? Best regards, Antony Polukhin

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[filesystem] noexcept question? [was: Scoped Enum Emulation]
by Beman Dawes 26 Jan '12

26 Jan '12

On Tue, Jan 24, 2012 at 8:38 PM, Joshua Boyce <raptorfactor(a)raptorfactor.com> wrote: > While I've got your attention, I have a similar question along the same > lines. I notice in the mailing list archives that you added some noexcept > related macros to Boost.Config on trunk back in October 2011, I can't see > them in the current trunk or release though. What happened to those? They won't go in 1.49.0, but will begin to go into trunk within the next month. Likewise some other C++11 support, such as rvalue reference signatures. --Beman

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