May 2016 - Boost-users - lists.preview.boost.org

[interprocess] Determine size of managed_shared_memory
by Kai Benndorf 12 Oct '19

12 Oct '19

Hi all, I want to create a managed_shared_memory in exactly the size I needed. Therefore I do something like this: size = sizeof( common_managed_shared_memory ); size += sizeof( MyClassInSharedMem ); managed_shared_memory segment(create_only, "name", size ); MyClassInSharedMem allocates itself some memory by segment->allocate(). I added this also to the size, but get a boost::interprocess::bad_alloc exception on allocating this additional memory. Are there some magic bytes I forgot to add? Many thanks in advance Kai

3 2

Weird compilation error when using boost::geometry
by 邓尧 16 Nov '17

16 Nov '17

Hi, I have implemented my own "point" as specified by the point concept http://www.boost.org/doc/libs/1_59_0/libs/geometry/doc/html/geometry/refere… When I use it along with boost::geometry::model::polygon/multi_polygon, GCC refuses to compile, tested on GCC 4.9/5.2. What's even more weird is that CLANG 3.6 would happy accept my code. BTW, the Point implementation is part of a large project, it difficult to replace it with boost::geometry::model::point. Here is my code: Point.hpp > #ifndef RAPTOR_POINT_HPP_INCLUDED_ > > #define RAPTOR_POINT_HPP_INCLUDED_ > > >> #include <boost/mpl/int.hpp> > > #include <boost/geometry/core/access.hpp> > > #include <boost/geometry/core/cs.hpp> > > #include <boost/geometry/core/coordinate_type.hpp> > > #include <boost/geometry/core/coordinate_system.hpp> > > #include <boost/geometry/core/coordinate_dimension.hpp> > > #include <boost/geometry/geometries/polygon.hpp> > > #include <boost/geometry/multi/geometries/multi_polygon.hpp> > > >> namespace raptor { > > >> template<typename T, int tDimension = 2> > > class Point { > > public: > > Point() = default; > > >> Point(T a, T b) { > > data[0] = a; > > data[1] = b; > > } > > >> Point(T a, T b, T c) { > > data[0] = a; > > data[1] = b; > > data[2] = c; > > } > > >> T& operator [] (long index) { > > return data[index]; > > } > > >> const T& operator [] (long index) const { > > return data[index]; > > } > > >> private: > > T data[tDimension]; > > }; > > >> using CubicPoint = Point<long, 3>; > > using PlanarPoint = Point<long>; > > using SphericalPoint = Point<double>; > > >> template<typename T> > > using Polygon = boost::geometry::model::polygon<T>; > > >> template<typename T> > > using PolySet = boost::geometry::model::multi_polygon<Polygon<T>>; > > >> } // namespace raptor > > >> namespace boost { namespace geometry { namespace traits { > > >> template<typename Type, std::size_t tDimension> > > struct tag<::raptor::Point<Type, tDimension>> { > > typedef point_tag type; > > }; > > >> template<typename Type, std::size_t tDimension> > > struct coordinate_type<::raptor::Point<Type, tDimension>> { > > typedef Type type; > > }; > > >> template<typename Type, std::size_t tDimension> > > struct coordinate_system<::raptor::Point<Type, tDimension>> { > > typedef boost::geometry::cs::cartesian type; > > }; > > >> template<typename Type, std::size_t tDimension> > > struct dimension<::raptor::Point<Type, tDimension>> > > : public boost::mpl::int_<tDimension> { > > // EMPTY > > }; > > >> template<typename Type, std::size_t tDimension, std::size_t tIndex> > > struct access<::raptor::Point<Type, tDimension>, tIndex> { > > static Type get(const ::raptor::Point<Type, tDimension>& p) { > > return p[tIndex]; > > } > > >> static void set(::raptor::Point<Type, tDimension>& p, > > const Type& value) { > > p[tIndex] = value; > > } > > }; > > >> }}} // namespace boost::geometry::traits > > >> #endif // RAPTOR_POINT_HPP_INCLUDED_ > > A real simple main.cpp: > #include "Point.hpp" > > >> int main() { > > raptor::Polygon<raptor::SphericalPoint> pl; > > raptor::PolySet<raptor::SphericalPoint> set; > > return sizeof(pl) + sizeof(set); > > } > > > GCC compilation error: g++ main.cpp -std=c++14 > In file included from /usr/include/boost/geometry/core/access.hpp:20:0, from Point.hpp:5, from main.cpp:1: /usr/include/boost/geometry/core/point_type.hpp: In instantiation of > 'struct boost::geometry::traits::point_type<raptor::Point<double> >': /usr/include/boost/geometry/core/point_type.hpp:66:17: required from > 'struct boost::geometry::core_dispatch::point_type<void, > raptor::Point<double> >' /usr/include/boost/geometry/core/coordinate_type.hpp:58:62: required from > 'struct boost::geometry::core_dispatch::coordinate_type<void, > raptor::Point<double> >' /usr/include/boost/geometry/core/coordinate_type.hpp:92:25: required from > 'struct boost::geometry::coordinate_type<raptor::Point<double> >' /usr/include/boost/geometry/geometries/concepts/point_concept.hpp:90:54: > required from 'class boost::geometry::concept::Point<raptor::Point<double> > >' /usr/include/boost/concept/detail/has_constraints.hpp:32:62: required by > substitution of 'template<class Model> boost::concepts::detail::yes > boost::concepts::detail::has_constraints_(Model*, > boost::concepts::detail::wrap_constraints<Model, (& Model:: constraints)>*) > [with Model = boost::geometry::concept::Point<raptor::Point<double> >]' /usr/include/boost/concept/detail/has_constraints.hpp:42:5: required from > 'const bool > boost::concepts::not_satisfied<boost::geometry::concept::Point<raptor::Point<double> > > >::value' /usr/include/boost/concept/detail/has_constraints.hpp:45:31: required > from 'struct > boost::concepts::not_satisfied<boost::geometry::concept::Point<raptor::Point<double> > > >' /usr/include/boost/mpl/if.hpp:67:11: required from 'struct > boost::mpl::if_<boost::concepts::not_satisfied<boost::geometry::concept::Point<raptor::Point<double> > > >, > boost::concepts::constraint<boost::geometry::concept::Point<raptor::Point<double> > > >, boost::concepts::requirement<boost::concepts::failed************ > boost::geometry::concept::Point<raptor::Point<double> >::************> >' /usr/include/boost/concept/detail/general.hpp:50:8: required from 'struct > boost::concepts::requirement_<void > (*)(boost::geometry::concept::Point<raptor::Point<double> >)>' /usr/include/boost/geometry/geometries/ring.hpp:60:5: required from > 'class boost::geometry::model::polygon<raptor::Point<double>, true, true, > std::vector, std::vector, std::allocator, std::allocator>' main.cpp:4:42: required from here /usr/include/boost/geometry/core/point_type.hpp:45:5: error: no matching > function for call to 'assertion_failed(mpl_::failed************ > (boost::geometry::traits::point_type<raptor::Point<double> > >::NOT_IMPLEMENTED_FOR_THIS_POINT_TYPE::************)(mpl_::assert_::types<raptor::Point<double>, > mpl_::na, mpl_::na, mpl_::na>))' BOOST_MPL_ASSERT_MSG ^ /usr/include/boost/mpl/assert.hpp:82:5: note: candidate: template<bool C> > int mpl_::assertion_failed(typename mpl_::assert<C>::type) int assertion_failed( typename assert<C>::type ); ^ /usr/include/boost/mpl/assert.hpp:82:5: note: template argument > deduction/substitution failed: /usr/include/boost/geometry/core/point_type.hpp:45:5: note: cannot > convert > 'boost::geometry::traits::point_type<Geometry>::NOT_IMPLEMENTED_FOR_THIS_POINT_TYPE48::assert_arg<raptor::Point<double> > >()' (type 'mpl_::failed************ > (boost::geometry::traits::point_type<raptor::Point<double> > >::NOT_IMPLEMENTED_FOR_THIS_POINT_TYPE::************)(mpl_::assert_::types<raptor::Point<double>, > mpl_::na, mpl_::na, mpl_::na>)') to type 'mpl_::assert<false>::type {aka > mpl_::assert<false>}' BOOST_MPL_ASSERT_MSG ^ In file included from > /usr/include/boost/geometry/core/coordinate_type.hpp:21:0, from /usr/include/boost/geometry/core/access.hpp:24, from Point.hpp:5, from main.cpp:1: /usr/include/boost/geometry/core/point_type.hpp: In instantiation of > 'struct boost::geometry::core_dispatch::point_type<void, > raptor::Point<double> >': /usr/include/boost/geometry/core/coordinate_type.hpp:58:62: required from > 'struct boost::geometry::core_dispatch::coordinate_type<void, > raptor::Point<double> >' /usr/include/boost/geometry/core/coordinate_type.hpp:92:25: required from > 'struct boost::geometry::coordinate_type<raptor::Point<double> >' /usr/include/boost/geometry/geometries/concepts/point_concept.hpp:90:54: > required from 'class boost::geometry::concept::Point<raptor::Point<double> > >' /usr/include/boost/concept/detail/has_constraints.hpp:32:62: required by > substitution of 'template<class Model> boost::concepts::detail::yes > boost::concepts::detail::has_constraints_(Model*, > boost::concepts::detail::wrap_constraints<Model, (& Model:: constraints)>*) > [with Model = boost::geometry::concept::Point<raptor::Point<double> >]' /usr/include/boost/concept/detail/has_constraints.hpp:42:5: required from > 'const bool > boost::concepts::not_satisfied<boost::geometry::concept::Point<raptor::Point<double> > > >::value' /usr/include/boost/concept/detail/has_constraints.hpp:45:31: required > from 'struct > boost::concepts::not_satisfied<boost::geometry::concept::Point<raptor::Point<double> > > >' /usr/include/boost/mpl/if.hpp:67:11: required from 'struct > boost::mpl::if_<boost::concepts::not_satisfied<boost::geometry::concept::Point<raptor::Point<double> > > >, > boost::concepts::constraint<boost::geometry::concept::Point<raptor::Point<double> > > >, boost::concepts::requirement<boost::concepts::failed************ > boost::geometry::concept::Point<raptor::Point<double> >::************> >' /usr/include/boost/concept/detail/general.hpp:50:8: required from 'struct > boost::concepts::requirement_<void > (*)(boost::geometry::concept::Point<raptor::Point<double> >)>' /usr/include/boost/geometry/geometries/ring.hpp:60:5: required from > 'class boost::geometry::model::polygon<raptor::Point<double>, true, true, > std::vector, std::vector, std::allocator, std::allocator>' main.cpp:4:42: required from here /usr/include/boost/geometry/core/point_type.hpp:66:17: error: no type named > 'type' in 'struct boost::geometry::traits::point_type<raptor::Point<double> > >' >::type type; ^ In file included from > /usr/include/boost/geometry/geometries/polygon.hpp:26:0, from Point.hpp:10, from main.cpp:1: /usr/include/boost/geometry/geometries/concepts/point_concept.hpp: In > instantiation of 'class > boost::geometry::concept::Point<raptor::Point<double> >': /usr/include/boost/concept/detail/has_constraints.hpp:32:62: required by > substitution of 'template<class Model> boost::concepts::detail::yes > boost::concepts::detail::has_constraints_(Model*, > boost::concepts::detail::wrap_constraints<Model, (& Model:: constraints)>*) > [with Model = boost::geometry::concept::Point<raptor::Point<double> >]' /usr/include/boost/concept/detail/has_constraints.hpp:42:5: required from > 'const bool > boost::concepts::not_satisfied<boost::geometry::concept::Point<raptor::Point<double> > > >::value' /usr/include/boost/concept/detail/has_constraints.hpp:45:31: required > from 'struct > boost::concepts::not_satisfied<boost::geometry::concept::Point<raptor::Point<double> > > >' /usr/include/boost/mpl/if.hpp:67:11: required from 'struct > boost::mpl::if_<boost::concepts::not_satisfied<boost::geometry::concept::Point<raptor::Point<double> > > >, > boost::concepts::constraint<boost::geometry::concept::Point<raptor::Point<double> > > >, boost::concepts::requirement<boost::concepts::failed************ > boost::geometry::concept::Point<raptor::Point<double> >::************> >' /usr/include/boost/concept/detail/general.hpp:50:8: required from 'struct > boost::concepts::requirement_<void > (*)(boost::geometry::concept::Point<raptor::Point<double> >)>' /usr/include/boost/geometry/geometries/ring.hpp:60:5: required from > 'class boost::geometry::model::polygon<raptor::Point<double>, true, true, > std::vector, std::vector, std::allocator, std::allocator>' main.cpp:4:42: required from here /usr/include/boost/geometry/geometries/concepts/point_concept.hpp:93:10: > error: 'value' is not a member of > 'boost::geometry::dimension<raptor::Point<double> >' enum { ccount = dimension<Geometry>::value }; ^ Where is the problem ? or it's a GCC bug ? Thanks

3 4

[Range, Phoenix] What am I missing...
by Robert Jones 25 Apr '17

25 Apr '17

Hi Folks Can anyone explain the output of this program... #include <iostream> #include <boost/range/algorithm/copy.hpp> #include <boost/range/counting_range.hpp> #include <boost/range/adaptor/reversed.hpp> #include <boost/range/adaptor/transformed.hpp> #include <boost/phoenix/bind/bind_function.hpp> #include <boost/phoenix/core/argument.hpp> int f( int i ) { return i * 2; } int main( ) { using boost::adaptors::reversed; using boost::adaptors::transformed; using boost::counting_range; using boost::copy; using boost::phoenix::arg_names::_1; copy( counting_range( 1, 5 ) | reversed | transformed( f ), std::ostream_iterator<int>( std::cout, " " ) ); std::cout << std::endl; copy( counting_range( 1, 5 ) | reversed | transformed( bind( f, _1 ) ), std::ostream_iterator<int>( std::cout, " " ) ); std::cout << std::endl; } Which is... 8 6 4 2 1768406272 1768406272 1768406272 1768406272 I'm using Gcc 4.6.2 & Boost 1.53 Thx All.

3 4

[statechart] Passing parameters from event to State Local Storage
by Christophe Bourez 16 Nov '16

16 Nov '16

I need to maintain a parameter into the state local storage. This parameter is initially contained in the event that causes the transition to the target state. I give hereafter a small illustrative example. typename sc = boost::statechart; class EvTest : public sc::event<EvTest> { public: EvTest(std::size_t val) : value(val) {} std::size_t getValue() const { return this->value; } private: std::size_t value; }; class MyStateMachine; class StSource; class StTarget; class StSource : public sc::simple_state<StSource, MyStateMachine> { public: typedef sc::custom_reaction<EvTest> reactions; sc::result react(const EvTest &event) { // How to pass event.getValue() to the target state ? transit<StTarget>(); } }; class StTarget : public sc::simple_state<StTarget, MyStateMachine> { public: StTarget(std::size_t val) : val(value) {} private: std::size_t value; }; Thanks, Christophe

5 6

Boost fusion problem
by Jess Morecroft 05 Jun '16

05 Jun '16

Hi guys, We're trying out the latest version of Boost (1.61, migrating from 1.55) and have some code calling the fusion library that now doesn't compile and it's not obvious (to me at least) why. I've created a simple program (below) to demonstrate the issue. As per the compile/run section below, this compiles and runs with Boost 1.55, not with 1.61. If anyone has any idea or pointers to what is wrong here I'd really appreciate it. Sorry if this isn't the right forum for this kind of issue too - if so please let me know how best to seek help on this. Regards Jess ******************** main.cpp #include <boost/fusion/algorithm/iteration/for_each.hpp> #include <boost/fusion/view/zip_view.hpp> #include <boost/fusion/tuple.hpp> #include <iostream> #include <string> struct Helper { template<typename Arg> void operator()(const Arg& arg) const { std::cout << boost::fusion::get<0>(arg) << std::endl; std::cout << boost::fusion::get<1>(arg) << std::endl; } }; int main() { const int myint(123); const double mydub(456.0); const std::string mystr("blah"); const bool mybool(false); typedef boost::fusion::tuple<const int&, const double&> Tuple1; typedef boost::fusion::tuple<const std::string&, const bool&> Tuple2; typedef boost::fusion::tuple<const Tuple1&, const Tuple2&> Tuple3; Helper helper; boost::fusion::for_each( boost::fusion::zip_view<Tuple3>( Tuple3(Tuple1(myint, mydub), Tuple2(mystr, mybool))), helper); return 0; } ******************** compile/run tests jess@flathead:~$ g++ --version g++ (Ubuntu 5.3.1-14ubuntu2) 5.3.1 20160413 Copyright (C) 2015 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. (boost 1.55) jess@flathead:~$ g++ -std=c++14 main.cpp jess@flathead:~$ ./a.out 123 blah 456 0 (boost 1.61) jess@flathead:~$ g++ -std=c++14 main.cpp In file included from /usr/local/include/boost/fusion/container/vector/vector10.hpp:25:0, from /usr/local/include/boost/fusion/view/transform_view/transform_view.hpp:22, from /usr/local/include/boost/fusion/algorithm/transformation/transform.hpp:11, from /usr/local/include/boost/fusion/view/zip_view/detail/begin_impl.hpp:14, from /usr/local/include/boost/fusion/view/zip_view/zip_view.hpp:16, from /usr/local/include/boost/fusion/view/zip_view.hpp:12, from main.cpp:2: /usr/local/include/boost/fusion/container/vector/vector.hpp: In instantiation of ‘constexpr boost::fusion::vector_detail::vector_data<std::integer_sequence<long unsigned int, _Idx ...>, T ...>::vector_data(boost::fusion::vector_detail::each_elem, U&& ...) [with U = {const boost::fusion::tuple<const boost::fusion::tuple<const int&, const double&>&, const boost::fusion::tuple<const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, const bool&>&>&}; long unsigned int ...I = {0ul, 1ul}; T = {const boost::fusion::tuple<const int&, const double&>&, const boost::fusion::tuple<const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, const bool&>&}]’: /usr/local/include/boost/fusion/container/vector/vector.hpp:305:97: required from ‘boost::fusion::vector<T>::vector(U&& ...) [with U = {const boost::fusion::tuple<const boost::fusion::tuple<const int&, const double&>&, const boost::fusion::tuple<const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, const bool&>&>&}; T = {const boost::fusion::tuple<const int&, const double&>&, const boost::fusion::tuple<const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, const bool&>&}]’ /usr/local/include/boost/fusion/view/zip_view/zip_view.hpp:128:30: required from ‘constexpr boost::fusion::zip_view<Sequences>::zip_view(const Sequences&) [with Sequences = boost::fusion::tuple<const boost::fusion::tuple<const int&, const double&>&, const boost::fusion::tuple<const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, const bool&>&>]’ main.cpp:32:64: required from here /usr/local/include/boost/fusion/container/vector/vector.hpp:230:52: error: mismatched argument pack lengths while expanding ‘boost::fusion::vector_detail::store<I, T>’ : store<I, T>(std::forward<U>(var))... ^ /usr/local/include/boost/fusion/container/vector/vector.hpp: In instantiation of ‘constexpr boost::fusion::vector_detail::store<<anonymous>, T>::store() [with long unsigned int <anonymous> = 0ul; T = const boost::fusion::tuple<const int&, const double&>&]’: /usr/local/include/boost/fusion/container/vector/vector.hpp:230:52: required from ‘constexpr boost::fusion::vector_detail::vector_data<std::integer_sequence<long unsigned int, _Idx ...>, T ...>::vector_data(boost::fusion::vector_detail::each_elem, U&& ...) [with U = {const boost::fusion::tuple<const boost::fusion::tuple<const int&, const double&>&, const boost::fusion::tuple<const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, const bool&>&>&}; long unsigned int ...I = {0ul, 1ul}; T = {const boost::fusion::tuple<const int&, const double&>&, const boost::fusion::tuple<const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, const bool&>&}]’ /usr/local/include/boost/fusion/container/vector/vector.hpp:305:97: required from ‘boost::fusion::vector<T>::vector(U&& ...) [with U = {const boost::fusion::tuple<const boost::fusion::tuple<const int&, const double&>&, const boost::fusion::tuple<const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, const bool&>&>&}; T = {const boost::fusion::tuple<const int&, const double&>&, const boost::fusion::tuple<const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, const bool&>&}]’ /usr/local/include/boost/fusion/view/zip_view/zip_view.hpp:128:30: required from ‘constexpr boost::fusion::zip_view<Sequences>::zip_view(const Sequences&) [with Sequences = boost::fusion::tuple<const boost::fusion::tuple<const int&, const double&>&, const boost::fusion::tuple<const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, const bool&>&>]’ main.cpp:32:64: required from here /usr/local/include/boost/fusion/container/vector/vector.hpp:137:24: error: value-initialization of reference type ‘const boost::fusion::tuple<const int&, const double&>&’ : elem() // value-initialized explicitly ^ /usr/local/include/boost/fusion/container/vector/vector.hpp: In instantiation of ‘constexpr boost::fusion::vector_detail::store<<anonymous>, T>::store() [with long unsigned int <anonymous> = 1ul; T = const boost::fusion::tuple<const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, const bool&>&]’: /usr/local/include/boost/fusion/container/vector/vector.hpp:230:52: required from ‘constexpr boost::fusion::vector_detail::vector_data<std::integer_sequence<long unsigned int, _Idx ...>, T ...>::vector_data(boost::fusion::vector_detail::each_elem, U&& ...) [with U = {const boost::fusion::tuple<const boost::fusion::tuple<const int&, const double&>&, const boost::fusion::tuple<const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, const bool&>&>&}; long unsigned int ...I = {0ul, 1ul}; T = {const boost::fusion::tuple<const int&, const double&>&, const boost::fusion::tuple<const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, const bool&>&}]’ /usr/local/include/boost/fusion/container/vector/vector.hpp:305:97: required from ‘boost::fusion::vector<T>::vector(U&& ...) [with U = {const boost::fusion::tuple<const boost::fusion::tuple<const int&, const double&>&, const boost::fusion::tuple<const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, const bool&>&>&}; T = {const boost::fusion::tuple<const int&, const double&>&, const boost::fusion::tuple<const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, const bool&>&}]’ /usr/local/include/boost/fusion/view/zip_view/zip_view.hpp:128:30: required from ‘constexpr boost::fusion::zip_view<Sequences>::zip_view(const Sequences&) [with Sequences = boost::fusion::tuple<const boost::fusion::tuple<const int&, const double&>&, const boost::fusion::tuple<const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, const bool&>&>]’ main.cpp:32:64: required from here /usr/local/include/boost/fusion/container/vector/vector.hpp:137:24: error: value-initialization of reference type ‘const boost::fusion::tuple<const std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&, const bool&>&’

2 3

installing on a local 2 core system
by Salvador Aguiñaga 30 May '16

30 May '16

> Installing on small system I want to use for temporary development, I get the following error. > > >parallel-bgl-0.7.0/boost/property_map/property_map.hpp:16:37: fatal error: boost/pending/cstddef.hpp: No such file or directory > compilation terminated > > I've configured the system: > >"sudo apt-get install build-essential" > > And successfully installed the openmpi: "openmpi-1.10.2.tar.bz2" > > But when I get to: > /parallel-bgl-0.7.0/build/cmake .. > > I can't find a good solution online to this cstddef.hpp error. > > Any suggestions? > > > My system: uname -a > > Linux atomix 4.2.0-16-generic #19-Ubuntu SMP Thu Oct 8 14:46:51 UTC 2015 i686 i686 i686 GNU/Linux

1 0

[proto] non-proto objects as terminals
by Igor R 30 May '16

30 May '16

I would like to use instances of a non-proto class as proto terminals for all purposes. To enable this functionality, I use is_terminal metafunction that I pass to BOOST_PROTO_DEFINE_OPERATORS(). This actually defines the operators, so the following expression makes an expression tree, as expected: non_proto_obj * proto_obj; However, I cannot do this: non_proto_obj = proto_obj; Or this: non_proto_obj[proto_obj]; While the opposite does compile: proto_obj = non_proto_obj; proto_obj[non_proto_obj]; How to solve this issue? Thanks! P.S.: here is an sscce: /////////////////// #include <iostream> #include <boost/proto/proto.hpp> #include <boost/mpl/int.hpp> namespace mpl = boost::mpl; namespace proto = boost::proto; using proto::_; template<typename Expr> struct my_expression; struct my_domain : proto::domain<proto::generator<my_expression> > {}; template<int I> struct placeholder {}; template<typename Expr> struct my_expression : proto::extends<Expr, my_expression<Expr>, my_domain> { explicit my_expression(Expr const &expr = Expr()) : my_expression::proto_extends(expr) {} BOOST_PROTO_EXTENDS_USING_ASSIGN(my_expression<Expr>) }; const my_expression<proto::terminal<placeholder<1>>::type> _1; namespace app { struct non_proto_type {}; template <typename T> struct is_terminal : mpl::false_ {}; template<> struct is_terminal<non_proto_type> : mpl::true_ {}; BOOST_PROTO_DEFINE_OPERATORS(is_terminal, my_domain) non_proto_type non_proto; } int main() { _1 = app::non_proto; // ok, builds temporary proto expression //app::non_proto = _1; // does not compile! no operator= _1[app::non_proto]; // ok //app::non_proto[_1]; // does not compile! no operator[] (+app::non_proto)[_1]; // ok! applying unary + to make a proto expression first, then operator[] is available }

1 0

Boost.Fiber mini-review May 23 - June 1
by Nat Goodspeed 30 May '16

30 May '16

Hi all, The Boost.Fiber candidate library by Oliver Kowalke begins a mini-review today, Monday May 23, which will close Wednesday June 1. It was last reviewed in September 2015; the verdict at that time was "not yet." Oliver has been working steadily to address review comments and to improve the library in other ways, and has brought the library back for mini-review. The updated documentation is here: http://olk.github.io/libs/fiber/doc/html/index.html The code is on the master branch of this repository: https://github.com/olk/boost-fiber/tree/master I believe it is Oliver's intention to respond to review feedback on the develop branch, leaving the master branch stable during the review. I will monitor reviews and discussion on both the boost-users@ list and the boost@ developers' list. Please include at least "fiber" and "review" in the subject line of your mail, e.g. by replying to this message. (Please reply to only ONE list, however.) I will also check the Boost Library Incubator for Fiber reviews: http://rrsd.com/blincubator.com/bi_library/fiber/?gform_post_id=859 though I check that less frequently than email. Please do remember to state in your review whether you think the library should be accepted as a Boost library. Thank you for your interest and your feedback! ----------------------------------------------------- Here follows a synopsis of issues raised during the September 2015 review: Cross-thread fiber migration: Evidently the community strongly desires the ability to transfer a suspended fiber from one thread to another. Now supported, with documentation. Cross-thread migration support implies a requirement to document the thread safety requirements of the customization API. Addressed. Standard required timing specifications: meet (30.2.4 Timing specifications [thread.req.timing]). Addressed. Adapt one or more existing test suites for thread facilities to validate the correctness of the Fiber library's synchronization constructs. The requester clarified in private mail that I misstated his suggestion: he wanted Oliver to review one or more such test suites to discover the kinds of issues that can arise with thread synchronization constructs. He has professed himself satisfied with the current state of the Fiber library's synchronization constructs. std::chrono support: ensure that wait_until() can accept any supported time_point specialization. Addressed. C++11 compatibility. Addressed. Document that this_fiber::yield() (et al.) are valid from main(), or in general from a thread function, as well as from explicitly-launched fibers. Addressed. Make shared_state lock requirements explicit: for example, make mark_ready_and_notify_() accept a std::unique_lock<>& (or &&) to force its caller to provide one. Addressed. Avoid holding mutex during condition_variable::notify_*() calls. Addressed. packaged_task must not decay-copy its task arguments. Addressed. Align fibers::async() signature, result description and invoke_helper implementation with std::async(). Avoid returning std::move(...). Addressed. Wait list implementation: try an intrusive linked list of fiber_context objects. Addressed. Avoid sleeping thread when no fibers are ready -- block on external event. Better handling of waiting tasks (decentralized wait queues?). Addressed. Optimization to resume awakened fiber on the thread that awakens it. Hooks provided. Template redundancy: eliminate duplication between specializations for T, T& and void. The future, shared_future, shared_state, promise and task_object templates were specifically cited. Addressed. Leverage predicate-based condition::wait() overload internally. Addressed. Nested schedulers: make schedulers be schedulable entities themselves. Not implemented. Improve robustness of `promise' handling in Asynchronous Callbacks documentation. Avoid overconfident remarks about it. Addressed. Fix Note overstating the requirements on condition_variable::wait(). Addressed.

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[test] how to test std::pair with BOOST_TEST
by Tan, Tom (Shanghai) 29 May '16

29 May '16

The following snippet does not compile with VS2015 and boost 1.61. What should the correct way to do it? Thanks. // compile with cl.exe /EHSc #define BOOST_TEST_MODULE pair #include <boost/test/included/unit_test.hpp> std::pair<uint32_t, uint32_t> v() { return std::make_pair(0, 0); } BOOST_AUTO_TEST_CASE(range) { BOOST_TEST(std::make_pair(0, 0) == v()); } Here's the error message: C:\3rd\boost_1_61_0\boost/test/tools/assertion.hpp(163): error C2678: binary '==': no operator found which takes a left-hand operand of type 'std::pair<int,int>' (or there is no acceptable conversion) C:\3rd\boost_1_61_0\boost/function/function_base.hpp(740): note: could be 'bool boost::operator ==(boost::detail::function::useless_clear_type *,const boost::function_base &)' C:\3rd\boost_1_61_0\boost/function/function_base.hpp(728): note: or 'bool boost::operator ==(const boost::function_base &,boost::detail::function::useless_clear_type *)' C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\INCLUDE\exception(329): note: or 'bool std::operator ==(const std::exception_ptr &,const std::exception_ptr &) throw()' [found using argument-dependent lookup] C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\INCLUDE\exception(334): note: or 'bool std::operator ==(std::nullptr_t,const std::exception_ptr &) throw()' [found using argument-dependent lookup] C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\INCLUDE\exception(339): note: or 'bool std::operator ==(const std::exception_ptr &,std::nullptr_t) throw()' [found using argument-dependent lookup] C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\INCLUDE\system_error(365): note: or 'bool std::operator ==(const std::error_code &,const std::error_code &) noexcept' [found using argument-dependent lookup] C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\INCLUDE\system_error(373): note: or 'bool std::operator ==(const std::error_code &,const std::error_condition &) noexcept' [found using argument-dependent lookup] C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\INCLUDE\system_error(381): note: or 'bool std::operator ==(const std::error_condition &,const std::error_code &) noexcept' [found using argument-dependent lookup] C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\INCLUDE\system_error(389): note: or 'bool std::operator ==(const std::error_condition &,const std::error_condition &) noexcept' [found using argument-dependent lookup] C:\3rd\boost_1_61_0\boost/function/function_base.hpp(799): note: or 'bool boost::operator ==<T>(Functor,const boost::function_base &)' with [ T=std::pair<int,int>, Functor=std::pair<int,int> ] C:\3rd\boost_1_61_0\boost/function/function_base.hpp(790): note: or 'bool boost::operator ==<T>(const boost::function_base &,Functor)' with [ T=std::pair<uint32_t,uint32_t>, Functor=std::pair<uint32_t,uint32_t> ] C:\3rd\boost_1_61_0\boost/test/tools/assertion.hpp(163): note: while trying to match the argument list '(std::pair<int,int>, std::pair<uint32_t,uint32_t>)' C:\3rd\boost_1_61_0\boost/test/tools/assertion.hpp(326): note: see reference to class template instantiation 'boost::test_tools::assertion::op::EQ<ValType,T,void>' being compiled with [ ValType=std::pair<int,int>, T=std::pair<uint32_t,uint32_t> ] s.cpp(14): note: see reference to class template instantiation 'boost::test_tools::assertion::binary_expr<ExprType,std::pair<uint32_t,uint32_t>,boost::test_tools::assertion::op::EQ<ValType,T,void>>' being compiled with [ ExprType=boost::test_tools::assertion::value_expr<std::pair<int,int>>, ValType=std::pair<int,int>, T=std::pair<uint32_t,uint32_t> ] C:\3rd\boost_1_61_0\boost/test/tools/assertion.hpp(377): warning C4624: 'boost::test_tools::assertion::binary_expr<ExprType,std::pair<uint32_t,uint32_t>,boost::test_tools::assertion::op::EQ<ValType,T,void>>': destructor was implicitly defined as deleted with [ ExprType=boost::test_tools::assertion::value_expr<std::pair<int,int>>, ValType=std::pair<int,int>, T=std::pair<uint32_t,uint32_t> ]

4 4

Call for Papers for Meeting C++ 2016 ends on Friday night!
by Jens Weller 25 May '16

25 May '16

Hello Boost Community! a short reminder, that the deadline is coming up for submitting your talk to this years Meeting C++ conference! Meeting C++ 2016 Page: http://meetingcpp.com/index.php/mcpp2016.html Talk submission page: https://meetingcpp.com/mcpp/submittalk/ thanks, Jens Weller

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File-mapped shared memory access through Boost interprocess is slow on some HPC file-systems due to mmap
by Scott Ritchie 24 May '16

24 May '16

Hi all, I'm wondering if there is some way to use the Boost interprocess library without the use of mmap for file I/O? I have developed an R-language package that uses another third party package (bigmemory) to access objects in shared memory when parallelising R across multiple cores. This third party package uses the Boost interprocess library to make these file-backed shared memory objects available to R. This worked perfectly, until I tested my package on a multi-node cluster. After some digging I found that the code calling these shared memory objects was extremely slow, and had hugely variable runtimes. Accessing these shared memory objects became exponentially slower as I parallelised over more and more cores. After talking to the authors of the bigmemory library and the administrators of the cluster, we have determined the route cause to be the use of mmap() on that particular filesystem (GPFS). On this filesystem, mmap() performs concurrency checking on every read and write since the filesystem is shared across multiple physical nodes. Marking the shared memory segments as read_only did not solve the issue. The advice of the cluster administrators is to not use mmap() for file I/O. I'm hoping there is a simple fix, such as a compilation flag I can provide to boost to use some alternative file I/O function/library? If not I will need to rewrite my code so that it is multi-threaded instead of multi-process without the use of Boost. Kind regards, --- Scott Ritchie, Ph.D. Student | Integrative Systems Biology | Pathology | http://www.inouyelab.org The University of Melbourne ---

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[Parallel Boost Graph Library] General Questions and Redistribution Questions
by Jun Kudo 24 May '16

24 May '16

Hi everyone, I've been playing around with the Parallel Boost Graph Library in hopes of using it for a distributed mesh with redistribution capabilities. Unfortunately, I've been having a lot of issues and I was hoping to get some clarification from the community on some points. I am trying to construct a distributed graph that represents a mesh. The idealized plan is to use this library to create a mesh class that allows for the easy introduction of new vertices and edges as well as repartitioning/data migration capabilities. For this effort, I created a simple struct called Cell that is attached as an interior vertex property and identified the cell id value as the key for indexing. I've attached a short program to really quickly demonstrate what I've been trying to prototype. At this point, I have some questions regarding some things about the library that I can't seem to figure out. 1. How do you control the initial distribution of the names? That is, how do you control which processes own what vertex names when you dynamically add named vertices? 2. How do you create a VertexProcessorMap to use with the redistribution function? The test adjlist_redist_test.cpp looks like it creates a property_map of the vertex_rank but I'm not sure how to do something similar when I have named graph. 3. Is there any way and any point to accomplish what I'm trying to do without using named graphs? I started down this route because the referenced test did not use named graphs. I quickly ran into a situation where I did not know how to grab a vertex descriptor for an off-process vertex without using the vertex(vertices_size_type n, const adjacency_list& g) function or without knowing a priori where that vertex lived. Similar to the named graph situation, I want to be able to dynamically add numbered vertices (which according to the documentation invalidates the use of vertex()) on different processes and then define edges between them based on these numbers. Does the fact that I'm trying to use a global numbering system as a name convention make this question silly? Sorry about the wall of text and I hope my questions are not too nonsensical! Thanks in advance for all the help. Sincerely, Jun

1 0

Rebooting Boost: Call for Lightning Talks @ CppCon
by Niall Douglas 23 May '16

23 May '16

At C++ Now a number of informal meetings showed there to be frustrations with the current ecosystem around the Boost C++ Libraries (to paraphrase a founder of Boost, "Boost is supposed to serve *the entire C++ community; it isn't Boost's goal to serve Boost's community*". Recent and recurrent boost-dev discussions have raised the lack of cmake based tooling; lack of ABI management and the consequent ODR violation when mixing Boost versions in the same process; the anti-social behaviour of Boost towards library end users, new ideas, new blood and the wider C++ community; and the chronic lack of maintenance of up to half the Boost libraries. One question which needs to be answered is whether a clean reboot of Boost from the first principles of proving high quality C++ libraries well suited for use with the latest C++ standard is viable. This new collection of C++ libraries would be started completely from scratch (even if some existing libraries were ported into the new organisation), so ANYTHING is possible. All we need is a critical mass of library developers willing to collaborate on developing a shared infrastructure mutually beneficial to all participants, whether library developer or library end user. To that end of discovering if this critical mass is there, five minute lightning talk topics are requested for CppCon this September on this topic: "What design pattern, practice or idiom should a standards aspiring collection of C++ 14/17 libraries share?" Please keep each talk topic focused on a single design pattern, practice or idiom (see suggested talk format below). Each speaker may submit up to THREE talk topics (not all may be accepted if there are a lack of slots, so please rank them in order of preference). Please send your talk topics to me privately by email, only if sufficient numbers present to fill a session will your name and your talk topic be shared with the CppCon Programme Committee. We'll try to arrange a short panel session at the end so attendees can ask questions of the speakers. After the lightning talk we'll arrange a restaurant so all the speakers and any interested attendees can dine together, followed by a night in a Bellevue bar. If after the dust has settled it is felt there is a critical mass sufficient to reboot a brand shiny new edition of Boost, we'll start development! I should *stress* that it is up to the CppCon Programme Committee whether these lightning talks are approved or not. I'll just copy and paste your proposed talk to the CppCon PC as-is. If insufficient lightning talk topics are received by me to fill a 60 minute session, I'll withdraw this talk proposal from CppCon. Suggested talk format ================ Five minutes is not much time, so here is a suggested lightning talk outline: 1. A current widely practiced library design pattern (show example). 2. The problems it generates for library users or maintainers. 3. Your proposed alternative design pattern (show example). 4. The problems the alternative design pattern fixes. 5. Any mockup, prototype or even live demo (!) of the alternative design pattern in action. Suggested talk themes might be documentation, packaging, distribution, testing, tooling, quality assessment, barriers to entry, governance, strategy, important gaps in the standard libraries, automation and deprecation/removal policies. Here is an example of such a lightning talk: 1. Current design pattern: Library v1.00: namespace boost { namespace lib { void foo(size_t, char); } } User code: boost::lib::foo(100, 'n'); 2. Problem: Library v1.01: namespace boost { namespace lib { void foo(char, size_t); } } User code: boost::lib::foo(100, 'n'); // oh oh! 3. Alternative: Library v1.00: namespace boost { namespace lib { inline namespace v100 { void foo(size_t, char); } } } #define BOOST_LIB_NAMESPACE_V100 boost::lib::v100 Library v1.01: namespace boost { namespace lib { inline namespace v101 { void foo(char, size_t); } } } #define BOOST_LIB_NAMESPACE_V101 boost::lib::v101 User code: // Mount v100 of Boost.Lib into "lib" namespace lib=BOOST_LIB_NAMESPACE_V100; lib::foo(100, 'n'); // ABI stable! No ODR violation possible! 4. Problems fixed: a) Mixing incompatible versions of individual Boost libraries in the same process (or even translation unit) is now safe. b) Libraries can now depend on other libraries without worrying about breaking code which depends on them which uses a different version of the same dependency. This greatly helps reduce change ripple effects. c) Forward compatibility or alternative implementation shims are now very easy to implement e.g. library users can externally configure either Boost.Filesystem or std::experimental::filesystem for your library to use, your code simply refers to _some_ Filesystem TS implementation e.g. namespace filesystem = FILESYSTEM_TS_IMPLEMENTATION; filesystem::path mypath; -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/

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How to write one property page .props to select the right x86 or x64 Boost libraries folder automatically using Visual Studio
by Paul A. Bristow 22 May '16

22 May '16

I have downloaded the shiny new release boost_1_61_0_b1 and am trying to set up so that I can test a lot of Boost-ish console applications using both 32 and 64-bit. This is easier with bjam, but I'd like to use the Visual studio IDE too. I'd like a single property page that can be placed in the same folder as my .sln file and added to each and every project. (or better, made the default for all projects). I have a I:\boost_1_61_0_b1; as the include directory, and that is common to all configurations and platforms. But the libraries files are in two separate folders because the name does not yet include the platform :-( Linking to lib file: libboost_chrono-vc140-mt-gd-1_61.lib lib32-msvc-14.0 and lib64-msvc-14.0 Googling gives some suggestions to select the right folder for libraries, but I wonder if anyone has found a slick solution? (I'll edit the property xml if necessary - it would seem that the IDE GUI tool isn't up to the job?) Paul --- Paul A. Bristow Prizet Farmhouse Kendal UK LA8 8AB +44 (0) 1539 561830

5 5

Windows 10 and VC14, fixing C2117 error when using Asio.
by Andrew Maclean 21 May '16

21 May '16

If you find that when using Asio in Windows 10 with the Windows 10 SDK and Visual Studio 2015 you get lots of C2177 errors in winnt.h and sdkdkver.h then this should fix it: Essentially, just add: #define WINVER 0x0A00 #define _WIN32_WINNT 0x0A00 before any header that includes SDKDDKVer.h either directly or indirectly. If using CMake, then in the CMakeLists.txt file just add these lines: if(WIN32) add_definitions(-DWINVER=0x0A00) add_definitions(-D_WIN32_WINNT=0x0A00) endif() The fix is documented at https://msdn.microsoft.com/en-us/library/6sehtctf.aspx I hope this helps others. Regards Andrew -- ___________________________________________ Andrew J. P. Maclean ___________________________________________

1 0

[test] Standalone use with multiple translation units?
by Adam Nielsen 20 May '16

20 May '16

Hi all, I am currently using Boost Test for my test code, however it is always an extreme headache trying to get Boost available on the target platforms I'm using. At the moment due to some environment restrictions it is just not possible to use a recent version of Boost, and since the Test library broke backwards compatibility with 1.59, my code will no longer compile on versions earlier than 1.59. So I am looking to see whether I can avoid the need to compile the full Boost, and just pull in the bits that I need. The Boost Test docs say that the library can be used in single-header mode, however this only works when there is one translation unit. Since my tests are spread across dozens of files, I don't think this will work for me. Is there any way to use this single-header mode, and flag one file as the "primary" one, and others as extras, so that you can use single-header mode across multiple translation units? This would remove the need to do battle with getting the Boost libraries installed on various platforms, which would make it much easier and allow me to spend more time on my code, and less time on writing build scripts. Many thanks, Adam.

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[boost::compute] [OS X 10.11.5] [GeForce GT 750M] Segmentation fault
by Prashant 20 May '16

20 May '16

Hi, Example code to sort a vector on GPU (GeForce GT 750M) generates SEGV. However, it runs fine on Iris Pro (Intel(R) Core(TM) i7-4850HQ CPU). Having said that, it works as long as size of vector being sorted is small(<2 million). The code throws an exception if the size of the vector is less 9 million. Exception: boost/1_61_0/include/boost/compute/command_queue.hpp(453): Throw in function boost::compute::event boost::compute::command_queue::enqueue_write_buffer(const boost::compute::buffer &, size_t, size_t, const void *, const boost::compute::wait_list &) Dynamic exception type: boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector <boost::compute::opencl_error> > std::exception::what: Invalid Value Another observation: if the size of vector is 50 million the sorting works fine, though the timings are worse than Iris Pro. Regards, Prashant ----------------------------Cut here------------------------------------- #include <iostream> #include <vector> #include <algorithm> #include <boost/foreach.hpp> #include <boost/compute/core.hpp> #include <boost/compute/platform.hpp> #include <boost/compute/algorithm.hpp> #include <boost/compute/container/vector.hpp> #include <boost/compute/functional/math.hpp> #include <boost/compute/types/builtin.hpp> #include <boost/compute/function.hpp> #include <boost/chrono/include.hpp> #include <boost/exception/all.hpp> namespace compute = boost::compute; int main(int argc, char* argv[]) { if (argc != 2) { std::cout << "Usage: " << argv[0] << " <size> " << std::endl; return 0; } // generate random data on the host std::vector<float> host_vector(atoi(argv[1])); std::generate(host_vector.begin(), host_vector.end(), rand); std::cout << "===============CPU==================\n"; for (size_t k=0; k<5; k++) { std::vector<float> host_copy_vector(host_vector); auto start = std::chrono::high_resolution_clock::now(); std::sort(host_copy_vector.begin(), host_copy_vector.end()); auto duration = std::chrono::duration_cast<std::chrono::milliseconds> (std::chrono::high_resolution_clock::now() - start); std::cout << "time: iteration ("<< k << ") : " << duration.count() << " ms" << std::endl; } std::vector<compute::platform> platforms = compute::system::platforms(); for(size_t i = 0; i < platforms.size(); i++){ const compute::platform &platform = platforms[i]; std::cout << "Platform '" << platform.name() << "'" << std::endl; std::vector<compute::device> devices = platform.devices(); for(size_t j = 0; j < devices.size(); j++){ const compute::device &device = devices[j]; std::string type; if(device.type() & compute::device::gpu) type = "GPU Device"; else if(device.type() & compute::device::cpu) type = "CPU Device"; else if(device.type() & compute::device::accelerator) type = "Accelerator Device"; else type = "Unknown Device"; if (type != "GPU Device") { std::cout << "Ignoring non GPU devices.\n"; continue; } std::cout << "====\n"; std::cout << " " << type << ": " << device.name() << std::endl; std::cout << "====\n"; compute::context context(device); compute::command_queue queue(context, device); for (size_t k=0; k<5; k++) { compute::vector<float> device_vector(host_vector.size(), context); // copy data from the host to the device compute::copy( host_vector.begin(), host_vector.end(), device_vector.begin(), queue ); auto start = std::chrono::high_resolution_clock::now(); try { compute::sort(device_vector.begin(), device_vector.end(), queue); } catch (boost::exception & e) { std::cerr << diagnostic_information(e); break; } auto duration = std::chrono::duration_cast<std::chrono::milliseconds> (std::chrono::high_resolution_clock::now() - start); std::cout << "time: iteration ("<< k << ") : " << duration.count() << " ms" << std::endl; } std::cout << "====\n"; } } return 0; }

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Boost 1.61.0 has been released
by Rene Rivera 19 May '16

19 May '16

Release 1.61.0 of the Boost C++ Libraries is now available. These open-source libraries work well with the C++ Standard Library, and are usable across a broad spectrum of applications. The Boost license encourages both commercial and non-commercial use. This release contains four new libraries and numerous enhancements and bug fixes for existing libraries. New Libraries * Compute: Parallel/GPU-computing library, from Kyle Lutz. * DLL: Library for comfortable work with DLL and DSO, from Renato Tegon Forti and Antony Polukhin * Hana: A modern C++ metaprogramming library, from Louis Dionne. * Metaparse: A library for generating compile time parsers parsing embedded DSL code as part of the C++ compilation process, from Abel Sinkovics. For details, including download links, see http://www.boost.org/users/news/version_1.61.0 You can also download directly from SourceForge: http://sourceforge.net/projects/boost/files/boost/1.61.0/ Tom Kent has made pre-built windows binaries, and they are available at: https://sourceforge.net/projects/boost/files/boost-binaries/1.61.0/ To install this release on your system, see http://www.boost.org/doc/libs/release/more/getting_started/index.html Thanks, --The Boost release team Vladimir Prus Rene Rivera Marshall Clow Eric Niebler Daniel James Beman Dawes

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DMARC and mailman
by James Sharpe 19 May '16

19 May '16

In June 2016 gmail is going to be changing its DMARC policy to reject any unaligned mail. This means that we will be seeing any mailing list responses from a gmail.com address to be considered spam by any mail server that enforces DMARC. For a while now yahoo.com has had this policy turned on which has meant that yahoo.com addresses have been considered spam. Mailman has released a workaround in version 2.1.18: https://www.mail-archive.com/mailman-users@python.org/msg64098.html The boost mailing list is currently on mailman 2.1.15. I'd strongly suggest that this should be updated as a matter of urgency else we'll find a lot of the conversations on this list will end up in the spam folder... Regards, James

1 0

[boost::python] cannot concatenate 'str' and 'property' objects
by sergei nazarenko 19 May '16

19 May '16

Hello! I have just simple question. python code: a = A() bla = "lala" + a.pp *Traceback (most recent call last):TypeError: cannot concatenate 'str' and 'property' objects* Why it is not work? How make it is work? boost c++ code: #include <boost/python/module.hpp> #include <boost/python/def.hpp> #include <boost/python/class.hpp> #include <boost/python/init.hpp> class A { public: std::string pp; A(): pp("babla") {}; }; using namespace boost::python; BOOST_PYTHON_MODULE (test1) { class_<A> ("A") .def(py::init<>()) .add_property ("pp", &A::pp) ; } Thanks, Sergiy

1 0

Documentation for Boost Range
by Christian Aichinger 19 May '16

19 May '16

Boost Range is a cool library, but it's sometimes hard to see how to actually use it: which headers to include, how to call it, what the return types are. To improve this situation, I wrote full, self-contained code examples for each function in Boost Range. They are available at: https://greek0.net/boost-range The examples also include links to the official docs and the into the library's source code, as well as a list of headers that give access to a specific function. I hope it's useful for other people as well. If you have any ideas for improvement, please let me know. Kind regards, Chris

6 13

Blocking sockets on Windows
by William Riancho 18 May '16

18 May '16

Hello all, I try to implement a simple http server with blocking sockets on Windows. Basically, I have a simple server that just write data to a socket when a network connection occurs before exit. The problem is that the last "socket.send" as no effect if I don't delay the process exit. Writing to this socket is supposed to block until all the data as been written. I have tried to use the completion condition of write, to use the non_blocking method of the socket. I still get the same problem. Note that the problem doesn't occur on Linux. Here is the code: ``` #include <boost/asio.hpp> int main(int argc, char *argv[]) { char *address = "0.0.0.0"; char *port = "8180"; boost::asio::io_service io_service; boost::asio::ip::tcp::acceptor acceptor(io_service); boost::asio::ip::tcp::resolver resolver(io_service); boost::asio::ip::tcp::resolver::query query(address, port); boost::asio::ip::tcp::endpoint endpoint = *resolver.resolve(query); acceptor.open(endpoint.protocol()); acceptor.bind(endpoint); acceptor.listen(); boost::asio::ip::tcp::socket sock(io_service); acceptor.accept(sock); std::string body("Hello, World!"); sock.send(boost::asio::buffer(std::string("HTTP/1.1 200 OK\r\n"))); sock.send(boost::asio::buffer(std::string("Content-Length: ") + std::to_string(body.size()) + "\r\n\r\n")); sock.send(boost::asio::buffer(body)); Sleep(1000); // The body would not be sent without this return 0; } ```

2 1

Review Wizard Report for May 2016
by Ronald Garcia 18 May '16

18 May '16

============================================== Review Wizard Status Report for May 2016 ============================================== News ==== 1. Boost 1.58 Released April 2015. New Libraries: Endian, Sort 2. Metaparse Library Accepted 3. Hana Library Accepted 4. DLL Library Accepted 5. Http Library Rejected 6. Boost 1.59 Released August 2015. New Libraries: Coroutine2, Convert 7. AFIO Library Reviewed 8. Fiber Library Conditionally Accepted 9. Boost 1.60 Released December 2015. New Libraries: Variadic Macro Data 10. Quaternions, Vectors, Matrices Accepted 11. Fit Library Rejected 11. Boost 1.61 Released May 2016. New Libraries: Compute, DLL, Metaparse, Hana Open Issues =========== The following libraries have review managers, but have not yet been scheduled for review: * Range Extensions - added May 2012; review manager: Neil Groves. The following libraries have been reviewed and await reports from their review managers: * AFIO - reviewed August 2015; review manager: Ahmed Charles. The following libraries have been accepted to Boost, but have not yet been integrated into Boost Git: * Contract - accepted September 2012; author: Lorenzo Caminiti. * Quaternions,Vectors,Matrices - accepted December 2015; author: Emil Dotchevski The following libraries have been accepted and submitted to Boost Git, but have not yet appeared in a release: * none The following libraries have been accepted provisionally to Boost, but have not been submitted for mini-review and full acceptance: * none General Announcements ===================== As always, we need experienced review managers. 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 ubc dot ca" and "johnphillipsithica at gmail dot com" 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, 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) * Block Pointer (M) * Singularity (M) * Extended Complex Numbers (M) * Boost.Range Extensions * Nowide (M) * Array (M) * STL Extensions (M) * Countertree (M) * Process (M) * Application (M) * Edit Distance (M) * Mixin (M) * Dependency Injection (M) * Segmented Tree * Fiber ``(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. Block Pointer ------------- :Author: Phil Bouchard :Review Manager: Needed :Download: https://svn.boost.org/svn/boost/sandbox/block_ptr/ :Description: Deterministic memory manager of constant complexity capable of handling cyclic collections. Singularity ----------- :Author: Ben Robinson :Review Manager: Needed :Download: https://github.com/cppmaven/Singularity :Description: The Singularity Design Pattern allows you to restrict any class to a single instance. Unlike the infamous Singleton, Singularity gives you direct control over the lifetime of the object, does not require you to grant global access to the object, nor does it limit you to the default constructor for that object. Extended Complex Numbers ------------------------ :Author: Matthieu Schaller :Review Manager: Needed :Download: http://code.google.com/p/cpp-imaginary-numbers/ :Description: The library is an extension of the std::complex class addressing two issues: 1. The standard does not guaranty the behaviour of the complex class if instantiated with types other than float/double/long double. 2. Some calculation where pure imaginary numbers (i.e. multiples of sqrt(-1)) appear are unnecessarily slowed down due to the lack of support for these numbers. The code I submit contains two interleaved classes boost::complex and boost::imaginary which can be instantiated with any type T provided T overloads the usual arithmetic operators and some basic (real) mathematical functions depending on which complex function will be used. It is thus an extended version of Thorsten Ottosen's n1869 proposal (http://www.open-std.org/JTC1/SC22/WG21/docs/papers/2005/n1869.html) Range Extensions ---------------- :Author: Akira Takahashi :Review Manager: Neil Groves :Download: https://github.com/faithandbrave/OvenToBoost :Description: This project adds some features of the Oven Range Library to Boost.Range. Features: - Additional Range Adaptors (taken, taken_while, dropped, dropped_while, elements, elements_key, memoized, outdirected) - Extensions for using Lambda (regular function, regular operator) - Infinite Range (iteration function) - and additional range utilities. Nowide ------ :Author: Artyom Beilis :Review Manager: Needed :Download: http://cppcms.com/files/nowide/ :Description: This library makes cross platform Unicode aware programming easier. It provides an implementation of standard C and C++ library functions, such that their inputs are UTF-8 aware on Windows without requiring to use Wide API. Array ----- :Author: Brian Smith :Review Manager: Needed :Download: https://github.com/BrianJSmith/Array :Description: The array class is a C++11 compatible implementation of static multidimensional arrays. STL Extensions -------------- :Author: Vadim Stadnik :Review Manager: Needed :Download: https://github.com/vstadnik/stl_ext_adv_review :Description: The proposed library [stl_ext_adv] offers augmented array based B+ trees and STL containers that support the interfaces of the C++03 sequences and associative containers. The library offers a number of extensions and performance improvements that are not available in C++03 and C++11 standard containers. Countertree ----------- :Author: Francisco Jose Tapia :Review Manager: Needed :Download: https://dl.dropbox.com/u/8437476/works/countertree_code_doc.zip :Description: This library is an implementation of a binary red-black counter tree. This tree have an additional counter in each leaf. This permit the access to the elements by the position, like in a vector. It is a random access container with random access iterators. COUNTERTREE This kind of trees have an additional counter in each leaf. This permit the access to the elements by the position, like in a vector. It is a random access container with random access iterators. With unordered information we have a vector with the same speed inserting and deleting in any position (O(log N)). With ordered information, we have the classes set, multiset, map and multimap, with identical interface than the STL classes, with the plus of access to the elements by position, like in a vector. The iterators are random access , and you can subtract them. SUBALLOCATOR The suballocator is a layer between the allocator and the data structures, compatible with any allocator with the STL definition. The suballocator replace to the allocator in the allocation of equal size elements. It provides speed, return the unused memory and decrease the memory used by the program and improve the cache performance due to the data locality improvement ( 30% of improvement of speed respect the std::allocator with GCC 4.7) Process ------- :Author: Boris Schaeling :Review Manager: Needed :Download: http://www.highscore.de/boost/process0.5/process.zip :Description: Boost.Process is a library to manage system processes. It can be used to: * create child processes * setup streams for child processes * communicate with child processes through streams (synchronously or asynchronously) * wait for processes to exit (synchronously or asynchronously) * terminate processes Application ----------- :Author: Renato Tegon Forti :Review Manager: Needed :Download: https://github.com/retf/Boost.Application :Documentation: http://www.dokfile.com/appbeta4/docs/libs/application/doc/html/index.html :Description: Application provides an application environment, or start point to any people that want a basic infrastructure to build an system application on Windows or Unix Variants (e.g. Linux, MacOS). Application uses behaviours modeled using 'aspects' concept proposed by 'Vicente J. Botet Escriba', that allow easy extension and customization of library components. The application modes uses these components internally to achieve the user desirable behaviours. Application provide many useful ready-to-use features, e.g: * Run application as Windows Service; * Run application as UNIX/POSIX Daemon; * Plugin extension system; * Process(executable) Single instance Instantiation support; * Application SIGNAL/Callbacks customization; * Windows Service Setup feature; * And many others. Edit Distance ------------- :Author: Erik Erlandson :Review Manager: Needed :Download: https://github.com/erikerlandson/algorithm/tree/edit_distance/sequence :Description: The edit distance is the length of the shortest (or least-cost) edit script from one sequence to another, where an edit script is defined as a sequence of insertion, deletion and (optionally) substitution operations. The function implementing the edit distance is named edit_distance. This function will return the edit distance between two sequences, where sequences may be any valid range object supporting forward iteration. The edit_distance function will also, if requested, return the edit script. Mixin ----- :Author: Borislav Stanimirov :Download: https://github.com/iboB/boost.mixin :Documentation: http://ibob.github.io/boost.mixin/ :Review Manager: Needed :Description: Boost.Mixin is a library that allows the composition and modifications of polymorphic types at run time. Types and objects are constructed out of building blocks called mixins. The library uses the type boost::mixin::object as a placeholder, whose instances can be extended with existing classes (mixins), thus providing a particular instance with the functionality of all those types. Accessing the newly formed type's interface is made through messages: stand-alone functions generated by the library, which can be thought of as methods. This is given while also having full abstraction between the interface and the definition of types. An existing feature in another language similar to Boost.Mixin and also an inspiration for the library are the mixins in Ruby. The library also has similarities with the pattern entity-component-system. Dependency Injection -------------------- :Author: :Download: https://github.com/krzysztof-jusiak/di :Documentation: http://krzysztof-jusiak.github.io/di/boost/libs/di/doc/html :Incubator: http://rrsd.com/blincubator.com/bi_library/di-dependency-injection/?gform_p… :Review Manager: Needed :Description: Boost.DI is a dependency injection library improving manual dependency injection by simplifying object instantiation with automatic dependencies injection. Using Boost.DI has many advantages over manual dependency injection. * Reduce boilerplate code (No factories, no objects creation in specific order) * Reduce cost of maintenance effort (Constructor signature change won't affect di configuration) * Reduce testing effort * Give better control of what and how is created (Policies, Providers) * Give better understanding about objects hierarchy (UML Dumper) Segmented Tree -------------- :Author: Chris Clearwater :Download: http://rrsd.com/blincubator.com/bi_library/segmentedtreeseq-2/?gform_post_i… :Repository: http://github.com/det/segmented_tree :Documentation: https://det.github.io/segmented_tree :Review Manager: Glen Fernandes :Description: SegmentedTreeSeq is a sequence data structure like vector and deque that supports efficient random access insert and erase. It is implemented using B+Trees and has an emphasis on speed and a low memory overhead. Fiber ----- :Author: Oliver Kowalke :Download: https://github.com/olk/boost-fiber :Documentation: http://olk.github.io/libs/fiber/doc/html/ :Review Manager: Nat Goodspeed :Description: Boost.Fit is a header-only C++11/C++14 library that provides utilities for functions and function objects. Libraries under development =========================== See The Boost Library Incubator Project at http://blincubator.com for discussion of libraries currently under development.

3 2

Memory deallocation concerning boost::bind, boost::asio and shared_ptr
by Norman Kradepohl 17 May '16

17 May '16

Hi there, my code is allocating memory and never freeing it, even though it should (at least in my opinion). The header looks like this: typedef boost::asio::ssl::stream<boost::asio::ip::tcp::socket> sslSocket_t; class Object { boost::asio::io_service ioService_; boost::asio::ip::tcp::acceptor acceptor_; boost::asio::ssl::context context_; void functionOne(); void functionTwo(shared_ptr<sslSocket_t>& sslSocket, const boost::system::error_code& error) } And my source like this: void Object::functionOne() { for (int i = 0; i < 10; i++) { shared_ptr<sslSocket_t> sslSocket(new sslSocket_t(ioService_, context_)); acceptor_.async_accept(sslSocket->lowest_layer(), boost::bind(&Object::functionTwo, this, sslSocket, boost::asio::placeholders::error)); } acceptor_.cancel(); boost::asio::io_service::work work(ioService_); ioService_.run(); } void functionTwo(shared_ptr<sslSocket_t>& sslSocket, const boost::system::error_code& err) { // Do nothing } So when i call *Object.functionOne()*, memory is getting allocated to the *Object.ioService_* object, in order to be able to call the bound asynchronous method. Then after the loop, all pending asynchronous actions on the acceptor are getting canceled. The appropriate handler is getting invoked as soon as *Object.ioService_.run()* is called (i've been testing that). BUT for some reason, the allocated memory does not get freed. I'm stuck on this problem for a while now, any hint or help would be really appreciated. Btw.: I'm working on debian and looking at "/proc/self/status" -> "VmRSS" to whatch the used memory.

6 14

- Units presentation
by Roman Fratczak 17 May '16

17 May '16

Dears, How to "correctly" display an quantity units for "specific energy" in [kJ/kg] - always? Is there a method for preventing units simplification down to [m2/s2]? Regards Roman

1 0

[proto] grammar to match operator in expression
by Igor R 16 May '16

16 May '16

Hi, Why the following grammar doesn't match dereference, and what's the correct way to do this? Thanks! ////////////////// #include <iostream> #include <boost/proto/proto.hpp> namespace proto = boost::proto; using proto::_; struct has_deref : proto::or_< proto::dereference<_>, proto::nary_expr<_, proto::vararg<has_deref>> > {}; template<class Expr> void test_expr(const Expr &e) { proto::display_expr(e); std::cout << "matches? " << std::boolalpha << proto::matches<Expr, has_deref>::value << std::endl; } int main() { test_expr(proto::lit(1) + *proto::lit(2)); }

1 0

qx(3):
by Silviu P 16 May '16

16 May '16

http://www.granfoundation.org/hmmhjhm.php ***********************Neither a wise man or a _brave man lies down on the tracks of history to wait for the train of the future to run over him.Leana Fargo

1 0

[Boost.Container] Problems in Solaris trying to use class flat_set
by dariomt＠gmail.com 12 May '16

12 May '16

Hi all, Trying to compile the following program is problematic with the Solaris compiler. $ cat kk.cpp #include <boost/container/flat_set.hpp> Yes, it is just one line #include'ing flat_set.hpp - with Boost 1.55.0 the compiler ICE's on me :( $ CC -Iboost/1_55_0 -features=extensions -library=stlport4 kk.cpp >> Assertion: (../lnk/v2mangler.cc, line 776) while processing boost/1_55_0/boost/container/detail/utilities.hpp at line 1036. - and with Boost 1.59.0 I have a compile error: $ CC -Iboost/1_59_0 -features=extensions -library=stlport4 kk.cpp "boost/1_59_0/boost/container/throw_exception.hpp", line 112: Error: Cannot cast from const char* to std::out_of_range. "boost/1_59_0/boost/container/throw_exception.hpp", line 128: Error: Cannot cast from const char* to std::length_error. "boost/1_59_0/boost/container/throw_exception.hpp", line 145: Error: Cannot cast from const char* to std::logic_error. "boost/1_59_0/boost/container/throw_exception.hpp", line 161: Error: Cannot cast from const char* to std::runtime_error. "boost/1_59_0/boost/container/detail/copy_move_algo.hpp", line 997: Error: type is not a member of boost::move_detail::enable_if_c<0, void>. 5 Error(s) detected. Compiler version: $ CC -V CC: Sun C++ 5.10 SunOS_i386 Patch 128229-32 2013/12/04 Any clues?

2 1

Shared memory: private node allocator for a boost::unordered_map
by trafdev 12 May '16

12 May '16

Hello. I'm trying to use a private node allocator for an unordered_map placed in the shared memory: #include <boost/interprocess/managed_shared_memory.hpp> #include <boost/interprocess/containers/map.hpp> #include <boost/unordered_map.hpp> #include <boost/interprocess/allocators/allocator.hpp> #include <boost/interprocess/allocators/private_node_allocator.hpp> #include <functional> #include <utility> int main () { using namespace boost::interprocess; struct shm_remove { shm_remove() { shared_memory_object::remove("MySharedMemory"); } ~shm_remove(){ shared_memory_object::remove("MySharedMemory"); } } remover; managed_shared_memory segment (create_only ,"MySharedMemory" //segment name ,65536); //segment size in bytes typedef int KeyType; typedef float MappedType; typedef std::pair<const int, float> ValueType; typedef private_node_allocator<ValueType, managed_shared_memory::segment_manager> ShmemAllocator; typedef boost::unordered_map<KeyType, MappedType, boost::hash<KeyType>, std::equal_to<KeyType>, ShmemAllocator> MyMap; ShmemAllocator alloc_inst (segment.get_segment_manager()); MyMap *mymap = segment.construct<MyMap>("MyMap") //object name (3, boost::hash<KeyType>(), std::equal_to<KeyType>(), alloc_inst); for(int i = 0; i < 100; ++i){ mymap->insert(std::pair<const int, float>(i, (float)i)); } return 0; } It gives a compilation error: /usr/local/include/boost/unordered/detail/unique.hpp:30:43: error: no type named 'pointer' in 'boost::interprocess::private_node_allocator<boost::unordered::detail::unique_node<boost::interprocess::private_node_allocator<std::__1::pair<const int, float>, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0>, 0>, iset_index>, 64>, std::__1::pair<const int, float> >, boost::interprocess::segment_manager<char, boost::interprocess::rbtree_best_fit<boost::interprocess::mutex_family, boost::interprocess::offset_ptr<void, long, unsigned long, 0>, 0>, iset_index>, 64>' A, unique_node<A, T> >::type::pointer node_pointer; What am I doing wrong?

2 1

[boost.lockfree][spsc_queue] runtime sizing and producer's thread
by Sampath Tilakumara 12 May '16

12 May '16

Hi, Two questions on lockfree spsc_queue: 1. Can spsc_queue be dynamically (runtime) sized, and if so how do you correctly do it? * Creating a mpmc queue with size 0 (i.e. queue<T>(0)) creates a dynamically sizes mpmc queue, but doing the same for spsc queue doesn't. * creating a spsc queue with size 10 (i.e. queue<T>(10)) seems to create a fixed sized ring buffer since at high transfer rates, push fails, however the constructor code that takes the size asserts that it's runtime sized. explicit spsc_queue(size_type element_count): base_type(element_count) { BOOST_ASSERT(runtime_sized); } * documentation mentions lockfree::fixed_sized<> in policies, and can also be found in (mpmc) queue.hpp, but it doesn't seem to be in spsc_queue.hpp * all examples I could find on the internet (and documentation) was for fixed size or for mpmc dynamic, but not for spsc dynamic. 2. In a normal (spsc using) program the producer will be a single OS thread; however is it still safe to use on something like an actor framework or fiber framework? (i.e. you only have a single producer object, but it can actually be executed in different threads -- though strictly on one thread at any given time). for example in spsc_queue.hpp there's some code such as: bool push(T const & t, T * buffer, size_t max_size) { const size_t write_index = write_index_.load(memory_order_relaxed); // only written from push thread Refs on actors/fibers: https://en.wikipedia.org/wiki/Fiber_%28computer_science%29 https://en.wikipedia.org/wiki/Actor_model Thank you. Sampath Tilakumara

2 1

FindBoost.cmake does not check for include headers
by j.wuttke 11 May '16

11 May '16

As per cmake 3.5.1, FindBoost.cmake does not check for include headers. Therefore it will give false positives - if a Boost project that only consists of a header file is not installed - if only a libboost* is installed, but not the headers from the corresponding *-dev package. I raised this issue long ago on the cmake bug tracker, and recently again on the cmake mailing list, but got no response. Would perhaps somebody from the Boost community volunteer to look into this issue? Or has already looked into it and could tell us what the problem is?

3 4

Fwd: [proto][variant] variant crashes proto expression
by Igor R 11 May '16

11 May '16

The following code is a slightly modified Proto calc2 example. Instead of doubles I use variant<int, double>, and the expression is just _1 = _2. This code triggers assertion in variant/detail/forced_return.hpp, so it looks like some variant instance gets messed up. It happens when the value returned from proto::eval(*this, ctx) is being copied. It can be reproduced both with MSVC and gcc, with Boost 1.60. Is there any workaround for this issue? Thanks. ////////////// #include <iostream> #include <boost/proto/proto_typeof.hpp> #include <boost/proto/core.hpp> #include <boost/proto/context.hpp> #include <boost/variant.hpp> namespace proto = boost::proto; using proto::_; typedef boost::variant<int, double> var_t; template<typename Expr> struct calculator_expression; // Tell proto how to generate expressions in the calculator_domain struct calculator_domain : proto::domain<proto::generator<calculator_expression> > {}; // Will be used to define the placeholders _1 and _2 template<int I> struct placeholder {}; // Define a calculator context, for evaluating arithmetic expressions // (This is as before, in calc1.cpp) struct calculator_context : proto::callable_context< calculator_context const > { // The values bound to the placeholders var_t d[2]; // The result of evaluating arithmetic expressions typedef var_t result_type; explicit calculator_context(const var_t &d1 = var_t(), const var_t &d2 = var_t()) { d[0] = d1; d[1] = d2; } // Handle the evaluation of the placeholder terminals template<int I> result_type operator ()(proto::tag::terminal, placeholder<I>) const { return d[ I - 1 ]; } }; // Wrap all calculator expressions in this type, which defines // operator () to evaluate the expression. template<typename Expr> struct calculator_expression : proto::extends<Expr, calculator_expression<Expr>, calculator_domain> { explicit calculator_expression(Expr const &expr = Expr()) : calculator_expression::proto_extends(expr) {} BOOST_PROTO_EXTENDS_USING_ASSIGN(calculator_expression<Expr>) // Override operator () to evaluate the expression var_t operator ()() const { calculator_context const ctx; return proto::eval(*this, ctx); } var_t operator ()(const var_t &d1) const { calculator_context const ctx(d1); return proto::eval(*this, ctx); } var_t operator ()(const var_t &d1, const var_t &d2) const { calculator_context const ctx(d1, d2); return proto::eval(*this, ctx); } }; // Define some placeholders (notice they're wrapped in calculator_expression<>) calculator_expression<proto::terminal< placeholder< 1 > >::type> const _1; calculator_expression<proto::terminal< placeholder< 2 > >::type> const _2; // Now, our arithmetic expressions are immediately executable function objects: int main() { BOOST_PROTO_AUTO(expr, _1 = _2); var_t a1(1), a2(2.5); expr(a1, a2); return 0; }

1 0

openmpi with boost::log and some late endl
by Peter Vollmer 11 May '16

11 May '16

I'm working on some Linux systems and boost:log. More in detail: After replacing a handmade solution for logging with boost:log and running it with mpi on a single computer I can observe a strange behavior in console. Normally as i understand it, with autoflush turn on, after streaming a message into the logger it follows a flush followed by an endl and flush. At my scenario after streaming messages on different mpi processes, it seem that the system make a thread change right after flushing my message not after the endl flush. The missing automatic endl isn't lost it will be printed directly after or later but it will be printed. One indication that it has to be a thread change of the system is that an increase of the usable mpi processes increases the presents dramatically. For example on 4 core 8 thread system it occurs with 4 mpi processes something around 1 or 2 times, with 8 it occurs more than 20 times. Is there a solution to prevent this? Thanks Peter

1 0

[proto][spirit] parsing into proto expressions
by Igor R 11 May '16

11 May '16

Hi, Long story short: I would like to create proto expressions at run-time using spirit parsers. Would it be possible? More in details: I'd like to parse disassembler output, creating proto expression template for instruction and its operands. Lets assume we define proto expressions that would allow to express the following asm: "lea eax, [ebx + 2 * ecx]" like this: BOOST_PROTO_AUTO(lea_instr, eax = &*(ebx + 2 * ecx)); // registers and immediates are proto terminals Of course, we can't write such an expression in C++ code, because the actual operands get known after the asm string is parsed. So we can express any "lea" in the code (at compile-time) in a more general form, using placeholders: _1 = &_2; Then, when the parser matches "lea", we need to parse and create at run-time the actual operands, i.e. to substitute _1 with eax and _2 with *(ebx + 2 * ecx). I'd appreciate any pointer! Thanks.

2 2

mpfr_float stack allocation
by Daniel Brake 10 May '16

10 May '16

Hi Boost Users, I use Boost.Multiprecision's wrappers for MPFR, particularly the boost::multiprecision::mpfr_float. I've had good success with this library and its types so far, enjoying performance gains because of expression templates, and easy access to mpfr and gmp for floats, ints, and rationals. However, in my complex number type, I am struggling with named real temporaries in arithmetic operators. I am looking for help with multiplication, and I can generalize to all other operations needing a real temporary later. Here's my current code for multiplication, implemented in terms of *=. /** Complex multiplication. uses a single temporary variable 1 temporary, 4 multiplications */ complex& operator*=(const complex & rhs) { mpfr_float re_cache(real_*rhs.real_ - imag_*rhs.imag_); // cache the real part of the result imag_ = real_*rhs.imag_ + imag_*rhs.real_; real_ = re_cache; return *this; } I am using the naive evaluation formula, for better or worse. But the particular method of evaluation doesn't matter to me right now, it's the temporary variable re_cache used to cache the real part is killing me. Profiling using Allinea, gprof, and Callgrind reveals that a significant percentage of time in the program is consumed creating and destroying re_cache, as well as other temporaries scattered throughout my code. In an effort to eliminate heap allocations, I first tried replacing my using mpfr_float = boost::multiprecision::number<boost::multiprecision::mpfr_float_backend<0,boost::multiprecision::allocate_dynamic>, boost::multiprecision::et_off>; with allocate_stack, just for these named temporary variables. However, the documentation <http://www.boost.org/doc/libs/1_60_0/libs/multiprecision/doc/html/boost_mul…> states that allocate_stack only works in fixed precision, so the 0 digits indicating variable precision should cause problems? I expected 0 digits to fail to compile, but compile it does. The conversion from the type with allocate_stack to allocate_dynamic is not provided by the = operator, so I can write re_cache.convert_to<mpfr_float_dynamic>(). But using variable precision with stack allocation appears to cause all sorts of problems. Everything depending on complex multiplication in my program breaks, indicated by massive failures in my test suite. Thus, I currently regard allocate_stack as a non-solution. My question fundamentally regards how to deal with re_cache and the *= operator for complex multiplication. Anyone have ideas on how to get rid of constant heap de/allocation of re_cache without inducing a ton more arithmetic? Using a static for it is not a solution, both because I anticipate multithreading in this application in the future, and the fact that precision will vary though the run, so I'd have to check the precision of re_cache on every evaluation. The C version of the program I am re-implementing used OpenMP for threads, and used a thread-id-indexed global for re_cache. That solution then forces OpenMP onto anyone wanting to use the complex class in multiple threads. Hence, I view this as a non-solution, too. Again, my initial thought was 'heap allocation is the problem here, so I'll use the stack allocated backend'. But variable precision doesn't appear to work with allocate_stack. And statics are no good. Any thoughts? Thanks for your time, Daniel Brake Postdoc University of Notre Dame Applied and Computational Math and Stats

2 1

Re: [Boost-users] [boost] Boost 1.61.0 Release Candidate 2
by Marshall Clow 09 May '16

09 May '16

On Sat, May 7, 2016 at 4:31 AM, Vladimir Prus <vladimir.prus(a)gmail.com> wrote: > > The second release candidates for the 1.61.0 release are now available at: > > http://boost.cowic.de/rc/boost_1_61_0_rc2.zip > http://boost.cowic.de/rc/boost_1_61_0_rc2.7z > http://boost.cowic.de/rc/boost_1_61_0_rc2.tar.bz2 > http://boost.cowic.de/rc/boost_1_61_0_rc2.tar.gz > > The SHA256 checksums are as follows: > > fa1c34862b7ba8674ed6e064a14667a11830c6252f702d9458451834b74f7815 > boost_1_61_0_rc2.7z > a547bd06c2fd9a71ba1d169d9cf0339da7ebf4753849a8f7d6fdb8feee99b640 > boost_1_61_0_rc2.tar.bz2 > a77c7cc660ec02704c6884fbb20c552d52d60a18f26573c9cee0788bf00ed7e6 > boost_1_61_0_rc2.tar.gz > 02d420e6908016d4ac74dfc712eec7d9616a7fc0da78b0a1b5b937536b2e01e8 > boost_1_61_0_rc2.zip > > The changes relative to RC1 are MSVC fixes for signals2 and graph > libraries. > > As always, the release managers would appreciate it if you download > the candidate of your choice and give building it a try. Please report > both success and failure, and anything else that is noteworthy. > > I successfully built the .bz2 release with Apple's clang with C++03/11/14/1z. -- Marshall

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Boost ASIO steady_timer and date change
by Sabino Colonna 09 May '16

09 May '16

Hello, I'm using a steady_timer to perform an asynchronous wait in the following manner: boost::asio::io_service io_service; boost::asio::steady_timer my_timer(io_service); void onTimeout(const boost::system::error_code& e) { // Print something } ... my_timer.expires_from_now(std::chrono::seconds(600)); my_timer.async_wait(onTimeout); io_service.run(); If system 'date' does not change, everything is ok. But if I change 'date' by hand while the timer is running, it expires before 600 seconds (more or less after 5 minutes) and 'onTimeout' is called. With synchronous wait, all is ok. According to documentation, steady_timer should not be affected by time change. Which may be the problem? Thanks, Sabino

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Re: [Boost-users] Compiler limitation (MSVS 2015 update 2) or real error using boost::async?
by James Swift 06 May '16

06 May '16

Hi, in case anyone wants to play with the example I provided but doesn't have access to MSVC you can do so online here. http://rextester.com/BAX37541 kind regards, James

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converting to float128 from double
by Cooper, Bridgette R D 04 May '16

04 May '16

Hi, I have a function that takes as an argument a vector of doubles and tries to convert it to a vector of float128. When I accumulate the values in the float128 vector it looks like it does double additions and only casts up at the last step. The initial vector is defined as const std::vector<double> The float128 vector is defined as std::vector<float128> epoint(num) And I try to do the casting (inside a loop) via: epoint.at(i)=(float128(e8.at(i))); If I do the accumulation on the original vector with no casting into a float128, I get the same as accumulating the vector that should be of float128 type. How should I be doing the casting? Thanks,

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Compiler limitation (MSVS 2015 update 2) or real error using boost::async?
by James Swift 04 May '16

04 May '16

Hi, I'm getting an error with the following code only with Visual C++. (VS 2015 update 2. I also tried preview of VS 15 but it's the same) Clang and GCC are OK with this but perhaps VS is just more strict but correct? The error is deep in boost internals and I can't work out which object is move only and/or has it's copy constructor deleted or if it's true at all! Any help greatly appreciated. kind regards, James Swift --------------------------------- #define BOOST_THREAD_PROVIDES_FUTURE #define BOOST_THREAD_PROVIDES_FUTURE_CONTINUATION #define BOOST_THREAD_PROVIDES_EXECUTORS #include <boost/thread/future.hpp> class TestEx { public: void submit(std::function<void()>) { } bool try_executing_one() { return false; } bool closed() { return false; } void close() { } }; int main() { TestEx tex; boost::async( tex, [](){}); return 0; } ----------------------------------- 1>------ Build started: Project: BoostFuture, Configuration: Debug Win32 ------ 1> BoostFuture.cpp 1>c:\users\james\documents\visual studio 2015\projects\boostfuture\boostfuture\boost_1_60\boost\thread\future.hpp(3801): error C2280: 'boost::detail::invoker<main::<lambda_4383c995bef90b35d4f40a119c795fc2>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>::invoker(const boost::detail::invoker<main::<lambda_4383c995bef90b35d4f40a119c795fc2>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type> &)': attempting to reference a deleted function 1> c:\users\james\documents\visual studio 2015\projects\boostfuture\boostfuture\boost_1_60\boost\thread\detail\invoker.hpp(731): note: compiler has generated 'boost::detail::invoker<main::<lambda_4383c995bef90b35d4f40a119c795fc2>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>::invoker' here 1> c:\users\james\documents\visual studio 2015\projects\boostfuture\boostfuture\boost_1_60\boost\thread\future.hpp(3800): note: while compiling class template member function 'boost::detail::shared_state_nullary_task<Rp,Cont>::shared_state_nullary_task(const boost::detail::shared_state_nullary_task<Rp,Cont> &)' 1> with 1> [ 1> Rp=Rp 1> ] 1> c:\program files (x86)\microsoft visual studio 14.0\vc\include\xutility(287): note: see reference to function template instantiation 'boost::detail::shared_state_nullary_task<Rp,Cont>::shared_state_nullary_task(const boost::detail::shared_state_nullary_task<Rp,Cont> &)' being compiled 1> with 1> [ 1> Rp=Rp 1> ] 1> c:\users\james\documents\visual studio 2015\projects\boostfuture\boostfuture\boost_1_60\boost\thread\future.hpp(3858): note: see reference to class template instantiation 'boost::detail::shared_state_nullary_task<Rp,Cont>' being compiled 1> with 1> [ 1> Rp=Rp 1> ] 1> c:\users\james\documents\visual studio 2015\projects\boostfuture\boostfuture\boost_1_60\boost\thread\future.hpp(3873): note: see reference to function template instantiation 'void boost::detail::future_executor_shared_state<Rp>::init<T,Executor>(Executor &,Fp &&)' being compiled 1> with 1> [ 1> Rp=Rp, 1> T=boost::detail::invoker<main::<lambda_4383c995bef90b35d4f40a119c795fc2>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>, 1> Executor=TestEx, 1> Fp=boost::detail::invoker<main::<lambda_4383c995bef90b35d4f40a119c795fc2>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type> 1> ] 1> c:\users\james\documents\visual studio 2015\projects\boostfuture\boostfuture\boost_1_60\boost\thread\future.hpp(3873): note: see reference to function template instantiation 'void boost::detail::future_executor_shared_state<Rp>::init<T,Executor>(Executor &,Fp &&)' being compiled 1> with 1> [ 1> Rp=Rp, 1> T=boost::detail::invoker<main::<lambda_4383c995bef90b35d4f40a119c795fc2>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>, 1> Executor=TestEx, 1> Fp=boost::detail::invoker<main::<lambda_4383c995bef90b35d4f40a119c795fc2>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type> 1> ] 1> c:\users\james\documents\visual studio 2015\projects\boostfuture\boostfuture\boost_1_60\boost\thread\future.hpp(3964): note: see reference to function template instantiation 'boost::future<void> boost::detail::make_future_executor_shared_state<Rp,boost::detail::invoker<main::<lambda_4383c995bef90b35d4f40a119c795fc2>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type>,Executor>(Executor &,Fp &&)' being compiled 1> with 1> [ 1> Executor=TestEx, 1> Fp=boost::detail::invoker<main::<lambda_4383c995bef90b35d4f40a119c795fc2>,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type,boost::tuples::null_type> 1> ] 1> c:\users\james\documents\visual studio 2015\projects\boostfuture\boostfuture\boostfuture.cpp(34): note: see reference to function template instantiation 'boost::future<void> boost::async<TestEx,main::<lambda_4383c995bef90b35d4f40a119c795fc2>>(Executor &,F &&)' being compiled 1> with 1> [ 1> Executor=TestEx, 1> F=main::<lambda_4383c995bef90b35d4f40a119c795fc2> 1> ] ========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========

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udp::endpoint - port change
by Alexander Carôt 04 May '16

04 May '16

Hello all, probably trivial but I am currently stuck with this: I create a UDP endpoint via udp::resolver::query query(udp::v4(),IP,port); destinationEndpoint = new udp::endpoint(*resolver.resolve(query)); but after the creation I want to change the port without deleting and recreating it with different parameters. How can I do this ? Thanks in advance, best Alex

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Re: [Boost-users] Extending boost graph edge class
by Rafael Gasperetti 03 May '16

03 May '16

Hi, The third option fit in my case. I haver a class that I need to be the edge of the graph, and i have another one that I need to be the vertex. Using this way, My classes Can be used inside the graph to calculate distance, scc, etc. Thanks,Rafael -------- Mensagem original -------- De : Daniel Hofmann <daniel(a)trvx.org> Data: 03/05/2016 19:23 (GMT-03:00) Para: boost-users(a)lists.boost.org Assunto: Re: [Boost-users] Extending boost graph edge class Can you elaborate on "extend the edge class"? Here are some possible interpretations: 1/ You want to optimize the memory consumption for large graphs. The edges and vertices still fit into uint32_t: using graph_t = compressed_sparse_row_graph<directedS, no_property, no_property, no_property, uint32_t /* Vertex */, uint32_t /* EdgeIndex */>; 2/ You want to store arbitrary metadata on your edges and retrieve this edge data based on your graph and a specific edge descriptor: struct edge_data_t { int distance = 0; }; using graph_t = compressed_sparse_row_graph<directedS, no_property, edge_data_t>; // .. auto duration = [&graph](auto edge) { return graph[edge].duration; }; auto total = accumulate(edges(graph) | transformed(duration), 0); This example is using "bundled properties". There is also the possibility to store edge data external to the graph and not couple the edge data's lifetime with the graph (e.g. if you need edge weights for a particular algorithm in your use-case). 3/ You want to provide your own graph representation and make it a model for the BGL graph concepts: http://www.boost.org/doc/libs/1_60_0/libs/graph/doc/leda_conversion.html http://www.boost.org/doc/libs/1_60_0/libs/graph/doc/graph_concepts.html Here are some more BGL examples that should get you started: https://github.com/daniel-j-h/cppnow2016 Cheers, Daniel J H On 05/03/2016 08:37 AM, Rafael Gasperetti wrote: > > > Hi, > My name is Rafael and I need to extend the edge class of de graph part > of the boost lib, but I always find problems trying to do this. Can you > help me with examples and explanations about how to do this? > I read a lotação of places trying to do this but no help was found, > please help me. > > Thanks a lot, > Rafael > > > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users > _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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Extending boost graph edge class
by Rafael Gasperetti 03 May '16

03 May '16

Hi,My name is Rafael and I need to extend the edge class of de graph part of the boost lib, but I always find problems trying to do this. Can you help me with examples and explanations about how to do this?I read a lotação of places trying to do this but no help was found, please help me. Thanks a lot,Rafael

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[boost.multiprecision] print cpp_int with a thousands separator
by Tassilo Glander 03 May '16

03 May '16

Dear List, how can I control the thousands separator behavior when streaming a cpp_int to std::cout? I think it is not possible without changing the global locale, as cpp_int.str uses lexical_cast, which uses the global locale object to read the thousands separator character. This prevents me from having a custom formatting like below. Is there another way? Best, Tassilo #include <iostream> #include <locale> #include <iomanip> int main() { struct my_numpunct : std::numpunct<char> { protected : virtual char do_thousands_sep() const override { return '.' ; } virtual std::string do_grouping() const override { return "\03" ; } }; cpp_int testNum(1000); std::cout.imbue( std::locale( std::cout.getloc(), new my_numpunct ) ) ; std::cout << testNum << '\n' ; // still get 1000, desired is 1.000 }

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Multiprecision vector pass to function by reference
by Cooper, Bridgette R D 02 May '16

02 May '16

Hi, I am having some difficulties passing a vector of type std::vector<float128> to a function. I'm getting multiple errors out. The first few of which are: tql2.cpp:13:50: error: 'float128' was not declared in this scope void tql2(const int nm, int n, const std::vector<float128> & d, const std::vector<float128> & e, const std::vector< std::vector<float128> > & z, int ierr) ^ tql2.cpp:13:50: note: suggested alternative: In file included from tql2.cpp:1:0: /home/bcooper/Tarballs/boost_1_57_0/boost/multiprecision/float128.hpp:124:42: note: 'boost::multiprecision::float128' typedef number<float128_backend, et_off> float128; ^ tql2.cpp:13:58: error: template argument 1 is invalid void tql2(const int nm, int n, const std::vector<float128> & d, const std::vector<float128> & e, const std::vector< std::vector<float128> > & z, int ierr) ^ tql2.cpp:13:58: error: template argument 2 is invalid tql2.cpp:13:83: error: 'float128' was not declared in this scope void tql2(const int nm, int n, const std::vector<float128> & d, const std::vector<float128> & e, const std::vector< std::vector<float128> > & z, int ierr) ^ tql2.cpp:13:83: note: suggested alternative: In file included from tql2.cpp:1:0: /home/bcooper/Tarballs/boost_1_57_0/boost/multiprecision/float128.hpp:124:42: note: 'boost::multiprecision::float128' typedef number<float128_backend, et_off> float128; ^ The first few lines of my code are: #include <boost/multiprecision/float128.hpp> #include <boost/math/cstdfloat/cstdfloat_types.hpp> #include <boost/math/cstdfloat/cstdfloat_limits.hpp> #include <boost/math/cstdfloat/cstdfloat_cmath.hpp> #include <boost/math/cstdfloat/cstdfloat_iostream.hpp> extern "C"{ #include <quadmath.h> } #include <iostream> #include <vector> #include <iterator> void tql2(const int nm, int n, const std::vector<float128> & d, const std::vector<float128> & e, const std::vector< std::vector<float128> > & z, int ierr) { using namespace boost::multiprecision; ... } Not sure where I am going wrong? Any advice? Thanks,

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Re: [Boost-users] [boost.multiprecision] export_bits throws on a negative
by Tassilo Glander 02 May '16

02 May '16

Hi John, I opened tickets to track both issues: - Ticket #12170 (new Bugs) boost::multiprecision::export_bits throws on a negative cpp_int number - Ticket #12171 (new Feature Requests) boost::multiprecision should provide a hash function Best, Tassilo

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boost log facility multithreading issue
by David Frank 01 May '16

01 May '16

Greetings,I have 4 threads, in each thread, I created its own log file using boost log facility, different from the ones in other thread.The problem is that the log entries I put into one file in one thread, got into all other log files in other threads, though the boost log instances are not shared among threads. Anyone know how to avoid this? Thanks, David

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boost/multiprecision/float128
by Cooper, Bridgette R D 01 May '16

01 May '16

I'm new to boost. I am trying to use the float128 type for calculating sqrts as a larger part of code, however I am not sure the values obtained are accurate to float128 precision. I have tried running the example for printing log(2) found here, I find the same for sqrt: http://www.boost.org/doc/libs/1_57_0/libs/multiprecision/doc/html/boost_mul… However, the value printed log(2) only agrees to 16 decimal places, i.e. double precision. The value I obtain is 0.693147180559945286226763982995180413 rather than 0.693147180559945309417232121458176575 I'm using: g++ (GCC) 4.8.2 20140120 (Red Hat 4.8.2-15) with boost 1.57.0. Any advice as to what I am doing incorrectly? My compile line is: g++ -I ~/$BOOSTLIB new.cpp -lquadmath -o new Thanks,

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