November 2021 - Boost - lists.boost.org

Re: [boost] boost.spawn: review requested
by Boris Kolpackov 30 Nov '21

30 Nov '21

Oliver Kowalke <oliver.kowalke(a)gmail.com> writes: > Am Mo., 29. Nov. 2021 um 15:54 Uhr schrieb Boris Kolpackov < > boris(a)codesynthesis.com>: > > > FWIW (and I may be out of context), but "spawn" seems like a > > too generic of a name. I, for example, thought this is about > > posix_spawn(). Maybe call it spawn_fiber or some such? > > > > boost.asio named the function spawn() - boost.spawn named it spawn_fiber() Sorry, looks I wasn't clear enough: I am talking about the library name being too generic: Boost.Spawn can mean spawning all kinds of things (processes, threads, fibers, etc). The fact that you called the function spawn_fiber() in a sense confirms this.

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[fusion] add support for view construction from movable view
by herve martin 28 Nov '21

28 Nov '21

Hi, When working with view of boost::fusion I feel something frustrated because of the limited set of possible constructors. Indeed, apart from copy constructor, views usually only provide constructors taken l-value reference on sequence as input. I would like to extend the constructors set of views with some new ones which would also accept r-value references on view as input. This would allow some fancy combination at construction time as for example: vector <https://www.boost.org/doc/libs/1_77_0/libs/fusion/doc/html/fusion/container…><bool> v0(true);vector <https://www.boost.org/doc/libs/1_77_0/libs/fusion/doc/html/fusion/container…><int, char> v1(3, 'x');vector <https://www.boost.org/doc/libs/1_77_0/libs/fusion/doc/html/fusion/container…><std::string, int> v2("hello", 123); using view1 = joint_view< vector <https://www.boost.org/doc/libs/1_77_0/libs/fusion/doc/html/fusion/container…><int, char> , vector <https://www.boost.org/doc/libs/1_77_0/libs/fusion/doc/html/fusion/container…><std::string, int>>;using view = joint_view< vector <https://www.boost.org/doc/libs/1_77_0/libs/fusion/doc/html/fusion/container…><bool> , view1>; view aview = view(v0, view1(v1, v2));std::cout << aview << std::endl; I would be glad to contribute to the boost library by updating the boost::fusion views with some new constructors bu I'm not familiar with development in boost. What would be the next step to give a chance to my proposal to integrate boost ? Best regards, Herve

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Adding my sorting algorithm, ska_sort, to boost, attempt 2
by Malte Skarupke 24 Nov '21

24 Nov '21

Hi everyone, I started a discussion about this in October, but at the time the maintainer of the sort library was busy, then I was busy, so now it's January... I wrote a generalized version of radix sort a couple years ago and gave a talk about it here: https://www.youtube.com/watch?v=zqs87a_7zxw I would like to get a new version of that sorting algorithm into boost. It's faster than what I showed several years ago. It's also even more general and has a new interface that should be easier to extend. I uploaded the code here: https://github.com/skarupke/sort/tree/master The documentation is also already updated with new benchmark results. Let me know what's required to get this into boost. Would you like this in the form of a pull request? One of the big things that probably needs review is the interface, since radix sorting works differently than comparison based sorting. For most normal uses you just need to provide a sort key, but more complicated cases can get more complicated. I tried very hard to make everything easy, but I'd also be curious if others can come up with better ways of doing the interface. Thanks, Malte -- Malte Skarupke malteskarupke(a)fastmail.fm

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[release] 1.78.0 post-beta merges
by Oliver Kowalke 20 Nov '21

20 Nov '21

Hi, I'd like to merge several fixes for boost.context, boost.coroutine, boost.coroutine2 and boost.fiber to branch master. Oliver

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Boost::any bad_any_cast issue
by rajesh daggumati 18 Nov '21

18 Nov '21

Hi Team, While doing typecasting from boost::any to DecodeErrorPayload_t, its throwing bad_any_cast .. class RegisterIONotification { public: enum NotifyType { TypeUnknown, TypeRegTx, TypeRegRx, TypeDecodeError }; NotifyType Type; boost::any Payload; typedef boost::tuple<std::string, BinaryBuffer_t> DecodeErrorPayload_t; RegisterIONotification(NotifyType type;,boost::any payload) { Type(type); Payload(payload); } }; I have called RegisterIONotification from other class function. void RegisterIOThreaded::OnDecodeError( const std::string& error, BinaryBuffer_t data ) { RegisterIONotification notify(RegisterIONotification::TypeDecodeError ,make_tuple(error, data)); ..... .... ... } While testing, I am getting bad_any_cast exception. TEST_F(...,...) { RegisterIONotification notify = sink.GetDataById(ID::NOTIFY_COMMS_STATUS, 0).GetValue<RegisterIONotification>(); ASSERT_EQ(RegisterIONotification::TypeDecodeError, notify.Type); //passed RegisterIONotification::DecodeErrorPayload_t payload; ASSERT_NO_THROW(payload = boost::any_cast<RegisterIONotification::DecodeErrorPayload_t>(notify.Payload));// Here its got failed…Please help me to fix this. } Regards, Rajesh D

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ASIO problem with boost 1.78.0.beta1 ?
by Stefan Heinzmann 13 Nov '21

13 Nov '21

Hi all, I'm observing a problem with boost::asio that has surfaced with the newest beta relative to version 1.77.0, using MSVC 16.11.6. I'm getting the following errors: 1>...src\libs\asio\include\boost/asio/impl/any_io_executor.ipp(26,18): error C2039: 'any_io_executor': is not a member of 'boost::asio::executor' 1>...src\libs\asio\include\boost/asio/executor.hpp(48): message : see declaration of 'boost::asio::executor' 1>...src\libs\asio\include\boost/asio/impl/any_io_executor.ipp(26,34): error C2059: syntax error: ')' 1>...src\libs\asio\include\boost/asio/impl/any_io_executor.ipp(28,1): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int ...and so on. The errors seem rather weird to me, so I might be doing something wrong myself, but the exact same code compiles fine with 1.77.0, using the same compiler. Has anyone got an idea what's wrong? Should I raise an issue in github? Cheers Stefan Heinzmann

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union support in describe
by Gero Peterhoff 12 Nov '21

12 Nov '21

Hello, first of all, thank you very much for the great work. But I miss the support for unions. Is that correct? namespace boost { namespace describe { #define BOOST_DESCRIBE_UNION(C, Public) \ static_assert(std::is_union<C>::value, "BOOST_DESCRIBE_UNION should only be used with union types"); \ BOOST_DESCRIBE_PUBLIC_MEMBERS_(C BOOST_DESCRIBE_PP_UNPACK Public) \ BOOST_DESCRIBE_PROTECTED_MEMBERS_(C) \ BOOST_DESCRIBE_PRIVATE_MEMBERS_(C) } // describe } // boost This version only supports public members. I also miss the support for std::get. Is that correct? namespace boost { namespace describe { #define BOOST_DESCRIBE_GET(C) \ template <std::size_t Index> \ inline constexpr const auto& get(const C& arg) noexcept \ { \ static_assert(std::is_class<C>::value || std::is_union<C>::value, "BOOST_DESCRIBE_GET should only be used with class, struct or union types"); \ using members = boost::describe::describe_members<C, boost::describe::mod_any_access>; \ static_assert(Index < boost::mp11::mp_size<members>()); \ return arg.*boost::mp11::mp_at_c<members, Index>().pointer; \ } \ template <std::size_t Index> \ inline constexpr auto& get(C& arg) noexcept \ { \ static_assert(std::is_class<C>::value || std::is_union<C>::value, "BOOST_DESCRIBE_GET should only be used with class, struct or union types"); \ using members = boost::describe::describe_members<C, boost::describe::mod_any_access>; \ static_assert(Index < boost::mp11::mp_size<members>()); \ return arg.*boost::mp11::mp_at_c<members, Index>().pointer; \ } } // describe } // boost However, the access rights are not taken into account. E.g.: struct A { int i; float f; }; BOOST_DESCRIBE_STRUCT(A, (), (i, f)) namespace std { BOOST_DESCRIBE_GET(A) } // std This also solves a very special problem, provided the compiler supports it: active member of a constexp union. Problem: union U { int64_t i; double d; }; constexpr U u{.d{3.1415}}; constexpr auto i=u.i; -> error In short: namespace std { template <typename Type> inline constexpr bool is_constant_initialized(const Type& arg) noexcept { #if __has_builtin(__builtin_constant_p) return __builtin_constant_p(arg); #elif defined(BOOST_MSVC) ??? #else static_assert(false, "is_constant_initialized not supportet"); return false; #endif } template <typename Type> inline constexpr bool is_constant_initialized_front(const Type& arg) noexcept { return is_constant_initialized(arg); } template <typename Type, size_t Size> inline constexpr bool is_constant_initialized_front(const Type(&arg)[Size]) noexcept { static_assert(Size > 0); return is_constant_initialized(arg[0]); } template <typename Type, size_t Size> inline constexpr bool is_constant_initialized_front(const std::array<Type, Size>& arg) noexcept { static_assert(Size > 0); return is_constant_initialized(arg[0]); } } // std namespace boost { namespace describe { template <typename Type> inline constexpr std::size_t active_index(const Type& arg) noexcept { static_assert(std::is_union_v<Type>); using any = describe_members<Type, mod_any_access>; std::size_t result{0}, index{0}; bool first{true}; boost::mp11::mp_for_each<any>([&](const auto& desc) constexpr noexcept { const auto& elem{arg.*desc.pointer}; if (std::is_constant_initialized_front(elem)) { if (first) { first = false; result = index; } } ++index; }); return first ? 0 : result; } template <auto Value> inline constexpr std::size_t active_index_v = std::integral_constant<std::size_t, active_index(Value)>::value; } // describe } // boost union __mm128_emu { float m128_f32[4]; double m128_f64[2]; int64_t m128_i64[2]; int32_t m128_i32[4]; int16_t m128_i16[8]; int8_t m128_i8[16]; uint64_t m128_u64[2]; uint32_t m128_u32[4]; uint16_t m128_u16[8]; uint8_t m128_u8[16]; }; BOOST_DESCRIBE_UNION(__mm128_emu, (m128_f32, m128_f64, m128_i64, m128_i32, m128_i16, m128_i8, m128_u64, m128_u32, m128_u16, m128_u8)) namespace std { BOOST_DESCRIBE_GET(__mm128_emu) } // std constexpr __mm128_emu m128{.m128_u32{4711}}; constexpr auto arr = std::to_array(std::get<boost::describe::active_index_v<m128>>(m128)); // works with gcc, clang, intel Do you have an idea how to implement __builtin_constant_p for all compilers? thx Gero

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Update on the 1.78.0 beta
by Marshall Clow 11 Nov '21

11 Nov '21

The beta was supposed to be released yesterday. It’s done, but there’s an issue on Jfrog that seems to make it hard to download. I’m talking to the JFrog folks to get this resolved, and when that’s done, I’ll announce that the beta is released. — Marshall

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[release] Boost 1.78.0 Beta 1 Release Candidate 1 is available
by Marshall Clow 09 Nov '21

09 Nov '21

The first release candidates for the 1.78.0 beta release are now available at: <https://boostorg.jfrog.io/ui/native/main/beta/1.78.0.beta1/source <https://boostorg.jfrog.io/ui/native/main/beta/1.78.0.beta1/source>> The SHA256 checksums are as follows: 7a3a025451dfa2923129214eef7d16b03c02310a353d02158a549f6caa4284b0 boost_1_78_0_b1_rc1.tar.bz2 c491b1dcb916195598aa6581d6708d57fcc750516641c22511c088d572de9c07 boost_1_78_0_b1_rc1.tar.gz 35e7a3b0eb412a3933e57c72ba96374eb7d88ff1f89dbec62a16d67ffea2105a boost_1_78_0_b1_rc1.7z e6b68feb2f63401c96ca9fe25e939b409189fbe526a6e784e4bd69832c8f09cb boost_1_78_0_b1_rc1.zip 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. -- The Release managers

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How to get started with contribution
by Anmol Singh 09 Nov '21

09 Nov '21

Respected Sir/Madam, I am Anmol Singh, an Information Technology undergrad. I have just entered my second year at ADGITM, IP University. I am new to open source contributions but I am well aware of C++,C and javascript. I would love to contribute to your organisation but could you please tell me how to get started? Regards Anmol

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