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Boost on apple silicon
by simsicon 06 Jul '21

06 Jul '21

Hi, I was following the tutorial ( https://www.boost.org/doc/libs/1_76_0/doc/html/boost_asio/tutorial/tuttimer…) on macbook with m1 chip, and try to run the simple code and I meet the following error: Undefined symbols for architecture arm64: "boost::chrono::steady_clock::now()", referenced from: boost::asio::detail::chrono_time_traits<boost::chrono::steady_clock, boost::asio::wait_traits<boost::chrono::steady_clock> >::now() in mock-93ab24.o ld: symbol(s) not found for architecture arm64 clang: error: linker command failed with exit code 1 (use -v to see invocation) I am kind of new to C++ and boost, but I think this issue may be related to apple silicon compatibility? -- Thanks&Best Regards Zhang Zheng

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boost iterator range and filter iterator exception using MSVC
by Olaf Peter 02 Jul '21

02 Jul '21

Hi, using MSVC 2019 in debug mode I get an exception "cannot compare incompatible string_view iterators for equality". Using release mode and Clang/G++ all went fine as expected. - Boost: 1.76 - Visual Studio 2019 16.10.3 in C++17 mode How can it changed to be "portable" for all compiler? What's the reason behind? Using range.data() + size or data.front() + size for e.g. end iterator didn't compile. Thanks in advance! Olaf #include <boost/iterator/filter_iterator.hpp> #include <boost/range/iterator_range.hpp> #include <boost/range/iterator_range_core.hpp> #include <boost/range/iterator_range_io.hpp> #include <string_view> #include <iostream> template <typename RangeType> static auto filter_range(RangeType const& range) { struct separator_predicate { bool operator()(char x) { return '_' != x; } }; // FixMe: MSVC 2019 with '_CONTAINER_DEBUG_LEVEL > 0' triggers // assertion: // "cannot compare incompatible string_view iterators for equality" return boost::make_iterator_range( boost::make_filter_iterator( separator_predicate{}, range.begin(), range.end()), boost::make_filter_iterator( separator_predicate{}, range.end())); } using iterator_type = std::basic_string_view<char>::const_iterator; using string_span = boost::iterator_range<iterator_type>; int main() { // input std::string_view const sv = "Hello_World"; // algorithm get boost::iterator_range, aka string_span auto const range = string_span(sv); // here we are auto const range_f = filter_range(range); std::cout << range_f << '\n'; }

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[nowide] Convert wstring to u8string (C++20)
by Jim Orcheson 01 Jul '21

01 Jul '21

In C++17 and earlier, nowide::narrow can be used to convert from UTF-16 encoded strings (std::wstring) to UTF-8 encoded strings, stored in std::string. C++20 introduced std::u8string for UTF-8 encoded strings and it is incompatible with std::string. Is there some way I can get from std::wstring to std::u8string? It is not at all obvious from the nowide documentation.

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[MP11] Initialize the Nth alternative of an std::variant based on a runtime index
by Dominique Devienne 01 Jul '21

01 Jul '21

Hi. I'm modernizing some code, to use std::variant instead of ad-hoc peudo-variant structs. These structs need to be encoded/decoded via avro::codec_traits specializations, but given that std::variant is variadic, I'm struggling a bit. I've done my research and found peter's [1] and also looked at [2], which I thought might work, but does not, and I don't understand the errors I'm getting with MSVC 2019 in C++17 mode. The code is below, with also a subset of the compiler errors I'm getting. [1] https://www.reddit.com/r/cpp/comments/f8cbzs/creating_stdvariant_based_on_i… [2] https://www.boost.org/doc/libs/develop/libs/mp11/doc/html/mp11.html#mp_with… template <> struct codec_traits<std::monostate> { static void encode(Encoder& e, const std::monostate&) { e.encodeNull(); } static void decode(Decoder& d, std::monostate&) { d.decodeNull(); } }; template <typename... Ts> struct codec_traits<std::variant<Ts...>> { static void encode(Encoder& e, const std::variant<Ts...>& var) { e.encodeUnionIndex(var.index()); std::visit( [&e](const auto& alternative) { avro::encode(e, alternative); }, var ); } static void decode(Decoder& d, std::variant<Ts...>& var) { const size_t index = d.decodeUnionIndex(); if (index >= sizeof...(Ts)) { throw avro::Exception("Invalid Union index"); } auto& alternative = boost::mp11::mp_with_index<sizeof...(Ts)>( index, [&var](auto I) { return var.emplace<I>(); // I is mp_size_t<index>{} here } ) ; avro::decode(d, alternative); } }; 1>Messages.cpp 1>D:\pdgm\trunk\psc3\SharedComponents\src\lib\pdgm\eml\etp12\Messages.hpp(70,1): error C2220: the following warning is treated as an error 1>D:\pdgm\trunk\psc3\SharedComponents\src\lib\pdgm\eml\etp12\Messages.hpp(70,1): warning C4239: nonstandard extension used: 'initializing': conversion from 'std::monostate' to 'std::monostate &' 1>D:\pdgm\trunk\psc3\SharedComponents\src\lib\pdgm\eml\etp12\Messages.hpp(70,1): message : A non-const reference may only be bound to an lvalue 1>D:\pdgm\trunk\psc3\SharedComponents\src\lib\pdgm\eml\etp12\Messages.hpp(70): message : while compiling class template member function 'void avro::codec_traits<T>::decode(avro::Decoder &,std::variant<std::monostate,int64_t,double> &)' 1> with 1> [ 1> T=pdgm::eml::etp12::Datatypes::IndexValue_item_v 1> ] 1>D:\pdgm\kits\trunk\Avrocpp\1.9.2-Boost-1.74.0\Win_x64_10_v16_debug\include\avro/Specific.hh(341): message : see reference to function template instantiation 'void avro::codec_traits<T>::decode(avro::Decoder &,std::variant<std::monostate,int64_t,double> &)' being compiled 1> with 1> [ 1> T=pdgm::eml::etp12::Datatypes::IndexValue_item_v 1> ] 1>D:\pdgm\kits\trunk\Avrocpp\1.9.2-Boost-1.74.0\Win_x64_10_v16_debug\include\avro/Specific.hh(333): message : see reference to class template instantiation 'avro::codec_traits<T>' being compiled 1> with 1> [ 1> T=pdgm::eml::etp12::Datatypes::IndexValue_item_v 1> ] 1>D:\pdgm\trunk\psc3\SharedComponents\src\lib\pdgm\eml\etp12\codegen/Messages.i.ipp(1527): message : see reference to function template instantiation 'void avro::encode<pdgm::eml::etp12::Datatypes::IndexValue_item_v>(avro::Encoder &,const T &)' being compiled 1> with 1> [ 1> T=pdgm::eml::etp12::Datatypes::IndexValue_item_v 1> ] 1>D:\pdgm\kits\trunk\boost\1.74.0\Win_x64_10_v16_debug\include\boost/mp11/detail/mp_with_index.hpp(87,1): error C2440: 'return': cannot convert from '__int64' to 'std::monostate' 1>D:\pdgm\kits\trunk\boost\1.74.0\Win_x64_10_v16_debug\include\boost/mp11/detail/mp_with_index.hpp(87,1): message : No constructor could take the source type, or constructor overload resolution was ambiguous 1>D:\pdgm\kits\trunk\boost\1.74.0\Win_x64_10_v16_debug\include\boost/mp11/detail/mp_with_index.hpp(371): message : see reference to function template instantiation 'std::monostate boost::mp11::detail::mp_with_index_impl_<3>::call<0,_Ty>(size_t,F &&)' being compiled 1> with 1> [ 1> _Ty=avro::codec_traits<pdgm::eml::etp12::Datatypes::IndexValue_item_v>::decode::<lambda_7e593df011d98e42859c6ecb357b3e3f>, 1> F=avro::codec_traits<pdgm::eml::etp12::Datatypes::IndexValue_item_v>::decode::<lambda_7e593df011d98e42859c6ecb357b3e3f> 1> ] 1>D:\pdgm\trunk\psc3\SharedComponents\src\lib\pdgm\eml\etp12\Messages.hpp(70): message : see reference to function template instantiation 'std::monostate boost::mp11::mp_with_index<3,avro::codec_traits<T>::decode::<lambda_7e593df011d98e42859c6ecb357b3e3f>>(size_t,F &&)' being compiled 1> with 1> [ 1> T=pdgm::eml::etp12::Datatypes::IndexValue_item_v, 1> F=avro::codec_traits<pdgm::eml::etp12::Datatypes::IndexValue_item_v>::decode::<lambda_7e593df011d98e42859c6ecb357b3e3f> 1> ] 1>D:\pdgm\trunk\psc3\SharedComponents\src\lib\pdgm\eml\etp12\Messages.hpp(70): message : while compiling class template member function 'void avro::codec_traits<T>::decode(avro::Decoder &,std::variant<std::monostate,int64_t,double> &)' 1> with 1> [ 1> T=pdgm::eml::etp12::Datatypes::IndexValue_item_v 1> ] 1>D:\pdgm\kits\trunk\Avrocpp\1.9.2-Boost-1.74.0\Win_x64_10_v16_debug\include\avro/Specific.hh(341): message : see reference to function template instantiation 'void avro::codec_traits<T>::decode(avro::Decoder &,std::variant<std::monostate,int64_t,double> &)' being compiled 1> with 1> [ 1> T=pdgm::eml::etp12::Datatypes::IndexValue_item_v 1> ]

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[Asio] boost::system symbols visible despite BOOST_ASIO_DISABLE_VISIBILITY being defined
by Angela Breuer 30 Jun '21

30 Jun '21

Hello, I'm developing a C++11 shared library that uses Boost.Asio (with Boost version 1.72) as a header-only library. Exceptions are disabled as the library is intended to be used on embedded devices that do not support exceptions and, to ensure this is the case, all interfaces in my library have the noexcept operator and I have BOOST_EXCEPTION_DISABLE and BOOST_NO_EXCEPTIONS defined. Additionally, all public interfaces in the library do not expose any Boost / Boost.Asio types. When attempting to hide private symbols in my shared library with the GCC visibility flags and annotations (i.e. -fvisibility=hidden), I learned that I needed to define BOOST_ASIO_DISABLE_VISIBILITY to disable the visibility pragmas in Boost.Asio so the boost::asio symbols will also be hidden. Although I was able to hide the boost::asio symbols with this strategy, this still results in a subset of boost::system symbols being visible. I do have some internal helper free functions that accept a boost::system::error_code. I suspect that they may have something to do with these visible symbols, but they are completely internal to the library and the symbols for those helper functions are not visible when I inspect the library's symbols with nm -DC. I will note that I was able to hide the boost::system symbols by using a linker version script, but I do not wish to maintain an unwieldy list of symbols to export if I can help it. Is there a supported way to hide the boost::system symbols aside from using a linker version script? I have attached nm -DC output along with gcc / g++ invocations for reference. Thank you, -Angela

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MSVC compiler error with boost ver 1.71
by John Emmas 24 Jun '21

24 Jun '21

Hi there - I'm using boost ver 1.71 and I'm seeing a strange problem with VS2019. Simply #including this line at the top of a source file will generate a compiler error if I try to build in Debug mode (Release builds are okay...) #include <boost/property_tree/json_parser.hpp> When I say a "compiler error" I'm not referring to one of the usual CXXXX messages - what happens is this:- >INTERNAL COMPILER ERROR in 'C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30037\bin\HostX86\x64\CL.exe' > Please choose the Technical Support command on the Visual C++ > Help menu, or open the Technical Support help file for more information >Done building project "ardour.vcxproj" -- FAILED. >========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ========== Just wondering if anyone else has encountered this..? Thanks, John

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Making multiprecision::int saturate
by Emilio Paolini 24 Jun '21

24 Jun '21

Hi everyone, i have the following problem: i need the integer type of boost::multiprecision to saturate, instead of wrapping. Is it possible to change its behaviour? Thanks!

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MPI_ERR_TRUNCATE with Boost.MPI and only blocking communication
by Alex Cumberworth 21 Jun '21

21 Jun '21

I am trying to run some Monte Carlo simulation code I wrote in C++ with MPI via the Boost.MPI wrapper. I use only blocking send and receive calls (i.e. send and recv, never isend or irecv), but after running the program for a few days, I inevitably end up with the following error terminate called after throwing an instance of boost::exception_detail::clone_impl >' what(): MPI_Recv: MPI_ERR_TRUNCATE: message truncated I have seen that this can happen with non-blocking calls are being made, but I cannot see how it can happen with only blocking calls. I am sending and receiving a vector of structs: struct Chain { bool operator==(Chain chain_2); int index; int identity; vector positions; vector orientations; private: friend class boost::serialization::access; template void serialize(Archive& ar, const unsigned int version) { ar& index; ar& identity; ar& positions; ar& orientations; } }; using Chains = vector; where VectorThree is declared elsewhere as class VectorThree { public: VectorThree(int x, int y, int z): m_container {{x, y, z}} {}; VectorThree(): m_container {{0, 0, 0}} {}; VectorThree operator-(); VectorThree operator+(const VectorThree& v_2) const; VectorThree operator-(const VectorThree& v_2) const; bool operator!=(const VectorThree& v_2) const; int& operator[](const size_t& i) { return m_container[i]; }; const int& at(const size_t& i) const { return m_container.at(i); }; VectorThree rotate_half(VectorThree axis); VectorThree rotate(VectorThree origin, VectorThree axis, int turns); VectorThree rotate(VectorThree axis, int turns); int sum(); int abssum(); VectorThree absolute(); VectorThree sort(); private: array m_container; friend class boost::serialization::access; template void serialize(Archive& arch, const unsigned int) { arch& m_container; } }; It sends and receives instances of this object many times before the error occurs. I have narrowed down the calls where the error occurs by printing statements before and after both sending and receiving. The sending code: Chains chains_send {m_us_sim->get_chains()}; cout << "Win " << m_rank << ": Sending chains (size " << chains_send.size() << ") to " << win_i << "\n"; m_world.send(win_i, swap_i, chains_send); cout << "Win " << m_rank << ": Sent chains to " << win_i << "\n"; The receiving code: Chains chains_rec; cout << "Win " << m_rank << ": Recieving chains from " << win_to_win[0] << "\n"; m_world.recv(win_to_win[0], swap_i, chains_rec); cout << "Win " << m_rank << ": Recieved chains (size " << chains_rec.size() << ") from " << win_to_win[0] << "\n"; In the output file before the crash I have Win 0: Recieving chains from 1 Win 1: Sending chains (size 2) to 0 Win 1: Sent chains to 0 I am using version 1.65 of Boost and OpenMPI 2.0.1.

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newbie, Getting Started on Unix Variants
by John 15 Jun '21

15 Jun '21

Please someone help me work through the Getting Started on Unix Variants. I've completed the steps up until 6 Link Your Program to a Boost Library. However, the library shown in the step 6 example, libboost_regex-gcc34-mt-d-1_36.a, doesn't seem to be present in my system. So, it looks like something was not right with the building of this library. What can I do to ensure that the library, libboost_regex-gcc34-mt-d-1_36.a, is made. Thank You, John

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[Serialization] archive_exception from bad interaction serialization() and load_construct_data()
by Boylan, Ross 14 Jun '21

14 Jun '21

In short, combining a class implementation of serialize() with load/save_construct_data as described in the docs writes and reads data twice. Varying the pattern can produce exceptions. My solution is to implement serialize() as a no-op and provide paired load/save_construct_data() functions. Is that actually a solution? Is there a better way? The code at the bottom of this message yields Microsoft C++ exception: boost::archive::archive_exception at memory location 0x000000B8189AC300. When attempting to read in what was just written out. Debugging shows that code attempts to read in the object twice, first in the class-specific load_construct_data function I wrote, and then again in the instance method A::serialize. Since the save operation only wrote it out once, there is nothing, or at least nothing expected, to read and things go badly. The documentation (https://www.boost.org/doc/libs/1_76_0/libs/serialization/doc/serialization.…) says "If there is no such default constructor, the function templates load_construct_data and perhaps save_construct_data will have to be overridden." "perhaps" seems to imply that it is not essential to do so, and since the lack of a default constructor only matters when materializing an object I only wrote a load_construct_data function. The example in the documentation does show both a save_construct_data and a load_construct_data function and if I uncomment save_construct_data in the code below, it runs without error and reconstructs the object. HOWEVER, this only works because the data are written out twice, and then read in twice. I think the problem is that TestBed.exe!boost::archive::detail::pointer_iserializer<boost::archive::text_iarchive,A>::load_object_ptr(boost::archive::detail::basic_iarchive & ar, void * t, const unsigned int file_version) Line 340 at J:\Programs\boost_1_76_0\boost\archive\detail\iserializer.hpp(340) first materializes the object and then--after it is already constructed--passes it off to ar_impl >> boost::serialization::make_nvp(NULL, * static_cast<T *>(t)); at the end, triggering the call to A::serialize and the 2nd read from the archive. For now I have kept the save_construct_data function and made A::serialize a no-op; the serialization framework seem to require that it exist. This appears to work. Boost 1.76 Microsoft Visual Studio Community 2019 v16.10.1 with Language Level /std:c++latest. // TestBed.cpp : This file contains the 'main' function. Program execution begins and ends there. // #include <iostream> #include <fstream> #include <string> #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> class A : boost::noncopyable { public: int a1; A(const int x1) : a1(x1) {}; virtual ~A() {}; template<class Archive> void serialize(Archive& ar, const unsigned int version) { ar& a1; }; }; namespace boost { namespace serialization { #if 0 template<class Archive> void save_construct_data(Archive& ar, const A* pa, const unsigned int version) { ar& pa->a1; }; #endif template<class Archive> inline void load_construct_data(Archive& ar, A* pa, const unsigned int file_version) { int x1; ar >> x1; ::new(pa)A(x1); } } } /* these are separate functions partly so RAII will close files*/ void write_out(const std::string& fpath, const A& a) { std::ofstream ofs(fpath); boost::archive::text_oarchive oa(ofs); oa << &a; } A* read_in(const std::string& fpath) { A* pa; std::ifstream ifs(fpath); boost::archive::text_iarchive ia(ifs); ia >> pa; return pa; } int main(int argc, char** argv) { const std::string fname("test.srl"); A a(810); write_out(fname, a); A* aa = read_in(fname); std::cout << "A(" << aa->a1 << std::endl; return 0; }

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[Boost::asio] How to set the name of work_scheduler thread started by boost::asio?
by Marco Guest 09 Jun '21

09 Jun '21

Hello, I'm looking to set custom names to std::threads started indirectly when using boost:asio library (on Linux operating system). I have seen this stack trace for such thread by gdb: pthread_cond_wait () from /lib64/libpthread.so.0 void boost::asio::detail::posix_event::wait<boost::asio::detail::conditionally_enabled_mutex::scoped_lock>(boost::asio::detail::conditionally_enabled_mutex::scoped_lock&) ()2 boost::asio::detail::conditionally_enabled_event::wait(boost::asio::detail::conditionally_enabled_mutex::scoped_lock&) () boost::asio::detail::scheduler::do_run_one(boost::asio::detail::conditionally_enabled_mutex::scoped_lock&, boost::asio::detail::scheduler_thread_info&, boost::system::error_code const&) () boost::asio::detail::scheduler::run(boost::system::error_code&) () boost::asio::detail::resolver_service_base::work_scheduler_runner::operator()() () boost::asio::detail::posix_thread::func<boost::asio::detail::resolver_service_base::work_scheduler_runner>::run() () boost_asio_detail_posix_thread_function () start_thread () from /lib64/libpthread.so.0 clone () from /lib64/libc.so.6 Setting names would be useful to debug my application behaviour in high throughput conditions and to be able to easily check the CPU usage of each thread using “top –H”. Is there a way to do so? Thanks

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[QUESTION] what's meaning of boost::asio::require()?
by ZheNing Hu 06 Jun '21

06 Jun '21

Hi, I ran into difficulties when I was reading boost::asio http server example[1], I see: work_.push_back( boost::asio::require(io_context->get_executor(), boost::asio::execution::outstanding_work.tracked)); I don't know what is the meaning of this code? Or what is boost::asio::require()? I did not find useful information to introduce it. [1] https://www.boost.org/doc/libs/1_76_0/doc/html/boost_asio/example/cpp03/htt… -- ZheNing Hu

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[Parameter Library] How to define a constexpr function
by pavel b 04 Jun '21

04 Jun '21

Hi all, Is it possible to define a constexpr function using BOOST_PARAMETER_FUNCTION? what is the correct syntax? Best regards, P

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WinDbgCached_exe recognize has threat by Bitdefender
by Mauro Ziliani 01 Jun '21

01 Jun '21

Hi all. I build boost 1.76.0 woth Visual Studio 2019. I try to scan my pc with bitdefender (free version). Bitdefender discover a threat in boost_1_76_0\bin.v2\stacktrace\build\msvc-142\release\address-model-32\link-static\threading-multi\WinDbgCached_exe.exe. The threat is recognized as Gen:Variant.Fugrafa.139255 Any idea about? Best regards, MZ Sent from Mailspring (https://getmailspring.com/) the best free email app for work

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OpenSSL 3.0 support in boost.asio
by Gehrs, Volker 31 May '21

31 May '21

Hi all, Will boost.asio add support for OpenSSL 3.0 as soon as it is officially available? Do you have already some very rough date in mind when this can be the case. I know OpenSSL 3.0 has not been released, yet. Maybe it can be expressed as X Month after OpenSSL 3.0 release... My understanding is that OpenSSL 3.0 is a big architectural change. Can I expect that this change will have big impact on the usage of boost.asio as well? Thanks and best regards! Volker

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Build issue utilizing Boost::regex
by Brad Smith 29 May '21

29 May '21

Hi, I am trying to upgrade from Boost 1.73 to Boost 1.76 and down to only one consumer left that will not build. This appears to be an issue with Boost::regex. I noticed this in the Boost 1.76 release notes.. "Regex is now header only except in C++03 mode." Clang defaults to C++14, but I noticed BOOST_REGEX_CXX03 is defined. The project does not specify a particular C++ version so it should be using C++14. The functions below exist in the Boost 1.73 Boost::regex library but not in the 1.76 library. The project in question uses the function regex_match(). Any hints as to how to resolve this? ld: error: undefined symbol: boost::scoped_static_mutex_lock::scoped_static_mutex_lock(boost::static_mutex&, bool) >>> referenced by Config.cpp >>> � Config.o:(boost::object_cache<boost::re_detail_500::cpp_regex_traits_base<char>, boost::re_detail_500::cpp_regex_traits_implementation<char> >::get(boost::re_detail_500::cpp_regex_traits_base<char> const&, unsigned long)) >>> referenced by Config.cpp >>> � Config.o:(boost::cpp_regex_traits<char>::get_catalog_name()) >>> referenced by Config.cpp >>> � Config.o:(boost::re_detail_500::save_state_init::~save_state_init()) >>> referenced 2 more times ld: error: undefined symbol: boost::scoped_static_mutex_lock::~scoped_static_mutex_lock() >>> referenced by Config.cpp >>> � Config.o:(boost::object_cache<boost::re_detail_500::cpp_regex_traits_base<char>, boost::re_detail_500::cpp_regex_traits_implementation<char> >::get(boost::re_detail_500::cpp_regex_traits_base<char> const&, unsigned long)) >>> referenced by Config.cpp >>> � Config.o:(boost::object_cache<boost::re_detail_500::cpp_regex_traits_base<char>, boost::re_detail_500::cpp_regex_traits_implementation<char> >::get(boost::re_detail_500::cpp_regex_traits_base<char> const&, unsigned long)) >>> referenced by Config.cpp >>> � Config.o:(boost::cpp_regex_traits<char>::get_catalog_name()) >>> referenced 5 more times c++: error: linker command failed with exit code 1 (use -v to see invocation)

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[locale] Boost.Locale cannot be used with std::regex
by Josue Andrade Gomes 24 May '21

24 May '21

It seems that Boost.Locale cannot be used with std::regex. See the code below: #include <regex> #include <boost/locale.hpp> int main() { try { boost::locale::generator gen; std::locale de_DE(gen("de_DE.UTF-8")); std::wstring in(L"Grün GRÜN grün"); std::wregex rx; rx.imbue(de_DE); rx.assign(L"grün", std::regex::icase); std::wcout << std::regex_replace(in, rx, L"green") << L"\n"; } catch (std::exception &e) { std::cout << "Exception: " << e.what() << "\n"; } } Outputs: green GRÜN green However this: #include <regex> #include <locale> int main() { try { std::locale de_DE("de_DE.UTF-8"); std::wstring in(L"Grün GRÜN grün"); std::wregex rx; rx.imbue(de_DE); rx.assign(L"grün", std::regex::icase); std::wcout << std::regex_replace(in, rx, L"green") << L"\n"; } catch (std::exception &e) { std::cout << "Exception: " << e.what() << "\n"; } } Correctly outputs: green green green Tested on Ubuntu 20.04.2. g++ 10.2, Boost.Locale built with ICU support using vcpkg (thus static link).

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Application leaves process behind
by Isabelle Poueriet 20 May '21

20 May '21

My application is not cleaning up properly - it leaves the process behind in task manager after exiting.I read about this below, but I'm setting all sinks from a configuration file. Can the shutdown documented in link below be done from the config file? If so, what are the options? I am using multi-threaded loggers. Thanks in advance. c++ - How to stop all asynchronous sinks when using Boost.Log - Stack Overflow Snippet of code referenced in link above: // Remove the sink from the core, so that no records are passed to it core->remove_sink(sink); // Break the feeding loop sink->stop(); // Flush all log records that may have left buffered sink->flush(); sink.reset(); Snippet of my config file: # Logging core settings section. May be omitted if no parameters specified within it.[Core]# <DisableLogging> true=disable all logging; false=enable all logging Q. do we care to disable specific channels?DisableLogging=false # Sink settings sections#GTSMAIN logs everything to a text file[Sinks.GTSMAIN]Destination="TextFile" #<Asynchronous> if true, a thread is dedicated to writing to log, otherwise blocks main thread to write.Asynchronous="true" # Enables automatic stream flush after each log record.AutoFlush="true" # Formatter string. Optional, by default only log record message text is written.Format="[%TimeStamp%][%ThreadID%][%Severity%][%Channel%] %Message%" #Target specifies where to save files when rotation occurrsTarget="C:/Temp/GtsLogs"FileName="gtsMainLog_%3N.log"#RotationSize in bytesRotationSize="1048576"#MaxSize - oldest file in the target directory will be deleted when Maxsize(in bytes) is reachedMaxSize=100485760OpenMode="append"#Apply no filter for the main log# Sink-specific filter. Optional, by default no filter is applied.#============================================================================================================[Sinks.ADM]Destination="TextFile"##<Asynchronous> if true, a thread is dedicated to writing to log, otherwise blocks main thread to write.Asynchronous="true"### Enables automatic stream flush after each log record.AutoFlush="true"### Formatter string. Optional, by default only log record message text is written.Format="[%TimeStamp%][%ThreadID%][%Severity%][%Channel%] %Message%"#Target="C:/Temp/GtsLogs"FileName="gtsAdm_%3N.log"##RotationSize in bytesRotationSize="1048576"##MaxSize - oldest file in the target directory will be deleted when Maxsize(in bytes) is reachedMaxSize=100485760##Apply no filter for the main log## Sink-specific filter - anything in AGR channel. Optional, by default no filter is applied.Filter="%Channel% matches \"ADM\""##============================================================================================================[Sinks.AGR]Destination="TextFile"###<Asynchronous> if true, a thread is dedicated to writing to log, otherwise blocks main thread to write.Asynchronous="true"### Enables automatic stream flush after each log record.AutoFlush="true"### Formatter string. Optional, by default only log record message text is written.Format="[%TimeStamp%][%ThreadID%][%Severity%][%Channel%] %Message%"#Target="C:/Temp/GtsLogs"FileName="gtsAgr_%3N.log"##RotationSize in bytesRotationSize="1048576"##MaxSize - oldest file in the target directory will be deleted when Maxsize(in bytes) is reachedMaxSize=100485760## Sink-specific filter - anything in AGR channel. Optional, by default no filter is applied.Filter="%Channel% matches \"AGR\""

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How to set open_mode "append" in configuration file
by Isabelle Poueriet 20 May '21

20 May '21

Howdy. I have the configuration file below and I load it from the code as depicted below.The log files are being created, but they get overwritten each time I run the application, instead of being appended each time I run. code to load settings from config file///////////////////////////////////////////////////////////////////////////////// Name: ConfigureSinksFromIniFile()// Purpose: Load filter settings from configuration file//////////////////////////////////////////////////////////////////////////////* static */ void GtsLog::ConfigureSinksFromIniFile(){ try { std::ifstream cfgFile(".\\gtsLogConfig.INI"); try { if (cfgFile.is_open()) { try { // Add some attributes logging::add_common_attributes(); // Read the settings and initialize logging library logging::init_from_stream(cfgFile); return; } catch (std::exception& e) { std::cout << "Could not load configuration file. Check for boost config syntax" << e.what() << std::endl; return; } } else { std::cout << "Could not open log configuration file" << std::endl; return; //should we exit instead? } } catch (std::exception& e) { std::cout << "Could not open log configuration file" << e.what() << std::endl; return; //should we exit instead? } } catch (std::exception& e) { std::cout << "FAILURE: could not associate cfgFile to .\\gtsLogCfg.ini " << e.what() << std::endl; return; //should we exit instead? }} Configuration File gtsConfig.INI===========================[Core]# <DisableLogging> true=disable all logging; false=enable all logging Q. do we care to disable specific channels?DisableLogging=false # Sink settings sections#GTSMAIN logs everything to a text file[Sinks.GTSMAIN]Destination="TextFile" #<Asynchronous> if true, a thread is dedicated to writing to log, otherwise blocks main thread to write.Asynchronous="true" # Enables automatic stream flush after each log record.AutoFlush="true" # Formatter string. Optional, by default only log record message text is written.Format="[%TimeStamp%][%ThreadID%][%Severity%][%Channel%] %Message%" #Target specifies where to save files when rotation occurrsTarget="C:/Temp/GtsLogs"FileName="gtsMainLog_%3N.log"#RotationSize in bytesRotationSize="1048576"#MaxSize - oldest file in the target directory will be deleted when Maxsize(in bytes) is reachedMaxSize=100485760OpenMode="append"#Apply no filter for the main log# Sink-specific filter. Optional, by default no filter is applied.#============================================================================================================[Sinks.ADM]Destination="TextFile"##<Asynchronous> if true, a thread is dedicated to writing to log, otherwise blocks main thread to write.Asynchronous="true"### Enables automatic stream flush after each log record.AutoFlush="true"### Formatter string. Optional, by default only log record message text is written.Format="[%TimeStamp%][%ThreadID%][%Severity%][%Channel%] %Message%"#Target="C:/Temp/GtsLogs"FileName="gtsAdm_%3N.log"##RotationSize in bytesRotationSize="1048576"##MaxSize - oldest file in the target directory will be deleted when Maxsize(in bytes) is reachedMaxSize=100485760##Apply no filter for the main log## Sink-specific filter - anything in AGR channel. Optional, by default no filter is applied.Filter="%Channel% matches \"ADM\""##============================================================================================================[Sinks.AGR]Destination="TextFile"###<Asynchronous> if true, a thread is dedicated to writing to log, otherwise blocks main thread to write.Asynchronous="true"### Enables automatic stream flush after each log record.AutoFlush="true"### Formatter string. Optional, by default only log record message text is written.Format="[%TimeStamp%][%ThreadID%][%Severity%][%Channel%] %Message%"#Target="C:/Temp/GtsLogs"FileName="gtsAgr_%3N.log"##RotationSize in bytesRotationSize="1048576"##MaxSize - oldest file in the target directory will be deleted when Maxsize(in bytes) is reachedMaxSize=100485760## Sink-specific filter - anything in AGR channel. Optional, by default no filter is applied.Filter="%Channel% matches \"AGR\""

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Spirit X3 comment parser
by Olaf Peter 17 May '21

17 May '21

Hallo Users, this time a question about retaining the comments in the recursive AST. I've never seen those question before. I have a grammar that can have a comment at any point while maintaining that same grammar. I am interested in the comments to be able to parse the possibly contained pragma etc. statement later (so parsed as raw). ... auto const comment_def = x3::lit("//") >> raw[*(char_ - x3::eol) >> x3::eol]; ... The AST is ready, an AST node for the comment is also there. How do I change the rule now? auto const start_def = x3::skip(x3::space)[ comment | toplevel_rule ]; with the actual parse function: ... x3::parse(iter, end, toplevel_parser >> x3::eoi, toplevel); .... originally the latter looked like this: .... x3::phrase_parse(iter, end, toplevel_parser >> x3::eoi, parser::skipper, toplevel); ... The above start_def unfortunately also changes the attribute for it, ast::toplevel_node now becomes a variant<ast::comment_node,ast::toplevel_node>. I'm also not sure how this rule affects the dependent rules, i.e. recursive and low level in terms of correctness and performance. For the AST visitor this just means another overload. Another point is the test suite. Currently I test the low level sub rules with a separate instance, where the test input can also contain comments for test case documentation purpose. With x3::phrase_parse() this was not a problem. With the new approach, for each rule to be tested, I also have to use a variant <comment,attribute> for the attribute, which is very inconvenient.... So the question, is this really the right way? Are there alternatives? Thanks in advance

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compiler error using boost::posix_time::time_facet
by Dan Bloomquist 08 May '21

08 May '21

Hi, I'm getting a strange error in that I've done this before without problems. But I've started a new MFC project and I'm getting this error. The same exact header in other projects compiles fine. I'm using all the same settings. with: auto* facet= new boost::posix_time::time_facet( "%d-%b-%Y %H:%M:%S" ); and if I comment that line the same error comes in further down where I: os << "[" << boost::posix_time::second_clock::local_time() << "] "; I just can not figure out what is different in this project that is causing this. using the latest MS compiler with c++17 Thanks, Dan. I'm getting: F:\cpp\boost_1_74_0\boost\algorithm\string\replace.hpp(654,37): error C2672: 'boost::algorithm::first_finder': no matching overloaded function found 1>F:\cpp\boost_1_74_0\boost\date_time\time_facet.hpp(312): message : see reference to function template instantiation 'void boost::algorithm::replace_all<std::basic_string<char,std::char_traits<char>,std::allocator<char>>,const char*,std::basic_string<char,std::char_traits<char>,std::allocator<char>>>(SequenceT &,const Range1T &,const Range2T &)' being compiled 1> with 1> [ 1> SequenceT=std::basic_string<char,std::char_traits<char>,std::allocator<char>>, 1> Range1T=const char *, 1> Range2T=std::basic_string<char,std::char_traits<char>,std::allocator<char>> 1> ] 1>F:\cpp\boost_1_74_0\boost\date_time\time_facet.hpp(285): message : while compiling class template member function 'OutItrT boost::date_time::time_facet<boost::posix_time::ptime,char,OutItrT>::put(OutItrT,std::ios_base &,char,const time_type &) const' 1> with 1> [ 1> OutItrT=std::ostreambuf_iterator<char,std::char_traits<char>>, 1> time_type=boost::posix_time::ptime 1> ] 1>F:\cpp\boost_1_74_0\boost\date_time\posix_time\posix_time_io.hpp(52): message : see reference to function template instantiation 'OutItrT boost::date_time::time_facet<boost::posix_time::ptime,char,OutItrT>::put(OutItrT,std::ios_base &,char,const time_type &) const' being compiled 1> with 1> [ 1> OutItrT=std::ostreambuf_iterator<char,std::char_traits<char>>, 1> time_type=boost::posix_time::ptime 1> ] 1>f:\cpp\include\logging.h(20): message : see reference to class template instantiation 'boost::date_time::time_facet<boost::posix_time::ptime,char,std::ostreambuf_iterator<char,std::char_traits<char>>>' being compiled 1>F:\cpp\boost_1_74_0\boost\algorithm\string\replace.hpp(654,1): error C2893: Failed to specialize function template 'boost::algorithm::detail::first_finderF<range_const_iterator<T,void>::type,boost::algorithm::is_equal> boost::algorithm::first_finder(const RangeT &)' 1>F:\cpp\boost_1_74_0\boost\algorithm\string\finder.hpp(52): message : see declaration of 'boost::algorithm::first_finder' 1>F:\cpp\boost_1_74_0\boost\algorithm\string\replace.hpp(654,1): message : With the following template arguments: 1>F:\cpp\boost_1_74_0\boost\algorithm\string\replace.hpp(654,1): message : 'RangeT=Range1T' 1>F:\cpp\boost_1_74_0\boost\algorithm\string\replace.hpp(652,33): error C2672: 'boost::algorithm::find_format_all': no matching overloaded function found 1>F:\cpp\boost_1_74_0\boost\algorithm\string\replace.hpp(655,1): error C2780: 'void boost::algorithm::find_format_all(SequenceT &,FinderT,FormatterT)': expects 3 arguments - 2 provided 1>F:\cpp\boost_1_74_0\boost\algorithm\string\find_format.hpp(250): message : see declaration of 'boost::algorithm::find_format_all' 1>F:\cpp\boost_1_74_0\boost\algorithm\string\erase.hpp(595,37): error C2672: 'boost::algorithm::first_finder': no matching overloaded function found 1>F:\cpp\boost_1_74_0\boost\date_time\time_facet.hpp(321): message : see reference to function template instantiation 'void boost::algorithm::erase_all<std::basic_string<char,std::char_traits<char>,std::allocator<char>>,const char*>(SequenceT &,const RangeT &)' being compiled 1> with 1> [ 1> SequenceT=std::basic_string<char,std::char_traits<char>,std::allocator<char>>, 1> RangeT=const char * 1> ] 1>F:\cpp\boost_1_74_0\boost\algorithm\string\erase.hpp(595,1): error C2893: Failed to specialize function template 'boost::algorithm::detail::first_finderF<range_const_iterator<T,void>::type,boost::algorithm::is_equal> boost::algorithm::first_finder(const RangeT &)' 1>F:\cpp\boost_1_74_0\boost\algorithm\string\finder.hpp(52): message : see declaration of 'boost::algorithm::first_finder' 1>F:\cpp\boost_1_74_0\boost\algorithm\string\erase.hpp(595,1): message : With the following template arguments: 1>F:\cpp\boost_1_74_0\boost\algorithm\string\erase.hpp(595,1): message : 'RangeT=RangeT' 1>F:\cpp\boost_1_74_0\boost\algorithm\string\erase.hpp(593,33): error C2672: 'boost::algorithm::find_format_all': no matching overloaded function found 1>F:\cpp\boost_1_74_0\boost\algorithm\string\erase.hpp(596,1): error C2780: 'void boost::algorithm::find_format_all(SequenceT &,FinderT,FormatterT)': expects 3 arguments - 2 provided 1>F:\cpp\boost_1_74_0\boost\algorithm\string\find_format.hpp(250): message : see declaration of 'boost::algorithm::find_format_all'

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[Math] Standalone beta release
by John Maddock 03 May '21

03 May '21

Just a heads up that Boost.Math now has a (beta) standalone release at https://github.com/boostorg/math/releases/tag/v1.76-standalone-beta We would very much appreciate any interested parties giving it a whirl and reporting back. With many thanks to Matt Borland and Nick Thompson for making this possible! Best, John Maddock. -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

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Final Notice: BinTray is shutting down 1-May (that's SATURDAY)
by Marshall Clow 29 Apr '21

29 Apr '21

Bintray is “sunsetting” on the 1st of May. At that time, you will be unable to download boost releases from there. Before that time, their service will be occasionally interrupted. The web site has been updated, all the download links now refer to https://boostorg.jfrog.io/artifactory/main/release/ <https://boostorg.jfrog.io/artifactory/main/release/> Example: Instead of downloading from: https://dl.bintray.com/boostorg/release/1.76.0/source/boost_1_76_0.tar.gz <https://dl.bintray.com/boostorg/release/1.76.0/source/boost_1_76_0.tar.gz> You should download from: https://boostorg.jfrog.io/artifactory/main/release/1.76.0/source/boost_1_76… <https://boostorg.jfrog.io/artifactory/main/release/1.76.0/source/boost_1_76…> This applies to all releases from 1.63.0 onward (The pre-1.63 releases are still hosted at SourceForge) — Marshall

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[beast] help with http::dynamic_body and http::buffer_body
by Klebsch, Mario 26 Apr '21

26 Apr '21

Hello, After using boost::asio for several years I thought, I might give beast a try. I need to write a http server processing a POST request with an upload of a big file. So I thought, I could start with libs/beast/example/http/server/async. I soon found the function handle_request() and that I have to add something like if (req.method() == http::verb::post && req.target()=="/xxx" ) to catch the http POST transaction. But since I have to process the upload of a large file, I thought that using a http::string_body might not be the best choice. I found several other body types in the documentation. I thought buffer_body ought to be fine, since the documentation says: ‘This allows for serialization of body data coming from external sources, and incremental parsing of message body content using a fixed size buffer.’. incremental processing of the input stream is what I need. But now, I have no clue, how to change the example to use a buffer_body. I changed http::request<http::string_body> req_ to http::request<http::buffer_body> req_. But now I must process the request message in chunks. How do I get my callback invoked for each chunk? Without additional changes, I get a read error: need buffer. But the documentation on buffer_body does not help me. Buffer_body does not seem to have any methods, that I can call. It does have a member type reader, that is documented as implementation-defined. So there is nothing I can do with this reader. ☹ There is a member type value_type, that does have data, size and more mebers, but I have no idea, how I could et hold of a variable of this type containing a part of my message body. The error message might indicate, that I need to provide a fixed size buffer to the buffer_body, but I have no idea, how to do this. I tried to add the following code to do_read(): req_.body().data = my_buffer; req_.body().size = sizeof(my_buffer); It compiles, so req_body() seems to be the way to get hold on a http::buffer_body::value_type, but simply initializing the two variables does not seem to be sufficient. I also tried to set req_.body().more to false or to true, but it didn’t change anything. I then thought, I might try a dynamic_body. This would store the entire upload in memory, but perhaps I get more familiar with the beat framework, when I try to use this body. And in deed, I managed to write some code, that shows all request headers and the request body on stdout. To get the body, I had to copy the buffer contents into a std::string: std::string body{ boost::asio::buffers_begin(req.body().data()), boost::asio::buffers_end(req.body().data()) }; Since large files have to be handled by my code, this additional copy of the data is to be avoided. So I tried to iterate the body using the iterators: const auto begin = boost::asio::buffers_begin(req.body().data()); const auto end = boost::asio::buffers_end(req.body().data()); for (auto it = begin; it != end; it++) putchar(*it); While it runs fine on the windows box, the loop crashes on linux in the 512th iteration in it++. Program received signal SIGSEGV, Segmentation fault. 0x0000555555592432 in boost::intrusive::list_node_traits<void*>::get_previous (n=@0x7fffffffc118: 0x1ff) at ../boost/boost/intrusive/detail/list_node.hpp:54 54 { return n->prev_; } (gdb) print n $1 = (const boost::intrusive::list_node_traits<void*>::node_ptr &) @0x7fffffffc118: 0x1ff (gdb) Here is the call stack: #0 0x0000555555592432 in boost::intrusive::list_node_traits<void*>::get_previous (n=@0x7fffffffc118: 0x1ff) at ../boost/boost/intrusive/detail/list_node.hpp:54 #1 boost::intrusive::list_iterator<boost::intrusive::bhtraits<boost::beast::basic_multi_buffer<std::allocator<char> >::element, boost::intrusive::list_node_traits<void*>, (boost::intrusive::link_mode_type)0, boost::intrusive::dft_tag, 1u>, true>::operator-- (this=0x7fffffffc118) at ../boost/boost/intrusive/detail/list_iterator.hpp:107 #2 std::__advance<boost::intrusive::list_iterator<boost::intrusive::bhtraits<boost::beast::basic_multi_buffer<std::allocator<char> >::element, boost::intrusive::list_node_traits<void*>, (boost::intrusive::link_mode_type)0, boost::intrusive::dft_tag, 1u>, true>, long> (__i=..., __n=0) at /usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/include/g++-v10/bits/stl_iterator_base_funcs.h:169 #3 0x000055555558daf0 in std::advance<boost::intrusive::list_iterator<boost::intrusive::bhtraits<boost::beast::basic_multi_buffer<std::allocator<char> >::element, boost::intrusive::list_node_traits<void*>, (boost::intrusive::link_mode_type)0, boost::intrusive::dft_tag, 1u>, true>, long> (__i=..., __n=-1) at /usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/include/g++-v10/bits/stl_iterator_base_funcs.h:206 #4 0x0000555555589254 in std::prev<boost::intrusive::list_iterator<boost::intrusive::bhtraits<boost::beast::basic_multi_buffer<std::allocator<char> >::element, boost::intrusive::list_node_traits<void*>, (boost::intrusive::link_mode_type)0, boost::intrusive::dft_tag, 1u>, true> > (__x=..., __n=1) at /usr/lib/gcc/x86_64-pc-linux-gnu/10.2.0/include/g++-v10/bits/stl_iterator_base_funcs.h:230 #5 0x0000555555589608 in boost::beast::basic_multi_buffer<std::allocator<char> >::subrange<true>::const_iterator::operator* (this=0x7fffffffc4f8) at ../boost/boost/beast/core/impl/multi_buffer.hpp:384 #6 0x0000555555589b4b in boost::asio::buffers_iterator<boost::beast::basic_multi_buffer<std::allocator<char> >::subrange<true>, char>::increment (this=0x7fffffffc4d0) at ../boost/boost/asio/buffers_iterator.hpp:370 #7 0x0000555555584894 in boost::asio::buffers_iterator<boost::beast::basic_multi_buffer<std::allocator<char> >::subrange<true>, char>::operator++ (this=0x7fffffffc4d0) at ../boost/boost/asio/buffers_iterator.hpp:229 #8 0x000055555557e7c0 in boost::asio::buffers_iterator<boost::beast::basic_multi_buffer<std::allocator<char> >::subrange<true>, char>::operator++ (this=0x7fffffffc4d0) at ../boost/boost/asio/buffers_iterator.hpp:237 #9 0x0000555555579ba8 in handle_request<boost::beast::http::basic_dynamic_body<boost::beast::basic_multi_buffer<std::allocator<char> > >, std::allocator<char>, session::send_lambda&> (doc_root=..., req=..., send=...) at t.cpp:164 I hope anybody can give my a hint on how to use this beast. Right now it feels that it might be easier to write the http server using plain boost::asio. Klebsch Mario Funktion | R&D Tel: +49 (0) 531 38 701 718 Raum: Braunschweig, E20 Diese E-Mail und die an sie angehängten Dateien sind ausschließlich für Personen oder Institutionen bestimmt, deren Namen oben aufgeführt sind. Sie können Informationen enthalten, die durch das Berufsgeheimnis geschützt sind und deren Weitergabe strengstens untersagt ist. Jede elektronische Nachricht kann geändert werden. ACTIA lehnt jede Verantwortung für diese Nachricht ab. Der Inhalt dieser Nachricht stellt keine Verpflichtung seitens unseres Unternehmens dar. Wenn Sie kein Empfänger sind, weisen wir Sie darauf hin, dass das Lesen, Vervielfältigen oder Verteilen strengstens untersagt ist. Wir bitten Sie daher, uns umgehend über diesen Brief zu informieren und diese Nachricht sowie eventuell beigefügte Unterlagen aus Ihrem Postfach zu löschen. Danke. This e-mail and the files attached to it are intended exclusively for persons or institutions whose names are listed above. They may contain information that is protected by professional secrecy and the disclosure of which is strictly prohibited. Any electronic message can be modified. ACTIA declines all responsibility for this message. The content of this message does not represent a commitment on the part of our company. If you are not a recipient, we would like to point out that reading, copying or distribution is strictly prohibited. We therefore ask you to inform us immediately about this letter and to delete this message and any accompanying documents from your mailbox. Thank you.

2 2

Boost + Emscripten: .bc files?
by Rainer Deyke 22 Apr '21

22 Apr '21

I managed to successfully compile a subset of Boost for Emscripten using the emscripten toolset. However, this for some reason produces .bc files for libraries instead of .a files, which causes link errors I try to link my project. How can I get Boost to generate .a files? (Emscripten uses .a files for libraries: https://emscripten.org/docs/compiling/Building-Projects.html#using-libraries) -- Rainer Deyke (rainerd(a)eldwood.com)

1 0