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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

Cannot build 1.76.0 for Windows (wrong path to compiler)
by Andreas Tscharner 22 Apr '21

22 Apr '21

Hello World, I try, according to the "Get started guide" >bootstrap.bat in the main boost directory. I get an error, because "C:\Program Files(x86)" ... contains a space and is not double quoted. So I replace all set "B2_CXX=%CXX% ..." with set "B2_CXX="%CXX%" ..." in tools\build\src\engine\config_toolset.bat After that I have the following problem: D:\Projects\development\QUARTIS-related\boost>.\bootstrap.bat Building Boost.Build engine LOCALAPPDATA=C:\Users\ATs\AppData\Local Found with vswhere C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise Found with vswhere C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise Call_If_Exists "C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\Common7\Tools\..\..\VC\Auxiliary\Build\vcvarsall.bat" AMD64 ********************************************************************** ** Visual Studio 2019 Developer Command Prompt v16.9.4 ** Copyright (c) 2021 Microsoft Corporation ********************************************************************** [vcvarsall.bat] Environment initialized for: 'x64' ### ### Using 'vc142' toolset. ### D:\Projects\development\QUARTIS-related\boost\tools\build\src\engine>"C:/Program Files (x86)/Microsoft Visual Studio/2019/Enterprise/VC/Tools/MSVC/14.27.29110/bin/Hostx64/x64/cl.exe" /nologo /MP /MT /TP /Feb2 /wd4996 /O2 /GL /EHsc -DNDEBUG builtins.cpp class.cpp command.cpp compile.cpp constants.cpp cwd.cpp debug.cpp debugger.cpp execcmd.cpp execnt.cpp filent.cpp filesys.cpp frames.cpp function.cpp glob.cpp hash.cpp hcache.cpp hdrmacro.cpp headers.cpp jam.cpp jamgram.cpp lists.cpp make.cpp make1.cpp md5.cpp mem.cpp modules.cpp native.cpp object.cpp option.cpp output.cpp parse.cpp pathnt.cpp pathsys.cpp regexp.cpp rules.cpp scan.cpp search.cpp jam_strings.cpp startup.cpp subst.cpp sysinfo.cpp timestamp.cpp variable.cpp w32_getreg.cpp modules/order.cpp modules/path.cpp modules/property-set.cpp modules/regex.cpp modules/sequence.cpp modules/set.cpp /link kernel32.lib advapi32.lib user32.lib Das System kann den angegebenen Pfad nicht finden. It tries to start "C:/Program Files (x86)/Microsoft Visual Studio/2019/Enterprise/VC/Tools/MSVC/14.27.29110/bin/Hostx64/x64/cl.exe". Unfortunately at my system, I don't have this path. I have C:\Program Files (x86)\Microsoft Visual Studio\2019\Enterprise\VC\Tools\MSVC\14.28.29910... Please note the different number after "MSVC" What is the problem? How can I fix this? TIA and best regards Andreas -- ("`-''-/").___..--''"`-._ `o_ o ) `-. ( ).`-.__.`) (_Y_.)' ._ ) `._ `. ``-..-' _..`--'_..-_/ /--'_.' .' (il).-'' (li).' ((!.-' Andreas Tscharner andy(a)stupidmail.ch ICQ-No. 14356454

1 0

Reminder: BinTray is shutting down 1-May
by Marshall Clow 21 Apr '21

21 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. We will be updating the web site before then, but the new location is: https://boostorg.jfrog.io/artifactory/main/release/ <https://boostorg.jfrog.io/artifactory/main/release/> So instead of downloading from: 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… This applies to all releases from 1.63.0 onward — Marshall

1 0

Boost Graph + Compute Libraries
by Muhammad Hassan Khan 20 Apr '21

20 Apr '21

Hi, I am new to boost libraries. I was wondering if I can use boost graph and boost compute libraries in one code to implement graphs on GPUs. Can you give any example if it is possible? or any other solution to it. Thank you. Regards, Hassan Khan

1 0

ASIO: acceptor::async_accept throws "Operation cancelled" after restart io_service
by Joost Kraaijeveld 19 Apr '21

19 Apr '21

Hi, In short my program: - creates an io_service - calls acceptor::async_accept - calls io_service.run - handle several connections OK - calls io_service.stop - the acceptor goes out of scope (i.e. the destructor of the owning object is ran) - calls io_service.restart - calls acceptor::async_accept which then throws "Operation cancelled" Should it be possible to do this? When/under what circumstances does async_accept throw this exception? Could it be connected with the fact that the acceptor's destructors documents that is does some cleanup but actually does nothing, from the source: /// Destroys the acceptor. /** * This function destroys the acceptor, cancelling any outstanding * asynchronous operations associated with the acceptor as if by calling * @c cancel. */ ~basic_socket_acceptor() { } OS: Linux Debian Bullseye, Boost 1.74, gcc 10 TIA Joost

3 2

[release] Boost 1.76.0
by Marshall Clow 17 Apr '21

17 Apr '21

Release 1.76.0 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 no new libraries and numerous enhancements and bug fixes for existing libraries. For details, including download links, see <http://www.boost.org/users/news/version_1.76.0> You can also download directly from: <https://boostorg.jfrog.io/artifactory/main/release/1.76.0/> To install this release on your system, see <http://www.boost.org/doc/libs/release/more/getting_started/index.html> Thanks to everyone who participated in this release. Thanks, -- The Boost Release Team Marshall Clow, Michael Caisse, Glen Fernandes

4 3

Boost.Test - test tree is empty
by Olaf Peter 17 Apr '21

17 Apr '21

Hello, I am in despair. The attached source compiles fine, but gives: $ bin/utf_dataset_loader_issue Test setup error: test tree is empty and I don't know why. It is based [Data-driven test cases parametrized from the command line <https://www.boost.org/doc/libs/1_73_0/libs/test/doc/html/boost_test/runtime…>](https://www.boost.org/doc/libs/1_73_0/libs/test/doc/html/boost_test/runtime_config/custom_command_line_arguments.html#boost_test.runtime_config.custom_command_line_arguments.data_driven_test_cases_parametri) but reduced to pure API, no cli parse, file loading etc. Any help is appreciated.

1 0

[release] Boost 1.76.0 Release Candidate 12
by Marshall Clow 14 Apr '21

14 Apr '21

The second release candidates for the 1.76.0 release are now available at: <https://boostorg.jfrog.io/artifactory/main/release/1.76.0/source/ <https://dl.bintray.com/boostorg/release/1.76.0/source/>> The SHA256 checksums are as follows: 7bd7ddceec1a1dfdcbdb3e609b60d01739c38390a5f956385a12f3122049f0ca boost_1_76_0_rc2.tar.gz 0fd43bb53580ca54afc7221683dfe8c6e3855b351cd6dce53b1a24a7d7fbeedd boost_1_76_0_rc2.zip 88782714f8701b6965f3fce087a66a1262601dd5ccd5b2e5305021beb53042a1 boost_1_76_0_rc2.7z f0397ba6e982c4450f27bf32a2a83292aba035b827a5623a14636ea583318c41 boost_1_76_0_rc2.tar.bz2 Changes from RC1: * A missing include was added to a Boost.Regex header. This fixes compilation on gcc 11. 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

3 3

Information about a Fixed Point type
by Emilio Paolini 13 Apr '21

13 Apr '21

Hi everyone, i'm new to Boost. I would like to know if there is a way, using this library, to declare a fixed point type, specifying the number of bits for the fractional part and the behaviour when overflow happens. Thank you very much. Regards, Emilio

2 2

A new home for Boost releases
by Marshall Clow 12 Apr '21

12 Apr '21

We’ve been using BinTray to host our releases for a few years, and it’s worked well for us However, JFrog is shutting down BinTray soon (at the end of this month). We have moved all the releases that were hosted on BinTray over to JFrog Artifactory. They are at https://boostorg.jfrog.io/artifactory/main/release <https://boostorg.jfrog.io/artifactory/main/release> For example, instead of: https://dl.bintray.com/boostorg/release/1.74.0/source/boost_1_74_0.tar.gz <https://dl.bintray.com/boostorg/release/1.74.0/source/boost_1_74_0.tar.gz> You should now use: https://boostorg.jfrog.io/artifactory/main/release/1.74.0/source/boost_1_74… <https://boostorg.jfrog.io/artifactory/main/release/1.74.0/source/boost_1_74…> I’ll be updating the web site soon, but if you have automation that relies on BinTray, you should update it to use the new home. — Marshall P.S. The “nightly” snapshots will live there too, as soon as we get that set up.

1 0

[release] Boost 1.76.0 Release Candidate 1
by Marshall Clow 10 Apr '21

10 Apr '21

IMPORTANT NOTE: This will be the last RC posted on BinTray! The first release candidates for the 1.76.0 release are now available at: <https://dl.bintray.com/boostorg/release/1.76.0/source/> The SHA256 checksums are as follows: aaf920e31ae815ff6b55d70a28bb614a6aa6f5cd2f6e4543461d20a4fe39df4e boost_1_76_0_rc1.7z 5dd0c91e1f0f18d452fcaa772d9c30815e449dd4fe99fadf224cca180d98cee3 boost_1_76_0_rc1.zip 5b9844335bc327272030b8050cf417178d26c8abbc64ed7aefc4d818facc1c10 boost_1_76_0_rc1.tar.gz cea1cf7609daf5bb285a625530e8d660dca51816007da7f5eb3f577b685a888d boost_1_76_0_rc1.tar.bz2 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

2 2

Multiprecision
by shady mohamed 09 Apr '21

09 Apr '21

I need to talk with mentor of this project to discuss the competency test

2 1

does boost::variant support 128 bit integer?
by David Frank 09 Apr '21

09 Apr '21

especially the gnu __int128?Thanks,David.

6 16

Multiprecision
by shady mohamed 07 Apr '21

07 Apr '21

I need to understand the competency test of multiprecision project

1 0

select_stdlib_config.hpp and <version> 1.73
by Allen Sanderson 05 Apr '21

05 Apr '21

Hello, A casual boost user and abuser here. Some specifics on my OS OS X Big Sur 11.2 Xcode 12.4 Compiler clang : Apple land version 12.0.0 Boost 1.73 - forward When select_stdlib_config.hpp is included it gets to this initial code to include the file “version" ... #if defined(__cplusplus) && defined(__has_include) # if __has_include(<version>) // It should be safe to include `<version>` when it is present without checking // the actual C++ language version as it consists solely of macro definitions. // [version.syn] p1: The header <version> supplies implementation-dependent // information about the C++ standard library (e.g., version number and release date). # include <version> ... The issue is that many projects have a file “VERSION” in their top level src directory. On a traditional Linux system the case sensitivity would make sure the right file is included. However, many/most OS X file systems are case insensitive. As such, the file VERSION gets included instead. And does not compile. I have no solution to the issue but wanted to raise it. Cheers, Allen Sanderson SCI Institute University of Utah

1 0

std::any serialization
by Isaac Lascasas 04 Apr '21

04 Apr '21

Hello, I wonder if there is a workaround to serialize std::any objects. I want to replace some old code that had similar functionality and all the types were registered via BOOST_CLASS_EXPORT_GUID. Regards.

1 0

Tried to unzip a file , and followed the example in the boost.org as well, but it doesn't work
by asfskfdjkj kfasjfkasjf 03 Apr '21

03 Apr '21

Hi guys I tried to unzip a file with code below which exactly like the example from boost.org, but it doesn't work the example is in the link which is Zlib Filters | | | | Zlib Filters | | | I tried the code like the below try{ ifstream file("d:\\202012303333629003180526491.txt.zip", ios_base::in | ios_base::binary); boost::iostreams::filtering_streambuf<boost::iostreams::input> in; in.push(boost::iostreams::zlib_decompressor()); in.push(file); boost::iostreams::copy(in, cout); return 0;}catch (const std::exception& error) { std::cerr << error.what() << std::endl; return (EXIT_FAILURE); } it's not working, it get exception when it excuted boost::iostreams::copy(in, cout); I got the zlib error: iostream stream error exception thoughwhat wrong I have done though? thank you

2 2

[Spirit] [Fusion] Concise way to construct attribute object
by Phil Endecott 28 Mar '21

28 Mar '21

Dear Experts, I currently have something like: struct S { string name; string value; }; BOOST_FUSION_ADAPT_STRUCT( S, name, value ) using S_rule = qi::rule<ITER, skipper, S()>; S_rule r %= identifier >> lit(':') >> identifier; Note that I can use %= here and I don't need to write an explicit semantic action to assign to S. Now say I modify S: class S { public: S(string name_, string value_); // May be default-constructable, copyable, assignable etc. // - but name and value are not individually assignable. }; Question: what is the best way to use that with the qi parser rule? I was hoping to find something in Fusion that would allow me to adapt the new class so that it can be used with %= as before, but I don't see anything appropriate. Currently the best that I can think of is: S_rule r = ( identifier >> lit(':') >> identifier ) [ _val = boost::phoenix::construct<S>(_1,_2) ]; How can I improve on that? Thanks, Phil.

1 0

[Core] scoped_enum and template arguments
by Alan Barr 24 Mar '21

24 Mar '21

Hi, I'm a little confused about the following statement in the docs for scoped enum: > The emulated scoped enum can not be used in switch nor in > template arguments. https://www.boost.org/doc/libs/1_75_0/libs/core/doc/html/core/scoped_enum.h… I understand the rationale for the switch statement part (and indeed it won't compile in C++03). However, I'm struggling to grasp the template argument part (and I'll be the first to admit I'm not particularly strong with templates). Unlike the switch case, any basic scenario I've thrown at it compiles. So I'm not sure if this is a case of "should not" vs "can not". When would using a "scoped_enum_type" in a template argument as opposed to "BOOST_SCOPED_ENUM_NATIVE(scoped_enum_type)" become a problem? Or, why should I use "boost::optional<BOOST_SCOPED_ENUM_NATIVE(future_errc)>" over "boost::optional<future_errc>" ? I've got a compiler explorer link with some test code here if it helps: https://godbolt.org/z/dfr6M6vrW Regards, Alan

1 0

Boost 64bit in Embarcadero C++ Builder
by Michael Morelli 17 Mar '21

17 Mar '21

Hi folks, we are testing the Boost.Test-Framework (installed with GetIt-Package Boost). We use C++ Builder 10.4.1 with Boost 1.70.0. We have created a new C++ Console-Application (with VCL enabled). Under Project->Options we have set '_TCHAR as char', because Boost.Test seems to need this mapping. It is not working with ' _TCHAR as wchar_t' The application main-entry-function is imported via #include <boost/test/included/unit_test.hpp>. The application then is run with the params : --log_level=all --report_level=detailed --build_info=true The console-output seems to be fuzzy : 1. Why is the platform win32? We use target-platform win64 and have installed boost 64bit via getit... 2. Paths are outputted with '\' and '/' 3. The fatal-error is correct but the consoleoutput 'St9exception' seems not correctly interpreted (charset ?) Are we doing something wrong or do you have some tipps regarding this ? Thx a lot. This is the console-output : [cid:image001.png@01D71B23.032439B0] Kind regards, Michael Morelli

1 0

[release] Boost 1.76.0 beta 1 released
by Marshall Clow 16 Mar '21

16 Mar '21

Boost release 1.76.0 beta 1 is now available at: <https://dl.bintray.com/boostorg/beta/1.76.0.beta1/source/> The SHA256 checksums are as follows: 39eecd9672e78b95c8e3fdec1430a63788d528a66d3c8799c4639238e5d785bd boost_1_76_0_b1.7z c32edd34f767dd4bb67b86f76ebf58cf76822a5993a9b434c028b2dd08cfeefc boost_1_76_0_b1.zip 3ec1f92fa0a159b7073e39dd88f527a55d1f35e8986a3c560f202a75bdb8d584 boost_1_76_0_b1.tar.gz eb098d6d5352e10b17a3c49d2927ed61f09b6544f7c534627de35dfa2560fe20 boost_1_76_0_b1.tar.bz2 For details of what's in the release, see <https://www.boost.org/users/history/version_1_76_0.html>. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

1 0

[release] Boost 1.76.0 Beta 1 Release Candidate 2
by Marshall Clow 13 Mar '21

13 Mar '21

The second release candidates for the 1.76.0 beta release are now available at: <https://dl.bintray.com/boostorg/beta/1.76.0.beta1/source/> The SHA256 checksums are as follows: c32edd34f767dd4bb67b86f76ebf58cf76822a5993a9b434c028b2dd08cfeefc boost_1_76_0_b1_rc2.zip eb098d6d5352e10b17a3c49d2927ed61f09b6544f7c534627de35dfa2560fe20 boost_1_76_0_b1_rc2.tar.bz2 39eecd9672e78b95c8e3fdec1430a63788d528a66d3c8799c4639238e5d785bd boost_1_76_0_b1_rc2.7z 3ec1f92fa0a159b7073e39dd88f527a55d1f35e8986a3c560f202a75bdb8d584 boost_1_76_0_b1_rc2.tar.gz The only changes from RC1 is an update to Boost.Interprocess, which was failing to compile on Mac OS X. 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

3 3

[release] Boost 1.76.0 Beta 1 Release Candidate 1
by Marshall Clow 11 Mar '21

11 Mar '21

The first release candidates for the 1.76.0 beta release are now available at: <https://dl.bintray.com/boostorg/beta/1.76.0.beta1/source/> The SHA256 checksums are as follows: a222d325cd3c9f66951ec9026eca6ff6f48dd563c9a025911d598d2aca8770ce boost_1_76_0_b1_rc1.tar.bz2 6b90b510a3de38fc30a071ac798da37545fb60a1d6b21aed1130b47c9c598977 boost_1_76_0_b1_rc1.zip b01627bd9ce934b092037da81696bb4482a44e6a31c8791dbed82eafe04b69fa boost_1_76_0_b1_rc1.tar.gz dbef57adbab1d4395d14000f0a2420fc82f87476e10d48359ceff7125a74b77a boost_1_76_0_b1_rc1.7z 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

1 3

(no subject)
by Jinlong Shen 11 Mar '21

11 Mar '21

Dear Madam/Sir, I used the boost::statechart asynchronous_state_machine to create a simple state machine. The state machine, the events and states are regular classes and are not class templates. Everything builds and works well on linux and qnx platform. However, on windows I got message that the the initial state is undefined. I think I have dealt with forward declaration well since it is build on linux and qnx. On Windows microsoft this compiler is used: Microsoft (R) C/C++ Optimizing Compiler Version 19.00.24215.1 for x64 The error message is like this. (ClCompile target) -> C:\Program Files\boost_1_64_0\boost/statechart/state_machine.hpp(701): error C2027: use of undefined type 'xxxx::FirstState' C:\Program Files\boost_1_64_0\boost/statechart/state_machine.hpp(701): error C3861: 'initial_deep_construct': identifier not found Any hint how it could be wrong with Microsoft C++? Best regards,Jinlong Shen

2 1

Boost accepted in Google Summer of Code 2021
by David Bellot 09 Mar '21

09 Mar '21

We're in again! https://github.com/boostorg/wiki/wiki/Google-Summer-of-Code%3A-2021 David

1 0

MSM and multithreading. Not clear what pattern to follow.
by Andrea Fiorito 08 Mar '21

08 Mar '21

Hi, I'm trying to use MSM to implement a client server component for my app. The client is broadcasting a msg, that servers in a local network will detect and respond. The client at that point will connect to one of the servers and interact following the network protocol. For the network and threading I'm using boost ASIO. I have 2 submachines that manage one the discovering part, and the other the connection and dialogue with one server part. I found that would be beneficial to run the submachines in one thread managed by an io_context, with the idea of stopping that context to cancel all the asynchronous operations. Unfortunately there are some weird behaviours with submachines, and not getting if I missed the right way of doing things or else. the description of my last stopper is here: https://github.com/boostorg/msm/issues/37 Is anyone able to point me on the right direction? Regards, Andrea

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CMake's PCH support and boost.test linker error
by Olaf Peter 04 Mar '21

04 Mar '21

Hello Boost users I have here a strange problem which occurs only if I try to build with precompiled headers using CMake. I've configured the project for use with dynamically linking. The error is: /usr/bin/ld: /usr/lib/gcc/x86_64-redhat-linux/10/../../../../lib64/crt1.o: in function `_start': (.text+0x24): undefined reference to `main' Something obvious? Thanks in advance The project's reduce is: ---8<--- test_driver.cpp --- 8< ---- #defineBOOST_TEST_MODULE "My Test Suite" #include<boost/test/unit_test.hpp> --->8------>8------>8--- ---8<--- test_x.cpp --- 8< ---- #include<boost/test/unit_test.hpp> .... --->8------>8------>8--- ---8<--- src/CMakeLists.txt --- 8< ---- ... set_source_files_properties(src/test_xxx.cpp APPEND PROPERTIES COMPILE_DEFINITIONS "BOOST_TEST_DYN_LINK" ) .... --->8------>8------>8------>8------>8------>8--- ---8<--- pch.pp --- 8< ---- #pragma once #include<boost/test/unit_test.hpp> --->8------>8------>8---

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How should a "using zlib ..." jam statement look, for Boost to link to ZLib in the form of SO filename (libz.so) instead of by -lz?
by Bob 03 Mar '21

03 Mar '21

Hello Boost mailing list, I am building a code project in my user home directory on OpenBSD, and doing this involves both a local build of Boost and also a local build of ZLib. I do the whole build using GCC. This is a relatively ordinary build use case, however GCC on OpenBSD (at least in its current version) has a peculiarity to it, which is that it adds to LD the argument "-L/usr/lib" in the leading position, and this means that LD's search for libz.so will find and use the operating system's bundled ZLib binary which is /usr/lib/libz.so ALWAYS, and NEVER use my local libz.so . Can you help me understand if Boost can be customized to link to ZLib in the following way: I can force GCC/LD to use a particular libz.so file, by specifying it by filename, e.g. "gcc ... libz.so ...", "gcc ... /my/dir/libz.so ...", instead of by the conventional "-lz". Boost's build process is hardwired to "-lz" and I ask you to help me understand if there is a way to circumvent that. ZLIB_LIBRARY_PATH will not make "-lz" hit anything else than /usr/lib/libz.so , per the compiler's default -L/usr/lib in leading position, so it will not be of help to solve my problem. To my best awareness ZLIB_INCLUDE has nothing to do with linking, so it will not be of help to solve my problem. ZLIB_NAME would only be to customize the library name would it e.g. to "-lmycustomz", or what is it for? Please clarify so I could figure if it could be of help, though ideally i keep my local ZLib having its default name "libz.so". And this brings me to the path of solving the problem that I imagine could work, but that I don't understand fully from the Boost documentation: There is the possibility to customize ZLib build settings through the JAM configuration, that is user-config.jam . The syntax used is "using zlib ...". Can you please help me understand if this route works, if so how would that "using zlib ..." statement look, such that Boost's build process will NOT build ZLib itself, and then will NOT link to it via "-lz", but will instead link to it by "$MYCUSTOMBUILDDIR/libz.so"?

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Boost.Python + `RecursionError` during deallocation
by Andrew Jones 01 Mar '21

01 Mar '21

Hi, I just raised the following issue on the Python issue tracker: https://bugs.python.org/issue43351 But I'm sharing it here to widen the net ... Basically, when moving from Python 2.7.14 to Python 3.7.5, and when using Boost.Python (Boost version 1.6.9), I'm seeing a crash in finalisation due to: ``` Exception ignored in: <Boost.Python.life_support object at 0x2acf473c5d10> RecursionError: maximum recursion depth exceeded while calling a Python object Fatal Python error: Cannot recover from stack overflow. ``` Everything else with the Python that's running, and the Boost.Python interface, is consistent between 2.7.14 and 3.7.5 -- it is just the Python version that's changing. I should say, Python 3.7.5 does otherwise seem operable, it just falls over when running this certain code (which just walks a linked-list of ~1400 elements via Boost.Python). Has anyone seen anything like this before? Does this list feel this is more likely a Python-proper issue, or a Boost.Python issue? Cheers, Andrew

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[boost::units] Best practices for implementing custom units and quantities
by Alexandru Onea 01 Mar '21

01 Mar '21

Hello community, I am working on a project which works with units such as scale intervals (cents, moria, etc.) depending on the temperament system used (24-EDO, 72-EDO, etc.). My implementation defines a namespace for each tuning system. Within the namespaces I define base units, units and a system, as well as conversion factors between the systems. The base dimension is defined in only one of the namespaces (corresponding to the tuning system which I consider "standard" which is the 1200 cents per octave system). 1. Does such an approach qualify as a good approach in general (leaving aside the musical aspects)? 2. Is it a good practice to place all these namespaces in boost::units (extend boost::units)? Or should I keep them within my own namespaces? Learning the answer to #2 is more interesting to me, even in the absence of an answer to #1. Best regards, Alexandru Onea

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Question about Boost Integer
by Emilio Paolini 28 Feb '21

28 Feb '21

Hi everyone, i'm pretty new to Boost. I need to use as a default type for the CNL. The problem is that i would need an integer type that can assume only 2^4 values (so basically that stays on 4 bits). What i am asking is that if there is a way to define an integer like int128_t but instead of 128 i would need to have 4. Thank you very much for your answers. Emilio

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flyweights, nested flyweights and shared libraries
by Andreas Buykx 25 Feb '21

25 Feb '21

I want to use boost::flyweight to capture some structures containing const data. The documentation states that if flyweights are exported across shared library boundaries that the intermodule holder should be used. Since my flyweights are all created in the same shared library I would prefer to use the static holder but I keep getting crashes. I tried the intermodule holder but I'm having trouble compiling my sources with that. So my thinking was to wrap all flyweight types in accessor classes which are exposed instead, and the accessor classes create the flyweights within the same shared library to store the data. Would that be a valid approach? Also, is it possible to have nested flyweights (when they are wrapped by accessor classes)? And would that cause any additional problems in the above scenario? Below is an example of what I'm trying to achieve... Thanks for your advice! Andreas === Foo.h === struct FooDetails { FooDetails( std::string text_, std::vector<double> values ); std::string text; std::vector<double> values; }; class STUFF_EXPORT Foo { public: Foo( std::string text_, std::vector<double> values ); // rule-of-5 constructors declared, and default-implemented in cpp file const std::string& text() const; const std::vector<double>& values() const; private: boost::flyweight<FooDetails> m_data; }; === Foo.cpp === FooDetails( ( std::string text_, std::vector<double> values_ ) : text(text_), values( values_ ) { } Foo::Foo( std::string text_, std::vector<double> values_ ) m_data( FooDetails( text_, values_ ) ) { } std::string Foo::text() const { return m_data.get().text; } std::vector<double> Foo::values() const { return m_data.get().values; } === Bar.h === struct BarDetails { BarDetails( Foo foo_, std::vector<long> ids_ ); Foo foo; //< Foo holds a flyweight std::vector<long> ids; }; class STUFF_EXPORT Bar { public: Bar( std::string text_, std::vector<double> values_, std::vector<long> ids_ ); // rule-of-5 constructors declared, and default-implemented in cpp file const std::string& text() const; const std::vector<double>& values() const; const std::vector<long>& ids() const; private: boost::flyweight<BarDetails> m_bar; }; === Bar.cpp === BarDetails::BarDetails( Foo foo_, std::vector<long> ids_ ) : foo( foo_ ), ids( ids_ ) { } Bar::Bar( std::string text_, std::vector<double> values_, std::vector<long> ids_ ) : m_bar( Foo( text_, values), ids_ ) { } const std::string& Bar::text() const { return m_bar.get().m_foo.text(); } const std::vector<double>& Bar::values() const { return m_bar.get().foo.values(); } const std::vector<long>& Bar::ids() const { return m_bar.get().ids; }

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Re: [Boost-users] Boost-users Digest, Vol 5456, Issue 1
by philippe DALET 23 Feb '21

23 Feb '21

Hi, I have built some binaries for boost and python https://sourceforge.net/projects/pcpu/files/Boost/ boost 1.71 python3.7&numpy3.7 for ubuntu 20.04 64 bits boost 1.75 python3.789&numpy3.789 for visual studio 2019 mscv14.2 - win10 Ph.DALET Le mar. 23 févr. 2021 à 11:03, <boost-users-request(a)lists.boost.org> a écrit : > Send Boost-users mailing list submissions to > boost-users(a)lists.boost.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.boost.org/mailman/listinfo.cgi/boost-users > or, via email, send a message with subject or body 'help' to > boost-users-request(a)lists.boost.org > > You can reach the person managing the list at > boost-users-owner(a)lists.boost.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Boost-users digest..." > > > Today's Topics: > > 1. Re: Boost cannot find numpy37 on Dockerized Ubuntu 20.04 > (Roy de Bokx) > 2. Re: flyweights, nested flyweights and shared libraries > (Andreas Buykx) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Mon, 22 Feb 2021 15:49:11 +0100 > From: Roy de Bokx <rdebokx1990(a)gmail.com> > To: boost-users(a)lists.boost.org > Subject: Re: [Boost-users] Boost cannot find numpy37 on Dockerized > Ubuntu 20.04 > Message-ID: > < > CAFLoxwXy8_an1jZh_PQMkjppbOWyixvR5Exw1DCeaUyV9xDfBA(a)mail.gmail.com> > Content-Type: text/plain; charset="utf-8" > > Op vr 19 feb. 2021 om 22:05 schreef Nathan Ernst via Boost-users < > boost-users(a)lists.boost.org>: > > > The missing symbols you quoted come from python itself. It looks like > > you're missing a "-lpython" linker flag. > > > Thanks! That definitely put me on the right track. Eventually I got it > working using the "-lpython3.6m" flag, since I found that the Python3.6 .so > file was situated at /usr/lib/x86_64-linux-gnu/libpython3.6m.so > Many thanks, this is much appreciated! I've pasted the full Dockerfile in > https://github.com/boostorg/boost/issues/462, in case anyone is > interested. > > > > > Regards, > > Nathan > > > > On Fri, Feb 19, 2021, 4:47 AM Roy de Bokx via Boost-users < > > boost-users(a)lists.boost.org> wrote: > > > >> > >> > >> Op wo 17 feb. 2021 om 20:30 schreef Anonymous Maarten < > >> anonymous.maarten(a)gmail.com>: > >> > >>> Thanks for your answer Maarten! > >>>> Please bare with me as I'm a little new to this. Is there some way I > >>>> can change the interpreter that is used for installing boost? Or do > you > >>>> think that adapting the --prefix flag may also work? > >>>> > >>> > >>> When using the pre-built boost packages of a linux distribution > >>> (ubuntu), you're generally stuck with the versions/options that its > >>> packagers have chosen. > >>> A distribution freezes versions to make a more robust experience. > >>> > >>> Adding a `--prefix` will not help because, first of all, it's not a > >>> valid gcc option, and second, ubuntu 18.04 does not provide a > >>> libboost-python-py37 shared/static library. > >>> Do you really need python 3.7? Doesn't 3.6 suffice? > >>> > >> > >> Thanks! This helped me understanding the issue a bit further. I think > 3.6 > >> should suffice indeed, so I tried using 3.6 by removing the 3.7 > >> installation from the Dockerfile and using the -lboost_numpy3 flag > instead. > >> It seems I ran into some linking issue after this. It was able to find > >> the right numpy3.so and libboost_python3-py36.so, but I'm getting a lot > of > >> errors like these: > >> > >> //usr/lib/x86_64-linux-gnu/libboost_numpy3.so: undefined reference to > >> `PyExc_ValueError' > >> > >> //usr/lib/x86_64-linux-gnu/libboost_python3-py36.so.1.65.1: undefined > >> reference to `PyLong_AsLong' > >> > >> //usr/lib/x86_64-linux-gnu/libboost_python3-py36.so.1.65.1: undefined > >> reference to `PyNumber_InPlaceFloorDivide' > >> > >> //usr/lib/x86_64-linux-gnu/libboost_python3-py36.so.1.65.1: undefined > >> reference to `PyBool_Type' > >> etc... > >> > >> I've pasted the full docker file and logs in > >> https://github.com/boostorg/boost/issues/462 > >> Thanks again for any help. > >> > >>> > >>> If you really want to use Boost.Python + python 3.7, you can do 2 > things: > >>> - stay on ubuntu bionic and build boost yourself (or use an alternative > >>> c/c++ package manager, e.g. [conan](https://conan.io/) has a [boost > >>> package](https://conan.io/center/boost)) > >>> - more to a more recent ubuntu release. e.g. ubuntu 20.10 has python > >>> 3.8: > >>> > https://packages.ubuntu.com/groovy/amd64/libboost-python1.71-dev/filelist > >>> > >> I've also given 20.10 a try, however I ran into the same linking issues > >> as mentioned above. > >> > >>> > >>> > >>> > >>> _______________________________________________ > >> Boost-users mailing list > >> Boost-users(a)lists.boost.org > >> https://lists.boost.org/mailman/listinfo.cgi/boost-users > >> > > _______________________________________________ > > Boost-users mailing list > > Boost-users(a)lists.boost.org > > https://lists.boost.org/mailman/listinfo.cgi/boost-users > > >

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Re: [Boost-users] Boost cannot find numpy37 on Dockerized Ubuntu 20.04
by Roy de Bokx 22 Feb '21

22 Feb '21

Op wo 17 feb. 2021 om 20:30 schreef Anonymous Maarten < anonymous.maarten(a)gmail.com>: > Thanks for your answer Maarten! >> Please bare with me as I'm a little new to this. Is there some way I can >> change the interpreter that is used for installing boost? Or do you think >> that adapting the --prefix flag may also work? >> > > When using the pre-built boost packages of a linux distribution (ubuntu), > you're generally stuck with the versions/options that its packagers have > chosen. > A distribution freezes versions to make a more robust experience. > > Adding a `--prefix` will not help because, first of all, it's not a valid > gcc option, and second, ubuntu 18.04 does not provide a > libboost-python-py37 shared/static library. > Do you really need python 3.7? Doesn't 3.6 suffice? > Thanks! This helped me understanding the issue a bit further. I think 3.6 should suffice indeed, so I tried using 3.6 by removing the 3.7 installation from the Dockerfile and using the -lboost_numpy3 flag instead. It seems I ran into some linking issue after this. It was able to find the right numpy3.so and libboost_python3-py36.so, but I'm getting a lot of errors like these: //usr/lib/x86_64-linux-gnu/libboost_numpy3.so: undefined reference to `PyExc_ValueError' //usr/lib/x86_64-linux-gnu/libboost_python3-py36.so.1.65.1: undefined reference to `PyLong_AsLong' //usr/lib/x86_64-linux-gnu/libboost_python3-py36.so.1.65.1: undefined reference to `PyNumber_InPlaceFloorDivide' //usr/lib/x86_64-linux-gnu/libboost_python3-py36.so.1.65.1: undefined reference to `PyBool_Type' etc... I've pasted the full docker file and logs in https://github.com/boostorg/boost/issues/462 Thanks again for any help. > > If you really want to use Boost.Python + python 3.7, you can do 2 things: > - stay on ubuntu bionic and build boost yourself (or use an alternative > c/c++ package manager, e.g. [conan](https://conan.io/) has a [boost > package](https://conan.io/center/boost)) > - more to a more recent ubuntu release. e.g. ubuntu 20.10 has python 3.8: > https://packages.ubuntu.com/groovy/amd64/libboost-python1.71-dev/filelist > I've also given 20.10 a try, however I ran into the same linking issues as mentioned above. > > > >

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Prooblem building software with fstream.hpp
by Mack Wallace 21 Feb '21

21 Feb '21

Hi all. I'm a noob and unfamiliar with boost. It has also been a long time since I have done any C++ programming. In any case, here are the details: I am trying to compile MecnRao/TCP-UDP-Proxy that uses the Boost Library. I am trying to compile this for Windows, ultimately Windows 10, but at the moment trying to compile on my Windows 7 VM. I am using Visual Studio Pro 2019. After trying the latest version of the Boost Library with some errors due to some deprecated members, I bounced around older versions until finding that Version 1.68.0 reduced my compile errors substantially, and of those 20 or so errors, are caused by some typedef problems in fstream.hpp. (I could be wrong, but the errors all seem to be related to fstream_fix.) Specifically, I get the following errors to begin with: 'fstream_fix<std::basic_ifstream<char,std::char_traits<char> > >' is not a variable template 'fstream_fix<std::basic_ofstream<char,std::char_traits<char> > >' is not a variable template This comes from the following lines in the fstream.hpp typedef basic_ifstream<char> ifstream; typedef basic_ofstream<char> ofstream; Where ifstream and ofstream are indicated as being redefined as #define ifstream fstream_fix<std::ifstream> #define ofstream fstream_fix<std::ofstream> Within the program with fstream_fix as template<class T> struct fstream_fix : public T { fstream_fix(){}; template<class T1> fstream_fix(T1 v1){ setlocale(LC_CTYPE, ""); T::open(v1); setlocale(LC_CTYPE, 0); } template<class T1,class T2> fstream_fix(T1 v1,T2 v2){ setlocale(LC_CTYPE, ""); T::open(v1,v2); setlocale(LC_CTYPE, 0); } template<class T1> void open(T1 v1){ setlocale(LC_CTYPE, ""); T::open(v1); setlocale(LC_CTYPE, 0); } template<class T1,class T2> void open(T1 v1,T2 v2){ setlocale(LC_CTYPE, ""); T::open(v1,v2); setlocale(LC_CTYPE, 0); } }; So I'm wondering if this is a newer/different compiler issue? Or the application itself? Or maybe just missing something like uses namespace std. I am hoping someone can help me nip this last problem so I can get this compiled. Thanks, Mack

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boost::asio::read() gets stuck when there's no internet
by Child OfGod 20 Feb '21

20 Feb '21

In TgBot library i use under MSVC++, in tgbot/net/BoostHttpOnlySslClient.cpp, a call to boost::asio::read() does not return when internet is disconnected for a few minutes. I would appreciate any help to get this resolved, i.e. for the read function to return if it fails after some timeout has passed the code block in the tgbot/net/BoostHttpOnlySslClient.cpp file: [code] string BoostHttpOnlySslClient::makeRequest(const Url& url, const vector<HttpReqArg>& args) const { tcp::resolver resolver(_ioService); tcp::resolver::query query(url.host, "443"); ssl::context context(ssl::context::tlsv12_client); context.set_default_verify_paths(); ssl::stream<tcp::socket> socket(_ioService, context); connect(socket.lowest_layer(), resolver.resolve(query)); #ifdef TGBOT_DISABLE_NAGLES_ALGORITHM socket.lowest_layer().set_option(tcp::no_delay(true)); #endif //TGBOT_DISABLE_NAGLES_ALGORITHM #ifdef TGBOT_CHANGE_SOCKET_BUFFER_SIZE #if _arm64 || _WIN64 || __amd64__ || __x86_64__ || __MINGW64__ || __aarch64__ || __powerpc64__ socket.lowest_layer().set_option(socket_base::send_buffer_size(65536)); socket.lowest_layer().set_option(socket_base::receive_buffer_size(65536)); #else //for 32-bit socket.lowest_layer().set_option(socket_base::send_buffer_size(32768)); socket.lowest_layer().set_option(socket_base::receive_buffer_size(32768)); #endif //Processor architecture #endif //TGBOT_CHANGE_SOCKET_BUFFER_SIZE socket.set_verify_mode(ssl::verify_none); socket.set_verify_callback(ssl::rfc2818_verification(url.host)); socket.handshake(ssl::stream<tcp::socket>::client); string requestText = _httpParser.generateRequest(url, args, false); write(socket, buffer(requestText.c_str(), requestText.length())); string response; #ifdef TGBOT_CHANGE_READ_BUFFER_SIZE #if _M_ARM64 || _WIN64 || __amd64__ || __x86_64__ || __MINGW64__ || __aarch64__ || __powerpc64__ char buff[65536]; #else //for 32-bit char buff[32768]; #endif //Processor architecture #else char buff[1024]; #endif //TGBOT_CHANGE_READ_BUFFER_SIZE boost::system::error_code error; while (!error) { std::size_t bytes = read(socket, buffer(buff), error); response += string(buff, bytes); } return _httpParser.extractBody(response); } [/code] Thankyou in advance😀🙏

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(no subject)
by Dk Jack 18 Feb '21

18 Feb '21

Hi, I am using boost 1.58 in my project. Ran into a crash in the boost filesystem library. I've included the relevant stack trace at the end of the email. My code is something like this: boost::filesystem::path fpath(mFilename.c_str()); if (!boost::filesystem::exists(fpath)) { // log a message and return. return; } auto curr_time = boost::filesystem::last_write_time(fpath); <== crash The crash is not consistent and happened randomly. I tested the above code in a small test program with just the above code. I made the input file unreadable etc, even then it was able to successfully read the last write timestamp of the file without any issues. Not sure why this particular call would throw an error. Since it's compiled with -O2, the error code is optimized out in the stack trace. Any ideas? Thanks for your help. Dk. (gdb) bt #0 0x00007f01651ba387 in raise () from /lib64/libc.so.6 #1 0x00007f01651bba78 in abort () from /lib64/libc.so.6 #2 0x00007f0160d087d5 in __gnu_cxx::__verbose_terminate_handler() () from /lib64/libstdc++.so.6 #3 0x00007f0160d06746 in ?? () from /lib64/libstdc++.so.6 #4 0x00007f0160d06773 in std::terminate() () from /lib64/libstdc++.so.6 #5 0x00007f0160d06993 in __cxa_throw () from /lib64/libstdc++.so.6 #6 0x00007f0161171f5f in boost::filesystem::detail::last_write_time(boost::filesystem::path const&, boost::system::error_code*) () from xxx.so #7 0x00007f0161089657 in last_write_time (p=...) at /usr/local/include/boost/filesystem/operations.hpp:594

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