- Boost - lists.preview.boost.org

regarding boost::exception
by rajesh daggumati 18 Oct '21

18 Oct '21

Hi Team, I need to create an object for catched exception . class exception: virtual public std::exception ,virtual public boost::exception {} inside my application code, try{ boost::rethrow_exception(exceptr)} catch(std::exception &e) { std::exception *e = stacktoHeapObject(e); } static std::exception* stacktoHeapObj(std::exception* e) { if (dynamic_cast<std::bad_alloc*>(e)) { return new std::bad_alloc(*(dynamic_cast<std::bad_alloc*>(e))); } else if (dynamic_cast<std::bad_cast*>(e)) { return new std::bad_cast(*(dynamic_cast<std::bad_cast*>(e))); } else if (dynamic_cast<std::bad_typeid*>(e)) { return new std::bad_typeid(*(dynamic_cast<std::bad_typeid*>(e))); } else if (dynamic_cast<std::bad_exception*>(e)) { return new std::bad_exception(*(dynamic_cast<std::bad_exception*>(e))); } else if (dynamic_cast<std::domain_error*>(e)) { return new std::domain_error(*(dynamic_cast<std::domain_error*>(e))); } else if (dynamic_cast<std::invalid_argument*>(e)) { return new std::invalid_argument(*(dynamic_cast<std::invalid_argument*>(e))); } else if (dynamic_cast<std::length_error*>(e)) { return new std::length_error(*(dynamic_cast<std::length_error*>(e))); } else if (dynamic_cast<std::out_of_range*>(e)) { return new std::out_of_range(*(dynamic_cast<std::out_of_range*>(e))); } else if (dynamic_cast<std::overflow_error*>(e)) { return new std::overflow_error(*(dynamic_cast<std::overflow_error*>(e))); } else if (dynamic_cast<std::range_error*>(e)) { return new std::range_error(*(dynamic_cast<std::range_error*>(e))); } else if (dynamic_cast<std::underflow_error*>(e)) { return new std::underflow_error(*(dynamic_cast<std::underflow_error*>(e))); } else if (dynamic_cast<std::runtime_error*>(e)) { return new std::runtime_error(*(dynamic_cast<std::runtime_error*>(e))); } else if (dynamic_cast<std::exception*>(e)) { return new std::exception(*(dynamic_cast<std::exception*>(e))); } } I have coded by taking order reference of below pic. please help me to get classes names in boost:exception which are not in std::exception . if they are in boost::exception only then how to catch that and send to stackToHeapObj and what order i need to follow to add those if checks. try { boost::rethrow_exception(exptr) } here in catch block , we don't know which exception type we have in exptr(ie. std:: or boost:;) then How to catch them. if i use std::exception in catch block then if exptr throws boost::exception type then ... and viceversa..? Please help me to clarify above queries [image: image.png]

3 6

Opinions on merging Assert, StaticAssert, ThrowException into Core
by Nikita Kniazev 17 Oct '21

17 Oct '21

Recently Core grew with additional dependencies on StaticAssert (in 1.76) and ThrowException (in the next release), previously it was only depending on Assert and Config. That made a lot of libraries checkout the same four repositories, three of them containing only a few headers. Merging into a single dependency will affect mostly positive about 100 libraries and negative 1: StlInterfaces (depends on Assert, and will on Core). Please leave a comment at https://github.com/boostorg/core/issues/97 if you think it is a good idea, or have concerns against doing that.

7 14

No more cycles going forward
by Glen Fernandes 16 Oct '21

16 Oct '21

Boost 1.77.0 released with no dependency cycles between libraries. This wasn't easy to achieve and we want to preserve it, going forward. We should not regress and allow libraries to introduce dependency cycles in any future Boost release. i.e. Doing so should be considered a release blocker. Currently, such a regression exists (introduced last month in Context): Asio -> Coroutine -> Context -> Asio It should be fixed before we lock the branches for the 1.78 release, or we should not take this change in the release. Glen

3 3

[Q] Help needed with boost::log, filters and a custom sink backend
by Volker 15 Oct '21

15 Oct '21

Dear Boost experts! I'm new to this list, so please have mercy if I'm not yet familiar with your best practices. Recently, I have been pulling my hair out while trying to use boost::log for a severity-logger-type functionality where the sink backend is not compatible with std::ostream. Best bet was to implement a custom sink backend that does the job in its consume() member. However, I can't get the attribute value for the severity level extracted to an int. For sure, there's something totally obvious I'm missing... Here's the source code (slightly abbreviated): #include <string> #include <boost/log/core.hpp> #include <boost/log/expressions.hpp> #include <boost/log/sinks/basic_sink_backend.hpp> #include <boost/log/sinks/sync_frontend.hpp> #include <boost/log/sources/logger.hpp> #include <boost/log/sources/severity_logger.hpp> #include <boost/log/trivial.hpp> #include <boost/smart_ptr/make_shared_object.hpp> #include <boost/smart_ptr/shared_ptr.hpp> namespace logging = boost::log; namespace sinks = boost::log::sinks; void SomeLogChannel(int severity, const std::string& message) {} class SinkBackend : public sinks::basic_sink_backend<sinks::synchronized_feeding> { public: explicit SinkBackend() {} void consume(logging::record_view const& rec) { std::string message = *rec[boost::log::expressions::smessage]; int severity = 0; if (rec.attribute_values().count("Severity")) { // severity = rec.attribute_values()["Severity"].extract<int>(); // cannot convert from 'boost::log::v2s_mt_nt6::value_ref<T,TagT>' to 'int' with T=int, TagT=void } SomeLogChannel(severity, message); } }; void init_logging() { typedef sinks::synchronous_sink<SinkBackend> sink_t; boost::shared_ptr<logging::core> core = logging::core::get(); boost::shared_ptr<SinkBackend> backend(new SinkBackend()); boost::shared_ptr<sink_t> sink(new sink_t(backend)); core->add_sink(sink); core->set_filter(logging::trivial::severity >= logging::trivial::error); } int main(int, char* []) { init_logging(); boost::log::sources::severity_logger< logging::trivial::severity_level > lg; BOOST_LOG_SEV(lg, logging::trivial::trace) << "Trace message"; BOOST_LOG_SEV(lg, logging::trivial::error) << "Error message"; return 0; } If this is a clumsy approach and there's a more elegant solution to feed log messages into SomeLogChannel() (in reality, it's a bit more complex because it involves a class, a couple interfaces, etc.), don't hesitate to comment as well. I'm still trying to wrap my mind around the topic. Thanks a bunch in advance and greets, Volker -- @: boost(a)bartheld.net

1 0

regarding spurious wakeup in boost 1.76
by Daggumati, Rajesh 13 Oct '21

13 Oct '21

HI Team, I have been facing an issue regarding conditionvariable.timed_wait() This function is returning false everywhere in my code(windows platform). It not waiting for notify signal. conditionvariable.timed_wait(lock1,boost::posix_time::milliseconds(100)) I have found same issue information in google. [Thread] thousands of spurious wakeups from timed_wait() per second (narkive.com)<https://boost-users.boost.narkive.com/xu7advkY/thread-thousands-of-spurious…> did this issue get fixed in boost 1.76.0? Please help me how to fix this issue. Regards, Rajesh D Please be advised that this email may contain confidential information. If you are not the intended recipient, please notify us by email by replying to the sender and delete this message. The sender disclaims that the content of this email constitutes an offer to enter into, or the acceptance of, any agreement; provided that the foregoing does not invalidate the binding effect of any digital or other electronic reproduction of a manual signature that is included in any attachment.

1 2

Evolving Boost.ContainerHash
by Peter Dimov 13 Oct '21

13 Oct '21

I've been thinking of updating and evolving Boost.ContainerHash, so I e-mailed Daniel James to see what his thoughts on that are. He says he's not going to come back to it, since he's moved on from C++. (Why would anyone do so is beyond me. :-)) More specifically, what I'm envisaging is updating boost::hash to take a seed: template<class T> struct hash { hash(); // as before explicit hash( size_t seed ); size_t operator()(T const& v) { return detail::hash_combine(seed, hash_value(v)); } }; The public hash_combine then becomes: template<class T> void hash_combine( size_t& seed, T const& v ) { return hash<T>(seed)(v); } This allows passing seeded hashes to unordered containers, without any changes to the latter: std::unordered_map<std::string, int, boost::hash<std::string>> map( 0, boost::hash<std::string>( 0x12345678 ) ); Seeding user-exposed hash tables is a good security practice which prevents (or makes less likely) some DoS attacks. The combiner function, detail::hash_combine, will also need to be updated to something that is state of the art for 2021, rather than for 2004. (ContainerHash is already using a more modern implementation of hash_combine, but not in all cases.) The implementation can be cleaned up by removing the C++98 era workarounds for compilers not supporting partial specialization, function template ordering, or argument-dependent lookup. The documentation is also due to a refresh, as the mentions of TR1 are no longer relevant. I also think that Boost.ContainerHash should just be renamed to Boost.Hash as that's what it is - it defines boost::hash. So, I am thinking of taking over ContainerHash and doing all that, if there are no objections.

2 3

[CMake] Can/should we specify optional dependencies
by John Maddock 11 Oct '21

11 Oct '21

I have a regex bug report relating to linking to ICU when using CMake: https://github.com/boostorg/regex/issues/143 Is there a correct way to specify in the CMake file that if you use header X, then you should also link to library Y, but otherwise not? Thanks, John. -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

5 9

Boost::posixtime issue
by mahesh pramod 07 Oct '21

07 Oct '21

Hi , I am getting false always for this timed_wait function . does posix_time supports in windows as its not looking for notify signal. scoped_lock_t lock(m_mutex); EXPECT_TRUE(m_condition_variable.timed_wait(lock, boost::posix_time::milliseconds(500))) << "Should get signalled (true) not time out";

1 0

boost::posix_time issue
by mahesh pramod 06 Oct '21

06 Oct '21

Hi , I am getting false always for this timed_wait function . does posix_time supports in windows as its not looking for notify signal. scoped_lock_t lock(m_mutex); EXPECT_TRUE(m_condition_variable.timed_wait(lock, boost::posix_time::milliseconds(500))) << "Should get signalled (true) not time out";

1 0

MSYS2 - MinGW64 - Windows 10 Pro - GCC 10.2.0 - undefined references
by Jens Kallup 05 Oct '21

05 Oct '21

Hello Community, I running Windows 10 Pro. MSYS2 - MinGW64-bit with gcc/g++ 10.2.0. I have download the 1_77 Version of Boost, compile it with b2 in the msys2 shell terminal. I could not replace cxx11 to cxx17. All options to build.bat, and b2.exe/sh to switch to cxx17 have not be worked. I downwrite the simple "Boost.program_options" example. I could compile it without any errors or warnings. But I ran into trouble at link stage. I have tried libs for x32/64, single/multi thread, debug/release, static/dynamic. All ends up with the same error of undefined reference explained below. Here comes the known source code to the problem: ---%<--- # include <boost/program_options.hpp> # include "common.h" namespace po = boost::program_options; int main(int argc, char *argv[]) { try { po::options_description desc("Allowed Options"); desc.add_options() ("help", "shows the help page") ("compression", po::value<int>(), "set compression level") ; po::variables_map vm; po::store(po::parse_command_line(argc, argv, desc), vm); po::notify(vm); if (vm.count("help")) { std::cout << desc << std::endl; return SUCCESS; } if (vm.count("compression")) { std::cout << "Compression level was set to " << vm["compression"].as<int>() << "." << std::endl; } else { std::cout << "Compression level was not set." << std::endl; } } catch(...) { std::cerr << "caugth a error.\n"; return FAILURE; } return SUCCESS; } --->%--- Here is a list of the files that are generated during the build time: devlab1@rk1700 MINGW64 /e/Projekte/news $ dir ../boost_1_77_0/stage/lib/ cmake libboost_atomic-mgw10-mt-d-x32-1_77.a libboost_atomic-mgw10-mt-d-x64-1_77.a libboost_atomic-mgw10-mt-s-x64-1_77.a libboost_atomic-mgw10-mt-x32-1_77.a libboost_atomic-mgw10-mt-x64-1_77.a libboost_chrono-mgw10-mt-d-x32-1_77.a libboost_chrono-mgw10-mt-d-x64-1_77.a libboost_chrono-mgw10-mt-s-x64-1_77.a libboost_chrono-mgw10-mt-x32-1_77.a libboost_chrono-mgw10-mt-x64-1_77.a libboost_container-mgw10-mt-d-x32-1_77.a libboost_container-mgw10-mt-d-x64-1_77.a libboost_container-mgw10-mt-s-x64-1_77.a libboost_container-mgw10-mt-x32-1_77.a libboost_container-mgw10-mt-x64-1_77.a libboost_context-mgw10-mt-d-x32-1_77.a libboost_context-mgw10-mt-d-x64-1_77.a libboost_context-mgw10-mt-s-x64-1_77.a libboost_context-mgw10-mt-x32-1_77.a libboost_context-mgw10-mt-x64-1_77.a libboost_contract-mgw10-mt-d-x32-1_77.a libboost_contract-mgw10-mt-d-x64-1_77.a libboost_contract-mgw10-mt-s-x64-1_77.a libboost_contract-mgw10-mt-x32-1_77.a libboost_contract-mgw10-mt-x64-1_77.a libboost_coroutine-mgw10-mt-d-x32-1_77.a libboost_coroutine-mgw10-mt-d-x64-1_77.a libboost_coroutine-mgw10-mt-s-x64-1_77.a libboost_coroutine-mgw10-mt-x32-1_77.a libboost_coroutine-mgw10-mt-x64-1_77.a libboost_date_time-mgw10-mt-d-x32-1_77.a libboost_date_time-mgw10-mt-d-x64-1_77.a libboost_date_time-mgw10-mt-s-x64-1_77.a libboost_date_time-mgw10-mt-x32-1_77.a libboost_date_time-mgw10-mt-x64-1_77.a libboost_exception-mgw10-mt-d-x32-1_77.a libboost_exception-mgw10-mt-d-x64-1_77.a libboost_exception-mgw10-mt-s-x64-1_77.a libboost_exception-mgw10-mt-x32-1_77.a libboost_exception-mgw10-mt-x64-1_77.a libboost_fiber-mgw10-mt-d-x64-1_77.a libboost_fiber-mgw10-mt-s-x64-1_77.a libboost_fiber-mgw10-mt-x64-1_77.a libboost_filesystem-mgw10-mt-d-x32-1_77.a libboost_filesystem-mgw10-mt-d-x64-1_77.a libboost_filesystem-mgw10-mt-s-x64-1_77.a libboost_filesystem-mgw10-mt-x32-1_77.a libboost_filesystem-mgw10-mt-x64-1_77.a libboost_graph-mgw10-mt-d-x32-1_77.a libboost_graph-mgw10-mt-d-x64-1_77.a libboost_graph-mgw10-mt-s-x64-1_77.a libboost_graph-mgw10-mt-x32-1_77.a libboost_graph-mgw10-mt-x64-1_77.a libboost_iostreams-mgw10-mt-d-x32-1_77.a libboost_iostreams-mgw10-mt-d-x64-1_77.a libboost_iostreams-mgw10-mt-s-x64-1_77.a libboost_iostreams-mgw10-mt-x32-1_77.a libboost_iostreams-mgw10-mt-x64-1_77.a libboost_json-mgw10-mt-d-x32-1_77.a libboost_json-mgw10-mt-d-x64-1_77.a libboost_json-mgw10-mt-s-x64-1_77.a libboost_json-mgw10-mt-x32-1_77.a libboost_json-mgw10-mt-x64-1_77.a libboost_locale-mgw10-mt-d-x32-1_77.a libboost_locale-mgw10-mt-d-x64-1_77.a libboost_locale-mgw10-mt-s-x64-1_77.a libboost_locale-mgw10-mt-x32-1_77.a libboost_locale-mgw10-mt-x64-1_77.a libboost_log-mgw10-mt-d-x32-1_77.a libboost_log-mgw10-mt-d-x64-1_77.a libboost_log-mgw10-mt-s-x64-1_77.a libboost_log-mgw10-mt-x32-1_77.a libboost_log-mgw10-mt-x64-1_77.a libboost_log_setup-mgw10-mt-d-x32-1_77.a libboost_log_setup-mgw10-mt-d-x64-1_77.a libboost_log_setup-mgw10-mt-s-x64-1_77.a libboost_log_setup-mgw10-mt-x32-1_77.a libboost_log_setup-mgw10-mt-x64-1_77.a libboost_math_c99-mgw10-mt-d-x64-1_77.a libboost_math_c99-mgw10-mt-s-x64-1_77.a libboost_math_c99-mgw10-mt-x64-1_77.a libboost_math_c99f-mgw10-mt-d-x64-1_77.a libboost_math_c99f-mgw10-mt-s-x64-1_77.a libboost_math_c99f-mgw10-mt-x64-1_77.a libboost_math_c99l-mgw10-mt-d-x64-1_77.a libboost_math_c99l-mgw10-mt-s-x64-1_77.a libboost_math_c99l-mgw10-mt-x64-1_77.a libboost_math_tr1-mgw10-mt-d-x64-1_77.a libboost_math_tr1-mgw10-mt-s-x64-1_77.a libboost_math_tr1-mgw10-mt-x64-1_77.a libboost_math_tr1f-mgw10-mt-d-x64-1_77.a libboost_math_tr1f-mgw10-mt-s-x64-1_77.a libboost_math_tr1f-mgw10-mt-x64-1_77.a libboost_math_tr1l-mgw10-mt-d-x64-1_77.a libboost_math_tr1l-mgw10-mt-s-x64-1_77.a libboost_math_tr1l-mgw10-mt-x64-1_77.a libboost_nowide-mgw10-mt-d-x32-1_77.a libboost_nowide-mgw10-mt-d-x64-1_77.a libboost_nowide-mgw10-mt-s-x64-1_77.a libboost_nowide-mgw10-mt-x32-1_77.a libboost_nowide-mgw10-mt-x64-1_77.a libboost_prg_exec_monitor-mgw10-mt-d-x32-1_77.a libboost_prg_exec_monitor-mgw10-mt-d-x64-1_77.a libboost_prg_exec_monitor-mgw10-mt-s-x64-1_77.a libboost_prg_exec_monitor-mgw10-mt-x32-1_77.a libboost_prg_exec_monitor-mgw10-mt-x64-1_77.a libboost_program_options-mgw10-mt-d-x32-1_77.a libboost_program_options-mgw10-mt-d-x64-1_77.a libboost_program_options-mgw10-mt-s-x64-1_77.a libboost_program_options-mgw10-mt-x32-1_77.a libboost_program_options-mgw10-mt-x64-1_77.a libboost_python39-mgw10-mt-d-x32-1_77.a libboost_python39-mgw10-mt-d-x64-1_77.a libboost_python39-mgw10-mt-x32-1_77.a libboost_python39-mgw10-mt-x64-1_77.a libboost_random-mgw10-mt-d-x32-1_77.a libboost_random-mgw10-mt-d-x64-1_77.a libboost_random-mgw10-mt-s-x64-1_77.a libboost_random-mgw10-mt-x32-1_77.a libboost_random-mgw10-mt-x64-1_77.a libboost_regex-mgw10-mt-d-x32-1_77.a libboost_regex-mgw10-mt-d-x64-1_77.a libboost_regex-mgw10-mt-s-x64-1_77.a libboost_regex-mgw10-mt-x32-1_77.a libboost_regex-mgw10-mt-x64-1_77.a libboost_serialization-mgw10-mt-d-x32-1_77.a libboost_serialization-mgw10-mt-d-x64-1_77.a libboost_serialization-mgw10-mt-s-x64-1_77.a libboost_serialization-mgw10-mt-x32-1_77.a libboost_serialization-mgw10-mt-x64-1_77.a libboost_stacktrace_basic-mgw10-mt-d-x32-1_77.a libboost_stacktrace_basic-mgw10-mt-x32-1_77.a libboost_stacktrace_noop-mgw10-mt-d-x32-1_77.a libboost_stacktrace_noop-mgw10-mt-d-x64-1_77.a libboost_stacktrace_noop-mgw10-mt-s-x64-1_77.a libboost_stacktrace_noop-mgw10-mt-x32-1_77.a libboost_stacktrace_noop-mgw10-mt-x64-1_77.a libboost_stacktrace_windbg-mgw10-mt-d-x64-1_77.a libboost_stacktrace_windbg-mgw10-mt-s-x64-1_77.a libboost_stacktrace_windbg-mgw10-mt-x64-1_77.a libboost_stacktrace_windbg_cached-mgw10-mt-d-x64-1_77.a libboost_stacktrace_windbg_cached-mgw10-mt-s-x64-1_77.a libboost_stacktrace_windbg_cached-mgw10-mt-x64-1_77.a libboost_system-mgw10-mt-d-x32-1_77.a libboost_system-mgw10-mt-d-x64-1_77.a libboost_system-mgw10-mt-s-x64-1_77.a libboost_system-mgw10-mt-x32-1_77.a libboost_system-mgw10-mt-x64-1_77.a libboost_test_exec_monitor-mgw10-mt-d-x32-1_77.a libboost_test_exec_monitor-mgw10-mt-d-x64-1_77.a libboost_test_exec_monitor-mgw10-mt-s-x64-1_77.a libboost_test_exec_monitor-mgw10-mt-x32-1_77.a libboost_test_exec_monitor-mgw10-mt-x64-1_77.a libboost_thread-mgw10-mt-d-x32-1_77.a libboost_thread-mgw10-mt-d-x64-1_77.a libboost_thread-mgw10-mt-s-x64-1_77.a libboost_thread-mgw10-mt-x32-1_77.a libboost_thread-mgw10-mt-x64-1_77.a libboost_timer-mgw10-mt-d-x32-1_77.a libboost_timer-mgw10-mt-d-x64-1_77.a libboost_timer-mgw10-mt-s-x64-1_77.a libboost_timer-mgw10-mt-x32-1_77.a libboost_timer-mgw10-mt-x64-1_77.a libboost_type_erasure-mgw10-mt-d-x32-1_77.a libboost_type_erasure-mgw10-mt-d-x64-1_77.a libboost_type_erasure-mgw10-mt-s-x64-1_77.a libboost_type_erasure-mgw10-mt-x32-1_77.a libboost_type_erasure-mgw10-mt-x64-1_77.a libboost_unit_test_framework-mgw10-mt-d-x32-1_77.a libboost_unit_test_framework-mgw10-mt-d-x64-1_77.a libboost_unit_test_framework-mgw10-mt-s-x64-1_77.a libboost_unit_test_framework-mgw10-mt-x32-1_77.a libboost_unit_test_framework-mgw10-mt-x64-1_77.a libboost_wave-mgw10-mt-d-x32-1_77.a libboost_wave-mgw10-mt-d-x64-1_77.a libboost_wave-mgw10-mt-s-x64-1_77.a libboost_wave-mgw10-mt-x32-1_77.a libboost_wave-mgw10-mt-x64-1_77.a libboost_wserialization-mgw10-mt-d-x32-1_77.a libboost_wserialization-mgw10-mt-d-x64-1_77.a libboost_wserialization-mgw10-mt-s-x64-1_77.a libboost_wserialization-mgw10-mt-x32-1_77.a libboost_wserialization-mgw10-mt-x64-1_77.a Here comes the command line for compile/link the application $ /mingw64/bin/x86_64-w64-mingw32-g++ -o winperm.exe ./tmp/main.o ./tmp/network.o ./tmp/threading.o ./tmp/translator.o ./tmp/tv_tui.o ./tmp/permutation.o -fopenmp -MD -I/E/Projekte/boost_1_77_0/stage/lib -L../boost_1_77_0/stage/lib -L../tvision/build -L/mingw64/lib -L/mingw64/x86_64-w64-mingw32/lib -ltvision -lkernel32 -luser32 -lwinmm -lws2_32 -lintl -lpthread -lboost_iostreams-mgw10-mt-x64-1_77 -lboost_program_options-mgw10-mt-x64-1_77 And here comes the error output from the linker LD: E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.text$_ZN5boost15program_options25basic_command_line_parserIcE12extra_parserENS_9 function1ISt4pairISsSsERKSsEE[_ZN5boost15program_options25basic_command_line_parserIcE12 extra_parserENS_9function1ISt4pairISsSsERKSsEE]+0x41): undefined reference to `boost::program_options::detail::cmdline::set_additional_parser(boost::function1 <std::pair<std::string, std::string>, std::string const&>)' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.text$_ZN5boost15program_options11to_internalISsEESt6vectorISsSaISsEERKS2_IT_Sa IS5_EE[_ZN5boost15program_options11to_internalISsEESt6vectorISsSaISsEERKS2_IT_Sa IS5_EE]+0x48): undefined reference to `boost::program_options::to_internal (std::string const&)' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64- mingw32/bin/ld.exe: ./tmp/main.o:main.cc: (.text$_ZN5boost15program_options25basic_command_line_parserIcEC1EiPKPKc [_ZN5boost15program_options25basic_command_line_parserIcEC1EiPKPKc]+0xaf): undefined reference to `boost::program_options::detail::cmdline::cmdline(std::vector<std::string, std::allocator<std::string> > const&)' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc:(.text.startup.main+0xb8): undefined reference to `boost::program_options::options_description::options_description(std::string const&, unsigned int, unsigned int)' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc:(.text.startup.main+0x281): undefined reference to `boost::program_options::abstract_variables_map::operator[](std::string const&) const' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.text$_ZN5boost15program_options10validators17get_single_stringIcEERKSbIT_St11 char_traitsIS3_ESaIS3_EERKSt6vectorIS7_SaIS7_EEb[_ZN5boost15program_options10validators17 get_single_stringIcEERKSbIT_St11char_traitsIS3_ESaIS3_EERKSt6vectorIS7_SaIS7_EEb]+0xa1): undefined reference to `boost::program_options::validation_error::get_template(boost::program_options:: validation_error::kind_t)' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.text$_ZN5boost15program_options10validators17get_single_stringIcEERKSbIT_St11 char_traitsIS3_ESaIS3_EERKSt6vectorIS7_SaIS7_EEb[_ZN5boost15program_options10validators17 get_single_stringIcEERKSbIT_St11char_traitsIS3_ESaIS3_EERKSt6vectorIS7_SaIS7_EEb]+0xba): undefined reference to `boost::program_options::error_with_option_name::error_with_option_name(std::string const&, std::string const&, std::string const&, int)' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.text$_ZN5boost15program_options10validators17get_single_stringIcEERKSbIT_St11 char_traitsIS3_ESaIS3_EERKSt6vectorIS7_SaIS7_EEb[_ZN5boost15program_options10 validators17get_single_stringIcEERKSbIT_St11char_traitsIS3_ESaIS3_EERKSt6vectorIS7_SaIS 7_EEb]+0x199): undefined reference to `boost::program_options::validation_error::get_template(boost::program_options:: validation_error::kind_t)' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.text$_ZN5boost15program_options10validators17get_single_stringIcEERKSbIT_St11 char_traitsIS3_ESaIS3_EERKSt6vectorIS7_SaIS7_EEb[_ZN5boost15program_options10validators17 get_single_stringIcEERKSbIT_St11char_traitsIS3_ESaIS3_EERKSt6vectorIS7_SaIS7_EEb]+0x1b2): undefined reference to `boost::program_options::error_with_option_name::error_with_option_name(std::string const&, std::string const&, std::string const&, int)' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.text$_ZN5boost15program_options8validateIicEEvRNS_3anyERKSt6vectorISbIT0_St11 char_traitsIS5_ESaIS5_EESaIS9_EEPT_l[_ZN5boost15program_options8validateIicEEvRNS_3any ERKSt6vectorISbIT0_St11char_traitsIS5_ESaIS5_EESaIS9_EEPT_l]+0x5db): undefined reference to `boost::program_options::invalid_option_value::invalid_option_value(std::string const&)' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.rdata$_ZTVN5boost10wrapexceptINS_15program_options20invalid_option_valueEEE[_ZTVN5 boost10wrapexceptINS_15program_options20invalid_option_valueEEE]+0x60): undefined reference to `boost::program_options::error_with_option_name::substitute_placeholders(std::string const&) const' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.rdata$_ZTVN5boost10wrapexceptINS_15program_options16validation_errorEEE[_ZTVN5boost10 wrapexceptINS_15program_options16validation_errorEEE]+0x60): undefined reference to `boost::program_options::error_with_option_name::substitute_placeholders(std::string const&) const' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.rdata$_ZTVN5boost15program_options16validation_errorE[_ZTVN5boost15program_options16 validation_errorE]+0x30): undefined reference to `boost::program_options::error_with_option_name::substitute_placeholders(std::string const&) const' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.rdata$_ZTVN5boost15program_options20invalid_option_valueE[_ZTVN5boost15 program_options20invalid_option_valueE]+0x30): undefined reference to `boost::program_options::error_with_option_name::substitute_placeholders(std::string const&) const' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.rdata$_ZTVN5boost15program_options11typed_valueIicEE[_ZTVN5boost15 program_options11typed_valueIicEE]+0x38): undefined reference to `boost::program_options::value_semantic_codecvt_helper<char>::parse(boost::any&, std::vector<std::string, std::allocator<std::string> > const&, bool) const' E:/msys64/mingw64/bin/../lib/gcc/x86_64-w64-mingw32/10.2.0/../../../../x86_64-w64-mingw32 /bin/ld.exe: ./tmp/main.o:main.cc: (.rdata$.refptr._ZN5boost15program_options3argE[.refptr._ZN5boost15program_options3 argE]+0x0): undefined reference to `boost::program_options::arg' collect2.exe: error: ld returned 1 exit status Did I miss something ? The question is now, how can I use boost under msys2 with mingw64 ? Thanks for helping hands, paule32

1 0

cybersecuriy for boost
by rajesh daggumati 04 Oct '21

04 Oct '21

HI, Is there any group who supports on cyber security while we are using boost 1.76.0

4 3

queries regarding usage of boost 1.76.0 .
by mahesh pramod 04 Oct '21

04 Oct '21

Hi, I have below queries regarding boost 1.76.0. I have been faced these below queries. 1.how to check boost is statically binded or dynamically binded with my code? is this binding related to virtual concept? 2.how boost interacts with any software? 3. does boost takes our data for any use? ex: when we use sql servers they take our data for testing purpose. Like that does boost take?

2 1

Re: [boost] Simple boost fix for sparc64
by John Klos 30 Sep '21

30 Sep '21

>> Here's a failure example: >> https://ftp.ziaspace.com/pub/pkgsrc/reports/9.0_2021Q2/sparc64/boost-libs-1… > > Seems like it's already fixed: > https://github.com/boostorg/predef/commit/1be0e4a2d8db15a405f64a6f65507b87c… Excellent. I'll look for that in 1.78.0. Thanks, John Klos

1 0

regarding exception_ptr
by rajesh daggumati 30 Sep '21

30 Sep '21

Hi Team, PFB code snippet: try { BOOST_THROW_EXCEPTION(std::invalid_argument("Blah")); } catch(...) { boost::exception_ptr exception = boost::current_exception(); const std::invalid_arguement* p; try{ boost :: rethrow_exception(exceptionptr) } catch(std::invalid_argument &e) { p = dynamic_cast<const std::invalid_argument*>(&e) } const std::invalid_argument* actualStdPtr = ExceptionHelper::ExtractConstPtr<std::invalid_argument>(exceptionptr); EXPECT_TRUE(((void*)p) == ((void*)actualStdPtr)) << "Same Object"; //this condition is getting failed. }} static const t* ExtractConstPtr(boost::exception_ptr ep) { try { boost::rethrow_excepton(ep); } catch(T &e){ const T* exceptType = dynamic_cast<const T*>(&e); return exceptType; } catch (std::exception & e){ const T* exceptType = dynamic_cast<const T*>(&e); return exceptType; } } //EXPECT_TRUE(((void*)p) == ((void*)actualStdPtr)) -->what will be the reason to get failed as I do same thing in both cases. Regards, Rajesh D

2 2

conversion issues from boost::exception_ptr to exception class shared_ptr
by rajesh daggumati 29 Sep '21

29 Sep '21

HI Team, // i have caught exception in exception_ptr and I and trying to convert to ExceptionPtr_t but I am facing issue at below derived->severity(). * unknown file: error: SEH exception with code 0xc0000005 thrown in the test body.* *code snippet is :* *E*xceptionPtr_t ExceptionHelper::TryGetExceptionPtr(boost::exception_ptr exception) { ExceptionPtr_t result ; std::string res; if(!exception) return result; try { boost::rethrow_exception(exception) *}catch(boost::exception &e)* *{boost::throw_file::value_type const* throw_file_data = boost::get_error_info<boost::throw_file>(e);* *if(* *throw_file_data)* *{* * result = exceptionPtr_t(new ExceptionWrapper(exception,*throw_filed_data,true))* *}* *return result;* *}* class Exception : public virtual std::exception, public virtual boost::exception { protected: string what; serviorytype m_severity; public: explicit Exception(const std::string& what); virtual ~Exception() throw() {} // we have some member functions like severity(),setseverity(value)... } class ExceptionWrapper : public Exception { private: string m_what_inner; boost::exception_ptr m_inner; public: explict ExceptionWrapper(boost::exception_ptr inner,string &what() = std::string,bool copythrow = true); explict ExceptionWrapper(boost::exceptionPtr_t inner,string &what() = std::string,bool copythrow = true); virtual ~ExceptionWrapper() throw(){} // some methods like severity(),setSeverity(value),.....) } I was doing like: const Exception* derived = reinterPret_cast<const Exception*> (&exception)// here exception is type of exception_ptr if(derived) { derived->severity(); // here exception is coming... if i put this line in try block then its going for catch block and new exception is being rasied. if i dont put try block then *unknown file: error: SEH exception with code 0xc0000005 thrown in the test body.* } Please help me to resolve this issue

2 1

Simple boost fix for sparc64
by John Klos 27 Sep '21

27 Sep '21

Hello, boost people, This is a small, simple patch to make boost compile properly on NetBSD/sparc64, at very least, and on SPARC and UltraSPARC in general. Here's a failure example: https://ftp.ziaspace.com/pub/pkgsrc/reports/9.0_2021Q2/sparc64/boost-libs-1… Thanks very much, John Klos --- libs/predef/include/boost/predef/architecture/sparc.h.orig 2021-09-27 16:03:19.965761565 +0000 +++ libs/predef/include/boost/predef/architecture/sparc.h 2021-09-27 16:11:18.084758689 +0000 @@ -34,10 +34,10 @@ #if defined(__sparc__) || defined(__sparc) # undef BOOST_ARCH_SPARC -# if !defined(BOOST_ARCH_SPARC) && (defined(__sparcv9) || defined(__sparc_v9__) +# if !defined(BOOST_ARCH_SPARC) && (defined(__sparcv9) || defined(__sparc_v9__)) # define BOOST_ARCH_SPARC BOOST_VERSION_NUMBER(9,0,0) # endif -# if !defined(BOOST_ARCH_SPARC) && (defined(__sparcv8) || defined(__sparc_v8__) +# if !defined(BOOST_ARCH_SPARC) && (defined(__sparcv8) || defined(__sparc_v8__)) # define BOOST_ARCH_SPARC BOOST_VERSION_NUMBER(8,0,0) # endif # if !defined(BOOST_ARCH_SPARC)

2 1

access violation and data stealing
by rajesh daggumati 27 Sep '21

27 Sep '21

Hi Team, I am preparing a document for boost library(1.76.0) to be used in our organisation. as part of documnet, I need some information. 1.Regarding data integrity and security of gtest and how it interacts with any software. 2.if we use boost, we see any access violation or data stealing? 3.is there any group who supports on cyber security while we are using boost 1.76.0 Please kindly answer above 3 queries. Regards, Raesh D

2 1

please guide me to open source world
by Saurabh Tiwari 23 Sep '21

23 Sep '21

Hai SIR/MAAM this side SAURABH TIWARI currently I am in my 3rd year of Btech I don’t know much about the open source can you please help how to get started for the same I know C++, C, basic data structures and algorithms I would be very thankful if you please help me sir so that I can contribute to this open-source world.

4 5

New to boost
by rajesh daggumati 22 Sep '21

22 Sep '21

Hi Team, in my code,I had to write like below: const int* p = boost::get_error_info<boost::throw_line>(exception); But while building the code,I am facing issue like below: error C2683: 'dynamic_cast':'boost::exception_ptr' is not a polymorphic type.. Then I have added one dummy virtual function in exception_ptr class then this issue got resolved but I am getting some test cases failed at this line: Const int* p = boost::get_error_info<boost::throw_line>(exception); Please help me where will be the issue is.what will be the solution.

4 3

Published various template libraries...
by David Bien 22 Sep '21

22 Sep '21

That I have been working on over the past 23 years (when not working for actual money). Directed Graph Template Library: https://github.com/davidbien/dgraph Original email to boost mailing list from year 2000: https://lists.boost.org/Archives/boost/2000/04/2834.php Lexical Analyzer Generator Template Library: https://github.com/davidbien/lexang Original email to boost mailing list from year 2000: https://lists.boost.org/Archives/boost/2000/04/2837.php This depends on the dgraph git submodule above. The above are written in "old" C++ - but updated to compiler in the latest compilers (MSVC, clang11). Built on the above: XML Parser/Writer/DOM Template Library: https://github.com/davidbien/xmlpinc This I developed over the last winter. It is written in C++20 and requires msvc19 or clang11. I heavily use C++20 concepts. There is a lack of documentation. As well: XML Parser/Writer/DOM Development Environment: https://github.com/davidbien/xmlp This contains the LEX specifications (which are written using overridden C++ operators in a namespace) that produce the state machines for UTF8, UTF16 and UTF32 versions of the XML parser - which are then, upon modification, checked into: https://github.com/davidbien/xmlpinc This as well requires the nearly latest versions of MSVC or clang. Once again: There is a lack of documentation. I don't use boost in these libraries - preferring not to have a dependency on it. I also published: https://github.com/davidbien/bienutil Which contains a lot of stuff from year 2000, but also contains some new stuff which is pretty cool: 1. An actually performant and memory-conservative implementation of a Van Emde Boas Tree: https://github.com/davidbien/bienutil/blob/master/_vebtree.h 2. An "exponential chunked array" (misnamed as "logarray.h") that uses a single piece of memory initially: https://github.com/davidbien/bienutil/blob/master/_logarray.h 3. A bunch of other stuff that I wrote back in 2000 since there wasn't much available back then in terms of C++ utility templates. There is a testbed for the dgraph impl but I haven't yet converted them to CMAKE/googletest. There is also a testbed for the vebtree impl but once again not converted to CMAKE/googletest. (I only have so many fingers). Anyway, I'd like to know what people think. The XML parser is meant to be fully compliant with XML Version 1.0 and meant to be a development environment that can be used to extend to full compatibility. I am currently working on a Parser Generator Template Library (think replacement for yacc or bison) that will work with my LEX replacement and allow use of the LEX terminals in the EBNF for the parser specification (which will again be encoding using C++ overridden operators in a namespace). Sincerely, David Bien

2 2

Please guide me for open source
by Saurabh Tiwari 21 Sep '21

21 Sep '21

Hai SIR/MAAM this side SAURABH TIWARI currently I am in my 3rd year of Btech I don’t know much about open source can you please help how to get started for the same I know C++ ,C, basic data structures and algorithms, html , css (basics), and learning web development. I would be very thankful of you please help me sir so that I can contribute to this open source world.

1 0

[any] [basic_any] This seems like a little pearl in Boost 1.77, but it's a bit underdocumented?
by Viktor Sehr 21 Sep '21

21 Sep '21

I just discovered basic_any which is a very nice addition for me. However it's a bit under-documented for the moment. For example: - I assume it's stack-allocated, does it allocate on the heap if assigned an object larger than the stack (like small_vector) or is this not allowed (like static_vector)? - An idea would also be to add a flag which breaks compilation if an object larger than the OptimizeForSize argument is assigned? - (For detail) If allocated on the stack, are the first bytes of the basic_any the same as the contained object? /Viktor

2 2

[ICL] Proposal to support other set/map implementations
by Martin Duvanel 18 Sep '21

18 Sep '21

Hello, We are using boost::icl::interval_set with very large amounts of intervals, and we are having some performance issues. Profiling showed that, in our use-case, a lot of time was spent on memory allocation/deallocation, and swapping std::set for boost::flat_set made a huge, positive difference. We may have a very specific use-case, but would you consider a small modification to the library inside "boost/icl/impl_config.hpp", in order to open the door for other set/map implementations? Here is the simple change we made to "boost/icl/impl_config.hpp" for this experiment: <code> #if defined(ICL_USE_BOOST_MOVE_IMPLEMENTATION) # define ICL_IMPL_SPACE boost::container #elif defined(ICL_USE_STD_IMPLEMENTATION) # define ICL_IMPL_SPACE std + #elif defined(ICL_USE_CUSTOM_IMPLEMENTATION) + # define ICL_IMPL_SPACE ICL_CUSTOM_IMPL_SPACE #else # define ICL_IMPL_SPACE std #endif </code> And then declaring the following before including: <code> namespace custom_icl { template <class Key, class T, class Compare, class Allocator> using map = boost::container::flat_map<Key, T, Compare, Allocator>; template <class Key, class Compare, class Allocator> using set = boost::container::flat_set<Key, Compare, Allocator>; } // namespace custom_icl #define ICL_USE_CUSTOM_IMPLEMENTATION 1 #define ICL_CUSTOM_IMPL_SPACE custom_icl </code> Would such a change make sense in your opinion? If that's the case, then I would be happy to participate in the contribution. Thank you and best regards, Martin Duvanel

3 4

New contributor in Boost
by RUCHIT RAUSHAN 18 Sep '21

18 Sep '21

Hey there, I am a student of branch Information Technology and currently gaining knowledge in C++. I would love to contribute to the Boost community in every possible way, so I would like to know how to start with it. Thank You! RUCHIT RAUSHAN

3 2

16th Google Summer of Code Participation
by Cem Bassoy 15 Sep '21

15 Sep '21

Since 16 years, the Boost foundation has been selected as a mentor organization by the Google Summer of Code <https://summerofcode.withgoogle.com/> committee. If I am not mistaken, Boost has mentored over 100 students who contributed to existing and experimental boost libraries. This year, 8 students successfully contributed to Boost.Real, Boost.Gil, Boost.Math, Boost.Python, Boost.uBlas, Boost.Multiprecision, see project descriptions <https://summerofcode.withgoogle.com/organizations/6722937052200960/#projects> . Here <https://opensource.googleblog.com/2021/06/google-summer-of-code-2021-studen…> are some stats about GSoC21. I would like to thank all students for their contribution and all mentors who have made this possible. Keep up the good work! All the best, Cem

2 1

New to Boost
by Abhishek Rathore 14 Sep '21

14 Sep '21

Hey! I am a student majoring in Computer Science and am currently learning C++. I would love to contribute to the Boost community in any way possible in the near future so that is why, I would like to know how to go about it. Thanks and Super excited! Abhishek

2 1

Re: [boost] New to Boost
by Kenneth Porter 14 Sep '21

14 Sep '21

--On Tuesday, September 14, 2021 3:41 PM +0530 Abhishek Rathore via Boost <boost(a)lists.boost.org> wrote: > I am a student majoring in Computer Science and am currently learning C++. > I would love to contribute to the Boost community in any way possible in > the near future so that is why, I would like to know how to go about it. Head to Github and check out the issues on all the libraries. Fork, fix, and submit pull requests. <https://svn.boost.org/trac10/wiki/StartModPatchAndPullReq> (I don't see anything here about legal issues. Does one need to file a contributor release?)

1 0

Regarding boost 1.76.0
by rajesh daggumati 09 Sep '21

09 Sep '21

Hi Team, Is boost 1.76.0 version is stable version or not.please confirm me asap. Regards, Rajesh D

4 4

Regarding usage of boost 1.76.0
by rajesh daggumati 08 Sep '21

08 Sep '21

Hi Team, Please help me for below query. What are the steps we need to do to include boost in to our code base and release bour software without any obligation? Ex: include license along with our binaries or we need to publish our code to boost platform....? Are we oblige to share anything to boost? Regards, Rajesh D

2 1

Regarding suppporting end date of boost 1.776.0
by rajesh daggumati 08 Sep '21

08 Sep '21

Hi Team, What is the supporting end date for boost 1.76.0 version? Please let me know asap. Regards, Rajesh D

2 1

Can we create boost-config
by Sreeraj K 06 Sep '21

06 Sep '21

*[I initialially raised this question in https://github.com/boostorg/boost/issues/548 <https://github.com/boostorg/boost/issues/548>, but @mclaw recommended this mailing list.]* Similar to many other packages (eg: curl, krb5, pcre, xml2, xslt etc..), can we also ship boost-config that would provide the installation options ? We can probably start with something like this ? $ /usr/bin/boost-config --help Usage: boost-config [ options ] Options: --cflags print compiler options --ldflags print linker options --prefix print the boost prefix --version print the boost version --help print this usage summary $ /usr/bin/boost-config --version 1.66.0 $ /usr/bin/boost-config --cflags -I/usr/include $ /usr/bin/boost-config --ldflags -L/usr/lib64 -Wl,-R/usr/lib64 Thanks.

4 4

[Asio] Propose optimization patch for QNX OS.
by Alex Steshkin 06 Sep '21

06 Sep '21

Hello, By default on QNX OS the select_reactor class is used, which uses the POSIX select() to wait for I/O and write to a pipe to interrupt the wait. Neither select() nor pipes are efficient on QNX OS. We propose to introduce new ionotify_reactor class for QNX OS, which uses ionotify() and pulses instead of select() and pipes. If you are interested in this patch please let me know how to proceed with it: - what repo and branch should I use for this patch? - what is mandatory test set should be done for this patch? - what documentation should be updated to reflect this patch? Thanks, Alex Steshkin ---------------------------------------------------------------------- This transmission (including any attachments) may contain confidential information, privileged material (including material protected by the solicitor-client or other applicable privileges), or constitute non-public information. Any use of this information by anyone other than the intended recipient is prohibited. If you have received this transmission in error, please immediately reply to the sender and delete this information from your system. Use, dissemination, distribution, or reproduction of this transmission by unintended recipients is not authorized and may be unlawful.

2 1

Fwd: Reg, Boost lib dijkstra_shortest_paths for ECMP paths
by kathireswaran thanuskodi 06 Sep '21

06 Sep '21

Hi Team, I came across the boost lib to identify the shortest paths in an network using vertex/edge properties, and have using dijkstra_shortest_paths method with predecessor_map concept with that able to get the shortest path in the graph. Have a requirement like to know about multiple shortest paths also if present, for example below find the below network diagram with 4 edges, A ------- B | | | | D ------- C Edges -> (A,B), (A,D), (B,C), (C,D) with equal distance 1. With the predecessor_map as of now able to get path as A->B->C so that the parent of C is noted as B. In this example we have ECMP(equal cost multiple path) from src A to destination C, tried to search for existing lib to achieve fetching all the paths but unfortunately unable to identify the way. kindly guide how to get such kind of multiple path info with the existing library itself or not. If there exists how to get those info. *<code snip>* const int num_nodes = 4; enum nodes { A, B, C, D}; Edge edge_array[] = { Edge(A, B), Edge(B, C), Edge(A, D), Edge(C,D) }; int weights[] = { 1, 1, 1,1 }; int num_arcs = sizeof(edge_array) / sizeof(Edge); graph_traits<graph_t>::vertex_iterator i, iend; graph_t g(edge_array, edge_array + num_arcs, weights, num_nodes); property_map<graph_t, edge_weight_t>::type weightmap = get(edge_weight, g); // Manually intialize the vertex index and name maps property_map<graph_t, vertex_index_t>::type indexmap = get(vertex_index, g); property_map<graph_t, vertex_name_t>::type name = get(vertex_name, g); int c = 0; for (boost::tie(i, iend) = vertices(g); i != iend; ++i, ++c) { indexmap[*i] = c; name[*i] = 'A' + c; } vertex_descriptor s = vertex(A, g); property_map<graph_t, vertex_distance_t>::type d = get(vertex_distance, g); property_map<graph_t, vertex_predecessor_t>::type p = get(vertex_predecessor, g); dijkstra_shortest_paths(g, s, predecessor_map(p).distance_map(d)); std::cout << "distances and parents:" << std::endl; graph_traits < graph_t >::vertex_iterator vi, vend; for (boost::tie(vi, vend) = vertices(g); vi != vend; ++vi) { std::cout << "distance(" << name[*vi] << ") = " << d[*vi] << ", "; std::cout << "parent(" << name[*vi] << ") = " << name[p[*vi]] << std:: endl; } std::cout << std::endl; *<code snip>* *<output>* distances and parents: distance(A) = 0, parent(A) = A distance(B) = 1, parent(B) = A*distance(C) = 2, parent(C) = B <<<<<<<<<<<<<<<* distance(D) = 1, parent(D) = A Regards, Kathir

1 0

Documentation is not updating since June 10
by Nikita Kniazev 03 Sep '21

03 Sep '21

https://www.boost.org/doc/libs/develop/doc/html/accumulators.html Last revised: June 10, 2021 at 02:32:49 GMT https://www.boost.org/doc/libs/master/doc/html/accumulators.html Last revised: June 10, 2021 at 15:48:57 GMT I thought it was related to the regression matrix not being updated but that was fixed while documentation is still stale.

1 0

Requesting feedback on boost::algorithm::is_clamped
by Ivan Matek 29 Aug '21

29 Aug '21

Hi everyone, I have made a MR for boost::algorithm::is_clamped. Details are on github <https://github.com/boostorg/algorithm/pull/86>. MR is in draft state since doc changes are missing, but tests and code should™ be correct. If you have no time for review of code I would highly appreciate the feedback on the usability of this function. In my work I needed it a few times within last year, but I would like to get feedback from 5-10 other professional developers from diverse backgrounds.

2 3

Re: [boost] Regression tests not updating
by Nikita Kniazev 27 Aug '21

27 Aug '21

> What do you suggest as a solution? I agree that autodetection with no > way to override it is bad. (In my not yet finished CMake guidelines, I > advocate for only using autodetection to determine the default for > the configuration option, while still allowing the user to override it.) > But how does this translate to something actionable? How would you > have written the Nowide build/Jamfile? Sigh, if I had a good solution I would have presented it. An easiest and no-brainer way to tackle this is to have a per-library variable `is-boost-<library>-required/optional` on which library would have to omit checks (do not import Boost.Config, and do not pass checks that return `<build>no` to project/library requirements): ``` if is-boost-<library>-optional { import ../../config/checks/config : requires ; $(do-not-build-if) = [ requires ... ] ; } lib boost_<library> : ... : $(do-not-build-if) ; ``` However, in my opinion, a library must never add `<build>no` to its requirements by itself. Something external should decide if the build/checks failure is fatal or not: ``` rule can-be-built ( ... ) { import ../../config/checks/config : requires ; return [ requires ... ] ; } boost-install boost_<library> : @can-be-built ; ``` It would be perfect if the library could provide a meaningful explanation why it could not be built/describe not satisfied requirements, but that obviously requires a way more sophisticated system. > This is not a Mailman problem, this is a problem with how you are > replying or your mail client setup. Other users with gmail seem to not > have reply problems so I suspect it is not a gmail specific issue. A > quick look reveals that at least one concern is that your headers lack > the "in reply to". I am subscribed to the daily digest, I cannot reply to a message because I do not receive emails even if someone replied to my message or posted something to a thread I interested to be updated more frequently. > As a side-note: there are non-trivial issues with upgrading to mailman > v3; however, hopefully we will be able to upgrade things in the > not-to-far-off future. Thanks for working on that.

1 0

Regression tests not updating
by Joaquin M López Muñoz 27 Aug '21

27 Aug '21

Hi, just a heads up that regression tests are not updating since Aug 12: https://www.boost.org/development/tests/develop/developer/summary.html https://www.boost.org/development/tests/master/developer/summary.html Thank you, Joaquín M López Muñoz

3 3

Re: [boost] Unconditional conditional building is cursed"
by Nikita Kniazev 27 Aug '21

27 Aug '21

> But the problem has nothing to do with silently not building libraries. It's > caused by libraries assuming that Boost.Config is at ../config. Both have the same root cause -- no way to turn off these build checks. If the checks are not needed there is no need to import Boost.Config and assume its location too. P.S. I do not understand how to reply in the Boost mailing lists, please do not blame me if the message went to the wrong thread, I expressed my frustration about that previously, Boost needs to upgrade its Mailman to v3.

3 2

Unconditional conditional building is cursed
by Nikita Kniazev 26 Aug '21

26 Aug '21

Some libraries (Context, Contract, Fiber, Json, Math, Nowide) are built conditionally and use checks from the Config library to do that (`import ../../config/checks/config : requires ;`). Apparently, it happens to be a PITA for some consumers. Vcpkg had to hack around that and update the hack every Boost release, but Boost 1.76 revealed problems in it ( https://github.com/boostorg/build/issues/724) and Boost 1.77 is blocked by it (https://github.com/microsoft/vcpkg/pull/19556#issuecomment-904702798) I have a mixed feeling about silently not building libraries. I understand that for a lot of people it is reasonable that the default stage build will not build a library on an unsupported compiler. However, it is absolutely bad and a confusing thing to a user that the input is silently ignored when a library is requested using the `--with-<library>` flag. A way to turn off the conditional building of the libraries could also be in debug purposes alongside fixing `--with-<library>` behaviour and making possible for vcpkg to live without resorting to hacking the boost build system. I have no affiliation to vcpkg and I am not a maintainer of any mentioned libraries. It is purely my observation about how Boost is used.

2 1

Does boost have an assert that works nicely with constexpr evaluation, and if not should we add one?
by Ivan Matek 25 Aug '21

25 Aug '21

As you may know assert does not play nicely with constexpr evaluation. But std::is_constant_evaluated/if consteval gives us a way to check when the execution happens. https://www.godbolt.org/z/dfder8h16 Does something like this exist in boost, and if not would that be a nice addition? I can not figure out how to support line numbers, filename in a same way assert does, since assert will obviously just take the line info from where it is called. P.S. smart_assert is just a first name I thought of, I am fine with any name as long as it is not some lengthy monstrosity like is_constant_evaluated

4 7

Need cancel() on async_resolve() to callback the resolve handler immediately
by sandeep m.v 25 Aug '21

25 Aug '21

Hi All, I'm looking for a solution for below problem. We're using async_resolve() to perform DNS resolution using boost::asio::ip::tcp::resolver. In few instances probably during network connectivity issues, async_resolve is taking more time. When our application timeouts in 15seconds while waiting for DNS resolution, cancel() is called on resolver. But, that doesn't callback to resolve handle immediately. When I tried to search for this, it looks like, when a cancel() is called on resolver, that doesn't cancel ongoing actual resolution but may cancel if there are any other pending asynchronous action. It's taking 40seconds at times to call resolve handler even when failed to resolve host and even after calling cancel on it. My application waits until resolve handler is called after cancel() to proceed further processing. Is it possible to stop that async_resolve() and get callback to resolve handle immediately after cancel()? If that's impossible, is there a way that we can stop that doesn't callback resolve handler later? Is it possible to close underlying socket related to async_resolve from my application? Thank you in advance. Regards, Sandeep

4 8

BOOST_IS_CONSTANT_EVALUATED_INT(integer-expression)(integer-expression)
by Robert Ramey 24 Aug '21

24 Aug '21

A couple of questions regarding the above new boost config macro. a) I note that this "breaks the pattern" of BOOST_NO_... which I was expecting. I've got no complaint about this, just like being consistent when possible. b) My intended usage is something like: template<typename T> constexpr interval<T> get_interval(const & T t){ return BOOST_IS_CONSTANT_EVALUATED_INT(t) ? interval<T>(t, t) : interval<T>( std::numeric_limits<T>::min(), std::numeric_limits<T>::max() ); } is this the intended way to use this? If not, what would be the correct usage. c) In my Jamfiles I generally have a few tests which run conditionally on the config macro values like this: test-bsl-run_files test_array : A : : requires cxx11_hdr_array ; #BOOST_NO_CXX11_HDR_ARRAY What should I use with the above macro? Particularly confusing is the usage of _NO_ in the macro and the exclusion of _no_ in the requires variable. Should it be something like this. test test_is_constant_evaluted : A : : requires cxx20_no_is_constant_evaluated_int ; #BOOST_IS_CONSTANT_EVALUATED_INT d) Looks like part of this already checked into config.hpp on the develop branch. I would like to add something to my current develop to permit me to start using this now until you get the final code checked in. Any suggestions about the easiest way to do this? I'm ok with inserting some code temporarily but would prefer not to have to sprinkle it all over the place. Robert Ramey

3 8

Strange b2 headers problem
by Edward Diener 24 Aug '21

24 Aug '21

I switched my main boost repository from the 'develop' branch to an earlier tagged boost release to try something out in that earlier release. Everything went fine with switching the main repository and all submodules. I wiped out all the header links from the boost subdirectory and I tried b2 headers, only to get: error: Cannot create link boost\property_map\parallel\basic_reduce.hpp to libs\property_map_parallel\include\boost\property_map\parallel\basic_reduce.hpp. error: Link previously defined to another file, libs\property_map\include\boost\property_map\parallel\basic_reduce.hpp. This makes no sense since there is a completely empty boost subdirectory under my main boost repository directory. How do I fix this problem ?

2 3

[release]Boost 1.77.0
by Marshall Clow 22 Aug '21

22 Aug '21

Release 1.77.0 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 two new libraries and numerous enhancements and bug fixes for existing libraries. * Describe: A C++14 reflection library, from Peter Dimov. Provides macros for describing enumerators and struct/class members, and primitives for querying this information. * Lambda2: A C++14, dependency-free, single header lambda library, from Peter Dimov. For details, including download links, see <http://www.boost.org/users/news/version_1.77.0> You can also download directly from: <https://boostorg.jfrog.io/artifactory/main/release/1.77.0/> 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 7

Discuss: Editorial Control Over Repositories and Libraries
by Vinnie Falco 21 Aug '21

21 Aug '21

So, I have a whole bunch of new libraries marching towards completion and proposal for Boost. I have Boost.URL and Boost.HTTP-Proto in the works, and there is some code that I want to share between the two. Files like these: Algorithms to assist processing RFC7230 compliant input: <https://github.com/vinniefalco/http_proto/blob/9d3144c60b3426509b45cc63dbb3…> <https://github.com/vinniefalco/http_proto/blob/9d3144c60b3426509b45cc63dbb3…> <https://github.com/vinniefalco/http_proto/blob/9d3144c60b3426509b45cc63dbb3…> These are public interfaces, and they are equally useful to both URL and HTTP-Proto. They will also be likely useful to processing websocket handshake field values. It would be nice if I could put them in a separate repository with its own tests, documentation, and CI. But I don't know that this is enough meat on the bone so to speak, to justify as a complete new Boost library offering. When Boost.URL returns a std:::string the user has the option of providing a custom allocator. The library comes with this interface which uses a local stack buffer: <https://github.com/CPPAlliance/url/blob/111b83cc4726f3144194dc3546e096d60ac…> This can be used to avoid dynamic allocation when, for example - you want to apply decoding to a URL-encoded input, which happens often. Boost.HTTP-Proto would benefit from this class as well. Again we have the case of a common component that belongs in a separate repository. But this allocator isn't really related to the BNF-processing utilities mentioned above. So where would it go? As I use MSVC exclusively for regular development, I have put together a small unit test facility which is tailored to my workflow: <https://github.com/vinniefalco/http_proto/blob/9d3144c60b3426509b45cc63dbb3…> This has the flavor of Boost lightweight test, but also: * Redirects output to the Visual Studio IDE if a debugger is attached * Supports the model where one executable is built which holds all the tests * A command-line argument facility to specify individual test suites to run I use this in all of my Boost libraries and to-be-proposed libraries. I wouldn't say that it is user-facing. Currently I put a copy of the file in each library but I have made some changes and it would be better if I could put it in a shared place in the Boost tree. But it isn't public so it shouldn't be grouped with the BNF and the allocator stuff above. I am working on new libraries which do ASIO networking, and they use this handy mocking class which is used for testing stream algorithms: <https://github.com/boostorg/beast/blob/21cd552399aa8167ed53c21a74f3711c2c31…> This is a public interface, which users deploy for their own tests (for example the windows-tls project uses it). Again the case where I want to use it in tests for my own new libraries but without making a copy of the source. In other words in its own shared place. It does require ASIO, so I'm not sure it should be grouped with the rest of the stuff above. Now going back to these new libraries, I have Boost.HTTP-Proto which is a brand new library that speaks HTTP/1 but you have to bring your own networking. It is purely a low-level protocol library, but with a scope expanded from Beast to support more useful things that users need. Since networking is obviously needed I am developing the companion library Boost.HTTP-IO in parallel which uses ASIO to drive the protocol library. They use separate repositories and thus the protocol library is physically isolated, has its own tests, CI, and documentation, and so forth. There is a cosmetic issue where users have to write boost::http_proto::request if they want to declare a request container but then they have to write boost::http_io::write if they want to send the request over a socket (note the different namespaces). This is kind of annoying, and becomes even more annoying when you have to remember which namespace the error constant is located in: http_proto::error::end_of_message or http_io::error::end_of_file. One possibility is for these libraries to use the same namespace: boost::http. Or boost::http_proto. But this breaks the rule of one-repository, one-unique-namespace. Once these libraries are done I will at some point want to write Boost.Websocket-Proto and Boost.Websocket-IO which are similar to their HTTP counterparts (*). And then we will have twice the number of namespaces and error constant enums: boost::http_proto boost::http_io boost::websocket_proto boost::websocket_io and boost::urls These all have their own error enums called "error". If we create a separate repository for common code that all 5 of these libraries use, then that's a sixth namespace also with error code. Okay so that's the stuff that I've been pondering as I write this new code, are any of these real problems? What can I do about it? I'm interested in your thoughts. * The purpose of writing these new, seemingly duplicative libraries is to build on the experience of Beast to smooth out the discovered rough edges and provide a superior interface and implementation. -- Regards, Vinnie Follow me on GitHub: https://github.com/vinniefalco

1 0

Any reason to not add asynchronous sink version of boost::log::add_file_log?
by Nicholas Neumann 19 Aug '21

19 Aug '21

The boost::log::add_file_log function in <boost/log/utility/setup/file.hpp> is a nice function for setting up a file sink. I had been using it and needed to switch from a synchronous frontend to an asynchronous one. But the sink returned is synchronous. Is there any reason to not add a version of the function which creates and returns an asynchronous frontend? Perhaps called something like add_async_file_log?

1 0

Master Branch now open for merging
by Marshall Clow 15 Aug '21

15 Aug '21

No restrictions; the release calendar is up to date. https://boost.org/development <https://boost.org/development> Next milestone: 20-Oct Boost 1.78.0 closed for new libraries and breaking changes — Marshall

1 0

Want to contribute
by Neeraj Khatri 15 Aug '21

15 Aug '21

Can I get help from the organization that how shall I start my contribution in this organization. Thank You ................ .........

1 0

[Boost.Units] Runtime Unit Conversions
by C.D. Clark 15 Aug '21

15 Aug '21

Good day, I have been using Boost.Units for several years now, and it is a great library. I find it difficult to write code without it anymore. However, it does not do runtime unit conversions, so I write a little library that does https://github.com/CD3/UnitConvert It uses Boost.Spirit to parse strings into quantities, and was an excuse for me to learn about spirit. It supports create a boost::units::quantity<T> object from the runtime quantity. Would anybody be interested in adding this type of capability to the boost unit library? I am not a computer scientists, so I don't believe I would be able to propose something up to the boost standard on my own. cdclark -- C.D. Clark III, PhD Associate Professor Department of Physics Fort Hays State University 600 Park Street Hays, KS 67601 Ph: 785.628.4502

2 1

I would like to add boost::algorithm::is_clamped, how to proceed?
by Ivan Matek 13 Aug '21

13 Aug '21

Hi, I would like to add is_clamped (that tests if the value is clamped, similar how we have std::is_sorted, std::sort). What would be the proper procedure? I have never committed to boost, so I have no access to any repository, no "contacts", so I have no idea if small proposals like this require just approval from owner or it needs broader discussion(for example in some cases it would be nice fix for missing chain comparison <https://www.geeksforgeeks.org/chaining-comparison-operators-python/> in core language, but then is_clamped name is not that nice, is_between might be nicer,...). Also I am not sure if this is the best place to ask for directions and do discussions, if you have some slack channel or forum you prefer please let me know. There was a proposal <http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1440r0.html>for std::, but it is not in C++20. I have no relation to that proposal. regards, Ivan

3 8

is_constant_evaluated
by Robert Ramey 11 Aug '21

11 Aug '21

Any chance of seeing a feature macro for HAS_IS_CONSTANT_EVALUATED appearing in Boost.Config any time soon? Robert Ramey

8 20

[release] Boost 1.77.0 Release Candidate 1
by Marshall Clow 06 Aug '21

06 Aug '21

The first release candidates for the 1.77.0 release are now available at: <https://boostorg.jfrog.io/artifactory/main/release/1.77.0/source/> The SHA256 checksums are as follows: fc9f85fc030e233142908241af7a846e60630aa7388de9a5fafb1f3a26840854 boost_1_77_0_rc1.tar.bz2 f2dd9722b21450daf5ce8ef82c2d99c7ec304f913ee6c6b7f047d5639503dda1 boost_1_77_0_rc1.7z 5347464af5b14ac54bb945dc68f1dd7c56f0dad7262816b956138fc53bcc0131 boost_1_77_0_rc1.tar.gz d2886ceff60c35fc6dc9120e8faa960c1e9535f2d7ce447469eae9836110ea77 boost_1_77_0_rc1.zip As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. -- The Release managers

3 3

[multiprecision/mpc][math/quadrature] Why boost::multiprecision::exp gets stuck when evaluating complex-valued integral?
by Kirill Kudashkin 05 Aug '21

05 Aug '21

Dear all, I have encountered a problem while using Boost C++ libraries ( multiprecision/mpc.hpp, math/quadrature) which I cannot resolve. This problems appears when running the following piece of code || |#include <boost/math/constants/constants.hpp> #include <boost/math/quadrature/exp_sinh.hpp> #include <boost/multiprecision/mpc.hpp> #include <boost/multiprecision/mpfr.hpp> #include <boost/math/special_functions/fpclassify.hpp> namespace mpns = boost::multiprecision; typedef mpns::number<boost::multiprecision::mpc_complex_backend <50> > mpc_type ; typedef mpc_type::value_type mp_type ; int main() { using boost::math::constants::root_pi ; mpc_type z{mp_type(1),mp_type(1)} ; auto f = [&](mp_type x) { //actually I did not test if all these conditions are needed... if (boost::math::fpclassify<mp_type> (x) == FP_ZERO) { return mpc_type(mp_type(1)) ; }; if (boost::math::fpclassify<mp_type> (x) == FP_INFINITE) { return mpc_type(mp_type(0)) ; }; mp_type x2 = mpns::pow(x,2U) ; if (boost::math::fpclassify<mp_type> (x2) == FP_ZERO) { return mpc_type(mp_type(1)) ; }; if (boost::math::fpclassify<mp_type> (x2) == FP_INFINITE) { return mpc_type(mp_type(0)) ; }; mpc_type ex2 = mpns::exp(-z*x2) ; if (boost::math::fpclassify<mpc_type> (ex2) == FP_ZERO) { return mpc_type(mp_type(0)) ; }; return ex2 ; } ; mp_type termination = boost::math::tools::root_epsilon <mp_type> () ; mp_type error; mp_type L1; size_t max_halvings = 12; boost::math::quadrature::exp_sinh<mp_type> integrator(max_halvings) ; mpc_type res = integrator.integrate(f,termination,&error,&L1) ; mpc_type div = 2U*mpns::sqrt(z) ; mpc_type result = (mpc_type(root_pi<mp_type> ())/div) - res ; return 0; } | ||Namely, the problem appears when evaluating the exponent. The code is compiled without any problems, but hangs on computing | mpc_type ex2 = mpns::exp(-z*x2) ;| It was possible to go into the function while debugging. It crashed eventually, when the compiler reached "unable to resolve non-existing file.../src/init2.c". I let it run for a while checking the call stack. It appears that the programs is stuck atcalling ___gmpn_sub_n_coreisbr(). Or better, in the call stuck it appeared frequently. I did several tests. The real-valued version (with mpfr_backend <2000>) works without any problems. cpp_complex_backend <100> works fine, but I could not test higher precision yet, since it is much slower. I found a work-around which is not ideal. Namely, mpc_type ex2 = mpc_type(mpns::exp(x2)) ; mpc_type ezx2 = mpns::pow(ex2,-z) ; works fine with mpc_complex_backend <2000>. The lambda-function as it is declared in the code above works and yields correct numbers. The problem appears when it is called from the integrator. My system. I use openSUSE Tumbeleweed. I installed boost libraries as provided by |boost_1_76_0-gnu-mpich-hpc-devel.| Complier -> g++, cppStandard gnu+17. I check that I have all libs, e.g. libgmp, libmpc, libmpfr and etc. All headers are present (the programs is complied without any warnings). Sorry for a lengthy question. Thank you in advance and Best wishes, Kirill ||

1 0

Reminder: The Master branch will be closing for the 1.77.0 release on WEDNESDAY 4-August
by Marshall Clow 04 Aug '21

04 Aug '21

Release calendar here: https://www.boost.org/development/index.html — Marshall

8 17

Re: [boost] Reminder: The Master branch will be closing for the 1.77.0 release on WEDNESDAY 4-August
by Gavin Lambert 03 Aug '21

03 Aug '21

On 3/08/2021 11:57 am, Andrey Semashev wrote: >> The docker image that the tools get run from doesn’t have “linux/magic.h” >> >> More as we discover it. > > I would like to know more about this issue. In particular, what Linux > system lacks this file (distro, kernel version, etc.). Maybe, this is > worth fixing before the release. Git history suggests that the file started existing in linux kernel 2.6.19 and remains since. Although it moved from one folder to another in the internal kernel source tree in kernel 3.7, but that shouldn't affect its existence in the userspace include dirs, unless something is using the wrong include paths.

3 3

Regexp performance guarantees
by Phil Endecott 30 Jul '21

30 Jul '21

Dear Experts, I recently wanted to add some input-sanitising code to a C++ web application, and as I had some existing Javascript code I decided to port its regex-based input checking to the C++ code. This didn't go as well as I had expected! Here's an example of the sort of thing I have: if (!regexp_match(s, regex("[A-Za-z0-9-_/]{1,8192}"))) throw MalformedInput(); The Javascript equivalent seems to be fine. In C++, with libstdc++'s regex implementation, it seems to take about 2 seconds to run. Boost.Regex didn't like the '-' after the '9' but when I fixed that the execution time became negligible. Boost.Xpressive seems also to be fast. On investigation it seems that this is due to there being two different algorithms, one of which (DFA) is linear in the string size but exponential in the pattern size (which in this case seems to mean exponential in the max repeat value of 8192), and the other (backtracking) is linear in the pattern size but exponential in the string size. It seems that the standard deliberately doesn't specify complexity guarantees for std::regex, leaving the choice of algorithm to the implementation. I find this a bit surprising. It's true that both algorithms have their strengths, but not knowing which you are going to get is the worst of both worlds - you would have to assume that it will be exponential in both pattern and string sizes in portable code! (Imagine a container that doesn't disclose whether it has vector or list complexity!) So I'm wondering if it would be useful for regex libraries to somehow be explicit about which algorithm they are and what the complexity is. Compare, for example, with the text search algorithms (Boyer-Moore etc) which indicate the algorithm in their names. Could we have regex_dfa / regex_backtracking, or something? Now having said that, I think that what I really need for my application is something that is worst-case linear in both the pattern size and the input string. I'm not sure if the apparently-fast Boost.Regex algorithm has a worst-case input that is slow. ("Regular Expression Denial Of Service"). It's clear that my example can be written without a regex as a simple linear loop, and maybe some regex libraries have heuristics that do that. Thoughts anyone? Regards, Phil.

8 13

[release] 1.77.0 post-beta merges
by Marshall Clow 30 Jul '21

30 Jul '21

The master branch is is now open for post-beta merges, but only as described in the Post-Beta Merge Policy. See <https://github.com/boostorg/wiki/wiki/Releases%3A-Beta-Merge-Policy> Reminder: The master branch closes for the release on Wednesday, August 4th. Full calendar here: https://www.boost.org/development/ <https://www.boost.org/development/> — Marshall P.S Doc changes and test changes do NOT require release manager approval to be merged.

5 13

Different Lib/CMake Layout between Pre-Build-Binaries and Build from source
by Dennis Luehring 26 Jul '21

26 Jul '21

target_link_libaries(... Boost::boost) seems not to work if the stagedir/<lib> folder is missing but the pre-build binaries missing this folder https://sourceforge.net/projects/boost/files/boost-binaries/1.75.0/ https://sourceforge.net/projects/boost/files/boost-binaries/1.75.0/boost_1_… boost_1_75_0 <boost> ... bootstrap.bat bootstrap.sh <lib64-msvc-14.1> <cmake> *.lib if i build 1.75.0 from source with b2 --toolset=msvc-14.1 --stagedir=./lib64-msvc-14.1 address-model=64 architecture=x86 link=static threading=multi i've get this hierachy c:\Boost\boost_1_75_0 <boost> ... bootstrap.bat bootstrap.sh ... <lib64-msvc-14.1> <-- stagedir <lib> <cmake> *.lib what is the very same hierarchy with Qt6 cmake-configs (so its seems to be "more" standard) C:\Qt\6.1.2 <msvc2017_64> <-- aka "stagedir" <lib> <cmake> Qt6*.lib why does the pre build binary package got a different hierarchy?

1 0

[bimap][PR RFC] Add std::initializer_list constructor
by Hu Jialun 23 Jul '21

23 Jul '21

C++11 allows list initialization for classes. STL map has been added a constructor with the signature map(initializer_list<value_type> il, const allocator_type& alloc = allocator_type()); Added a similar constructor to bimap, allowing for initialization in the form of initializer list, such as boost::bimap<double, long> tdn { {114.514, 1919}, {891.931, 810} }; --- Seems that the pull request is not being seen for a while... Could someone please take a quick look at it and possibly give some directions? :) https://github.com/boostorg/bimap/pull/31 include/boost/bimap/bimap.hpp | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/include/boost/bimap/bimap.hpp b/include/boost/bimap/bimap.hpp index 5fe7a3f..a3603e5 100644 --- a/include/boost/bimap/bimap.hpp +++ b/include/boost/bimap/bimap.hpp @@ -265,6 +265,29 @@ class bimap {} + #ifndef BOOST_NO_CXX11_HDR_INITIALIZER_LIST + bimap(std::initializer_list<BOOST_DEDUCED_TYPENAME base_::core_type::value_type> init, + const allocator_type& al = allocator_type()) : + + base_::relation_set( + ::boost::multi_index::get< + BOOST_DEDUCED_TYPENAME base_::logic_relation_set_tag>(core) + ), + + core(init,ctor_args_list(),al), + + left ( + ::boost::multi_index::get< + BOOST_DEDUCED_TYPENAME base_::logic_left_tag>(core) + ), + right ( + ::boost::multi_index::get< + BOOST_DEDUCED_TYPENAME base_::logic_right_tag>(core) + ) + + {} + #endif + bimap(const bimap& x) : base_::relation_set(

1 0

CMake: using boosts own package finding stuff, howto?
by Dennis Luehring 19 Jul '21

19 Jul '21

in short: CMake does need to change (i'll need to wait for updates) to support newer released boost versions i've heard that Boost supports cmake now directly but i don't get the direct cmake support of boost working with my CMakeLists.txt i know that CMake supports 1.75 in the lastest releases directly but 1.76 and 1.77 are still not on the list and i don't want to wait for CMake release to test new features/betas etc. my system: Ubuntu 21.04/x64, CMake 3.19.4/3.21.0, GCC 10.x Boost 1.75 (want to upgrade to 1.76 soon) my boost build: mkdir ~/dev/3rdparty-liux-gcc cd ~/dev/3rdparty-linux-gcc wget https://dl.bintray.com/boostorg/release/1.75.0/source/boost_1_75_0.tar.bz2 tar -xf boost_1_75_0.tar.bz2 ln -s boost_1_75_0 ./boost cd boost_1_75_0 ./bootstrap.sh ./b2 --toolset=gcc cxxflags=-fPIC --build-dir=./_build address-model=64 architecture=x86 link=static threading=multi --with-graph --with-nowide --with-test --width-config --with-system --with-filesystem --stagedir=./_x64 ln -s _x64/lib lib my simple test hierarchy: boost_using_cmake_tests boost_using_cmake_tests\_build boost_using_cmake_tests\boost_using_cmake boost_using_cmake_tests\boost_using_cmake\CMakeLists.txt cmake_minimum_required (VERSION 3.16) set(Boost_NO_BOOST_CMAKE TRUE) set(Boost_NO_SYSTEM_PATHS TRUE) project (using_boost_with_cmake) set( MY_THIRD_PARTY_LIBS "~/dev/3rdparty-linux-gcc" ) set( BOOST_ROOT ${MY_THIRD_PARTY_LIBS}/boost ) set( BOOST_INCLUDEDIR ${BOOST_ROOT}/boost) set( BOOST_LIBRARYDIR ${BOOST_ROOT}/lib) find_package(Boost REQUIRED COMPONENTS unit_test_framework filesystem system) cmake run: using 3.19.4 cmake without 1.75 support ~/dev/boost_using_cmake/_build$ ../../cmake-3.19.4-linux-x86_64/bin/cmake ../boost_using_cmake/ -- The C compiler identification is GNU 10.3.0 -- The CXX compiler identification is GNU 10.3.0 -- Detecting C compiler ABI info -- Detecting C compiler ABI info - done -- Check for working C compiler: /usr/bin/cc - skipped -- Detecting C compile features -- Detecting C compile features - done -- Detecting CXX compiler ABI info -- Detecting CXX compiler ABI info - done -- Check for working CXX compiler: /usr/bin/c++ - skipped -- Detecting CXX compile features -- Detecting CXX compile features - done CMake Warning at /home/linux/dev/cmake-3.19.4-Linux-x86_64/share/cmake-3.19/Modules/FindBoost.cmake:1204 (message): New Boost version may have incorrect or missing dependencies and imported targets Call Stack (most recent call first): /home/linux/dev/cmake-3.19.4-Linux-x86_64/share/cmake-3.19/Modules/FindBoost.cmake:1326 (_Boost_COMPONENT_DEPENDENCIES) /home/linux/dev/cmake-3.19.4-Linux-x86_64/share/cmake-3.19/Modules/FindBoost.cmake:1935 (_Boost_MISSING_DEPENDENCIES) CMakeLists.txt:14 (find_package) CMake Warning at /home/linux/dev/cmake-3.19.4-Linux-x86_64/share/cmake-3.19/Modules/FindBoost.cmake:1204 (message): New Boost version may have incorrect or missing dependencies and imported targets Call Stack (most recent call first): /home/linux/dev/cmake-3.19.4-Linux-x86_64/share/cmake-3.19/Modules/FindBoost.cmake:1326 (_Boost_COMPONENT_DEPENDENCIES) /home/linux/dev/cmake-3.19.4-Linux-x86_64/share/cmake-3.19/Modules/FindBoost.cmake:1935 (_Boost_MISSING_DEPENDENCIES) CMakeLists.txt:14 (find_package) CMake Warning at /home/linux/dev/cmake-3.19.4-Linux-x86_64/share/cmake-3.19/Modules/FindBoost.cmake:1204 (message): New Boost version may have incorrect or missing dependencies and imported targets Call Stack (most recent call first): /home/linux/dev/cmake-3.19.4-Linux-x86_64/share/cmake-3.19/Modules/FindBoost.cmake:1326 (_Boost_COMPONENT_DEPENDENCIES) /home/linux/dev/cmake-3.19.4-Linux-x86_64/share/cmake-3.19/Modules/FindBoost.cmake:1935 (_Boost_MISSING_DEPENDENCIES) CMakeLists.txt:14 (find_package) -- Found Boost: /home/linux/dev/3rdparty-linux-gcc/boost (found version "1.75.0") found components: unit_test_framework filesystem system -- Configuring done -- Generating done -- Build files have been written to: /home/linux/dev/boost_using_cmake_tests/_build it works but cmake 3.19.4 is missing direct support for 1.75 so its some way "unsupported", cmake does not detect the correct lib names automaticly, only some styles are working etc. i've talked about the problem on the cmake forum and the answer was https://discourse.cmake.org/t/fail-to-use-self-build-boost-1-75-under-ubunt… Brad King: "...However, Boost upstream now provides a proper CMake package file BoostConfig.cmake which should work for using Boost in any layout..." 1.75 is now directly supported by cmake - but now i want to use 1.76 and the problem re-occures i've tried serveral things to force cmake to use the boost own package findings stuff without any success i hope its possible to use 1.75 and 1.76 in the future without always wait for cmake to support it directly any hints what changes are needed with my CMakeLists.txt to support boost own cmake package finding (and get rid of these problems)?

4 17

boost still supports C++03?
by Oliver Kowalke 19 Jul '21

19 Jul '21

Hi, does boost still support Cpp03 or is Cpp11 the min. standard? Oliver

6 10

[1.77][multi_index] post-beta merge request
by Joaquin M López Muñoz 17 Jul '21

17 Jul '21

Hi, I'd like to merge this commit (only testing code and docs affected): https://github.com/boostorg/multi_index/commit/3dad7f38a44783c297b2d477cba2… This is a trivial change for C++23 forward compatibility (and C++<23 UB avoidance), as explained in https://github.com/boostorg/multi_index/issues/45 Best, Joaquín M López Muñoz

2 2

Integrating Boost into client project build via FetchContent
by Stefan Heinzmann 16 Jul '21

16 Jul '21

Hi all, the recent activity regarding adding CMake support to some remaining libraries (many thanks go to Peter Dimov), encouraged me to try using FetchContent to integrate Boost into client projects. I'm sure many people are interested in such a possibility in order to reduce dependencies on the build environment. The brief result seems to be: It almost works. Enough to make it interesting. The reason for my message is to ask if this is supposed to work, i.e. if I am trying something that should work, either now or in the near future, or if it is a frivolous expectation on my part. A toy project's CMakeLists.txt might look like this: ============================================================= cmake_minimum_required(VERSION 3.21) project(boost_test) include(FetchContent) set(BOOST_ENABLE_CMAKE ON) FetchContent_Declare(build_boost GIT_REPOSITORY https://github.com/boostorg/boost.git GIT_TAG boost-1.77.0.beta1 ) FetchContent_GetProperties(build_boost) if(NOT build_boost_POPULATED) FetchContent_Populate(build_boost) add_subdirectory( ${build_boost_SOURCE_DIR} ${build_boost_BINARY_DIR} EXCLUDE_FROM_ALL ) endif() add_executable(boost_test boost_test.cpp) target_link_libraries(boost_test PRIVATE Boost::format) ============================================================= The corresponding source file would look like this: ============================================================= #include <boost/format.hpp> #include <iostream> int main() { std::cout << boost::format("Hello %1%!") % "everybody"; } ============================================================= I used the CMake GUI version 3.21.0 on Windows 10 to configure the project for Visual Studio 2019 Release 16.10.3 with a 64-bit build. It produced lots of install-related errors in the generation phase, but it nevertheless pruduced a solution that successfully built the project. Now, there are of course a couple of issues, which I'd like to get your opinion on: 1. Optimized source download As listed, FetchContent pulls in the entire boost sources, regardless whether they're needed or not. This takes a significant amount of time and uses a lot of disk space for no benefit. Clearly, you would want to fetch only the sources you need, but there doesn't seem to be a good way to handle the dependencies between the various boost libraries. You could use the GIT_SUBMODULES option of FetchContent, but you'd need to list not only the libraries you directly use (Boost::format in my example above), but you also need to list the dependencies of those, which is tedious and brittle. I imagine that this can be handled via a special tool that gets invoked as a PATCH_COMMAND, which is able to scan through the submodules that have been populated and populates all its dependencies. I haven't seen such a tool anywhere, but maybe somebody has got a solution already? 2. Dealing with install Obviously, when using Boost like this, I don't want it to add installation items into the install of my own project, therefore I used the option EXCLUDE_FROM_ALL of add_subdirectory(). That doesn't eliminate all of the problems, as is evidenced by the myriad install-related errors that CMake flags up. Do you have an idea how to properly deal with that? I'm slightly out of my depth here. If you want to check this on your system, the CMake errors may prevent building. I have been able to build when generating a Visual Studio solution, but not when I openend the folder in Visual Studio directly, relying on Visual Studio's own CMake support. Of couse, if you have other suggestions, please tell! Cheers Stefan Heinzmann

2 1

[1.77] Requesting post-beta merges
by John Maddock 15 Jul '21

15 Jul '21

I have some late changes I'd like to merge to master if possible: For multiprecision, it's basically a single bug fix (for https://github.com/boostorg/multiprecision/issues/342) details here: https://github.com/boostorg/multiprecision/pull/344, note that the single CI failure is spurious. For Math, the collected changes are here: https://github.com/boostorg/math/pull/661 The really big changes here are documentation, the remaining issues fixed are documented in the PR above. There is one further change for Math, that I've neglected to cherry pick to the PR above, but it's this one: https://github.com/boostorg/math/pull/659 which fixes some invalid code that had slipped through. Many thanks! John. -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

2 2

[1.77] Permission to merge to master
by Andrey Semashev 15 Jul '21

15 Jul '21

Hi, I'd like to merge the following changes to master: https://github.com/boostorg/filesystem/commit/003f00239963e4b270a47d7e78664… https://github.com/boostorg/filesystem/commit/9e5a3e231e5a5d3c501447ca307a3… Fixes Boost.Filesystem compilation for Android and Mac OS. https://github.com/boostorg/utility/commit/6cca23a63a1c038b9afc261037548b78… Removes dependency of Boost.Utility on Boost.ContainerHash.

2 1

Master branch now closed for 1.77.0 beta release
by Marshall Clow 14 Jul '21

14 Jul '21

Please do not make any commits to the master branch. — Marshall

2 1

[release] Boost 1.77.0 beta 1 released
by Marshall Clow 14 Jul '21

14 Jul '21

Boost release 1.77.0 beta 1 is now available at: <https://boostorg.jfrog.io/artifactory/main/beta/1.77.0.beta1/source/> The SHA256 checksums are as follows: 1aba2bf9416d71026c9e6bbd10a2b7cfb31b0950baa7ad0861dfb74984d96bd9 boost_1_77_0_b1.zip 55126d149664541ffc9fd1f41b2ec67146d69bdab92e41da4bb8610b755ca9ec boost_1_77_0_b1.7z 1aabe7704e91f4f8d97b81d03ddc21c3396f4b72fc4041f01bfcfc128bac0d73 boost_1_77_0_b1.tar.gz 3d5801790c96d2bc9ed23372c4f9fd963bc2f39fe540e35d7b4fe586ba77dfa7 boost_1_77_0_b1.tar.bz2 For details of what's in the release, see <https://www.boost.org/users/history/version_1_77_0.html>. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

1 0

boost.python compilation error (newbie)
by maths soso 11 Jul '21

11 Jul '21

I'm new to boost, I decided installing it by following instructions provided at SO: https://stackoverflow.com/a/24086375/10213771 (The only difference is that I used version 1.76) Everything went fine, then I decided to compile this C++ file: char const* greet(){ return "hello, world";} #include <boost/python.hpp> BOOST_PYTHON_MODULE(hello_ext){ using namespace boost::python; def("greet", greet);} Since boost.python is not header only library, I needed to link to it on compilation, I used the following compile command: g++ -I ~/Desktop/boost_1_76_0/ -I /usr/include/python2.7/ main.cpp -o prog ~/Desktop/boost_1_76_0/stage/lib/libboost_python27.a but I get the following errors: /usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/9/../../../x86_64-linux-gnu/Scrt1.o: in function `_start': (.text+0x24): undefined reference to `main' /usr/bin/ld: /home/sofiane/Desktop/boost_1_76_0/stage/lib/libboost_python27.a(registry.o): in function `boost::python::converter::registration::get_class_object() const': ... /usr/bin/ld: function_doc_signature.cpp:(.text+0x1de): undefined reference to `PyObject_IsTrue' /usr/bin/ld: function_doc_signature.cpp:(.text+0x23e): undefined reference to `PyInt_FromLong' /usr/bin/ld: function_doc_signature.cpp:(.text+0x28b): undefined reference to `PyInt_FromLong' ...

3 2

[release] Boost 1.77.0 Beta 1 Release Candidate 1 is available
by Marshall Clow 10 Jul '21

10 Jul '21

The first release candidates for the 1.77.0 beta release are now available at: https://boostorg.jfrog.io/artifactory/main/beta/1.77.0.beta1/source/ 1aba2bf9416d71026c9e6bbd10a2b7cfb31b0950baa7ad0861dfb74984d96bd9 boost_1_77_0_b1_rc1.zip 55126d149664541ffc9fd1f41b2ec67146d69bdab92e41da4bb8610b755ca9ec boost_1_77_0_b1_rc1.7z 1aabe7704e91f4f8d97b81d03ddc21c3396f4b72fc4041f01bfcfc128bac0d73 boost_1_77_0_b1_rc1.tar.gz 3d5801790c96d2bc9ed23372c4f9fd963bc2f39fe540e35d7b4fe586ba77dfa7 boost_1_77_0_b1_rc1.tar.bz2 The web site has NOT YET been updated. 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

The Master branch will be closing for the 1.77.0 beta release TODAY!
by Marshall Clow 07 Jul '21

07 Jul '21

If you have changes for the beta, they need to be merged to master today. See https://www.boost.org/development/index.html <https://www.boost.org/development/index.html> for the full calendar — The Release managers

1 0

The deadline for Major changes for Boost 1.77.0 is TODAY!
by Marshall Clow 04 Jul '21

04 Jul '21

See https://www.boost.org/development/index.html <https://www.boost.org/development/index.html> for the full calendar — The Release Managers

4 6

Poor performance on windows with logging sinks::file_collector when two file logs use same directory. Thoughts?
by Nicholas Neumann 24 Jun '21

24 Jun '21

I've got two different rotating file logs that point to the same directory (with different file name patterns). Is this in general just a bad idea? They end up sharing the same file_collector, which seems wrong, so perhaps that is a clue that I shouldn't have my logs set up like this. In production I've got a service that compresses, archives, and manages the size of the logs. But in dev, I don't, so the number of files in the directory slowly grew. But the startup time for my program grew much faster. On windows the scan_for_files function in the collector has a loop that is O(mn), where m is the number of files in the directory, and n is the number that matched in previous calls to the scan_for_files function This means the scan_for_files for the first rotating file log in the directory has no issue (n is 0), but the second can be problematic. It iterates over the files in the directory and for each file in the directory, it calls filesystem::equivalent on all of the matches from previous scan_for_files calls. On windows, filesystem::equivalent is particularly heavy, opening handles to both files. Thoughts? Is the two file logs getting the same collector the real issue? Or is it my pointing two file logs to the same directory? I see some ways to mitigate the slowdown in scan_for_files - e.g., filesystem::equivalent could be called after all of the method/match_pattern check, but the two file logs sharing the same collector feels like the real issue.

3 3

The deadline for new libraries and breaking changes in Boost 1.77.0 is this Wednesday, June 23
by Marshall Clow 21 Jun '21

21 Jun '21

See https://www.boost.org/development/index.html <https://www.boost.org/development/index.html> for the full calendar — The Release Managers

1 0

Re: [boost] What has become of John Maddock's implementation of the Remez algorithm for Chebychev approximation?
by Bjorn Reese 18 Jun '21

18 Jun '21

On 6/15/21 11:48 PM, Joachim Wuttke via Boost wrote: > Until v1.53, Boost Math had doc pages [1,2] on the Remez algorithm. > This algorithm [3] computes the coefficents of the Chebyshev polynomial > that approximates a given function. Page [2] refers to actual code In addition to John's reply, I wanted to add that Boost.Math has direct support for Chebyshev polynomials now: https://www.boost.org/doc/libs/release/libs/math/doc/html/math_toolkit/sf_p…

4 5

What has become of John Maddock's implementation of the Remez algorithm for Chebychev approximation?
by Joachim Wuttke 16 Jun '21

16 Jun '21

Until v1.53, Boost Math had doc pages [1,2] on the Remez algorithm. This algorithm [3] computes the coefficents of the Chebyshev polynomial that approximates a given function. Page [2] refers to actual code in directory libs/math/minimax. This code can still be found on GitHub [4], but maintenance status and dependences are unclear. Anybody around who knows anything about this code? Kind regards, Joachim [1] https://www.boost.org/doc/libs/1_53_0/libs/math/doc/sf_and_dist/html/math_t… [2] https://www.boost.org/doc/libs/1_53_0/libs/math/doc/sf_and_dist/html/math_t… [3] https://en.wikipedia.org/wiki/Remez_algorithm [4] https://github.com/boostorg/math/tree/develop/tools/minimax -- Dr. Joachim Wuttke group leader Scientific Computing Forschungszentrum Jülich GmbH Jülich Centre for Neutron Science at MLZ https://computing.mlz-garching.de https://jugit.fz-juelich.de/mlz

2 1

Using Boost.Test header-only from CMake
by Peter Dimov 15 Jun '21

15 Jun '21

Some libraries (I encountered this when porting the tests of Signals2) use Boost.Test in header-only mode, by including <boost/test/included/unit_test.hpp> without linking to anything. This worked in the "legacy" structure where all headers are always available, but doesn't work under CMake where you have to link to header-only libraries in order to get the proper include path. Should we make an attempt to support this use by declaring a special header-only target in Boost.Test (e.g. Boost::included_unit_test), or is that a waste of time? One can as well link to the proper Boost::unit_test_framework (and then even use it header-only, although there's not much point in doing so.) I'm inclined towards "waste of time".

10 34

Re: [boost] boost-json apt-get packge
by Vollaro, John 14 Jun '21

14 Jun '21

Date: Fri, 11 Jun 2021 01:42:18 +0300 From: "Peter Dimov" <pdimov(a)gmail.com> To: <boost(a)lists.boost.org> Subject: Re: [boost] boost-json apt-get packge Message-ID: <05f001d75e49$decba2f0$9c62e8d0$(a)gmail.com> Content-Type: text/plain; charset="utf-8" Vollaro, John wrote: > Is their a apt package that includes boost-json? For what distro? debian > This apt packages did not include boost-json > > apt-get install libboost1.76-all-dev Should be libboost1.76-json-dev. Could not find this package. This e-mail, including attachments, may include confidential and/or proprietary information, and may be used only by the person or entity to which it is addressed. If the reader of this e-mail is not the intended recipient or his or her authorized agent, the reader is hereby notified that any dissemination, distribution or copying of this e-mail is prohibited. If you have received this e-mail in error, please notify the sender by replying to this message and delete this e-mail immediately.

2 1

CMake minimum version to support
by Peter Dimov 11 Jun '21

11 Jun '21

I suppose the time has come to have the discussion on the minimum CMake version we will support for building Boost. Currently that's set to 3.5, which kind of works, but is fairly inconvenient. The interesting options are - CMake 3.8: required for use of the compile features cxx_std_11, cxx_std_14, cxx_std_17, etc. Also allows source_group(TREE, which is used by Json and PropertyTree. - CMake 3.9: required by Nowide, I'm not sure why. Also, required for FindMPI to define an imported target. Building Boost.MPI is optional though. - CMake 3.13: required for Boost installation support. - CMake 3.14: required for FindPython to be modern enough to make building Boost.Python reasonably easy. (Building Boost.Python is optional, though.) There are also less important nice-to-have things such as - CMake 3.10: adds include_guard() - CMake 3.12: adds CONFIGURE_DEPENDS to file(GLOB - CMake 3.15: adds VERBOSE/DEBUG to message( Opinions?

15 40

boost-json apt-get packge
by Vollaro, John 10 Jun '21

10 Jun '21

Is their a apt package that includes boost-json? This apt packages did not include boost-json apt-get install libboost1.76-all-dev ____________________________ John Vollaro 185 Asylum St 6th Floor, Hartford, CT 06103 O: 860-702-8563 | M: 860-919-9443 | john.vollaro(a)optum.com<mailto:john.vollaro@optum.com> This e-mail, including attachments, may include confidential and/or proprietary information, and may be used only by the person or entity to which it is addressed. If the reader of this e-mail is not the intended recipient or his or her authorized agent, the reader is hereby notified that any dissemination, distribution or copying of this e-mail is prohibited. If you have received this e-mail in error, please notify the sender by replying to this message and delete this e-mail immediately.

2 1

Re: [boost] Using Boost.Test header-only from CMake
by Glen Fernandes 10 Jun '21

10 Jun '21

On Sun, Jun 6, 2021 at 9:51 PM Peter Dimov wrote: > For completeness, the libraries using the deprecated boost/test/minimal.hpp are: > > foreach > graph > graph_parallel > iterator > logic > numeric/conversion > numeric/interval > property_map > tokenizer > units > yap > > These need to migrate to either LWT or the non-deprecated Boost.Test. I've migrated all of the above to LWT. Graph is still a PR that needs to be merged. Glen

1 0

Fwd: Interested in contribution to this organisation.
by Chandrakant Jena 16 09 Jun '21

09 Jun '21

---------- Forwarded message --------- From: Chandrakant Jena 16 <chandrakant.barcelona(a)gmail.com> Date: Wed, Jun 9, 2021 at 9:47 AM Subject: Interested in contribution to this organisation. To: <boost(a)lists.boost.org> hello devs, I am chandrakant jena currently studying computer science in utkal university, bhubaneshwar,Odisha. my current interest is c++ and I found this organisation really interesting and suitable for me. I want to know how can I get started? here are some of my profile links: linked in: https://www.linkedin.com/in/chandrakant-jena-5aab131a7/ github profile: https://github.com/chandrakant100

2 1

[cmake] Problem with dependencies for configure checks
by Andrey Semashev 08 Jun '21

08 Jun '21

Hi, I've been having this problem with CMake in Boost.Filesystem, where I need to have the Boost::library targets available before Boost::filesystem target is defined. This is needed in order to perform configuration checks that will affect how Boost::filesystem will be defined. For example, see the check_cxx_source_compiles calls: https://github.com/boostorg/filesystem/blob/af6ac28b5785820b93a2af7dd6e9b80… For the check_cxx_source_compiles calls, I would have liked to add targets like Boost::config and Boost::winapi to CMAKE_REQUIRED_LIBRARIES so that the checks are compiled with include directories of those dependencies added in the command line. This doesn't work because these targets may not be defined at the point when the configuration checks are performed. My current workaround, as you can see, is to add the Boost root to CMAKE_REQUIRED_INCLUDES, where the boost directory with the common headers tree is located. However, this will not work if we're going to make that directory optional or remove it. Also, you can see that I'm reusing checks implemented in Boost.Config, for which I also had to hard code its relative location from Boost.Filesystem. If we're going to allow different libraries located in separate directory trees, this will also break. My question is, can this be fixed and how? I was wondering if it is possible to make the target generation two-stage, where the first stage identifies library locations, including directories with their headers, and the second stage would define build targets. This way all library directories would be available to the second stage. Although I can already see the problem with second order dependencies with this approach...

5 34

CMake progress report
by Peter Dimov 06 Jun '21

06 Jun '21

At the moment, we're down to the following libraries missing CMake support on develop: asio locale log numeric/odeint numeric/ublas parameter_python python sync I've asked Chris how we can proceed with adding a CMakeLists.txt file to ASIO so that we can unblock Log (and Beast.) In addition, the following libraries are currently disabled as having incompatible CMakeLists.txt files in their root directories: beast callable_traits compute gil hana hof safe_numerics static_string stl_interfaces yap I'm working on documenting the CMake support infrastructure, but I'm not done yet.

2 3

Best way to hash_combine a bool?
by John Maddock 05 Jun '21

05 Jun '21

What's the best way to combine a hash value with a bool? Specifically, if you're generating a hash value for a class which has a one member a bool. Normally I would just boost::hash_combine all the class members together, but doing that with a bool member leads to: 1>d:\data\boost\boost\boost\multiprecision\detail\hash.hpp(20,88): warning C4805: '^': unsafe mix of type 'T' and type 'size_t' in operation 1> with 1> [ 1> T=bool 1> ] Followed by a long instantiation backtrace (this is from Boost.Multiprecision). Since there's only one bool in this class, I could just apply a unary ~ to the value when the bool is true, but obviously that wouldn't work for classes with multiple bool's. Should we modify hash_combine for this use case? Cheers, John. -- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

2 2

license violations
by tom.beacon 03 Jun '21

03 Jun '21

To whom should possible license violations be reported? Sent with [ProtonMail](https://protonmail.com) Secure Email.

1 0

Reviewing my first file transfer using Asio
by Farbod Ahmadian 01 Jun '21

01 Jun '21

Hi everyone, I was learning Boost.Asio recently and to learn by doing a project, I decided to write a simple file transfer. So I wrote an *Async TCP Server* and a *Sync TCP Client; *you can use a client to send any kind of file to the server. This is how it works: 1) Clients connect to the server. 2) Clients send the file name to the server. 3) If everything is okay, the server will return an "OK" to that client and wait for that client to send the file. 4) If the client received "OK", it'll send the file. 5) If everything goes well, the file is received by server and the connection will be closed. I will attach the source codes in this email. So here are my questions: 1) Would you mind please review my code and say the problems? I'm a newbie in Asio ;) 2) How to make my client and server talk with a special protocol? Let's say HTTP. (If a socket server understands HTTP, will it be a web server? something like Nginx and Apache.) 3) What is the next step? How can I improve this? What should I learn/do next? Anything is kindly appreciated :) With best regards, Farbod

2 2

Adding CMakeLists.txt files
by Peter Dimov 31 May '21

31 May '21

I'm adding CMakeLists.txt files (mostly generated by `boostdep --cmake <libname>` to libraries that don't have one yet. Apologies (in advance) to all the maintainers for not going through the proper procedure, but this is much easier done in bulk (and order matters).

14 40

Tool maintenance
by Edward Diener 27 May '21

27 May '21

There is a list of maintainers for Boost libraries at libs/maintainers.txt. Is there likewise a list of maintainers for Boost tools ? I have discovered a serious bug with BoostBook and nested namespaces, created an issue, but fear that no one will respond. I would like to e-mail anybody who is a maintainer for BoostBook who might be able to look at the issue and fix it, but there is no list of maintainers for Boost tools which I can find. The person who appears to have worked with BoostBook in the past, Daniel James, is no longer active with Boost so I have no idea who might be able to fix the issue.

6 12

Develop Regression Tests Failing
by Tom Kent 26 May '21

26 May '21

Since sometime yesterday, all the gcc/clang develop runners I maintain (not sure about Visual Studio, that machine has been down for updates) have been failing, before the tests suite can even start running. Master still looks good. They end with the following: - bzip2 : yes [30] - lzma : yes [30] - zstd : no [30] - lzma : yes (cached) [30] - has_lzma_cputhreads builds : no [2] - auto_ptr : yes [3] error: Unable to find file or target named error: '/python//numpy' error: referred to from project at error: '../libs/python/build' I believe this is because of the python ( https://github.com/boostorg/python/pull/362) and build ( https://github.com/boostorg/build/pull/726) pull requests that were merged in around that time. The question is, why is this causing an issue....I have some vague memory of the regression test suite always using build from master? Am I remembering this correctly? If so, I think we may need to back out the python change until build's develop branch merges to master? I'm seeing this across multiple docker images, one that has been rather stable is this: https://hub.docker.com/layers/teeks99/boost-cpp-docker/clang-11/images/sha2… running with this user-config.jam: https://github.com/teeks99/boost-cpp-docker/blob/master/clang-11/user-confi… and numpy installed for both python 2 and 3. Thoughts? Tom

3 3

[boostbook] Doxygen nested namespaces entities not being handled
by Edward Diener 20 May '21

20 May '21

I am seeing an issue where nested namespace doxygen documented entities are not being generated by BoostBook for the final documentation of a reference section in a library's documentation. I am using the quickbook -> boostbook -> html set of tools in the doc jamfile. If I just use doxygen directly to generate the documentation the nested namespace entities are there, so this appears to be a BoostBook problem. Has this problem always existed ? Has anyone else ever encountered it ? I first reported this as a Boost Build issue at https://github.com/bfgroup/b2/issues/18, but then reported this at https://github.com/boostorg/boostbook/issues/10.

1 0

Re: [boost] Boost Governance?
by Glen Fernandes 18 May '21

18 May '21

Rene wrote: > It's now been at least a year since Boost switched from the Software Freedom Conservancy to the Boost Foundation for its governance organization. 13:14 <glenfe> @grafikrobot The Software Freedom Conservancy never governed the Boost C++ Libraries, nor did the Boost Steering committee, nor does the Boost Foundation. Only the Boost community does that. 13:15 <grafikrobot> Hopefully you'll clarify that on the dev list. i.e. The "Boost Steering Committee"[1] became "Boost Foundation"[2]. [1] https://sites.google.com/a/boost.org/steering/home [2] https://sites.google.com/a/boost.org/steering/boost-foundation It still deals with the C++Now conference, providing the mailing lists, hosting, etc. But any decision making and governance of the Boost libraries is still the domain of the Boost community (i.e. you, me, and the other Boost library authors and maintainers). Glen

6 10

[sync] Optimizing Boost's sync using futex2
by André Almeida 15 May '21

15 May '21

Hi there, I'm the author of futex2[0], a WIP new set of Linux's syscalls that allows userspace to write efficient sync mechanisms. I would like to hear from Boost's developers if the project would benefit from this new interface. >From Boost/sync's codebase, I can see that you are already familiar with futexes, but just in case: * What's futex? futex stands for "fast userspace mutexes". It's a syscall that basically exposes a wait queue, where userspace can ask to put threads to sleep and to wake them. The index of such queue is an unsigned int address (that is usually called a futex). It's value doesn't mean anything for the kernel, userspace is responsible to defining the rules of it and implementing the logic. * Why futex2? futex has long standing issues that seems impossible to be solved in the current interface, so we are designing a new set of syscalls taking those problems in account (more on that at [0]). It's not merged yet, and I'm researching some uses cases to validate and get feedback about the API. The new API has the following new features: * Variable sized futexes (6, 16, 32 and 64 bits): we aren't restrict to only 32 bits anymore, and this can be used for decreasing memory usage or to wait on an address * Wait for multiple futexes: this function enables userspace to wait on a list of futexes and wake on the first that triggers a wake. Our current use case for this is for game engines and to emulate WaitForMultipleObjects from WinAPI in Wine * NUMA-awarenes: current futex has a single global hash table that is allocated in some node. Every futex() call that happens on the other nodes will have a access penalty. At futex2, there'll be a single table per node, so you can specify which one you want to operate on to increase locality. The detailed description of the API can be seen in the documentation patch[1]. Do you think that Boost would benefit from it? Thanks, André - futex2 talk at OpenSource Summit: https://www.youtube.com/watch?v=eG6GMBTcPQ8 [0] https://lore.kernel.org/lkml/20210427231248.220501-1-andrealmeid@collabora.… [1] https://lore.kernel.org/lkml/20210427231248.220501-7-andrealmeid@collabora.…

3 9

Final Notice: BinTray is shutting down 1-May (that's SATURDAY)
by Marshall Clow 07 May '21

07 May '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

5 6

[GSoC] - Boost.Multiprecision Quad Double
by Γιάννης Γονιδέλης 07 May '21

07 May '21

Hello! Christopher, Unfortunately, due to some urgent issues I won't be able to contribute during the summer. Thus, in case you have been considering picking me I would ask you to make a new choice. Apologies, Giannis

2 1

Google Summer of Code 2021
by David Bellot 05 May '21

05 May '21

Hi Boost community, The mentors are now finalizing their selection of the students. Google has been very generous this year with the number of slots we were allocated and we are happy to say that we will again have a nice (and large) team of incredible students developing with us this summer (or winter if you're down under like me). Stay tuned because we will announce the list of projects very soon. Best regards, David

1 0

[Math] Standalone beta release
by John Maddock 05 May '21

05 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

3 4

wrong result in complex pow
by Gero Peterhoff 03 May '21

03 May '21

Hello, the pow-function pow(scalar, complex) in boost/math/cstdfloat/cstdfloat_complex_std.hpp get wrong result. Current implementation: inline complex<BOOST_CSTDFLOAT_EXTENDED_COMPLEX_FLOAT_TYPE> pow(const BOOST_CSTDFLOAT_EXTENDED_COMPLEX_FLOAT_TYPE& x, const complex<BOOST_CSTDFLOAT_EXTENDED_COMPLEX_FLOAT_TYPE>& a) { return std::exp(a * std::log(x)); } I think that's correct: inline complex<BOOST_CSTDFLOAT_EXTENDED_COMPLEX_FLOAT_TYPE> pow(const BOOST_CSTDFLOAT_EXTENDED_COMPLEX_FLOAT_TYPE& x, const complex<BOOST_CSTDFLOAT_EXTENDED_COMPLEX_FLOAT_TYPE>& a) { return std::exp(a * std::log(complex<BOOST_CSTDFLOAT_EXTENDED_COMPLEX_FLOAT_TYPE>(x))); } regards Gero

6 25

Cannot build 1.76.0 for Windows (wrong path to compiler)
by Andreas Tscharner 03 May '21

03 May '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

Persistent CI failures for old compilers
by Jeff Garland 02 May '21

02 May '21

On at least the clang 3.8 and gcc4.8 I'm seeing python errors block the CI from running correctly. Downloading/unpacking pip==20.3.4 Cannot fetch index base URL https://pypi.python.org/simple/ Could not find any downloads that satisfy the requirement pip==20.3.4 Which of course has nothing to do with the compiler. Here's an active change where the CI is running. https://github.com/boostorg/date_time/pull/192 So the question is -- are these two old and now unsupported? Is there some CI setup change I need? I'd like to stop having to override the CI obviously. Thanks, Jeff

1 0

Re: [boost] C++Now 2021 -- Library in a Week: Boosting Boost
by Bjorn Reese 02 May '21

02 May '21

On 2021-05-01 00:55, Jeff Garland via Boost wrote: > Every year at the end of the session, I solicit ideas from the community > about what 'library' we should work on in the following year. One Boost.Tokenizer could do with a modernization. It generates a lot of code for even simple tokenizations, which makes it unsuitable for embedded devices. Some issues to consider: * Separate the browsing API from the conversion API. ** The browsing API should use string_view. ** The conversion API should use output buffers instead of returing a string. * Provide an API with narrow contracts * Provide a constexpr API.

2 2

C++Now 2021 -- Library in a Week: Boosting Boost
by Jeff Garland 01 May '21

01 May '21

C++Now 2021 is next week. For those that have never been, every year we have a workshop session called Library in a Week. While the goal of the session might be obvious from the title, needless to say, final Boost libraries don't happen in a week. So, actually, the real underlying goal is to build boost community and discuss c++ library design with projects that don't conflict with attendees day jobs. Every year at the end of the session, I solicit ideas from the community about what 'library' we should work on in the following year. One consistent suggestion has been to work on boost community maintenance. With the conference all virtual this year, I think this is the year to do it. The goal will be to generate pull requests from new or even old boost participants to improve our code base. While I'm sure we could wander around the various libraries and find issues that need some work to generate pull requests, I'm posting this looking for suggestions from the bigger community. Note that this doesn't need to be exclusive to new code -- it can be documentation or tests. Are there particular libraries we should look at? Are there particular issues that someone would like a hand tackling? Are there some upgrades to newer c++ features that someone could jump in on? Thanks, Jeff

2 2

Boost N-Dimensional Array Library
by pencilcaseman＠gmail.com 28 Apr '21

28 Apr '21

Hi All, Would there be any interest in an n-dimensional array library for boost? There is Boost.MultiArray library, but as far as I can tell, this only supports containing the arrays, not performing arithmetic on them. It would provide an interface similar to what Numpy provides, would be fully templated and might, if possible, support BLAS routines to accelerate the functions. Thanks, Toby

2 2

[ci][security] Codecov security breach
by Andrey Semashev 27 Apr '21

27 Apr '21

Hi, I found this in my news feed today: The codecov-bash script that is used to upload codecov reports from CI to codecov.io was maliciously modified to collect sensitive information and send to a third party server. Things like private keys, credentials, auth tokens used in the CI might be compromised. https://discuss.hashicorp.com/t/hcsec-2021-12-codecov-security-event-and-ha… https://about.codecov.io/security-update/ I'm not using codecov, and I have vague understanding how it works, but I've seen it used in Boost libraries' CI. I don't know if they are affected, this is an FYI to the maintainers.

1 0

Fwd: [BOOST][GIL][Histogram]Ordered Maps in place of unordered maps
by sayan chaudhuri 26 Apr '21

26 Apr '21

---------- Forwarded message --------- From: sayan chaudhuri <sayanchaudhuri758(a)gmail.com> Date: Sat, Apr 24, 2021 at 3:08 PM Subject: [BOOST][GIL][Histogram]Ordered Maps in place of unordered maps To: <boost-gil(a)lists.boost.org> Dear Matseuz, The histogram implemented in boost gil uses an unordered map.Wont it have been better with an ordered map? Because the worst case time complexity is better in case of ordered maps. Regards, Yours sincerely, Sayan Chaudhuri

3 2

[Boost][Multiarray]Move for_each.hpp from examples to boost/multi_array
by sayan chaudhuri 25 Apr '21

25 Apr '21

Hello Everyone, I wish to draw attention to the fact that the for_each header file for multiarrays in boost is not present in the include/boost section of the boost multiarray repository. Also, the header file does not have a namespace defined inside it and so the compiler becomes confused as to which for_each function to follow, the one from stl or this one. The for_each is a great utility for boost multiarrays reducing code size and increasing readability. I would like to what others would like to say about these changes. Making these changes allows contributors to other boost libraries to use that functionality in a proper manner. Thanking everyone, Yours sincerely, Sayan Chaudhuri

1 0

[iostreams] [build] Why do iostream tests link against static libraries ?
by Brian Kuhl 22 Apr '21

22 Apr '21

Cross-posting since boost-build is quiet these days. I’m trying to get iostreams working with shared libraries on VxWorks The tests will compile with clang 11 if I comment out the forced dependency on static libraries But I’d like to understand the reason for forcing a link of static libraries with a dynamic executable? https://github.com/boostorg/iostreams/blob/4d2e763ba8b88f3350fbea29b54507a3… rule test-iostreams ( sources * : requirements * : target-name ? ) { return [ run $(sources) /boost/test//boost_unit_test_framework # /<link>static /boost/filesystem//boost_filesystem # /<link>static : # command : # input files : # build requirements <toolset>msvc:<define>_CRT_SECURE_NO_DEPRECATE <toolset>msvc:<define>_SCL_SECURE_NO_DEPRECATE <toolset>cw-9.3,<os>darwin:<runtime-link>static <define>BOOST_IOSTREAMS_NO_LIB <link>shared:<define>BOOST_IOSTREAMS_DYN_LINK=1 $(requirements) : $(target-name) ] ; } If I don’t comment, I get a link error. VxWorks only supports -fpic vs -fPIC clang-vxworks.compile.c++ ../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/unit_test_parameters.o "wr-c++" -x c++ -Wno-c99-extensions -Wno-variadic-macros -O3 -finline-functions -Wno-inline -Wall -pedantic -g -Wno-inline -DBOOST_ALL_NO_LIB=1 -DBOOST_BEAST_ALLOW_DEPRECATED -DBOOST_BEAST_SEPARATE_COMPILATION -I".." -c -o "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/unit_test_parameters.o" "../libs/test/src/unit_test_parameters.cpp" clang-vxworks.archive ../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/libboost_unit_test_framework.a "wr-ar" rcu "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/libboost_unit_test_framework.a" "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/compiler_log_formatter.o" "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/debug.o" "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/decorator.o" "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/execution_monitor.o" "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/framework.o" "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/plain_report_formatter.o" "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/progress_monitor.o" "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/results_collector.o" "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/results_reporter.o" "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/test_framework_init_observer.o" "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/test_tools.o" "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/test_tree.o" "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/unit_test_log.o" "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/unit_test_main.o" "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/unit_test_monitor.o" "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/unit_test_parameters.o" "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/junit_log_formatter.o" "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/xml_log_formatter.o" "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/xml_report_formatter.o" clang-vxworks.link ../bin.v2/libs/iostreams/test/array_test.test/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/array_test.vxe "wr-c++" -o "../bin.v2/libs/iostreams/test/array_test.test/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/array_test.vxe" "../bin.v2/libs/iostreams/test/array_test.test/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/array_test.o" "../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/libboost_unit_test_framework.a" "../bin.v2/libs/filesystem/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/libboost_filesystem.a" -shared --start-group --end-group -fpic /opt/git/vx7/compilers/llvm-11.0.0.1/LINUX64/bin/ldarm: ../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/libboost_unit_test_framework.a(test_tools.o): relocation R_ARM_MOVW_ABS_NC against `a local symbol' can not be used when making a shared object; recompile with -fPIC /opt/git/vx7/compilers/llvm-11.0.0.1/LINUX64/bin/ldarm: ../bin.v2/libs/test/build/clang-vxworks-11.0.0.1/debug/cross-compile-vxworks/link-static/libboost_unit_test_framework.a(test_tree.o): relocation R_ARM_MOVW_ABS_NC against `a local symbol' can not be used when making a shared object; recompile with -fPIC

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

Master branch now open for merging
by Marshall Clow 19 Apr '21

19 Apr '21

No restrictions; the release calendar is up to date. https://boost.org/development <https://boost.org/development> Next milestone: 23-Jun Boost 1.77.0 closed for new libraries and breaking changes — Marshall

1 0

Re: [boost] [Boost-users] [release] Boost 1.76.0
by Glen Fernandes 17 Apr '21

17 Apr '21

On Fri, Apr 16, 2021 at 7:28 PM Edward Diener wrote: > I noticed on the main web page where it has under > "News" the "Version 1.76.0" that "Updated Libraries:" list nothing even > though there are plenty of updates for libraries at > https://www.boost.org/users/history/version_1_76_0.html. The fix for this has been committed; it should take effect automatically in about an hour or so. Glen

1 0

[release] Boost 1.76.0
by Marshall Clow 16 Apr '21

16 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

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

[gsoc21][boost.multiprecision] Realisation of Quad Double
by Abhishek Kujur 13 Apr '21

13 Apr '21

Greetings, My name is Abhishek Kujur, I am CSE student at Kalinga Institute of Technology. I have used c++ for like 6 years and I have understanding of C++ Stl, object orientation and template metaprogramming. I would love to be selected at GSOC 2021 by contributing to C++'s well known library, Boost Library. I would be interested in feedback and suggestions. The link to my proposal is: https://docs.google.com/document/d/1NnrBhA4Hu0JYwjSSQJgCTlgYZaYl2FrVinp6h-Z…

3 2

Unable to utilize Boost C++ libraries in VS Code 2021.
by Sidhaant Gupta 13 Apr '21

13 Apr '21

I added the boost root directory to my workspace, it didn't work. I have also installed the boost using bootstrap.bat but it still doesn't work.

2 2

[gsoc2021]Proposal: Image Processing Algorithms
by ansh grover 13 Apr '21

13 Apr '21

------------------------------ Hi, I am Ansh Grover, a GSoC applicant. I am interested in contributing to the Boost C++ library on the project "*Generic Image Library. I have been coding in C++ for over 6 months, with no prior experience working with Boost libraries. But I am interested in start working with boost libraries and I am willing to put effort into this project by proposing to work for over 30+ hours per week. I have read the problem statement and under GIL there's a project 2 about implementing image processing algorithms and in that list, I would like to work on implementing the k-means clustering algorithm. It would be very helpful if you can guide me through this project. Honestly, I don't expect to be selected for the project with my experience as I am aware of how much work and experience is required, I am just applying with a positive attitude. I am open to any suggestions and I shall proceed with the task upon your acknowledgment. Regards, Ansh Grover

1 0

I will be uploading my GSoC 2021 proposal today
by Sidhaant Gupta 13 Apr '21

13 Apr '21

I have been working on my proposal for a week now, but didn't draft it for review yet as I was making it on MS Word and wasn't aware of the review feature on the official GSoC application portal. Kindly pardon me if it falls short of your expectations but rest assured that I will be in touch with all of you from now on. So please do not end the judgement on the proposal and give me a chance to prove my mettle in the coming month before finalising the selections. Kind regards, Sidhaant Gupta

1 0

[gsoc21] - Provide quad-double precision for Boost.Multiprecision
by Γιάννης Γονιδέλης 13 Apr '21

13 Apr '21

Hello, My name is Giannis Gonidelis. I am an Electrical & Computer Engineering student from Greece and a regular open-source contributor on HPX developed by STE||AR Group. The past year I have been working on trying to adapt the HPX Parallel Algorithms to C++20 by providing the interface dictated by Ranges-TS (by Niebler). HPX, being a C++ Standards library for Concurrency and Parallelization, has its roots on Boost and widely adopts template meta-programming (our project leader is also the founder of Boost.Spirit). I recognize that I might kick in a little late for a GSoC application, but before sharing my proposal, I would like to know if you plan on mentoring the project about providing the "Quad-Double Backend Type". If so, I would be glad to share my initial thoughts on the project with the mentor, along with my Programming competency test script, in order to submit a cohesive and thorough proposal. Please inform me on the project availability. Regards, Giannis Gonidelis GitHub: gonidelis<https://github.com/gonidelis>

2 5

select_stdlib_config.hpp including <version> vs <VERSION> on OS X
by Allen Sanderson 12 Apr '21

12 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 <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 (gnuplot, builtbot, and others) have a VERSION file 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 project's VERSION file gets included instead. And does not compile. I have no solution to the issue other than I renamed our project’s VERSION file for the time being. However, I wanted to raise the issue as I noticed it when moving to 1.75 and backtracked out that it was a recent changed starting with boost 1.73 Cheers, Allen Sanderson SCI Institute University of Utah

5 9

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

[GSoC][GSoC21] Proposal for new quad-double type in Boost.Multiprecision
by Fahad Syed 12 Apr '21

12 Apr '21

Greetings, My name is Syed Fahad, and I am a Electrical Engineering undergraduate student at National Institute of Technology, Srinagar. I have outlined a proposal for implementation of a new quad-double type based on David Bailey’s QD package. So the plan outline is to initially implement quad-double and double-double types as a wrapper around the QD packages qd_real and dd_real classes, and write the testing and benchmarking routines. Eventually, write a generic multiple-double class from scratch using the same algorithms as QD, and remove dependency on external libraries wherever possible. I would be very interested in feedback, questions, and comments. I am looking for supervisors/mentors to undertake this project as part of GSoC 2021. Apologies for the apparently late proposal submission. The link to my proposal is: https://docs.google.com/document/d/10_y6bMk8YkBXXZk5iZr4zJafBwsmJI910Tl K8mDYa80/edit?usp=sharing Best, Syed Fahad.

2 1

Multiprecision
by shady mohamed 12 Apr '21

12 Apr '21

I need to understand the competency test of multiprecision project

2 1

boost root include folder
by Alexander Grund 12 Apr '21

12 Apr '21

Hi all, I wanted to propose moving the top-level include folder "boost" (basically a symlink to all libs/*/include/boost headers) into a subfolder "include" and add (only) that to `-I` by the root Jamfile. See https://github.com/boostorg/boost/issues/501 In short: The current practice of adding the project root folder to the include paths leads to compilers picking up non-header files, like <version>, which has led to trouble in other projects already. (Not a problem with Boost yet AFAIK, so this is a general observation) Boost should be a good example, and NOT do that too. There might be some fallout outside of Boost for users not using an installed or staged Boost version but rely on the root boost folder, but the fix is trivial and IMO well reasoned. And e.g. CMake (very likely) would already handle that change just fine without modifications. Regards, Alex

1 0

Re: [boost] Vector with compile-time polymorphism
by Ivica B 11 Apr '21

11 Apr '21

Yes, I guess it is very similar (if not the same) to polly_collection, or more specifically to: boost::any_collection. Is there a data structure that is similar to polly_collection but can be sorted? On Fri, Apr 9, 2021 at 2:47 PM Ivica B via Boost <boost(a)lists.boost.org> wrote: > multivector<rectangle, circle, triangle> mvect; > Each type is held in a separate std::vector for that type. So in the above > case, multivector<rectangle, circle, triangle> consists of three > std::vectors: std::vector<rectangle>, std::vector<circle> and > std::vector<triangle>. > Sounds a bit like https://www.boost.org/doc/libs/1_75_0/doc/html/poly_collection.html no? --DD

2 1

[GSOC2021][Boost.uBLAS][Draft Proposal]Create new matrix and vector types
by Mr. Cell 11 Apr '21

11 Apr '21

Create new matrix and vector types This is with reference to the communication and as advised by my mentor (Mr. Amit Singh). I am hereby attaching my draft project proposal for boost::uBlas for review and suggestions if any. https://docs.google.com/document/d/1SXB9r_3dbgD0kT5xNmFzQ5mD0FuvTO0Y5TOkdyr… Thanks & Regards.

2 1

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

11 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

4 4

The descriptor does not fit into the select call's fd_set
by George Nistor 10 Apr '21

10 Apr '21

Hi all, I am having a problem with the following error message '' The descriptor does not fit into the select call's fd_set" The setup I have is QNX , VSomeIP lib (socket abstractisation lib) , lib Boost 1.61 (a very old version) I get the error in this lib VSomeIp from the bellow boost call. The call to boost::asio::async_write(3 params) gives the above error message. I have tried to see also on QNX with > pidin -p vsomeip fds How many open file descriptor do I have and I got value 123. As far as I know there is a limitation 1024 of open file descriptors. Could you provide some help? Does the latest boost lib solve this particular case? I appreciate any suggestion, Also please say if any info is missing Thanks George Nistor

2 1

Vector with compile-time polymorphism
by Ivica B 09 Apr '21

09 Apr '21

Hi! I am doing a performance C++ work and there is a data structure that we use and I think it is very useful even for the general public. Here is the description: Currently, I call it *multivector* (I know there is a data structure with the same name, this is a temporary name). It works like this: You specify all the types you want to hold in your multivector: multivector<rectangle, circle, triangle> mvect; Each type is held in a separate std::vector for that type. So in the above case, multivector<rectangle, circle, triangle> consists of three std::vectors: std::vector<rectangle>, std::vector<circle> and std::vector<triangle>. Now, the magic happens when we use templates to process all three vectors at once. Imagine there is a function *draw* for all three types. We can do something like this: mvect.for_each([&](auto& shape) { shape.draw(bitmap); }); The above code generates three for_each loops, for rectangle, circle and triangle. Inside the loops it calls the draw method for each type. There is no dispatching inside the loops, and the loops are really easy for the compiler to optimize (due to their simplicity). Prototype implementation: https://github.com/ibogosavljevic/johnysswlab/blob/master/2021-02-virtualfu… Advantages over std::vector<std::variant>>: * Uses less memory (std::variant uses the amount of memory per element that is big enough to store the biggest type) * Is more optimal: each type generates its own processing loop, there is no dispatching code inside the loop. The compilers vectorized these loops easier. Downsides: * You cannot sort the elements in the whole vectors (even though you can sort them in individual containers) * Code bloat (many types can create a lot of code, this is the case with std::vector<std::variant>> too) Please let me know what you think. Ivica

5 5

GSoC proposal review
by Aditya Tiwari 09 Apr '21

09 Apr '21

Hello all, I'm Aditya Tiwari, a GSoC aspirant. I've submitted my proposal for Boost GIL (generic image library) on GSoC's website under boost. I would be grateful if someone review's my proposal and give me suggestions if needed. I've shared the doc link of my proposal with commenter rights. Thanks and Regards, Aditya Tiwari

1 0

Request to review my proposal
by Pratik Awasthi 08 Apr '21

08 Apr '21

Hello Mentor, I Pratik Awasthi request you to review my GSOC 2021 proposal and do suggest updates https://docs.google.com/document/d/1eeuXx4x2birJXxQChEUnBrLbWTzKd8oc9UspeYU…

1 0

[GSoC'21]Seeking Review of draft Proposal for Project 3: Finalize DataFrame Implementation
by Kowndinya Renduchintala 08 Apr '21

08 Apr '21

Hello everyone! I am Kowndinya Renduchintala, a second Year Undergrad in Computer Science and Engineering Department at Indian Institute of Technology Bombay(IIT Bombay). TO THE COMMUNITY: In short, this project’s end goal is to add to the dataframe implementation of GSoC’19, inspired from R, Python and others. This already has features like constructing a column of data frame, the data frame itself in a couple of ways and also supports operations like select, join etc. My main focus is on adding features that are most desired by a data scientist working with REAL WORLD data and I have added some such possible features in the draft linked below. I have never been into Open Source Software Development before. I would like to make this first attempt of mine a success and I hence seek for advice from anyone willing to spare time, to improve upon my list of deliverables, for establishing the foundation of Boost.uBlas as a new data science library. TO THE MENTOR(David): My progress so far: I have glanced through the GSoC’19 implementation, and referred to some pandas docs to make this draft. I am actually a bit worried because I was too late at completing my Competency test and contacting you, the main reason being a very hectic coursework of mine. The only remaining things are – Modifying the README.md for GitHub Actions Usage and some basic error handling in the code. I have shared the draft in the Google’s portal which also contains a link to my forked repository of ublas, containing my solutions to the competency test. I will also be completing the remaining things(possibly also improve small parts like updating naïve matrix multiplication to Strassen’s) in about 2 days. Also, I want to have a little chat with you as I found out that you were the mentor for this project in 2019 and you might be having some pre-conceived ideas on improving the current implementation, from your previous interaction. Please let me know what you think… Here is the link to my proposal draft : https://drive.google.com/file/d/1cnSrrOWfbteJKlmGxiIY9R5H_-YSkb-n/view? usp=sharing Cheers, Kowndinya

1 0

regarding submission of my first proposal
by amit kumar 08 Apr '21

08 Apr '21

Hello i am Amit kumar. I am currently in third year of undergraduate bachelor's degree program , my field of study is Information Technology.I really curious about open source development and i always support open source software , but i have never contributed to any open source project . I have intermediate level command on c++ and i am doing competitive programming from my first year two and half year from now this is my codeforces <https://codeforces.com/profile/stream_cipher> and codechef <https://www.codechef.com/users/ammitkumar> profile link. I am very beginner to the field of software development but i know some website development . I really want to contribute to the Boost C++ library but i don't have any idea about how to submit the first proposal and how to select the topic on which i should work on please suggest me the path way. waiting for your reply. Thaks :)

2 1

[Boost] [Lambda2] Review starts Monday March 22, 2021 to March 31, 2021
by Joel de Guzman 08 Apr '21

08 Apr '21

The Boost formal review of the Lambda2, authored by Peter Dimov, starts Monday, March 22, 2021 to March 31, 2021 (inclusive). Documentation: https://pdimov.github.io/lambda2/doc/html/lambda2.html Source: https://github.com/pdimov/lambda2/ Lambda2 is a simple, but functional, C++14 lambda library. It takes advantage of the fact that the standard <functional> header already provides placeholders _1, _2, _3, and so on, for use with std::bind, and function objects such as std::plus, std::greater, std::logical_not, and std::bit_xor, corresponding to arithmetic, relational, logical and bitwise operators. Please provide in your review information you think is valuable to understand your choice to ACCEPT or REJECT including Lambda2 as a Boost library. Please be explicit about your decision (ACCEPT or REJECT). Some other questions you might want to consider answering: - What is your evaluation of the design? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - What is your evaluation of the potential usefulness of the library? - Did you try to use the library? With which compiler(s)? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? More information about the Boost Formal Review Process can be found at: http://www.boost.org/community/reviews.html The review is open to anyone who is prepared to put in the work of evaluating and reviewing the library. Prior experience in contributing to Boost reviews is not a requirement. Thank you for your efforts in the Boost community. They are very much appreciated. Peter is often available in the CppLang Slack #boost channel should you require any clarification not covered by the documentation. I am not frequently available in the Slack channel, but I'll certainly pay attention to the discussions. Please don't hesitate to ping me if needed. Cheers, --Joel de Guzman

17 34

FFT proposal for gsoc 2021
by Eduardo Quintana 08 Apr '21

08 Apr '21

Hi Boost community, I've been working on a C++ templated library for Fast Fourier Transforms, https://github.com/Lagrang3/fftx. Templated because some FFT algorithms are algebraic-field independent, eg. you could FFT an array of N matrices provided a Nth matrix-root-of-unity is given. As a result you could have a single algorithm for a variety of underlying, eg. `std::complex<float>`, `std::complex<double>`, `std::complex<long double>`, `boost::math::quaternion`, finite field types (this would yield the "Number theoretic transform" https://cp-algorithms.com/algebra/fft.html#toc-tgt-6) I would like to improve this library during the GSOC 2021, as a proposal for inclusion inside Boost.Math or Boost.Algorithms. Is there anyone interested in supervising this project? Any opinions? Best regards, Eduardo Quintana

6 29

[GSoC 2021] Proposal for Boost.xml
by qiqi tang 07 Apr '21

07 Apr '21

Hello, My name is Fuqi Tang who is a graduate student in China. I am majoring in Software engineering. I want to take part in GSoC 2021 for the Boost.xml project and I will really appreciate it if the community can watch my proposal and give me some advice to improve it. Below is my proposal link https://docs.google.com/document/d/1GYuiVqU8ChaTG2RO2qhQbpF9QSuK5uGRRNDx0M2… Thanks a lot! Regards, Fuqi

2 1

Review and Feedback for Boost.XML proposal
by YAGNIK VAGHELA 07 Apr '21

07 Apr '21

Hello, I am Yagnik Vaghela. I live in India. I am a 3rd year undergraduate student pursuing B.tech in ICT(Information and communication Technology) at DA-IICT. I would like to participate in GSoC this year. I would like to work on a project Boost.XML library. Here's my draft proposal. Please kindly review it and give feedback. any suggestions would be appreciated. https://docs.google.com/document/d/14rzb_3W_5lNM5_qfYpV4zVOh3QmOwuQgWLfeem_…

2 1

[GSoC] Boost.Real GSoC Proposal Feedback
by Divyam Singal 07 Apr '21

07 Apr '21

Hi all, This is Divyam, a 2nd year CSE student at IIT Guwahati. I have shared my draft proposal through GSoC website. I have shared the drive link to the pdf, as docs don't support rendering of LaTeX maths and graphs. You can comment to provide review by right-clicking that portion in the pdf. Do have a look at it and provide the feedback so that I can make the necessary changes. Thanks and Regards, Divyam Singal

1 0

boost mailing list archive stopped updating
by Janek Kozicki 07 Apr '21

07 Apr '21

Just a heads-up, boost mailing list archive stopped updating 3 days ago: https://lists.boost.org/Archives/boost/ best regards Janek -- Janek Kozicki, PhD. DSc. Arch. Assoc. Prof. Gdańsk University of Technology Faculty of Applied Physics and Mathematics Department of Theoretical Physics and Quantum Information -- http://yade-dem.org/ http://pg.edu.pl/jkozicki (click English flag on top right)

2 2

[Boost][GIL][GSOC21]Review and Feedback for Boost GIL project proposal
by sayan chaudhuri 07 Apr '21

07 Apr '21

Hello Everyone, My name is Sayan Chaudhuri. I am a final year,undergraduate student,in the Computer Science and Engineering department of IEM,India . I am eager to participate in the GSOC 2021 and willing to contribute to the Boost GIL library. I am looking to implement the ORB feature descriptor for BOOST GIL . Currently the only keypoint detector present is Harris Corner. And no separate descriptors are present. ORB comes with both a keypoint detector and descriptor bundled and it is suitable for real time systems and also license free. Feature descriptors are important for tasks like object recognition, structure from motion, image stitching etc. And ORB is a good choice for real time systems. I am attaching the link of my project proposal for the same below. I would request anyone who is interested to mentor me or co-mentor to kindly have a look at my proposal. I would really appreciate any feedback from your side and I am looking to continue the discussion of the project further. Proposal link : https://docs.google.com/document/d/1ARL57qRdNWPGe3GlqY1n8E31LyUCvyIyvBk_agz… Thank you.

1 0

[release] 1.76.0 post-beta merges
by Marshall Clow 06 Apr '21

06 Apr '21

The master branch is is now open for post-beta merges, but only as described in the Post-Beta Merge Policy. See <https://github.com/boostorg/boost/wiki/Releases%3A-Beta-Merge-Policy> Reminder: The master branch closes for the release on Wednesday, Apr 7. Full calendar here: https://www.boost.org/development/ <https://www.boost.org/development/> — Marshall P.S Doc changes and test changes do NOT require release manager approval to be merged.

12 34

[gsoc21] Feedback and advice on proposal
by Haoran Xu 04 Apr '21

04 Apr '21

Hi, I'm really interested in applying for GSoC 2021 and implementing the Boost.XML library. I have completed the competency test and have drafted by proposal. https://docs.google.com/document/d/1KP-g1zMXQdqUzSFMtsURcSpZisjjspvX8lRkdRj… Please tell me what you think this proposal is missing and what I should add on. It's my first time applying for GSoC so I'm not very familiar with the process. Thank you!

2 4

Re: [boost] [Boost][GIL][GSOC21] Draft Proposal for Boost GIL
by sayan chaudhuri 04 Apr '21

04 Apr '21

Hello Everyone, My name is Sayan Chaudhuri. I am a final year,undergraduate student,in the Computer Science and Engineering department of IEM,India . I am eager to participate in the GSOC 2021 and willing to contribute to the Boost GIL library. I am looking to implement the ORB feature descriptor for BOOST GIL . Currently the only keypoint detector present is Harris Corner. And no separate descriptors are present. ORB comes with both a keypoint detector and descriptor bundled and it is suitable for real time systems and also license free. Feature descriptors are important for tasks like object recognition, structure from motion, image stitching etc. And ORB is a good choice for real time systems. I am attaching the link of my project proposal for the same below. I would request anyone who is interested to mentor me or co-mentor to kindly have a look at my proposal. I would really appreciate any feedback from your side and I am looking to continue the discussion of the project further. Proposal link : https://docs.google.com/document/d/1ARL57qRdNWPGe3GlqY1n8E31LyUCvyIyvBk_agz… . Thank you.

1 0

Re: [boost] FFT proposal for gsoc 2021
by Eduardo Quintana 03 Apr '21

03 Apr '21

Hi Kostas, Good critics are necessary for the sake of improvement. All of your comments are welcome. > 1) The discussion of NTT. While boost.multiprecision can potentially be used > to implement the Zp ring, it currently does not contain any such construct. > Reading further, there is nothing about NTT in the deliverables. If the idea > is peripheral to the GSOC project, then it does not need to be mentioned at > all. Note that even the PARI library does not yet have NTT implemented and > for them I think it is a high priority (must be a very hard problem). 1) I mentioned the NTT because is part of the motivation for having a general DFT instead just complex-DFT. Maybe the text it is not clear. You'll get the NTT for free. See these two examples https://github.com/Lagrang3/fftx/blob/master/examples/ex02.cpp https://github.com/Lagrang3/fftx/blob/master/examples/ex03.cpp Unfortunately I haven't produced a convolution routine yet, hence in ex03 I had to compute it explicitely. There is also a small implementation of Zp https://github.com/Lagrang3/fftx/blob/master/examples/modulo.h if there was one in Boost I would gladly use it. > 2) Section 2.2. Most people know the Convolution Theorem, but at least myself > do not know anything about the Rader algorithm. Since you propose to > implement it, why not describe it in that Section, maybe instead of the > Convolution Theorem. 2) The Convolution Theorem is very well known yes. I wanted just to make a small subsection in order to clarify which flavour of the Convolution I am using: the Circular Discrete Convolution (CDC) which fits naturally into the DFT scheme. The other Discrete Convolution is the one that you write as c_i = \sum_{j} a_j b_{i-j} produces, in my opinion, many questions to the reader for instance: what do we do with the negative indexes? Zero-pad them or wrap around from the end? I think writing proofs and detailed algorithms is not necessary for the text of the proposal. Last year when I started the fftx experiment I came to the conclusion at some point that I needed, besides Cooley-Tukey and mixed-radix, another algorithm to compute the DFT for prime sizes. Then I found the description of Rader's algorithm in Wikipedia. FFTW uses it, by the way. > 3) Section 2.3. You say: "FFTW was designed to compute DFT for complex > numbers, like in Example 1. There is no support for DFT in the broader sense > of Definition 1. For example, we cannot use FFTW to compute the NTTs described > in the Example 2." Since you are not going to be able to solve this problem in > this GSOC project, it is better to not make such comments. 3) Yes I will solve that problem. There will be two back-ends: mine for general purposes DFTs and FFTW for complex DFTs. My back-end is half-way through I have implemented: - two versions of the mixed-radix Cooley-Tukes (aka Good-Thomas) recursively and not, - a pure Cooley-Tukey in-place which is the one in the blue line shown here: https://github.com/Lagrang3/fftx/blob/master/assets/powers-2.png That makes the back-end functional for any DFT size, with the inconvenience of the O(n^2) slow-down for prime numbers. The work to be done from now on will include the Rader algorithm (for the prime case) and further performance improvements. A funny thing about this general purpose DFT back-end is that I can test its performance against other complex-DFT (eg. FFTW). If some knows of a NTT library or the implementation of weirder DFTs to compare with, please raise your hand. > 4) Section 2.3. "scalability of the parallel MPI routines for computing > 3-dimensional DFT" , "domain decomposition" - here again I think it is worth > to remember that if the project is not going to address domain decomposition, > then it is better to not talk about it. 4) That's true. But that's a very urgent problem that we could very well solve originally within Boost. However it cannot be done until we produce a Boost FFT. Hence you get an extra motivation for doing the Boost FFT. > 5) Since this project is done under Boost, it seems logical to make sure the > proposed code work with Boost.Math complex types. Is this not part of the > plan? Why no word about it in the deliverables? 5) It did cross my mind, but I clearly forgot to talk about it. Thanks for alerting me. Thanks for the feedback. Eduardo

2 2

[lambda2] Andrzej's review
by Andrzej Krzemienski 02 Apr '21

02 Apr '21

Hi Everyone, I recommend to REJECT Boost.Lambda2 library in its current form. My opinion is not very strong, and it is based on the perceived trade-off between usefulness and technical problems. I acknowledge that there are practical use cases that the library can address, that are not provided in documentation. (I recommend that examples with pointers, and maybe a complex one with column-oriented design be added). I consider the ADL issue that Barry pointed out a serious one. This will be an additional place where users would suddenly be caught by a magical problem that they will spend hours understanding. I think that the main problem here is that Boost.Lambda2 defines the operators that should belong to namespace std::placeholders. I also note that if this was added to the Standard Library, the problem would be nonexistent, because they would reside in namespace std. Could I propose an alternative design. Add placeholders _1, _2, ... into namespace `boost::lambda2::placeholders` specialize std::is_placeholder` for them, so that `std::bind` can recognize them. Add operators in the same namespace. Then, recommend the following usage of the library: ``` using namespace boost::lambda2::placeholders; void fun() { auto pred = std::bind(_1, &Employee::name) == std::bind(_2, &Employee::name); } ``` This single using directive would make both `std::bind` and Boost.Lambda2 operators work. I would find such a library acceptable. And in fact I could make it a condition for a conditional acceptance. Now, the standard questions: > - What is your evaluation of the design? > I object to the choice to add operators for placeholders from one namespace (std::placeholders) into another namespace (boost::lambda2). Save for that, I find anything else good. - What is your evaluation of the implementation? > Very sweet and clean. I only expect other operators to also work. But Peter already explained that this is his plan. - What is your evaluation of the documentation? > This library doesn't require much documentation of the interface. But I fill it is missing the Motivation section. I would expect to see practical examples: not long ones, but ones that I will find in real programs, like dealing with pointers. - What is your evaluation of the potential usefulness of the library? > Others have convinced me that it will find sufficient application in real programs. - Did you try to use the library? With which compiler(s)? Did you > have any problems? > I tried to reimplement it, and played with some toy examples in Wandbox. (newest GCC). It worked fine. - How much effort did you put into your evaluation? A glance? A quick > reading? In-depth study? > I was able to reimplement it, read the entire implementation (which was not difficult: it is like seventy lines). I spent like three hours in total studying it. - Are you knowledgeable about the problem domain? > I used Boost.Lambda and Boost.Bind in the past. Finally, I would like to thank Peter for writing and sharing this library. Regards, &rzej;

3 9

Idea Suggestion for GsOC'21
by Sanyam Bhaskar 01 Apr '21

01 Apr '21

Hey! This is Sanyam Bhaskar. I read over the default Ideas provided to us and XML Parser really caught my eye. I would like to contribute to the same but don’t know where to start. Also, as per my understanding, XML is relatively outdated , when compared to data languages like JSON. So in addition to this being an XML Parser, I think adding a JSON parser alongside it would boost the library’s utility in the modern day industry. I Would appreciate it if someone could tell me how to get started and some feedback on the suggestion. Looking forward to contributing to the project. Yours, Sanyam Bhaskar

4 7

[range] the strange behavior of adjacent_filter
by Andrzej Krzemienski 31 Mar '21

31 Mar '21

Hi everyone, Boost.Range has two GitHub issues on the strange behavior of adjacent_find that have been sitting there for more than two years: https://github.com/boostorg/range/issues/80 https://github.com/boostorg/range/issues/81 The behavior of the algorithm is not well described, but the intuitive expectation would be that it returns for every pair of adjacent elements that match the predicate the second of the pair. However, the unexpected behavior of the algorithm is that for a non-empty range it literally always returns the first element. I do not think that this is by accident, because Ranges V3 also expose the same behavior: https://godbolt.org/z/P33j1qvT6 Does anyone happen to know the reasoning or motivation behind this behavior? Regards, &rzej;

1 0

Interested in creating new matrix and vector types
by Gagandeep Bhatia 31 Mar '21

31 Mar '21

Hey, I'm Gagandeep Bhatia, currently pursuing the 2nd year in Christ University, Bangalore, India. You can reach me at gagandeepbhatia2303(a)gmail.com or +919466935025. I went through your upcoming projects on Google Summer of Code, your idea on creating new matrix and vector types is really impressive. The best part about your project is It supports all matrix sizes, from small fixed-size matrices to arbitrarily large dense matrices, and even sparse matrices. It supports all standard numeric types, including std::complex, integers, and is easily extensible to custom numeric types. It supports various matrix decompositions and geometry features I truly want to become part of this project for a better mutual achievement, in the past I have done a few projects, which will help me to contribute my best in this project. It will be really kind if you can share some more details about your project, so I learn more about your project. with regards.

2 2

Boost.Lambda2 usage
by Barry Revzin 31 Mar '21

31 Mar '21

Hey all, I spent this morning implementing views::zip using Boost.Lambda2 (because views::zip requires writing lots of single-operator lambdas, so it fits the problem quite well). You can see the implementation here: https://godbolt.org/z/jcjdd3xeo I ran into a few issues I wanted to point out. First, several operators are missing. This is the standard library's fault (it's weird that not even dereference is there). But if the standard library isn't going to provide them, I figure Boost.Lambda2 should, since these are probably going to come up so may as well just add a few more lines of code and call it a day. I needed to define five: * (unary), ++ and -- (prefix), +=, and -=. Second, this library has name lookup issues. Here's a reduced example ( https://godbolt.org/z/z8oEqnTnG) #include < https://raw.githubusercontent.com/pdimov/lambda2/develop/include/boost/lamb… > namespace N { struct Irrelevant { }; void operator+(Irrelevant, Irrelevant); int plus_one(int i) { using namespace boost::lambda2; return (_1 + 1)(i); } } This doesn't compile. _1 + 1 finds the appropriately-named irrelevant operator+ and stops there, and we never get to the operator+ in namespace boost::lambda2. Either the operators need to be put in namespace std::placeholders for ADL (which seems naughty, but also seems like something the standard library could potentially do?) or the library should provide its own placeholders. That would lose the nice _1 name, but gain the ability to provide both [] and (). Thanks for the library, Barry

3 3

Re: [boost] [Boost][GIL][GSOC21]Wish to know about code review process
by sayan chaudhuri 30 Mar '21

30 Mar '21

Hello Everyone, I am a bit new to the world of open source and so I would like to know how the code review of pull requests is actually done. I have come to know that when I add a new feature to the library, I have to submit a test file along with my pull request. After that,what happens is unknown to me.Understanding this would help me to realize the entire process from pull requests to merging and therefore increase the quality of my contribution. I shall be highly thankful to anyone who may take time out of his/her busy schedule to explain this a bit to me. Thank you all.

2 1

gsoc21: Boost.Multiprecision: New Quad-Double Backend Type: Project 1: Implement a Feasible Realization of Quad-Double
by Orlando Nkengafac 29 Mar '21

29 Mar '21

Hello, My Name is Orlando. I am a nursing student at the Faculty of Health Sciences at the University of Buea, Cameroon. However, I have had in-depth private studies in C++. What is my next step for the test and submission of a proposal, for gsoc21: “Project 1: Implement a Feasible Realization of Quad-Double”. I would like to have a mentor? Sincerely, Orlando

1 0

gsoc21: Boost.uBlas: Matrix and Tensor Computations: Project 3: Finalize Dataframe Implementation
by Fatima Zifac 29 Mar '21

29 Mar '21

Hello, My name is Fatima. I study accounting in the University of Buea, Cameroon. However, I am very good in C++. I want to do the test and submit a proposal for gsoc21: “Project 3: Finalize Dataframe Implementation”. I would like to have a mentor? Sincerely, Fatima

1 0

gsoc21: Boost.uBlas: Matrix and Tensor Computations: Project 2: Create New Matrix and Vector Types
by Forcha Pearl 29 Mar '21

29 Mar '21

Hello, My name is Pearl. I am a student at the Faculty of Engineering, in University of Buea, Cameroon. I am enrolled for a Master’s Degree in Network Engineering and Security. I would like to do gsoc21: “Project 2: Create new matrix and vector types”. I would like to have a mentor? Regards, Pearl

1 0

gsoc21: Boost.uBlas: Matrix and Tensor Computations: Project 1: Finalize and Improve the Subtensor Type
by Glen forcha 29 Mar '21

29 Mar '21

Hello, I am Glen. I am doing my Phd in Software Engineering, at the University of Buea, Cameroon. I am interested in gsoc21: “Project 1: Finalize and Improve the Subtensor Type”. I would like to have a mentor? Regards, Glen

1 0

Re: [boost] [Boost][GIL][GSOC 2021] Contribute to the library
by sayan chaudhuri 28 Mar '21

28 Mar '21

Hello Everyone, I wish to convey my thanks to Matseuz Loskot and Pranam Lashkari, maintainers of Boost GIL for taking out time to go through my mail posting and also my pull request for KMeans Clustering. I have made the changes as suggested by Pranam Lashkari by replacing the .cpp file in example folder with .hpp file in the image_processing folder. I would request to kindly have a look at the submitted changes. Here is the link for the pull request : https://github.com/boostorg/gil/pull/587.. I shall soon be posting my project proposal in the mailing list.

1 0

[Boost][GIL][GSOC 2021] Contribute to the library
by sayan chaudhuri 28 Mar '21

28 Mar '21

Hello Everyone, My name is Sayan Chaudhuri. I am a final year,undergraduate student,in the Computer Science and Engineering department of IEM,India . I am eager to participate in the GSOC 2021 and willing to contribute to the Boost GIL library. I have already gone through the wiki list of Boost GIL listing the various image processing and computer vision algorithms that have not been implemented yet. I have also gone through the Contributing documents for BOOST GIL. . While going through the Boost Mailing List Archives, I found that Igor Antropov had suggested to develop ORB descriptor during his GSOC tenure but it has not been implemented yet.. I am therefore eager to develop the ORB descriptor for Boost GIL during GSOC 2021. ORB is useful in many situations like object recognition and structure for motion and also it is suitable for real time applications unlike SIFT and SURF. I also found out that while using Boost , everytime I need to see the output , I need to save the output in order to view it,thereby unnecessarily wasting memory when I do not wish to save the output. So, the functionality of imshow() for OPENCV is missing for Boost GIL. I am also eager to work on that functionality as well during GSOC 2021. Would therefore anyone is interested in mentoring me? As my programming competency test for Boost GIL, I have implemented the KMeans algorithm from scratch using Boost GIL and I have raised a pull request- https://github.com/boostorg/gil/pull/587. I would kindly request if someone can kindly review it. Also, I would like to know whether there are any similar issues that I can work on currently.

2 1

Re: [boost] 14 to contact for introduction and guidance with gsoc mentor.
by Chandana Gubba 28 Mar '21

28 Mar '21

Sir/madam I does not have that great idea regarding Gsoc ,so firstly I want to know what about it exactly and how to apply and do project,and even about the eligibility ,I am ok with c++ programming. Is it enough ,these are my queries regarding gsoc. On Sun, 28 Mar, 2021, 7:20 pm , <boost-request(a)lists.boost.org> wrote: > Send Boost mailing list submissions to > boost(a)lists.boost.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.boost.org/mailman/listinfo.cgi/boost > or, via email, send a message with subject or body 'help' to > boost-request(a)lists.boost.org > > You can reach the person managing the list at > boost-owner(a)lists.boost.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Boost digest..." > > > The boost archives may be found at: http://lists.boost.org/Archives/boost/ > > > Today's Topics: > > 1. Re: [Boost] [Lambda2] Review starts Monday March 22, 2021 to > March 31, 2021 (Peter Dimov) > 2. Re: [Lambda2] Review starts Monday March 22, 2021 to March > 31, 2021 (Peter Dimov) > 3. To contact project's mentor for GSoC21 (prince raj) > 4. Re: To contact project's mentor for GSoC21 > (Vin?cius dos Santos Oliveira) > 5. Re: To contact project's mentor for GSoC21 (Mateusz Loskot) > 6. Re: [Lambda2] Review starts Monday March 22, 2021 to March > 31, 2021 (Christian Mazakas) > 7. Re: [Boost] [Lambda2] Review starts Monday March 22, 2021 to > March 31, 2021 (Emil Dotchevski) > 8. Re: [Lambda2] Review starts Monday March 22, 2021 to March > 31, 2021 (Phil Endecott) > 9. Re: [Lambda2] Review starts Monday March 22, 2021 to March > 31, 2021 (Peter Dimov) > 10. [Boost][GIL][GSOC 2021] Contribute to the library > (sayan chaudhuri) > 11. (no subject) (Suraj Nehra) > 12. [GSoC] Boost.Real: Introduction and Guidence (Suraj Nehra) > 13. Changelog for 1.76 is outdated (Antony Polukhin) > 14. Re: Changelog for 1.76 is outdated (Antony Polukhin) > 15. Re: Boost Digest, Vol 6566, Issue 1 (shady mohamed) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 26 Mar 2021 14:10:43 +0200 > From: "Peter Dimov" <pdimov(a)gmail.com> > To: <boost(a)lists.boost.org> > Subject: Re: [boost] [Boost] [Lambda2] Review starts Monday March 22, > 2021 to March 31, 2021 > Message-ID: <144201d72239$0c182c30$24488490$(a)gmail.com> > Content-Type: text/plain; charset="utf-8" > > Mathias Gaunard wrote: > > It is not clear from the documentation what the capture behaviour of > > terminals is. > > I assume it's capturing rvalues by value and lvalues by reference? > > The capture behavior is inherited from std::bind, which captures > everything by value by default unless overridden with std::ref. > > > > ------------------------------ > > Message: 2 > Date: Fri, 26 Mar 2021 14:19:24 +0200 > From: "Peter Dimov" <pdimov(a)gmail.com> > To: <boost(a)lists.boost.org> > Subject: Re: [boost] [Lambda2] Review starts Monday March 22, 2021 to > March 31, 2021 > Message-ID: <144401d7223a$42e76ef0$c8b64cd0$(a)gmail.com> > Content-Type: text/plain; charset="utf-8" > > Andrzej Krzemienski wrote: > > Is it not just that the library is missing some operators? If > Boost.Lambda2 > > overloaded all overloadable operators there would be no point in users > doing > > it. > > I'll add the shift operators and the unary * at minimum, will see about any > others. The current set is determined by the function objects in > <functional>. > > > > ------------------------------ > > Message: 3 > Date: Fri, 26 Mar 2021 20:50:52 +0530 > From: prince raj <sdavil318(a)gmail.com> > To: "boost(a)lists.boost.org" <boost(a)lists.boost.org> > Subject: [boost] To contact project's mentor for GSoC21 > Message-ID: <B9EC3FCE-61E8-47E7-8665-FFFE6088824F(a)hxcore.ol> > Content-Type: text/plain; charset="utf-8" > > > > Hello, > > > My self Anish Kumar Singh and I want to participate to in boost > organisation. > > But I have no idea how to contact mentor for project discussion and my > ideas with him. > > So please help me contacting to mentor so that I can make my proposal > good to summit. > > > Thankyou... > > > ------------------------------ > > Message: 4 > Date: Fri, 26 Mar 2021 12:46:26 -0300 > From: Vin?cius dos Santos Oliveira <vini.ipsmaker(a)gmail.com> > To: Boost <boost(a)lists.boost.org> > Cc: prince raj <sdavil318(a)gmail.com> > Subject: Re: [boost] To contact project's mentor for GSoC21 > Message-ID: > < > CAK9RveLeh66nHX-ZBRpPs4mP+fDZ5JjwN3beVVRd8X0dnHCvRA(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > Em sex., 26 de mar. de 2021 ?s 12:22, prince raj via Boost < > boost(a)lists.boost.org> escreveu: > > > But I have no idea how to contact mentor for project discussion and my > > ideas with him. > > > > What's the project you're interested in? > > > -- > Vin?cius dos Santos Oliveira > https://vinipsmaker.github.io/ > > > ------------------------------ > > Message: 5 > Date: Fri, 26 Mar 2021 17:32:14 +0100 > From: Mateusz Loskot <mateusz(a)loskot.net> > To: boost(a)lists.boost.org > Subject: Re: [boost] To contact project's mentor for GSoC21 > Message-ID: > < > CABUeae8fsFiX6CS6_HXH-u59_GQJscbEdEJEZ-W0naq_WJRHiA(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > On Fri, 26 Mar 2021 at 16:22, prince raj via Boost > <boost(a)lists.boost.org> wrote: > > > > But I have no idea how to contact mentor for project discussion and my > > ideas with him. > > > > So please help me contacting to mentor so that I can make my proposal > > good to summit. > > First, read this and the materials linked there > https://github.com/boostorg/wiki/wiki/Google-Summer-of-Code%3A-Overview > > Best regards, > -- > Mateusz Loskot, http://mateusz.loskot.net > > > ------------------------------ > > Message: 6 > Date: Fri, 26 Mar 2021 19:45:39 -0700 > From: Christian Mazakas <christian.mazakas(a)gmail.com> > To: "boost(a)lists.boost.org List" <boost(a)lists.boost.org> > Cc: Peter Dimov <pdimov(a)gmail.com> > Subject: Re: [boost] [Lambda2] Review starts Monday March 22, 2021 to > March 31, 2021 > Message-ID: > < > CAHf7xWsqNHEt8-nxBRFz1+BjNMiwXasoYsFOuFR+tpd2EWZkog(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > Hey everyone, > > I vote to *ACCEPT *Lambda2. > > I first heard of Lambda2 when Peter asked me how many lines I thought > it would take to recreate Boost.Lambda. > > Naturally, I should've seen this as a loaded question but I guessed a few > hundred. Maybe something just below a couple thousand by the time all > the dust settles. > > Peter told me it could be done in ~50 lines. Now I was intrigued. The > source code of > Lambda2 is wonderfully clever and short. Moreso, sufficiently clever that > it's worth > not repeating every time we want to use it. > > Higher-order functions are all the rage in C++ and writing lambdas is > cumbersome > and annoying. Lambda2 gives us a C++14 solution that relies on nothing else > but > simple language features and stdlib headers making it faster to compile > than older > solutions such as Phoenix or the original Lambda. > > Lambda2 also has the fortune of interop'ing greatly with existing > constructs like > Boost.HOF and the new `<ranges>` STL header. See: > https://godbolt.org/z/hfxfhfEqv > > Keeping this short, Lambda2 gives us fresh paint over an old technology > that we know > works and one that (while polarizing in its style) does its job well. I > think it ultimately > serves Boost and the larger C++ community to keep this Lambda-style of > coding alive > and well-maintained as C++ evolves. > > - Christian > > > ------------------------------ > > Message: 7 > Date: Fri, 26 Mar 2021 23:18:47 -0700 > From: Emil Dotchevski <emildotchevski(a)gmail.com> > To: Boost <boost(a)lists.boost.org> > Subject: Re: [boost] [Boost] [Lambda2] Review starts Monday March 22, > 2021 to March 31, 2021 > Message-ID: > <CAN5fK5HJmHeZOoQ-nYwrHxKnQMjcAX8bLR4KMKz3= > QsXwrM-Pw(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > Here is my review of lambda2: > > I remember when I first learned boost::bind, and realized how much more > useful STL is because of it. Even after C++11 I still find myself using > bind, it sometimes looks more readable to my eyes than a lambda. > > The lambda2 library is one more proof for the solid design behind > std::bind. That, or std::bind was designed with things like lambda2 in > mind. Either way, lambda2 is an elegant utility for writing elegant C++, > albeit only in the (rare?) cases when it is a perfect fit. Given this, and > the miniature size of the library, my vote is to ACCEPT. > > > ------------------------------ > > Message: 8 > Date: Sat, 27 Mar 2021 17:42:36 +0000 > From: "Phil Endecott" <spam_from_boost_dev(a)chezphil.org> > To: <boost(a)lists.boost.org> > Subject: Re: [boost] [Lambda2] Review starts Monday March 22, 2021 to > March 31, 2021 > Message-ID: <1616866956454(a)dmwebmail.dmwebmail.chezphil.org> > Content-Type: text/plain; format="flowed"; charset="UTF-8" > > Peter Dimov wrote: > > The goals of the library are > > [...] > > - Prepare a proposal to extend the standard with these same additions by > > gathering experience in Boost first. > > Am I correct in thinking that this functionality could have been > added to the standard library when std::bind was added in C++11, > except that it requires something in the core language that was not > added until C++14 ? > > If not, what is the reason why this was not added when std::bind > was added? (I've failed to locate any pre-C++11 WG21 papers about > std::bind.) > > > Regards, Phil. > > > > > > > ------------------------------ > > Message: 9 > Date: Sat, 27 Mar 2021 19:58:03 +0200 > From: "Peter Dimov" <pdimov(a)gmail.com> > To: <boost(a)lists.boost.org> > Subject: Re: [boost] [Lambda2] Review starts Monday March 22, 2021 to > March 31, 2021 > Message-ID: <14fe01d72332$bc76fad0$3564f070$(a)gmail.com> > Content-Type: text/plain; charset="utf-8" > > Phil Endecott wrote: > > Peter Dimov wrote: > > > The goals of the library are > > > [...] > > > - Prepare a proposal to extend the standard with these same additions > by > > > gathering experience in Boost first. > > > > Am I correct in thinking that this functionality could have been added > to the > > standard library when std::bind was added in C++11, except that it > requires > > something in the core language that was not added until C++14 ? > > Return type deduction makes it easier to write, and the function objects in > <functional> acquired their <void> forms in C++14, but it's possible to > make > this work in C++11 as well. > > > If not, what is the reason why this was not added when std::bind was > added? > > (I've failed to locate any pre-C++11 WG21 papers about std::bind.) > > I didn't propose it. :-) > > > > ------------------------------ > > Message: 10 > Date: Sat, 27 Mar 2021 22:38:36 +0530 > From: sayan chaudhuri <sayanchaudhuri758(a)gmail.com> > To: boost(a)lists.boost.org > Subject: [boost] [Boost][GIL][GSOC 2021] Contribute to the library > Message-ID: > <CAJH= > o2N_rOMqaPg+jt823+Nj9Z+fD+w-4LqQw8ZOOBkEUMAUzw(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > Hello Everyone, > My name is Sayan Chaudhuri. I am a final > year,undergraduate student,in the Computer Science and Engineering > department of IEM,India . I am eager to participate in the GSOC 2021 and > willing to contribute to the Boost GIL library. > I have already gone through the wiki list of Boost > GIL listing the various image processing and computer vision algorithms > that have not been implemented yet. I have also gone through the > Contributing documents for BOOST GIL. . While going through the Boost > Mailing List Archives, I found that Igor Antropov had suggested to develop > ORB descriptor during his GSOC tenure but it has not been implemented yet.. > I am therefore eager to develop the ORB descriptor for Boost GIL during > GSOC 2021. ORB is useful in many situations like object recognition and > structure for motion and also it is suitable for real time applications > unlike SIFT and SURF. I also found out that while using Boost , everytime I > need to see the output , I need to save the output in order to view > it,thereby unnecessarily wasting memory when I do not wish to save the > output. So, the functionality of imshow() for OPENCV is missing for Boost > GIL. I am also eager to work on that functionality as well during GSOC > 2021. Would therefore anyone is interested in mentoring me? > As my programming competency test for Boost GIL, I > have implemented the KMeans algorithm from scratch using Boost GIL and I > have raised a pull request- https://github.com/boostorg/gil/pull/587. I > would kindly request if someone can kindly review it. Also, I would like to > know whether there are any similar issues that I can work on currently. > > > ------------------------------ > > Message: 11 > Date: Sun, 28 Mar 2021 03:22:35 +0000 > From: Suraj Nehra <surajnehra112(a)gmail.com> > To: boost(a)lists.boost.org > Subject: [boost] (no subject) > Message-ID: > <CAJR02FfuUhWpDYveadts9Xd5QD5_tzV5z= > hgMmar1greSBmzSw(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > Hi, > I am Suraj Nehra, a pre-final year student at the National Institute of > Technology (NIT), Warangal, India. This mail is to introduce myself to the > boost community. Boost.Real is not added to boost project ideas page yet > but I was discussing ideas with Vikram(vikram2000b(a)gmail.com) and also > made > several contributions to the library. > > I wish to work on this library in this GSoC and will start drafting > the proposal. I received the competency task from Vikram and will start > working on those. I was informed of the following potential ideas by him: > 1. Library comparison and benchmarking with other similar libraries. > 2. DAG internal representation > 3. Propose and implement optimizations for trigonometric functions. > > I wish to work on ideas 1 and 3. I will start making the proposal for these > ideas and share the draft with you. > It will be a pleasure to hear any suggestions and guidance from you. > > Thanks & Regards > Suraj Nehra > > > ------------------------------ > > Message: 12 > Date: Sun, 28 Mar 2021 03:30:54 +0000 > From: Suraj Nehra <surajnehra112(a)gmail.com> > To: boost(a)lists.boost.org > Subject: [boost] [GSoC] Boost.Real: Introduction and Guidence > Message-ID: > < > CAJR02Fe4w-FfDcjDK4NfLs1LNqBwThi5uxF-nhefMo6NhrSSkw(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > Hi, > I am Suraj Nehra, a pre-final year student at the National Institute of > Technology (NIT), Warangal, India. This mail is to introduce myself to the > boost community. Boost.Real is not added to boost project ideas page yet > but I was discussing ideas with Vikram(vikram2000b(a)gmail.com) and also > made > several contributions to the library. > > I wish to work on this library in this GSoC and will start drafting > the proposal. I received the competency task from Vikram and will start > working on those. I was informed of the following potential ideas by him: > 1. Library comparison and benchmarking with other similar libraries. > 2. DAG internal representation > 3. Propose and implement optimizations for trigonometric functions. > > I wish to work on ideas 1 and 3. I will start making the proposal for these > ideas and share the draft with you. > It will be a pleasure to hear any suggestions and guidance from you. > > Thanks & Regards > Suraj Nehra > > > ------------------------------ > > Message: 13 > Date: Sun, 28 Mar 2021 09:54:11 +0300 > From: Antony Polukhin <antoshkka(a)gmail.com> > To: "boost(a)lists.boost.org List" <boost(a)lists.boost.org> > Subject: [boost] Changelog for 1.76 is outdated > Message-ID: > < > CAKqmYPazb_JKWwwy-DZGdpfseJ4wB0KXR3FsK22o-nZ0w6G+0Q(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > Hi, > > The https://www.boost.org/users/history/version_1_76_0.html seems quite > outdated. Please update > > Thanks in advance! > > > ------------------------------ > > Message: 14 > Date: Sun, 28 Mar 2021 09:56:43 +0300 > From: Antony Polukhin <antoshkka(a)gmail.com> > To: "boost(a)lists.boost.org List" <boost(a)lists.boost.org> > Subject: Re: [boost] Changelog for 1.76 is outdated > Message-ID: > <CAKqmYPaXN-c= > k45pCMWVDYAdHX+p916H2fjkfHXZ4pvVchRV6A(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > By "outdated" I mean that > > https://github.com/boostorg/website/blob/master/feed/history/boost_1_76_0.q… > has more info > > > ------------------------------ > > Message: 15 > Date: Sun, 28 Mar 2021 15:05:07 +0200 > From: shady mohamed <shadimabdrawy1999(a)gmail.com> > To: boost(a)lists.boost.org > Subject: Re: [boost] Boost Digest, Vol 6566, Issue 1 > Message-ID: > < > CAPwR5ipUjbt4R5E_W4qO3wvfkm7NfmiT1Q99AhMwWvGxTUyk2A(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > I want to talk with engineer david bellot and engineer cem bassoy > Thanks > > ?? ??????? ?? ????? ???? ??:?? ? <boost-request(a)lists.boost.org> ???: > > > Send Boost mailing list submissions to > > boost(a)lists.boost.org > > > > To subscribe or unsubscribe via the World Wide Web, visit > > https://lists.boost.org/mailman/listinfo.cgi/boost > > or, via email, send a message with subject or body 'help' to > > boost-request(a)lists.boost.org > > > > You can reach the person managing the list at > > boost-owner(a)lists.boost.org > > > > When replying, please edit your Subject line so it is more specific > > than "Re: Contents of Boost digest..." > > > > > > The boost archives may be found at: > http://lists.boost.org/Archives/boost/ > > > > > > Today's Topics: > > > > 1. Re: [Boost] [Lambda2] Review starts Monday March 22, 2021 to > > March 31, 2021 (Andrzej Krzemienski) > > 2. Re: [release] 1.76.0 post-beta merges (Niall Douglas) > > 3. Re: [Boost] [Lambda2] Review starts Monday March 22, 2021 to > > March 31, 2021 (Peter Dimov) > > 4. Re: [release] 1.76.0 post-beta merges (Marshall Clow) > > 5. Re: [release] 1.76.0 post-beta merges (Niall Douglas) > > 6. Re: [release] 1.76.0 post-beta merges (Glen Fernandes) > > 7. Re: [Lambda2] Review starts Monday March 22, 2021 to March > > 31, 2021 (Julien Blanc) > > 8. Re: [Lambda2] Review starts Monday March 22, 2021 to March > > 31, 2021 (Andrzej Krzemienski) > > 9. Re: [Lambda2] Review starts Monday March 22, 2021 to March > > 31, 2021 (Julien Blanc) > > 10. Re: [Boost] [Describe] Summary Review Summary (Emil Dotchevski) > > 11. Re: [Lambda2] Review starts Monday March 22, 2021 to March > > 31, 2021 (Mathias Gaunard) > > 12. Re: [Boost] [Lambda2] Review starts Monday March 22, 2021 to > > March 31, 2021 (Mathias Gaunard) > > > > > > ---------------------------------------------------------------------- > > > > Message: 1 > > Date: Thu, 25 Mar 2021 14:54:17 +0100 > > From: Andrzej Krzemienski <akrzemi1(a)gmail.com> > > To: Boost mailing list <boost(a)lists.boost.org> > > Cc: Peter Dimov <pdimov(a)gmail.com> > > Subject: Re: [boost] [Boost] [Lambda2] Review starts Monday March 22, > > 2021 to March 31, 2021 > > Message-ID: > > <CAOenAXhsJ1yCRRBYgJuPh8xws5MMVCks7p6GvfmBG+= > > 28QDNPg(a)mail.gmail.com> > > Content-Type: text/plain; charset="UTF-8" > > > > pon., 22 mar 2021 o 16:44 Peter Dimov via Boost <boost(a)lists.boost.org> > > napisa?(a): > > > > > Edward Diener wrote: > > > > My first reaction, after quickly looking at the submission, is what > > does > > > this > > > > library offer that the original lambda library, which appears to > have a > > > much > > > > larger amount of functionality than this lambda2 library, not offer ? > > > Also there > > > > is the Phoenix library, which also offers an even greater amount of > > > function > > > > object and lambda-like functionality, of which the review manager is > > the > > > main > > > > author I believe. > > > > > > Purely from a user perspective, what this library offers is being a > > > lightweight, > > > single header dependency, and... > > > > > > > Is it basically so that the programmer can easily interface with > > > > the std::bind/std::function classes with the lambda2 placeholders, > > > whereas the > > > > C++03 libraries don't have this possibility wit their placeholders ? > > > > > > ... indeed, a way to port boost::bind code that uses its operators to > > > std::bind, > > > something that comes up from time to time as projects are modernized. > > > > > > From a different perspective, another goal of the submission is to > gather > > > experience and provide a tested and widely available implementation for > > an > > > eventual proposal to add this functionality to the standard. (Better > late > > > than > > > never.) > > > > > > > My opinion so far is that there is not enough motivation to warrant the > > addition of this library into Boost. > > > > First, the design goals, or the purpose, of the library is not clearly > > defined. > > > > Is the goal that tandem std::bind + Boost.Lambda2 should be a replacement > > over boost::bind and Boost.Lambda? If so, in the current form of the > > library the goal will not be satisfied, because current Boost.Lambda > offers > > quite more things. Just look at the motivating examples of Boost.Lambda: > > https://www.boost.org/doc/libs/1_75_0/doc/html/lambda/using_library.html > > In particular, the usage of assignment or function constant(). > > Boost.Lambda2 will not work as a drop-in replacement for Boost.Lambda. > > > > For a moment I thought that the goal is to have a cooler syntax for the > > current standard arithmetic function objects, such as std::plus, > > std::multiplies. But the advantage is dubious. You gain a few characters, > > but you pay the cost of > > * employing a different library > > * messy error messages > > * no debugger support > > > > The suggestion that we would enable constructs like > > `std::bind(&Employee::name, e1) < std::bind(&Employee::name, e2)`also > > doesn't seem like a good motivation. std::bind only works well when it is > > used for binding arguments to functions. Overusing it for implementing > > lambdas made sense in C++03, because there was no other way. Now with > > generic lambdas it can only be considered a bad (or at least > controversial) > > practice. > > > > I am far from imposing my programming style on others. But promoting a > > programming style like this through the inclusion into Boost seems too > > much. My vision of Boost is that it should support certain programming > > styles that are considered good, but not any programming style. > > > > Regarding the implementation, on the other hand, it is as elegant as a > > library implementation could ever be. It is extremely short! (78 lines, > > including whitespace, header guards, and copyright notice). > > > > Regards, > > &rzej; > > > > > > ------------------------------ > > > > Message: 2 > > Date: Thu, 25 Mar 2021 15:06:02 +0000 > > From: Niall Douglas <s_sourceforge(a)nedprod.com> > > To: boost(a)lists.boost.org > > Subject: Re: [boost] [release] 1.76.0 post-beta merges > > Message-ID: <6efb04af-9f26-4d04-a187-8bc08369caf3(a)nedprod.com> > > Content-Type: text/plain; charset=utf-8 > > > > On 16/03/2021 20:24, Marshall Clow via Boost wrote: > > > The master branch is is now open for post-beta merges, but only as > > described in the Post-Beta Merge Policy. > > > See < > > https://github.com/boostorg/boost/wiki/Releases%3A-Beta-Merge-Policy> > > > > I would like to fix https://github.com/ned14/outcome/issues/249 by > > improving the logic at > > > > > https://github.com/ned14/outcome/blob/develop/include/outcome/convert.hpp#L… > > please. > > > > Niall > > > > > > ------------------------------ > > > > Message: 3 > > Date: Thu, 25 Mar 2021 17:24:15 +0200 > > From: "Peter Dimov" <pdimov(a)gmail.com> > > To: "'Andrzej Krzemienski'" <akrzemi1(a)gmail.com>, "'Boost mailing > > list'" <boost(a)lists.boost.org> > > Subject: Re: [boost] [Boost] [Lambda2] Review starts Monday March 22, > > 2021 to March 31, 2021 > > Message-ID: <131601d7218a$eb1033b0$c1309b10$(a)gmail.com> > > Content-Type: text/plain; charset="utf-8" > > > > Andrzej Krzemienski wrote: > > > First, the design goals, or the purpose, of the library is not clearly > > defined. > > > > The goals of the library are > > > > - Give people the choice of using an abbreviated lambda syntax that is > able > > to express simple operations in fewer characters; > > - Bring std::bind to parity with boost::bind feature-wise so that porting > > is > > easier; > > - Prepare a proposal to extend the standard with these same additions by > > gathering experience in Boost first. > > > > > Is the goal that tandem std::bind + Boost.Lambda2 should be a > replacement > > > over boost::bind and Boost.Lambda? If so, in the current form of the > > library > > > the goal will not be satisfied, because current Boost.Lambda offers > > quite more > > > things. > > > > This doesn't make it useless. When porting "operator-enhanced" > boost::bind, > > or Boost.Lambda, code, you need to go over all the uses and change them > > into language lambdas. This is routine mechanical work that as a result > is > > highly error-prone and without good test coverage, mistakes can easily > pass > > review because of the repetitive nature of the diff. It's much better if > > you > > could port at least some of the uses without making changes beyond > > replacing > > boost:: with std::, and adding/changing the using directive. > > > > It's not necessary to be able to port _all_ uses without any changes; a > > portion > > is enough to reduce the error rate significantly. > > > > And if you're going to ask what's the point of porting from one Boost > > library > > to another, the difference is that it's much easier to "vendor" a single > > short > > header. > > > > > For a moment I thought that the goal is to have a cooler syntax for the > > current > > > standard arithmetic function objects, such as std::plus, > > std::multiplies. But the > > > advantage is dubious. You gain a few characters, but you pay the cost > of > > > * employing a different library > > > * messy error messages > > > * no debugger support > > > > This could be true, but it has nothing to do with the library lacking > > clarity of > > purpose. > > > > > The suggestion that we would enable constructs like > > > `std::bind(&Employee::name, e1) < std::bind(&Employee::name, e2)`also > > > doesn't seem like a good motivation. > > > > As explained, this is only an issue when porting boost::bind code using > > these constructs. You obviously aren't going to use this in new code > > because > > the equivalent language lambda is shorter (not by much) and clearer. > > > > > > > > ------------------------------ > > > > Message: 4 > > Date: Thu, 25 Mar 2021 08:45:22 -0700 > > From: Marshall Clow <mclow.lists(a)gmail.com> > > To: Boost Developers List <boost(a)lists.boost.org> > > Subject: Re: [boost] [release] 1.76.0 post-beta merges > > Message-ID: <0EAF569D-A080-4217-BC77-D7CE4057EC0A(a)gmail.com> > > Content-Type: text/plain; charset=utf-8 > > > > On Mar 25, 2021, at 8:06 AM, Niall Douglas via Boost < > > boost(a)lists.boost.org> wrote: > > > > > > On 16/03/2021 20:24, Marshall Clow via Boost wrote: > > >> The master branch is is now open for post-beta merges, but only as > > described in the Post-Beta Merge Policy. > > >> See < > > https://github.com/boostorg/boost/wiki/Releases%3A-Beta-Merge-Policy> > > > > > > I would like to fix https://github.com/ned14/outcome/issues/249 by > > > improving the logic at > > > > > > https://github.com/ned14/outcome/blob/develop/include/outcome/convert.hpp#L… > > > please. > > > > Do you have a commit that fixes this? > > > > ? Marshall > > > > > > > > > > ------------------------------ > > > > Message: 5 > > Date: Thu, 25 Mar 2021 16:04:17 +0000 > > From: Niall Douglas <s_sourceforge(a)nedprod.com> > > To: Boost Developers List <boost(a)lists.boost.org> > > Subject: Re: [boost] [release] 1.76.0 post-beta merges > > Message-ID: <2dc9222a-592a-6b85-c76b-d62ef55611b3(a)nedprod.com> > > Content-Type: text/plain; charset=utf-8 > > > > On 25/03/2021 15:45, Marshall Clow wrote: > > > On Mar 25, 2021, at 8:06 AM, Niall Douglas via Boost < > > boost(a)lists.boost.org> wrote: > > >> > > >> On 16/03/2021 20:24, Marshall Clow via Boost wrote: > > >>> The master branch is is now open for post-beta merges, but only as > > described in the Post-Beta Merge Policy. > > >>> See < > > https://github.com/boostorg/boost/wiki/Releases%3A-Beta-Merge-Policy> > > >> > > >> I would like to fix https://github.com/ned14/outcome/issues/249 by > > >> improving the logic at > > >> > > > https://github.com/ned14/outcome/blob/develop/include/outcome/convert.hpp#L… > > >> please. > > > > > > Do you have a commit that fixes this? > > > > The change is trivial. Current: > > > > ```c++ > > #if !defined(_MSC_VER) && !defined(__clang__) && (__GNUC__ < 9 || > > __cpp_concepts < 201907L) > > #define OUTCOME_GCC6_CONCEPT_BOOL bool > > #else > > #define OUTCOME_GCC6_CONCEPT_BOOL > > #endif > > ``` > > > > To be replaced with: > > > > ```c++ > > #if (defined(_MSC_VER) || defined(__clang__) || (defined(__GNUC__) && > > __cpp_concepts >= 201707) || OUTCOME_FORCE_STD_CXX_CONCEPTS) && > > !OUTCOME_FORCE_LEGACY_GCC_CXX_CONCEPTS > > #define OUTCOME_GCC6_CONCEPT_BOOL > > #else > > #define OUTCOME_GCC6_CONCEPT_BOOL bool > > #endif > > ``` > > > > To explain, GCC expects bool with concept, or not, in varying > > configuration combinations which have evolved over GCC versions, > > including apparently point releases, which is deeply unhelpful. This has > > led to repeated bug reports for not just Outcome, but also for ASIO and > > many other C++ projects. > > > > If this above fix doesn't permanently shut this constant source of bug > > reports, I'll be permanently disabling legacy GCC concepts support in > > Outcome. I couldn't be arsed with supporting how unpredictably broken > > GCC is with this. > > > > Niall > > > > > > ------------------------------ > > > > Message: 6 > > Date: Thu, 25 Mar 2021 12:12:03 -0400 > > From: Glen Fernandes <glen.fernandes(a)gmail.com> > > To: boost(a)lists.boost.org > > Subject: Re: [boost] [release] 1.76.0 post-beta merges > > Message-ID: > > <CAHVPgznFdSVYJ9gR8LzP7qQV7w5+fcjBvKq95ReUKkFR-ct= > > Qg(a)mail.gmail.com> > > Content-Type: text/plain; charset="UTF-8" > > > > On Thu, Mar 25, 2021 at 12:04 PM Niall Douglas via Boost > > <boost(a)lists.boost.org> wrote: > > > > > > On 25/03/2021 15:45, Marshall Clow wrote: > > > > On Mar 25, 2021, at 8:06 AM, Niall Douglas via Boost < > > boost(a)lists.boost.org> wrote: > > > >> > > > >> I would like to fix https://github.com/ned14/outcome/issues/249 by > > > >> improving the logic at > > > >> > > > https://github.com/ned14/outcome/blob/develop/include/outcome/convert.hpp#L… > > > >> please. > > > > > > > > Do you have a commit that fixes this? > > > > > > The change is trivial. Current: > > > > If you're asking for permission to merge to master now, you should > > have a commit on outcome's develop branch that we can look at. You are > > free to commit to develop at any time. Only master is locked. > > > > Glen > > > > > > ------------------------------ > > > > Message: 7 > > Date: Thu, 25 Mar 2021 19:10:33 +0100 > > From: Julien Blanc <julien.blanc(a)tgcm.eu> > > To: boost(a)lists.boost.org > > Subject: Re: [boost] [Lambda2] Review starts Monday March 22, 2021 to > > March 31, 2021 > > Message-ID: <2773cbf43ec651fdf2b3a3262c8476d814047eb0.camel(a)tgcm.eu> > > Content-Type: text/plain; charset="UTF-8" > > > > Le lundi 22 mars 2021 ? 10:35 +0800, Joel de Guzman via Boost a ?crit?: > > > The Boost formal review of the Lambda2, authored by Peter Dimov, > > > starts Monday, March 22, 2021 to March 31, 2021 (inclusive). > > > > Here's my small review of the lambda 2 library. > > > > TLDR: ACCEPT > > > > > ?? - What is your evaluation of the design? > > > ?? - What is your evaluation of the implementation? > > > > The library is a really small piece of code, like other reviewers > > already noticed. During my tests, i came across two things that could > > be improved: > > * the internal macro BOOST_LAMBDA2_UNARY_LAMBDA and > > BOOST_LAMBDA2_BINARY_LAMBDA #undefed at the end of the file. While i > > undestand that it is an internal macro, it could be exposed to the user > > to allow implementation for other operators > > * that macro hardcode the std prefix, it could be part of its call, ie: > > > > BOOST_LAMBDA2_BINARY_LAMBDA(+, std::plus) // instead of > > BOOST_LAMBDA2_BINARY_LAMBDA(+, plus) > > > > This would allow the user of the library to get the building blocks to > > customize other operators to its needs (I have implemented unary > > operator* easily that way). > > > > > ?? - What is your evaluation of the documentation? > > > > The documentation is really good at telling what the library does, is > > clean, nice looking. > > > > > ?? - What is your evaluation of the potential usefulness of the > > > library? > > > > At first glance, i was thinking that this was the kind of library that > > i would never use. I find the count_if examples in the documentation > > not really convincing. > > > > Then, it happened that i made some experiments with c++20 ranges. And i > > find that, in this context, shortening the lambdas gives a real benefit > > to the code. It basically started from the need to feed a function that > > was needing a list of non owner references to T from a > > vector<unique_ptr<T>>. As I was not satisfied with the solution, I > > checked whether c++20 ranges could provide an elegant solution to this. > > Something like > > > > f(std::views::transform(vec, deref)); > > > > implementing deref is easy. Then, out of curiosity, i checked if i > > could use Peter's library to be able to write something like: > > > > f(std::views::transform(vec, *_1)); > > > > I actually find that this way of writing is more natural than the > > former. > > > > So, i wrote : > > > > namespace std // BAD, don't do that > > { > > template<typename T = void> > > struct deref > > { > > decltype(auto) operator()(T& v) { return *v; } > > }; > > template<> > > struct deref<void> > > { > > template<typename T> > > decltype(auto) operator()(T& v) { return *v; } > > }; > > } > > > > BOOST_LAMBDA2_UNARY_LAMBDA(*, deref); > > > > modified Peter's library to remove the #undef, and voila, it just > > works. > > > > I see a lot of potential for the short writing form for lambdas, in > > conjunction with the ranges library. I find convenient to write: > > > > f(std::views::transform(vec, _1 + 1)) // convert from 0-based to 1- > > based index > > > > > ?? - Did you try to use the library? With which compiler(s)? Did you > > > ???? have any problems? > > > > No specific issue encountered, with gcc-10. Error messages are a bit > > cryptic. > > > > > ?? - How much effort did you put into your evaluation? A glance? A > > > quick > > > ???? reading? In-depth study? > > > > A few hours playing with the library. > > > > > ?? - Are you knowledgeable about the problem domain? > > > > Not at all. > > > > My feeling is the following. At first glance, i was wondering what was > > the use case the library addressed. After playing a bit with it, i'm > > now convinced that people will want to use it, and, like me, will > > probably want to expand it to fit their need. I was not suspecting that > > it was possible to write code that way. I suspect most developers are > > not either. Now that it is known it's possible, people will come up > > with their own, probably inferior, solution. Having such a feature in > > boost would at least provide everyone with a correct implementation of > > it. Because people will want to write code like this, and i believe, > > especially with ranges. > > > > Thanks to Peter for writing this library, and proposing it to boost. > > Reviewing it has been very interesting and instructive. > > > > Regards, > > > > Julien > > > > > > > > ------------------------------ > > > > Message: 8 > > Date: Fri, 26 Mar 2021 05:54:36 +0100 > > From: Andrzej Krzemienski <akrzemi1(a)gmail.com> > > To: Boost mailing list <boost(a)lists.boost.org> > > Subject: Re: [boost] [Lambda2] Review starts Monday March 22, 2021 to > > March 31, 2021 > > Message-ID: > > <CAOenAXgEDx= > > kmKY5gVdST-oAeipoa2oG2s5j_y0brxs34r7ojw(a)mail.gmail.com> > > Content-Type: text/plain; charset="UTF-8" > > > > czw., 25 mar 2021 o 19:11 Julien Blanc via Boost <boost(a)lists.boost.org> > > napisa?(a): > > > > > Le lundi 22 mars 2021 ? 10:35 +0800, Joel de Guzman via Boost a ?crit : > > > > The Boost formal review of the Lambda2, authored by Peter Dimov, > > > > starts Monday, March 22, 2021 to March 31, 2021 (inclusive). > > > > > > Here's my small review of the lambda 2 library. > > > > > > TLDR: ACCEPT > > > > > > > - What is your evaluation of the design? > > > > - What is your evaluation of the implementation? > > > > > > The library is a really small piece of code, like other reviewers > > > already noticed. During my tests, i came across two things that could > > > be improved: > > > * the internal macro BOOST_LAMBDA2_UNARY_LAMBDA and > > > BOOST_LAMBDA2_BINARY_LAMBDA #undefed at the end of the file. While i > > > undestand that it is an internal macro, it could be exposed to the user > > > to allow implementation for other operators > > > * that macro hardcode the std prefix, it could be part of its call, ie: > > > > > > BOOST_LAMBDA2_BINARY_LAMBDA(+, std::plus) // instead of > > > BOOST_LAMBDA2_BINARY_LAMBDA(+, plus) > > > > > > This would allow the user of the library to get the building blocks to > > > customize other operators to its needs (I have implemented unary > > > operator* easily that way). > > > > > > > Is it not just that the library is missing some operators? If > Boost.Lambda2 > > overloaded all overloadable operators there would be no point in users > > doing it. > > > > > > > > - What is your evaluation of the documentation? > > > > > > The documentation is really good at telling what the library does, is > > > clean, nice looking. > > > > > > > - What is your evaluation of the potential usefulness of the > > > > library? > > > > > > At first glance, i was thinking that this was the kind of library that > > > i would never use. I find the count_if examples in the documentation > > > not really convincing. > > > > > > Then, it happened that i made some experiments with c++20 ranges. And i > > > find that, in this context, shortening the lambdas gives a real benefit > > > to the code. It basically started from the need to feed a function that > > > was needing a list of non owner references to T from a > > > vector<unique_ptr<T>>. As I was not satisfied with the solution, I > > > checked whether c++20 ranges could provide an elegant solution to this. > > > Something like > > > > > > f(std::views::transform(vec, deref)); > > > > > > implementing deref is easy. Then, out of curiosity, i checked if i > > > could use Peter's library to be able to write something like: > > > > > > f(std::views::transform(vec, *_1)); > > > > > > I actually find that this way of writing is more natural than the > > > former. > > > > > > > This is an interesting observation. In my experience, storing collections > > of ints is a rare case in production code (it is frequent in tests, > > tutorials, books, presentations), maybe this is why arithmetic operators > do > > not appear as something practical. However pointers (including smart > ones) > > to user-defined types is something that I see a lot. The following als > > looks as something I would see often in the code: > > > > assert(std::ranges::all_of(records, _1 != nullptr)); > > > > Regards, > > &rzej; > > > > > > > So, i wrote : > > > > > > namespace std // BAD, don't do that > > > { > > > template<typename T = void> > > > struct deref > > > { > > > decltype(auto) operator()(T& v) { return *v; } > > > }; > > > template<> > > > struct deref<void> > > > { > > > template<typename T> > > > decltype(auto) operator()(T& v) { return *v; } > > > }; > > > } > > > > > > BOOST_LAMBDA2_UNARY_LAMBDA(*, deref); > > > > > > modified Peter's library to remove the #undef, and voila, it just > > > works. > > > > > > I see a lot of potential for the short writing form for lambdas, in > > > conjunction with the ranges library. I find convenient to write: > > > > > > f(std::views::transform(vec, _1 + 1)) // convert from 0-based to 1- > > > based index > > > > > > > - Did you try to use the library? With which compiler(s)? Did you > > > > have any problems? > > > > > > No specific issue encountered, with gcc-10. Error messages are a bit > > > cryptic. > > > > > > > - How much effort did you put into your evaluation? A glance? A > > > > quick > > > > reading? In-depth study? > > > > > > A few hours playing with the library. > > > > > > > - Are you knowledgeable about the problem domain? > > > > > > Not at all. > > > > > > My feeling is the following. At first glance, i was wondering what was > > > the use case the library addressed. After playing a bit with it, i'm > > > now convinced that people will want to use it, and, like me, will > > > probably want to expand it to fit their need. I was not suspecting that > > > it was possible to write code that way. I suspect most developers are > > > not either. Now that it is known it's possible, people will come up > > > with their own, probably inferior, solution. Having such a feature in > > > boost would at least provide everyone with a correct implementation of > > > it. Because people will want to write code like this, and i believe, > > > especially with ranges. > > > > > > Thanks to Peter for writing this library, and proposing it to boost. > > > Reviewing it has been very interesting and instructive. > > > > > > Regards, > > > > > > Julien > > > > > > > > > _______________________________________________ > > > Unsubscribe & other changes: > > > http://lists.boost.org/mailman/listinfo.cgi/boost > > > > > > > > > ------------------------------ > > > > Message: 9 > > Date: Fri, 26 Mar 2021 07:44:43 +0100 > > From: Julien Blanc <julien.blanc(a)tgcm.eu> > > To: boost(a)lists.boost.org > > Subject: Re: [boost] [Lambda2] Review starts Monday March 22, 2021 to > > March 31, 2021 > > Message-ID: <54d581dd2987773250b0f822393ea819a03297bc.camel(a)tgcm.eu> > > Content-Type: text/plain; charset="UTF-8" > > > > Le vendredi 26 mars 2021 ? 05:54 +0100, Andrzej Krzemienski via Boost a > > ?crit?: > > > > This would allow the user of the library to get the building blocks > > > > to > > > > customize other operators to its needs (I have implemented unary > > > > operator* easily that way). > > > > > > > > > > Is it not just that the library is missing some operators? If > > > Boost.Lambda2 > > > overloaded all overloadable operators there would be no point in > > > users > > > doing it. > > > > Agreed. But I don't have a strong opinion on whether the library should > > implement everything, or just be more open to user extensions. > > > > > The following als looks as something I would see often in the code: > > > > > > assert(std::ranges::all_of(records, _1 != nullptr)); > > > > Definitely. That's the kind of motivating example that i think should > > appear in the documentation. > > > > Regards, > > > > Julien > > > > > > > > ------------------------------ > > > > Message: 10 > > Date: Fri, 26 Mar 2021 00:23:56 -0700 > > From: Emil Dotchevski <emildotchevski(a)gmail.com> > > To: Boost <boost(a)lists.boost.org> > > Subject: Re: [boost] [Boost] [Describe] Summary Review Summary > > Message-ID: > > < > > CAN5fK5H0Cr5OmaX2ryTjRcboLu8xqiv3eKuYdCaft6EZXKFh9Q(a)mail.gmail.com> > > Content-Type: text/plain; charset="UTF-8" > > > > On Wed, Mar 24, 2021 at 7:35 AM Jeff Garland via Boost < > > boost(a)lists.boost.org> wrote: > > > > The committee seems to be concerned more with internal and external > > > > politics than with serving the community. If that wasn't true there > > would > > > > be ZERO library additions that haven't been battle hardened by being > > > > deployed and established themselves as the defacto standard already. > > > > > > Unlike the boost review where there's 'a decider', the committee uses > > > consensus. It's a much higher bar, as frankly, it should be. > > > > A "much higher bar" can prevent a good library from being accepted or > > prevent a bad library from being rejected. That is, consensus cuts both > > ways. > > > > > As for battle hardened, sometimes it's not quite so simple as sometimes > > > language changes are needed or vendor support is needed. Every > proposal > > > gets vetted for usage experience and it's clear that without experience > > > it's unlikely to go forward. Is the process perfect -- no. Will it > make > > > everyone, even the members happy -- no. Can it be improved -- surely > -- > > > but like many things in life it's not as simple as we'd like. > > > > We can talk about the case when language changes are needed but let's > focus > > on libraries. > > > > > > The only thing they should be doing is rubber-stamping libraries that > > are > > > > already the standard for doing something. > > > > > > And if we 'just did that', things like generic programming wouldn't > exist > > > in c++. If the 'Roque Wave' container design was adopted in 1998 the > > world > > > would be very different now. > > > > There was no GitHub in 1998. Today it feels like some authors treat the > > standard library as a vehicle for making their library available > everywhere > > in hopes it'll get adopted. All I'm saying is that adoption should come > > before standardization. Git pull requests are better than Subversion > > commits. > > > > > And if you want one of those 'battle hardened' libraries > > > adopted, that's fine > > > > You see, I think it is problematic to "want" to standardize a library. > IMO > > the standardization process should be dull and boring, rather than driven > > by exciting innovation. > > > > > > ------------------------------ > > > > Message: 11 > > Date: Fri, 26 Mar 2021 10:11:43 +0000 > > From: Mathias Gaunard <mathias.gaunard(a)ens-lyon.org> > > To: Boost mailing list <boost(a)lists.boost.org> > > Subject: Re: [boost] [Lambda2] Review starts Monday March 22, 2021 to > > March 31, 2021 > > Message-ID: > > <CALnjya9TV+n=N-0_8zWsu_+zGTAW= > > xezCsQ4C3vnBU6wZ6LkNw(a)mail.gmail.com> > > Content-Type: text/plain; charset="UTF-8" > > > > On Fri, 26 Mar 2021 at 04:54, Andrzej Krzemienski via Boost > > <boost(a)lists.boost.org> wrote: > > > > > > This is an interesting observation. In my experience, storing > collections > > > of ints is a rare case in production code (it is frequent in tests, > > > tutorials, books, presentations), maybe this is why arithmetic > operators > > do > > > not appear as something practical. > > > > They do appear frequently if you use column-oriented data structures, > > which are generally better at dealing with large collections of data. > > > > > > ------------------------------ > > > > Message: 12 > > Date: Fri, 26 Mar 2021 10:16:17 +0000 > > From: Mathias Gaunard <mathias.gaunard(a)ens-lyon.org> > > To: Boost mailing list <boost(a)lists.boost.org> > > Subject: Re: [boost] [Boost] [Lambda2] Review starts Monday March 22, > > 2021 to March 31, 2021 > > Message-ID: > > < > > CALnjya8bbeFs1d4q2pSbr8azU3aELbXVDtyCDtj+xioUDdkaEw(a)mail.gmail.com> > > Content-Type: text/plain; charset="UTF-8" > > > > On Mon, 22 Mar 2021 at 02:35, Joel de Guzman via Boost > > <boost(a)lists.boost.org> wrote: > > > > > > The Boost formal review of the Lambda2, authored by Peter Dimov, > > > starts Monday, March 22, 2021 to March 31, 2021 (inclusive). > > > > > > Documentation: https://pdimov.github.io/lambda2/doc/html/lambda2.html > > > Source: https://github.com/pdimov/lambda2/ > > > > > > Lambda2 is a simple, but functional, C++14 lambda library. It takes > > advantage > > > of the fact that the standard <functional> header already provides > > placeholders > > > _1, _2, _3, and so on, for use with std::bind, and function objects > such > > > as std::plus, std::greater, std::logical_not, and std::bit_xor, > > corresponding to > > > arithmetic, relational, logical and bitwise operators. > > > > > > Please provide in your review information you think is valuable to > > > understand your choice to ACCEPT or REJECT including Lambda2 as a > > > Boost library. Please be explicit about your decision (ACCEPT or > REJECT). > > > > > > Some other questions you might want to consider answering: > > > > > > - What is your evaluation of the design? > > > - What is your evaluation of the implementation? > > > - What is your evaluation of the documentation? > > > > It is not clear from the documentation what the capture behaviour of > > terminals is. > > I assume it's capturing rvalues by value and lvalues by reference? > > > > What about the expression tree itself, is it fully by value, and > > therefore safely copyable? > > Boost.Proto for example by default is binding everything by reference, > > meaning that you couldn't even store the expression in a variable. Is > > it avoiding this issue? > > > > > > ------------------------------ > > > > Subject: Digest Footer > > > > _______________________________________________ > > Unsubscribe & other changes: > > http://lists.boost.org/mailman/listinfo.cgi/boost > > > > > > ------------------------------ > > > > End of Boost Digest, Vol 6566, Issue 1 > > ************************************** > > > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Unsubscribe & other changes: > http://lists.boost.org/mailman/listinfo.cgi/boost > > > ------------------------------ > > End of Boost Digest, Vol 6567, Issue 1 > ************************************** >

2 1

Changelog for 1.76 is outdated
by Antony Polukhin 28 Mar '21

28 Mar '21

Hi, The https://www.boost.org/users/history/version_1_76_0.html seems quite outdated. Please update Thanks in advance!

2 4

Re: [boost] Boost Digest, Vol 6566, Issue 1
by shady mohamed 28 Mar '21

28 Mar '21

I want to talk with engineer david bellot and engineer cem bassoy Thanks في الجمعة، ٢٦ مارس، ٢٠٢١ ١٢:٢٣ م <boost-request(a)lists.boost.org> كتب: > Send Boost mailing list submissions to > boost(a)lists.boost.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.boost.org/mailman/listinfo.cgi/boost > or, via email, send a message with subject or body 'help' to > boost-request(a)lists.boost.org > > You can reach the person managing the list at > boost-owner(a)lists.boost.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Boost digest..." > > > The boost archives may be found at: http://lists.boost.org/Archives/boost/ > > > Today's Topics: > > 1. Re: [Boost] [Lambda2] Review starts Monday March 22, 2021 to > March 31, 2021 (Andrzej Krzemienski) > 2. Re: [release] 1.76.0 post-beta merges (Niall Douglas) > 3. Re: [Boost] [Lambda2] Review starts Monday March 22, 2021 to > March 31, 2021 (Peter Dimov) > 4. Re: [release] 1.76.0 post-beta merges (Marshall Clow) > 5. Re: [release] 1.76.0 post-beta merges (Niall Douglas) > 6. Re: [release] 1.76.0 post-beta merges (Glen Fernandes) > 7. Re: [Lambda2] Review starts Monday March 22, 2021 to March > 31, 2021 (Julien Blanc) > 8. Re: [Lambda2] Review starts Monday March 22, 2021 to March > 31, 2021 (Andrzej Krzemienski) > 9. Re: [Lambda2] Review starts Monday March 22, 2021 to March > 31, 2021 (Julien Blanc) > 10. Re: [Boost] [Describe] Summary Review Summary (Emil Dotchevski) > 11. Re: [Lambda2] Review starts Monday March 22, 2021 to March > 31, 2021 (Mathias Gaunard) > 12. Re: [Boost] [Lambda2] Review starts Monday March 22, 2021 to > March 31, 2021 (Mathias Gaunard) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 25 Mar 2021 14:54:17 +0100 > From: Andrzej Krzemienski <akrzemi1(a)gmail.com> > To: Boost mailing list <boost(a)lists.boost.org> > Cc: Peter Dimov <pdimov(a)gmail.com> > Subject: Re: [boost] [Boost] [Lambda2] Review starts Monday March 22, > 2021 to March 31, 2021 > Message-ID: > <CAOenAXhsJ1yCRRBYgJuPh8xws5MMVCks7p6GvfmBG+= > 28QDNPg(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > pon., 22 mar 2021 o 16:44 Peter Dimov via Boost <boost(a)lists.boost.org> > napisa?(a): > > > Edward Diener wrote: > > > My first reaction, after quickly looking at the submission, is what > does > > this > > > library offer that the original lambda library, which appears to have a > > much > > > larger amount of functionality than this lambda2 library, not offer ? > > Also there > > > is the Phoenix library, which also offers an even greater amount of > > function > > > object and lambda-like functionality, of which the review manager is > the > > main > > > author I believe. > > > > Purely from a user perspective, what this library offers is being a > > lightweight, > > single header dependency, and... > > > > > Is it basically so that the programmer can easily interface with > > > the std::bind/std::function classes with the lambda2 placeholders, > > whereas the > > > C++03 libraries don't have this possibility wit their placeholders ? > > > > ... indeed, a way to port boost::bind code that uses its operators to > > std::bind, > > something that comes up from time to time as projects are modernized. > > > > From a different perspective, another goal of the submission is to gather > > experience and provide a tested and widely available implementation for > an > > eventual proposal to add this functionality to the standard. (Better late > > than > > never.) > > > > My opinion so far is that there is not enough motivation to warrant the > addition of this library into Boost. > > First, the design goals, or the purpose, of the library is not clearly > defined. > > Is the goal that tandem std::bind + Boost.Lambda2 should be a replacement > over boost::bind and Boost.Lambda? If so, in the current form of the > library the goal will not be satisfied, because current Boost.Lambda offers > quite more things. Just look at the motivating examples of Boost.Lambda: > https://www.boost.org/doc/libs/1_75_0/doc/html/lambda/using_library.html > In particular, the usage of assignment or function constant(). > Boost.Lambda2 will not work as a drop-in replacement for Boost.Lambda. > > For a moment I thought that the goal is to have a cooler syntax for the > current standard arithmetic function objects, such as std::plus, > std::multiplies. But the advantage is dubious. You gain a few characters, > but you pay the cost of > * employing a different library > * messy error messages > * no debugger support > > The suggestion that we would enable constructs like > `std::bind(&Employee::name, e1) < std::bind(&Employee::name, e2)`also > doesn't seem like a good motivation. std::bind only works well when it is > used for binding arguments to functions. Overusing it for implementing > lambdas made sense in C++03, because there was no other way. Now with > generic lambdas it can only be considered a bad (or at least controversial) > practice. > > I am far from imposing my programming style on others. But promoting a > programming style like this through the inclusion into Boost seems too > much. My vision of Boost is that it should support certain programming > styles that are considered good, but not any programming style. > > Regarding the implementation, on the other hand, it is as elegant as a > library implementation could ever be. It is extremely short! (78 lines, > including whitespace, header guards, and copyright notice). > > Regards, > &rzej; > > > ------------------------------ > > Message: 2 > Date: Thu, 25 Mar 2021 15:06:02 +0000 > From: Niall Douglas <s_sourceforge(a)nedprod.com> > To: boost(a)lists.boost.org > Subject: Re: [boost] [release] 1.76.0 post-beta merges > Message-ID: <6efb04af-9f26-4d04-a187-8bc08369caf3(a)nedprod.com> > Content-Type: text/plain; charset=utf-8 > > On 16/03/2021 20:24, Marshall Clow via Boost wrote: > > The master branch is is now open for post-beta merges, but only as > described in the Post-Beta Merge Policy. > > See < > https://github.com/boostorg/boost/wiki/Releases%3A-Beta-Merge-Policy> > > I would like to fix https://github.com/ned14/outcome/issues/249 by > improving the logic at > > https://github.com/ned14/outcome/blob/develop/include/outcome/convert.hpp#L… > please. > > Niall > > > ------------------------------ > > Message: 3 > Date: Thu, 25 Mar 2021 17:24:15 +0200 > From: "Peter Dimov" <pdimov(a)gmail.com> > To: "'Andrzej Krzemienski'" <akrzemi1(a)gmail.com>, "'Boost mailing > list'" <boost(a)lists.boost.org> > Subject: Re: [boost] [Boost] [Lambda2] Review starts Monday March 22, > 2021 to March 31, 2021 > Message-ID: <131601d7218a$eb1033b0$c1309b10$(a)gmail.com> > Content-Type: text/plain; charset="utf-8" > > Andrzej Krzemienski wrote: > > First, the design goals, or the purpose, of the library is not clearly > defined. > > The goals of the library are > > - Give people the choice of using an abbreviated lambda syntax that is able > to express simple operations in fewer characters; > - Bring std::bind to parity with boost::bind feature-wise so that porting > is > easier; > - Prepare a proposal to extend the standard with these same additions by > gathering experience in Boost first. > > > Is the goal that tandem std::bind + Boost.Lambda2 should be a replacement > > over boost::bind and Boost.Lambda? If so, in the current form of the > library > > the goal will not be satisfied, because current Boost.Lambda offers > quite more > > things. > > This doesn't make it useless. When porting "operator-enhanced" boost::bind, > or Boost.Lambda, code, you need to go over all the uses and change them > into language lambdas. This is routine mechanical work that as a result is > highly error-prone and without good test coverage, mistakes can easily pass > review because of the repetitive nature of the diff. It's much better if > you > could port at least some of the uses without making changes beyond > replacing > boost:: with std::, and adding/changing the using directive. > > It's not necessary to be able to port _all_ uses without any changes; a > portion > is enough to reduce the error rate significantly. > > And if you're going to ask what's the point of porting from one Boost > library > to another, the difference is that it's much easier to "vendor" a single > short > header. > > > For a moment I thought that the goal is to have a cooler syntax for the > current > > standard arithmetic function objects, such as std::plus, > std::multiplies. But the > > advantage is dubious. You gain a few characters, but you pay the cost of > > * employing a different library > > * messy error messages > > * no debugger support > > This could be true, but it has nothing to do with the library lacking > clarity of > purpose. > > > The suggestion that we would enable constructs like > > `std::bind(&Employee::name, e1) < std::bind(&Employee::name, e2)`also > > doesn't seem like a good motivation. > > As explained, this is only an issue when porting boost::bind code using > these constructs. You obviously aren't going to use this in new code > because > the equivalent language lambda is shorter (not by much) and clearer. > > > > ------------------------------ > > Message: 4 > Date: Thu, 25 Mar 2021 08:45:22 -0700 > From: Marshall Clow <mclow.lists(a)gmail.com> > To: Boost Developers List <boost(a)lists.boost.org> > Subject: Re: [boost] [release] 1.76.0 post-beta merges > Message-ID: <0EAF569D-A080-4217-BC77-D7CE4057EC0A(a)gmail.com> > Content-Type: text/plain; charset=utf-8 > > On Mar 25, 2021, at 8:06 AM, Niall Douglas via Boost < > boost(a)lists.boost.org> wrote: > > > > On 16/03/2021 20:24, Marshall Clow via Boost wrote: > >> The master branch is is now open for post-beta merges, but only as > described in the Post-Beta Merge Policy. > >> See < > https://github.com/boostorg/boost/wiki/Releases%3A-Beta-Merge-Policy> > > > > I would like to fix https://github.com/ned14/outcome/issues/249 by > > improving the logic at > > > https://github.com/ned14/outcome/blob/develop/include/outcome/convert.hpp#L… > > please. > > Do you have a commit that fixes this? > > ? Marshall > > > > > ------------------------------ > > Message: 5 > Date: Thu, 25 Mar 2021 16:04:17 +0000 > From: Niall Douglas <s_sourceforge(a)nedprod.com> > To: Boost Developers List <boost(a)lists.boost.org> > Subject: Re: [boost] [release] 1.76.0 post-beta merges > Message-ID: <2dc9222a-592a-6b85-c76b-d62ef55611b3(a)nedprod.com> > Content-Type: text/plain; charset=utf-8 > > On 25/03/2021 15:45, Marshall Clow wrote: > > On Mar 25, 2021, at 8:06 AM, Niall Douglas via Boost < > boost(a)lists.boost.org> wrote: > >> > >> On 16/03/2021 20:24, Marshall Clow via Boost wrote: > >>> The master branch is is now open for post-beta merges, but only as > described in the Post-Beta Merge Policy. > >>> See < > https://github.com/boostorg/boost/wiki/Releases%3A-Beta-Merge-Policy> > >> > >> I would like to fix https://github.com/ned14/outcome/issues/249 by > >> improving the logic at > >> > https://github.com/ned14/outcome/blob/develop/include/outcome/convert.hpp#L… > >> please. > > > > Do you have a commit that fixes this? > > The change is trivial. Current: > > ```c++ > #if !defined(_MSC_VER) && !defined(__clang__) && (__GNUC__ < 9 || > __cpp_concepts < 201907L) > #define OUTCOME_GCC6_CONCEPT_BOOL bool > #else > #define OUTCOME_GCC6_CONCEPT_BOOL > #endif > ``` > > To be replaced with: > > ```c++ > #if (defined(_MSC_VER) || defined(__clang__) || (defined(__GNUC__) && > __cpp_concepts >= 201707) || OUTCOME_FORCE_STD_CXX_CONCEPTS) && > !OUTCOME_FORCE_LEGACY_GCC_CXX_CONCEPTS > #define OUTCOME_GCC6_CONCEPT_BOOL > #else > #define OUTCOME_GCC6_CONCEPT_BOOL bool > #endif > ``` > > To explain, GCC expects bool with concept, or not, in varying > configuration combinations which have evolved over GCC versions, > including apparently point releases, which is deeply unhelpful. This has > led to repeated bug reports for not just Outcome, but also for ASIO and > many other C++ projects. > > If this above fix doesn't permanently shut this constant source of bug > reports, I'll be permanently disabling legacy GCC concepts support in > Outcome. I couldn't be arsed with supporting how unpredictably broken > GCC is with this. > > Niall > > > ------------------------------ > > Message: 6 > Date: Thu, 25 Mar 2021 12:12:03 -0400 > From: Glen Fernandes <glen.fernandes(a)gmail.com> > To: boost(a)lists.boost.org > Subject: Re: [boost] [release] 1.76.0 post-beta merges > Message-ID: > <CAHVPgznFdSVYJ9gR8LzP7qQV7w5+fcjBvKq95ReUKkFR-ct= > Qg(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > On Thu, Mar 25, 2021 at 12:04 PM Niall Douglas via Boost > <boost(a)lists.boost.org> wrote: > > > > On 25/03/2021 15:45, Marshall Clow wrote: > > > On Mar 25, 2021, at 8:06 AM, Niall Douglas via Boost < > boost(a)lists.boost.org> wrote: > > >> > > >> I would like to fix https://github.com/ned14/outcome/issues/249 by > > >> improving the logic at > > >> > https://github.com/ned14/outcome/blob/develop/include/outcome/convert.hpp#L… > > >> please. > > > > > > Do you have a commit that fixes this? > > > > The change is trivial. Current: > > If you're asking for permission to merge to master now, you should > have a commit on outcome's develop branch that we can look at. You are > free to commit to develop at any time. Only master is locked. > > Glen > > > ------------------------------ > > Message: 7 > Date: Thu, 25 Mar 2021 19:10:33 +0100 > From: Julien Blanc <julien.blanc(a)tgcm.eu> > To: boost(a)lists.boost.org > Subject: Re: [boost] [Lambda2] Review starts Monday March 22, 2021 to > March 31, 2021 > Message-ID: <2773cbf43ec651fdf2b3a3262c8476d814047eb0.camel(a)tgcm.eu> > Content-Type: text/plain; charset="UTF-8" > > Le lundi 22 mars 2021 ? 10:35 +0800, Joel de Guzman via Boost a ?crit?: > > The Boost formal review of the Lambda2, authored by Peter Dimov, > > starts Monday, March 22, 2021 to March 31, 2021 (inclusive). > > Here's my small review of the lambda 2 library. > > TLDR: ACCEPT > > > ?? - What is your evaluation of the design? > > ?? - What is your evaluation of the implementation? > > The library is a really small piece of code, like other reviewers > already noticed. During my tests, i came across two things that could > be improved: > * the internal macro BOOST_LAMBDA2_UNARY_LAMBDA and > BOOST_LAMBDA2_BINARY_LAMBDA #undefed at the end of the file. While i > undestand that it is an internal macro, it could be exposed to the user > to allow implementation for other operators > * that macro hardcode the std prefix, it could be part of its call, ie: > > BOOST_LAMBDA2_BINARY_LAMBDA(+, std::plus) // instead of > BOOST_LAMBDA2_BINARY_LAMBDA(+, plus) > > This would allow the user of the library to get the building blocks to > customize other operators to its needs (I have implemented unary > operator* easily that way). > > > ?? - What is your evaluation of the documentation? > > The documentation is really good at telling what the library does, is > clean, nice looking. > > > ?? - What is your evaluation of the potential usefulness of the > > library? > > At first glance, i was thinking that this was the kind of library that > i would never use. I find the count_if examples in the documentation > not really convincing. > > Then, it happened that i made some experiments with c++20 ranges. And i > find that, in this context, shortening the lambdas gives a real benefit > to the code. It basically started from the need to feed a function that > was needing a list of non owner references to T from a > vector<unique_ptr<T>>. As I was not satisfied with the solution, I > checked whether c++20 ranges could provide an elegant solution to this. > Something like > > f(std::views::transform(vec, deref)); > > implementing deref is easy. Then, out of curiosity, i checked if i > could use Peter's library to be able to write something like: > > f(std::views::transform(vec, *_1)); > > I actually find that this way of writing is more natural than the > former. > > So, i wrote : > > namespace std // BAD, don't do that > { > template<typename T = void> > struct deref > { > decltype(auto) operator()(T& v) { return *v; } > }; > template<> > struct deref<void> > { > template<typename T> > decltype(auto) operator()(T& v) { return *v; } > }; > } > > BOOST_LAMBDA2_UNARY_LAMBDA(*, deref); > > modified Peter's library to remove the #undef, and voila, it just > works. > > I see a lot of potential for the short writing form for lambdas, in > conjunction with the ranges library. I find convenient to write: > > f(std::views::transform(vec, _1 + 1)) // convert from 0-based to 1- > based index > > > ?? - Did you try to use the library? With which compiler(s)? Did you > > ???? have any problems? > > No specific issue encountered, with gcc-10. Error messages are a bit > cryptic. > > > ?? - How much effort did you put into your evaluation? A glance? A > > quick > > ???? reading? In-depth study? > > A few hours playing with the library. > > > ?? - Are you knowledgeable about the problem domain? > > Not at all. > > My feeling is the following. At first glance, i was wondering what was > the use case the library addressed. After playing a bit with it, i'm > now convinced that people will want to use it, and, like me, will > probably want to expand it to fit their need. I was not suspecting that > it was possible to write code that way. I suspect most developers are > not either. Now that it is known it's possible, people will come up > with their own, probably inferior, solution. Having such a feature in > boost would at least provide everyone with a correct implementation of > it. Because people will want to write code like this, and i believe, > especially with ranges. > > Thanks to Peter for writing this library, and proposing it to boost. > Reviewing it has been very interesting and instructive. > > Regards, > > Julien > > > > ------------------------------ > > Message: 8 > Date: Fri, 26 Mar 2021 05:54:36 +0100 > From: Andrzej Krzemienski <akrzemi1(a)gmail.com> > To: Boost mailing list <boost(a)lists.boost.org> > Subject: Re: [boost] [Lambda2] Review starts Monday March 22, 2021 to > March 31, 2021 > Message-ID: > <CAOenAXgEDx= > kmKY5gVdST-oAeipoa2oG2s5j_y0brxs34r7ojw(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > czw., 25 mar 2021 o 19:11 Julien Blanc via Boost <boost(a)lists.boost.org> > napisa?(a): > > > Le lundi 22 mars 2021 ? 10:35 +0800, Joel de Guzman via Boost a ?crit : > > > The Boost formal review of the Lambda2, authored by Peter Dimov, > > > starts Monday, March 22, 2021 to March 31, 2021 (inclusive). > > > > Here's my small review of the lambda 2 library. > > > > TLDR: ACCEPT > > > > > - What is your evaluation of the design? > > > - What is your evaluation of the implementation? > > > > The library is a really small piece of code, like other reviewers > > already noticed. During my tests, i came across two things that could > > be improved: > > * the internal macro BOOST_LAMBDA2_UNARY_LAMBDA and > > BOOST_LAMBDA2_BINARY_LAMBDA #undefed at the end of the file. While i > > undestand that it is an internal macro, it could be exposed to the user > > to allow implementation for other operators > > * that macro hardcode the std prefix, it could be part of its call, ie: > > > > BOOST_LAMBDA2_BINARY_LAMBDA(+, std::plus) // instead of > > BOOST_LAMBDA2_BINARY_LAMBDA(+, plus) > > > > This would allow the user of the library to get the building blocks to > > customize other operators to its needs (I have implemented unary > > operator* easily that way). > > > > Is it not just that the library is missing some operators? If Boost.Lambda2 > overloaded all overloadable operators there would be no point in users > doing it. > > > > > - What is your evaluation of the documentation? > > > > The documentation is really good at telling what the library does, is > > clean, nice looking. > > > > > - What is your evaluation of the potential usefulness of the > > > library? > > > > At first glance, i was thinking that this was the kind of library that > > i would never use. I find the count_if examples in the documentation > > not really convincing. > > > > Then, it happened that i made some experiments with c++20 ranges. And i > > find that, in this context, shortening the lambdas gives a real benefit > > to the code. It basically started from the need to feed a function that > > was needing a list of non owner references to T from a > > vector<unique_ptr<T>>. As I was not satisfied with the solution, I > > checked whether c++20 ranges could provide an elegant solution to this. > > Something like > > > > f(std::views::transform(vec, deref)); > > > > implementing deref is easy. Then, out of curiosity, i checked if i > > could use Peter's library to be able to write something like: > > > > f(std::views::transform(vec, *_1)); > > > > I actually find that this way of writing is more natural than the > > former. > > > > This is an interesting observation. In my experience, storing collections > of ints is a rare case in production code (it is frequent in tests, > tutorials, books, presentations), maybe this is why arithmetic operators do > not appear as something practical. However pointers (including smart ones) > to user-defined types is something that I see a lot. The following als > looks as something I would see often in the code: > > assert(std::ranges::all_of(records, _1 != nullptr)); > > Regards, > &rzej; > > > > So, i wrote : > > > > namespace std // BAD, don't do that > > { > > template<typename T = void> > > struct deref > > { > > decltype(auto) operator()(T& v) { return *v; } > > }; > > template<> > > struct deref<void> > > { > > template<typename T> > > decltype(auto) operator()(T& v) { return *v; } > > }; > > } > > > > BOOST_LAMBDA2_UNARY_LAMBDA(*, deref); > > > > modified Peter's library to remove the #undef, and voila, it just > > works. > > > > I see a lot of potential for the short writing form for lambdas, in > > conjunction with the ranges library. I find convenient to write: > > > > f(std::views::transform(vec, _1 + 1)) // convert from 0-based to 1- > > based index > > > > > - Did you try to use the library? With which compiler(s)? Did you > > > have any problems? > > > > No specific issue encountered, with gcc-10. Error messages are a bit > > cryptic. > > > > > - How much effort did you put into your evaluation? A glance? A > > > quick > > > reading? In-depth study? > > > > A few hours playing with the library. > > > > > - Are you knowledgeable about the problem domain? > > > > Not at all. > > > > My feeling is the following. At first glance, i was wondering what was > > the use case the library addressed. After playing a bit with it, i'm > > now convinced that people will want to use it, and, like me, will > > probably want to expand it to fit their need. I was not suspecting that > > it was possible to write code that way. I suspect most developers are > > not either. Now that it is known it's possible, people will come up > > with their own, probably inferior, solution. Having such a feature in > > boost would at least provide everyone with a correct implementation of > > it. Because people will want to write code like this, and i believe, > > especially with ranges. > > > > Thanks to Peter for writing this library, and proposing it to boost. > > Reviewing it has been very interesting and instructive. > > > > Regards, > > > > Julien > > > > > > _______________________________________________ > > Unsubscribe & other changes: > > http://lists.boost.org/mailman/listinfo.cgi/boost > > > > > ------------------------------ > > Message: 9 > Date: Fri, 26 Mar 2021 07:44:43 +0100 > From: Julien Blanc <julien.blanc(a)tgcm.eu> > To: boost(a)lists.boost.org > Subject: Re: [boost] [Lambda2] Review starts Monday March 22, 2021 to > March 31, 2021 > Message-ID: <54d581dd2987773250b0f822393ea819a03297bc.camel(a)tgcm.eu> > Content-Type: text/plain; charset="UTF-8" > > Le vendredi 26 mars 2021 ? 05:54 +0100, Andrzej Krzemienski via Boost a > ?crit?: > > > This would allow the user of the library to get the building blocks > > > to > > > customize other operators to its needs (I have implemented unary > > > operator* easily that way). > > > > > > > Is it not just that the library is missing some operators? If > > Boost.Lambda2 > > overloaded all overloadable operators there would be no point in > > users > > doing it. > > Agreed. But I don't have a strong opinion on whether the library should > implement everything, or just be more open to user extensions. > > > The following als looks as something I would see often in the code: > > > > assert(std::ranges::all_of(records, _1 != nullptr)); > > Definitely. That's the kind of motivating example that i think should > appear in the documentation. > > Regards, > > Julien > > > > ------------------------------ > > Message: 10 > Date: Fri, 26 Mar 2021 00:23:56 -0700 > From: Emil Dotchevski <emildotchevski(a)gmail.com> > To: Boost <boost(a)lists.boost.org> > Subject: Re: [boost] [Boost] [Describe] Summary Review Summary > Message-ID: > < > CAN5fK5H0Cr5OmaX2ryTjRcboLu8xqiv3eKuYdCaft6EZXKFh9Q(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > On Wed, Mar 24, 2021 at 7:35 AM Jeff Garland via Boost < > boost(a)lists.boost.org> wrote: > > > The committee seems to be concerned more with internal and external > > > politics than with serving the community. If that wasn't true there > would > > > be ZERO library additions that haven't been battle hardened by being > > > deployed and established themselves as the defacto standard already. > > > > Unlike the boost review where there's 'a decider', the committee uses > > consensus. It's a much higher bar, as frankly, it should be. > > A "much higher bar" can prevent a good library from being accepted or > prevent a bad library from being rejected. That is, consensus cuts both > ways. > > > As for battle hardened, sometimes it's not quite so simple as sometimes > > language changes are needed or vendor support is needed. Every proposal > > gets vetted for usage experience and it's clear that without experience > > it's unlikely to go forward. Is the process perfect -- no. Will it make > > everyone, even the members happy -- no. Can it be improved -- surely -- > > but like many things in life it's not as simple as we'd like. > > We can talk about the case when language changes are needed but let's focus > on libraries. > > > > The only thing they should be doing is rubber-stamping libraries that > are > > > already the standard for doing something. > > > > And if we 'just did that', things like generic programming wouldn't exist > > in c++. If the 'Roque Wave' container design was adopted in 1998 the > world > > would be very different now. > > There was no GitHub in 1998. Today it feels like some authors treat the > standard library as a vehicle for making their library available everywhere > in hopes it'll get adopted. All I'm saying is that adoption should come > before standardization. Git pull requests are better than Subversion > commits. > > > And if you want one of those 'battle hardened' libraries > > adopted, that's fine > > You see, I think it is problematic to "want" to standardize a library. IMO > the standardization process should be dull and boring, rather than driven > by exciting innovation. > > > ------------------------------ > > Message: 11 > Date: Fri, 26 Mar 2021 10:11:43 +0000 > From: Mathias Gaunard <mathias.gaunard(a)ens-lyon.org> > To: Boost mailing list <boost(a)lists.boost.org> > Subject: Re: [boost] [Lambda2] Review starts Monday March 22, 2021 to > March 31, 2021 > Message-ID: > <CALnjya9TV+n=N-0_8zWsu_+zGTAW= > xezCsQ4C3vnBU6wZ6LkNw(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > On Fri, 26 Mar 2021 at 04:54, Andrzej Krzemienski via Boost > <boost(a)lists.boost.org> wrote: > > > > This is an interesting observation. In my experience, storing collections > > of ints is a rare case in production code (it is frequent in tests, > > tutorials, books, presentations), maybe this is why arithmetic operators > do > > not appear as something practical. > > They do appear frequently if you use column-oriented data structures, > which are generally better at dealing with large collections of data. > > > ------------------------------ > > Message: 12 > Date: Fri, 26 Mar 2021 10:16:17 +0000 > From: Mathias Gaunard <mathias.gaunard(a)ens-lyon.org> > To: Boost mailing list <boost(a)lists.boost.org> > Subject: Re: [boost] [Boost] [Lambda2] Review starts Monday March 22, > 2021 to March 31, 2021 > Message-ID: > < > CALnjya8bbeFs1d4q2pSbr8azU3aELbXVDtyCDtj+xioUDdkaEw(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > On Mon, 22 Mar 2021 at 02:35, Joel de Guzman via Boost > <boost(a)lists.boost.org> wrote: > > > > The Boost formal review of the Lambda2, authored by Peter Dimov, > > starts Monday, March 22, 2021 to March 31, 2021 (inclusive). > > > > Documentation: https://pdimov.github.io/lambda2/doc/html/lambda2.html > > Source: https://github.com/pdimov/lambda2/ > > > > Lambda2 is a simple, but functional, C++14 lambda library. It takes > advantage > > of the fact that the standard <functional> header already provides > placeholders > > _1, _2, _3, and so on, for use with std::bind, and function objects such > > as std::plus, std::greater, std::logical_not, and std::bit_xor, > corresponding to > > arithmetic, relational, logical and bitwise operators. > > > > Please provide in your review information you think is valuable to > > understand your choice to ACCEPT or REJECT including Lambda2 as a > > Boost library. Please be explicit about your decision (ACCEPT or REJECT). > > > > Some other questions you might want to consider answering: > > > > - What is your evaluation of the design? > > - What is your evaluation of the implementation? > > - What is your evaluation of the documentation? > > It is not clear from the documentation what the capture behaviour of > terminals is. > I assume it's capturing rvalues by value and lvalues by reference? > > What about the expression tree itself, is it fully by value, and > therefore safely copyable? > Boost.Proto for example by default is binding everything by reference, > meaning that you couldn't even store the expression in a variable. Is > it avoiding this issue? > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Unsubscribe & other changes: > http://lists.boost.org/mailman/listinfo.cgi/boost > > > ------------------------------ > > End of Boost Digest, Vol 6566, Issue 1 > ************************************** >

1 0

[GSoC] Boost.Real: Introduction and Guidence
by Suraj Nehra 28 Mar '21

28 Mar '21

Hi, I am Suraj Nehra, a pre-final year student at the National Institute of Technology (NIT), Warangal, India. This mail is to introduce myself to the boost community. Boost.Real is not added to boost project ideas page yet but I was discussing ideas with Vikram(vikram2000b(a)gmail.com) and also made several contributions to the library. I wish to work on this library in this GSoC and will start drafting the proposal. I received the competency task from Vikram and will start working on those. I was informed of the following potential ideas by him: 1. Library comparison and benchmarking with other similar libraries. 2. DAG internal representation 3. Propose and implement optimizations for trigonometric functions. I wish to work on ideas 1 and 3. I will start making the proposal for these ideas and share the draft with you. It will be a pleasure to hear any suggestions and guidance from you. Thanks & Regards Suraj Nehra

1 0

(no subject)
by Suraj Nehra 28 Mar '21

28 Mar '21

Hi, I am Suraj Nehra, a pre-final year student at the National Institute of Technology (NIT), Warangal, India. This mail is to introduce myself to the boost community. Boost.Real is not added to boost project ideas page yet but I was discussing ideas with Vikram(vikram2000b(a)gmail.com) and also made several contributions to the library. I wish to work on this library in this GSoC and will start drafting the proposal. I received the competency task from Vikram and will start working on those. I was informed of the following potential ideas by him: 1. Library comparison and benchmarking with other similar libraries. 2. DAG internal representation 3. Propose and implement optimizations for trigonometric functions. I wish to work on ideas 1 and 3. I will start making the proposal for these ideas and share the draft with you. It will be a pleasure to hear any suggestions and guidance from you. Thanks & Regards Suraj Nehra

1 0

To contact project's mentor for GSoC21
by prince raj 26 Mar '21

26 Mar '21

Hello, My self Anish Kumar Singh and I want to participate to in boost organisation. But I have no idea how to contact mentor for project discussion and my ideas with him. So please help me contacting to mentor so that I can make my proposal good to summit. Thankyou...

3 2

[Boost] [Describe] Summary Review Summary
by Richard Hodges 26 Mar '21

26 Mar '21

Boost Describe Review Summary Boost Describe was submitted by Peter Dimov. The review period lasted from 1st March 2021 until 10th March 2021, inclusive. Overall Verdict Boost.Describe has been accepted into Boost. Detailed Results In all, 13 people submitted reviews. Of these 13, 11 reviews were an unconditional ACCEPT. The remaining two reviews were marked CONDITIONAL ACCEPT. This seems to be common practice, as committing firmly to accept or reject can seem like a bold position either way. However the Boost review process has no provision for attaching conditions to library acceptance. The verdict must be either that the library is sufficiently well written and documented, as well as providing sufficient utility, to be included in the Boost offering, or it is not. Conditional Acceptances In this review I counted the two remaining conditional acceptances as ACCEPT, and decided to pass the conditions as comments/suggestions on to the author for consideration, as well as enumerate them in this report in the hope that further study/debate is stimulated. Libraries evolve over time, and the comments will no doubt be useful to Peter when making future decisions about Boost.Describe. I will deal with the conditions mentioned by Julain Blanc first. Julian’s concerns centered around the fact that the bitfield supplied to the describe_members macro is not additive. I will quote his example here. Given the following code: struct C { int a; std::string b; double c; void f(float a, int b) { } void g() { } static void s() {} private: int p_; void h_(std::string const& s) {} BOOST_DESCRIBE_CLASS(C, (), (a, b, c, f, g, s), (), (p_, h_)) }; I would expect the following: static_assert(mp_size<describe_members<C, mod_public>>::value == 6); static_assert(mp_size<describe_members<C, mod_private>>::value == 2); That's not the case. Instead, the results are resp 3 and 1. By default, only data members are returned, not member functions. So, let's try another one. I want all my member functions: static_assert(mp_size<describe_members<C, mod_function | mod_public | mod_protected | mod_private >>::value == 4) --> fails. By default, it only returns non-static functions. So, let's try to include static function as well: static_assert(mp_size<describe_members<C, mod_static | mod_function | mod_public | mod_protected | mod_private >>::value == 4) That also fails. The result is one, now i only get the static functions. It looks that there's a mix of apples and orange in this enum. Some values acts as they will include more data in the results, some on the contrary will filter, and some will change completely the type of the members enumerated. This concern resonates with me, as I raised a similar (but less well written) query with Peter in the same area. Barrett Adair was the author of the second conditional accept. His reasoning was along the same lines as Julian’s, quoted: I don't like that I need to call describe_members multiple times to get static, non-static, data, and functions. I would appreciate the addition of mod_data and mod_nonstatic to keep the flags consistent. This is my only acceptance condition. Peter took time to respond to this concern: The reason the static/nonstatic and data/function members are returned separately is that the type of `pointer` changes. For nonstatic data, it's M T::*. For static data, it's M*. For nonstatic function, it's R (T::*)(A...). For static function, it's R (*)(A...). Since one typically does things with `pointer` in the loop over members, it's rarely the case that you want all of these at once, because the syntactic form of the code manipulating them changes. So I've found it in practice more convenient to separate them by default. It is fair to say that in less recent variants of C++, iterating over different pointer types would be problematic, although arguably less so with later variants of C++ if some accessor function template overloads or CPOs were made available in the library. The decision on whether this should be explored rests with Peter. Documentation and Examples Reviewers almost universally commented on the quality and completeness of the documentation. Particular attention was drawn to the numerous examples that clearly represent common real-world use cases. Features Requested Rainer Deyke requested the ability to annotate members with further attributes. Peter responded that he would look into whether this was possible while retaining compatibility with likely future standards adoptions of reflection, which is a design goal of the library. Maximilian Riemensberger wondered whether it would be possible to support reference members and overloaded functions. Peter’s response was that alas, no. The language itself is a limiting factor there. Maximilian also requested the ability to annotate enums with associated data. For example, representing an enum value as text when the text cannot be reasonably computed from the value’s symbolic name. Peter agreed to consider this further. Maximilian also touched on the single-pass iteration issue, which brings the number of observers who feel there is good grounds for future evolution to four. Overall Usefulness of the Library The reviewers were unanimous in calling out the need for this kind of library. From reading the reviews it is apparent that a great deal of developer effort is duplicated in writing custom reflection mechanisms. It struck me that (any kind of) language-level compile-time reflection would be welcomed with open arms by the developer community. Perhaps we can hope that the acceptance of Describe into Boost and its subsequent use can inform and encourage the C++ language group to bring something to the community sooner than later. Please join me in extending gratitude to Peter, who has taken time and painstaking effort to present us with such a useful, succinct and well documented library. Please also join me in thanking the reviewers, who can be sure that the detailed analysis included has been read and in for the most part, already elicited a response/bug-fix from Peter. Sincerely, Richard Hodges -- Richard Hodges hodges.r(a)gmail.com office: +442032898513 mobile: +376380212

12 31

C++17 and "Alice in Wonderland"
by Edward Diener 24 Mar '21

24 Mar '21

I apologize for this non-Boost related post, but I ran into what I thought was a C++17 bug in clang ( also in vc++14.2 C++17 ), whose explanation to me of why it is not a bug really sounds like the non-logic of "Alice in Wonderland". I am not putting down the person who explains to me why it is not a bug in any way, as I know he is a C++ expert, but if this is really C++17 something must be wrong with my admittedly limited understanding of C++ and where it is going. My bug report is at https://bugs.llvm.org/show_bug.cgi?id=49684 and the explanation given there just eludes me as to what C++17 is doing, as my further comments makes apparent. Does anyone actually understand how this can possibly be ? How does C++17 apparently deduce a template argument different from what the actual type is and than declare therefore a mismatch ? This is really something from another world. My apologies for bringing this up in Boost, as it is purely a C++ issue, but my original problem comes from something I have been working on in the hopes it might eventually be a Boost library, so I decided to see if any of the expert Boost contributors might know what is going on in C++17. I realize that if everyone did as I have done here the mailing list would be a mass of irrelevant posts not Boost related.

9 11

Boost 1.76 beta - linking error when including Boost
by Luigi Ballabio 24 Mar '21

24 Mar '21

Hello, I'm afraid I don't have a minimal example yet, but I thought I'd give you a heads-up in case it rings a bell. I've been trying the Boost 1.76 beta to build a library I'm maintaining. The library builds, but when I link it to an executable I'm getting an "undefined reference to `bool boost::math::isnan<long double>(long double)". Everything works with 1.75 and earlier. My code is not using boost::math::isnan directly, so I'm guessing some other included boost component is forward-declaring it or doing something similar? The linking error disappears if I include <boost/math/special_functions/fpclassify.hpp> in a config file that is included by every file in the library. Today I'll try to pinpoint the problem by removing it there and including it before specific boost headers in the source files, but as I said, I'm posting this in case someone already has an idea about the underlying issue. Thanks, Luigi

3 4

Any Interest in a port of ZLib to C++?
by Vinnie Falco 24 Mar '21

24 Mar '21

Beast currently has its own port of ZLib to C++: <https://github.com/boostorg/beast/tree/develop/include/boost/beast/zlib> Is there any interest in having this proposed as its own separate Boost library (with a separate review, which has nothing to do with Beast)? The differences would be as follows: * Ported to use C++11 idioms * Same header-only / compiled source model as Boost.JSON * Better documentation and clear API * Improved tests Programs which use this C++ port of ZLib would get their zlib dependency from Boost instead of the official zlib distribution. And they can integrate it into their projects the same way that Boost libraries are integrated. Or they can include <boost/zlib/src.hpp> in any one translation unit (like JSON). The motivation for this is twofold: * Provide an easier way for users to access ZLib's functionality * To use this in some new libraries that I'm going to propose -- Regards, Vinnie Follow me on GitHub: https://github.com/vinniefalco

11 14

[Boost.JSON] Security Review
by Vinnie Falco 23 Mar '21

23 Mar '21

As part of our commitment to producing the very finest C++ libraries that application developers can trust, the C++ Alliance has commissioned Bishop Fox to perform a security audit of the Boost.JSON library. The report is linked here: <https://cppalliance.org/pdf/C%20Plus%20Plus%20Alliance%20-%20Boost%20JSON%2…> This will report will be published starting in Boost 1.76.0 -- Regards, Vinnie Follow me on GitHub: https://github.com/vinniefalco

1 0

boost library incubator planning shutdown
by Robert Ramey 22 Mar '21

22 Mar '21

I had high hopes for the boost library incubator when I made it. But I think it's pretty clear that those hopes haven't been realized. Maintaining and Enhancing this website required more effort than I had anticipated so it hasn't evolved. I do notice that people do use it from time to time (a couple hundred page hits/day), so it's not totally dead. But it would either have to go forward or be shut down. If someone wanted to take it over that would be fine. But I don't expect anyone to come forward so I'll be shutting it down probably in the next 30 days or so. Robert Ramey

1 0

Mentor application for Boost.Real
by Vikram Chundawat 21 Mar '21

21 Mar '21

Hello everyone, I am Vikram Singh Chundawat, I worked on Boost.Real previous GSoC and I am actively working on the library since. Now, one of the potential mentors Damian Vicino is not mentoring this year, I wish to mentor this project in GSoC 2021 with Laouen Belloli. We have some potential candidates who are working on the library and also some good ideas for the library. The aim last year was to bring Boost.Real to review ready state and some work is still remaining to make it review ready, we found some bugs in the review. Now, we are working on optimizations, bug fixes, and benchmarking. I went through the guidelines of Google and wish to know the procedure for mentor application. Thank You Regards Vikram Singh Chundawat

2 1

Proposing a library to include in Boost
by Mohit Saini 20 Mar '21

20 Mar '21

Hi, This is Mohit Saini. I developed a lazy_map library, whose interface is similar to std::unordered_map but lazy_map is O(1) copiable. Other operations like Deletion, Lookup, Insertion etc. continue to cost O(1).. which also implies that lazy_map is not a simple cow_wrapper<std::unordered_map> .. lazy_map is way more clever than that. Learn more at : https://github.com/tinytrashbin/lazy_map Specially, checkout the section which explains the "Fragment" tree. Lazy_map is heavily used in our codebase for taking snapshot of a very large state ( of size ~ 5 GBs), enabling "fork" of a snapshot in O(1) time for further modification in the forked snapshot, allowing a large number of threads to operate on different snapshots of very large size, concurrently without interfering with each other where each of the thread is even "writing" to their snapshot. I believe such a utility will be very helpful for others too. I'm looking for boost-maintainers who can review and suggest what all I need to do so that lazy_map can be accepted in Boost. Thanks -- Mohit Saini

1 0

Re: [boost] Feedback on GSoC'21 project proposal
by krushnalpatel11＠gmail.com 20 Mar '21

20 Mar '21

I have updated the proposal with the changes you proposed. Please check if all things are updated as per your feedback. https://docs.google.com/document/d/1Bvno6ifHjo8EdMRuzFqCk9AEB5IgAxf2ag4xdc4… Krushnal http://krushnal.me/ _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost </quote> Quoted from: http://boost.2283326.n4.nabble.com/Feedback-on-GSoC-21-project-proposal-tp4… _____________________________________ Sent from http://boost.2283326.n4.nabble.com

1 0

Re: [boost] Boost website changes and .'cxxstd'
by Donovan Dikaio 20 Mar '21

20 Mar '21

I can look into it. But needs to make the requirements clear. So, the task is to show *C++ standard minimum level: C++nn* for Standard attribute for each lib in this page: C++ standard minimum level: C++nn ? And we could replace nn with the actual number by checking the *cxxstd* key in a library's meta info json file. Please let me know if I got it right. On Fri, Dec 25, 2020 at 10:00 AM Louis Tatta <louis(a)cppalliance.org> wrote: > > > ---------- Forwarded message --------- > From: Edward Diener via Boost <boost(a)lists.boost.org> > Date: Wed, Dec 23, 2020 at 7:39 PM > Subject: [boost] Boost website changes and .'cxxstd' > To: <boost(a)lists.boost.org> > CC: Edward Diener <eldiener(a)tropicsoft.com> > > > Even though I have worked a little with PHP in the past I do not have > the talent to make the change to the website which would incorporate the > addition of the meta information json field 'cxxstd' to the Boost > documentation web page for each library. The idea is that if 'cxxstd' is > set to a value the documentation for that library would also show: > > C++ standard minimum level: C++nn > > where nn would be 11, 14, 17, or 20 depending on the value of 'cxxstd'. > Alternatively if there is no 'cxxstd' entry for a library or if the > value of 'cxxstd' is '03', we could either specify 'nn' as '03' or leave > off the line stating the 'C++ standard minimum level completely. > > On the face of it this should be doable in the website code but > evidently Daniel James is the only one who really understands how this > works in the code and he is no longer active in Boost. So if someone > else who understands the website code and PHP could do this it would be > appreciated, since I think it will be valuable telling end-users whether > a Boost library is usable at the C++ compiler level they are using. > > > _______________________________________________ > Unsubscribe & other changes: > http://lists.boost.org/mailman/listinfo.cgi/boost >

8 43

Providing a link to GitHub commit from documentation
by pbristow＠hetp.u-net.com 19 Mar '21

19 Mar '21

I've been considering adding commit hash info to some documentation made using the Quickbook/Boostbook/Docbook/b2/bjam toolchain Using git command line git log or ls-remote I can show the necessary hex digit string: commit 5609fa86e37e1b0eae6466065ba6c8eb3ac0ab2f (HEAD -> refactor1) (It would be useful to have the local commit (rather than remote) so that the generated documentation including this has can be pushed up to remote). Paul@hetpD MINGW64 /i/boost/libs/quan/doc (refactor1) $ git log -n1 HEAD > commit.txt That contains commit 5609fa86e37e1b0eae6466065ba6c8eb3ac0ab2f Author: pabristow <pbristow(a)hetp.u-net.com> Date: Fri Mar 19 15:46:45 2021 +0000 Generated super new version. So this gets this info into a file, but I have yet to see how to get this into the Quickbook or ? during the b2 build. I note that the Boost documentation headers provide this information in the form a link like displayed as d57d645009 with contents https://github.com/boostorg/boost/commit/d57d6450098300343c6fe3a22129791524… but I don't know how this works. Has anyone done anything like this? Suggestions most welcome. Paul

4 4

Feedback on GSoC'21 project proposal
by Krushnal Patel 19 Mar '21

19 Mar '21

Hi, I am applying for the project Boost.XML. I have completed the competency test and the next step being proposal feedback from mentors, I have made a draft proposal. https://docs.google.com/document/d/1Bvno6ifHjo8EdMRuzFqCk9AEB5IgAxf2ag4xdc4… As this is a new library, I have not been able to add much in the 'Project Proposal' details except the bare minimum details. Mentors please have a look at it and let me know what you think. Should I make additions, remove or edit some things? -- Awaiting your feedback, Krushnal Patel http://krushnal.me/

2 1

(no subject)
by Sakshi Singh 19 Mar '21

19 Mar '21

Hello Sir/Mam I'm Sakshi Singh Dangi from India l'm interested in one of your project bit I don't know what to do regarding application process please guide me.

1 0

[GSoC'21] Boost.Math : FFT Utilities PROJECT 1 Guidance
by Tushar k 19 Mar '21

19 Mar '21

Hello, I am Tushar Khandelwal from BITS Pilani 2019 batch, I am working with C++ for the past 2 years so I have a decent understanding of C++. In the past few days, I went through different boost libraries and different project ideas. So, I liked one of the projects of Boost.Math library: FFT Utilities, I have studied Fast Fourier Transform a few months back in my university course signals and system, also I have read many different articles and videos related to this beautiful concept. I have some doubts related to it like what exactly are your expectations from this project? how should I proceed? So I request a potential mentor of this project Christopher Kormanyos or others to please guide me. thanks! Looking forward to this open-source project in GSoC'21. With regards Tushar Khandelwal

3 2

Re: [boost] [release] 1.76.0 post-beta merges
by Glen Fernandes 18 Mar '21

18 Mar '21

John Maddock wrote: > I've had a request to merge these new Boost.Config feature > checks to release as Serialization depends on them: > https://github.com/boostorg/config/pull/369 > Also related to Serialization, this bugfix for BOOST_HAS_HASH should > probably go in: https://github.com/boostorg/config/pull/374. OK to merge both. Glen

1 0

[asio] [regex] 1.76.0 beta 1 compilation failure
by Scott Determan 18 Mar '21

18 Mar '21

There appears to be a problem compiling a program that includes both asio and regex in 1.76.0 beta 1. The following program fails to compile: ``` #include <boost/asio.hpp> #include <boost/regex.hpp> int main(int argc, char** argv) { return 0; } ``` The error is: ``` /home/swd/projs/common/boost_1_76_0_b1/boost/regex/v5/match_flags.hpp:38:14: error: multiple definition of ‘enum boost::regex_constants::_match_flags’ 38 | typedef enum _match_flags | ^~~~~~~~~~~~ In file included from /home/swd/projs/common/boost_1_76_0_b1/boost/asio/detail/regex_fwd.hpp:21, from /home/swd/projs/common/boost_1_76_0_b1/boost/asio/read_until.hpp:23, from /home/swd/projs/common/boost_1_76_0_b1/boost/asio.hpp:146, from ../src/main.cpp:2: /home/swd/projs/common/boost_1_76_0_b1/boost/regex/v4/match_flags.hpp:38:14: note: previous definition here 38 | typedef enum _match_flags ```

4 4

(GSoC '21) uBlas Project 2/3 Guidance
by Laxman 18 Mar '21

18 Mar '21

Hi, I, Laxman Desai, am interested in ublas Project 2 and 3. I’ve built a few C++ libraries before (for personal use) and I am familiar with C++17, MATLAB, TensorFlow, NumPy and Pandas to a good extent. I am currently learning R. I also have a good mathematical background, especially in Linear Algebra. I have currently completed the Competency Test for uBlas, and would request the mentors: David Bellot, Cem Bassoy or Amit Singh to guide me further for Project 2: creating new matrix and vector types and Project 3: Finalize Dataframe Implementation. Project 2: I dont understand what experimental templates and ublas::experimental::matrix means. I although have a strong feeling that it just refers to the tensor implementation of the same. I haven’t used uBlas tensor_core before, so could a mentor explain further (a basic intuition of the improvement, and the workflow for this project)? I would also appreciate more information on submatrix, and its implementation! To my understanding, it is to solve the problem that C++ doesn’t allow overloading of the colon operator. Project 3: I also am interested in project 3 (Finalising the DataFrames Implementation), and am currently exploring the available features. I have been using Pandas for a while now, and recently learnt R. “Finalize and productionize” seemed a bit vague to me, could I get more information on what all the current implementation is lacking (except for documentation)? I would also like to know if the mentors have a shortlist of features to add in mind? Any feedback on this would be greatly appreciated. Kind Regards, Laxman Desai Mail: desai.laxman2001(a)gmail.com

1 0

SVN/Trac account settings not accessible
by Andrey Semashev 17 Mar '21

17 Mar '21

Hi, It looks like SVN/Trac manager is no longer working. Is there a way to change account password?

1 1

Remove obsolete Coding Guidelines for Integral Constant Expressions
by Nikita Kniazev 17 Mar '21

17 Mar '21

Boost Library Requirements and Guidelines has a page https://www.boost.org/development/int_const_guidelines.html which contains highly outdated information. I think the guideline no longer applies and should be simply removed.

1 0

[GSoC'21] Seeking Further Guidance for Project3:Finalize Dataframe Implementation (Boost.uBlas: Matrix and Tensor Computations)
by Kowndinya Renduchintala 17 Mar '21

17 Mar '21

Hi Community! I am Kowndinya Renduchintala, a Second Year Undergraduate majoring in Computer Science and Engineering at Indian Institute of Technology Bombay. I am completely new to Open Source Software Development. Having worked on C++ extensively for the last two years of my Undergraduate studies, I consider myself a proficient C++ programmer. I also had a great amount of exposure in Math, specifically in Linear Algebra and Calculus. This led me to do more work related to them and I started working in the field Data Science where I have largely used Python’s numpy and pandas libraries, also MATLAB in some cases. I am very much interested in developing equivalent capabilities of above mentioned libraries in C++ too! I have gone through the Project Description on the GSoC’21 Ideas Page, and I am highly delighted to see that “Project:3 Finalize Dataframe Implementation” (in Matrix and Tensor Computation category), matches my interests to a very large extent. I am also ready to spend 40-50 hours per week for the completion of the project, thereby helping in productionizing the code by the end of the GSoC’21. But I have some questions left out in my mind after reading the “Project Description” and the “Competency Test” following it. The description says- “add a collection of free form functions, modern data analysis procedures (as found in R tidyverse, in Python pandas/numpy, and in many other packages)”. 1. Do the mentor(s) have some preconceived “list” of the sort of functions to be implemented, or am I expected to include the details of “my” ideas in the project proposal that I submit to Google starting from Mar29 to Apr13? 2. Is the Competency Test(providing matrix and vector C++17 implementation similar to MATLAB syntax) meant for giving us a taste for how the work in actual project is going to look like? If it is the case, then I am highly interested to work on such things/ similar things for that matter. I request David Bellot(The Potential Mentor as per the Wiki page) or any one else who is involved with the above project to please guide me further. After clarifying above two questions, I can straight away get into business and start the work, try to make a list of deliverables and probably ask more “technical” questions that I have in the code base, in my next mail. Looking forward to collaborate with Boost.uBlas and successfully complete my first Open Source Software Development project at GSoC’21 in my most favourite programming language!!! Regards Kowndinya Renduchintala rharisrikowndinya333(a)gmail.com Sent from [1]Mail for Windows 10 References 1. https://go.microsoft.com/fwlink/?LinkId=550986

1 0

[sort] How does pdq-sort allocated memory?
by Viktor Sehr 17 Mar '21

17 Mar '21

According to the documentation boost::pdq_sort uses Log N additional memory. Assuming this memory is allocated via new, is it possible to pass an allocator, or even better, a pre-reserved std::vector<T> to the algorithm in order to avoid allocation? I could not find anything in the documentation about this. /VIktor

1 0

Confusion regarding projects
by Ameya Chawla 17 Mar '21

17 Mar '21

Respected sir/madam I want to contribute to Boost C++ libraries , but i am confused that do I have to contribute to all the 3 projects mentioned in Boost.uBlas <https://github.com/boostorg/ublas>: Matrix and Tensor Computations or I can contribute to any one of them .and competency test is for project 2 only or for all 3 projects ? https://github.com/CGAL/cgal/wiki/Project-Ideas Thank you

1 0

Confusion regarding projects
by Ameya Chawla 17 Mar '21

17 Mar '21

Respected sir/madam I want to contribute to Boost C++ libraries , but i am confused that do I have to contribute to all the 3 projects mentioned or I can contribute to any one of them .and competency test is for project 2 only or for all 3 projects ? https://github.com/CGAL/cgal/wiki/Project-Ideas Thank you

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

Introduction-Tushar Khandelwal
by Tushar k 16 Mar '21

16 Mar '21

Hi, I am Tushar Khandelwal from BITS Pilani 2019 Batch, I have a decent understanding of C++, I have been practicing C++ for the past 2 years, I am proficient in data structures and algorithms, I am new to open source and would love to contribute to this organization. How should I get started?

1 0

Headers only or .o
by Damian Vicino 15 Mar '21

15 Mar '21

Hi, I was reading the development section of the docs: https://www.boost.org/development/index.html And, I noticed there was nothing in the development guidelines about when to implement as headers-only vs built library. I got my own ideas of why most libraries are headers-only. But, I was wondering if someone with the historical context (someone who was here when those first libraries were developed) can share how boost got into the current shape and what new library developers should look into when deciding to go headers-only or not. I appreciate any anecdotes, guidelines, tradeoffs, thumb rules, comments on the topic. I would love to collect as much as possible here in this thread and write something to post in the development doc section in the website for future reference. Best, Damian

4 4

[Describe] Review - Part 2: Class types
by Andrzej Krzemienski 15 Mar '21

15 Mar '21

Hi Everyone, Some feedback from playing with Boost.Describe for class types. 1. As others pointed out, it is confusing that BOOST_DESCRIBE_STRUCT() and BOOST_DESCRIBE_CLASS() have such close names, but their interface and requirements are so different. Maybe rename the latter to BOOST_DESCRIBE_THIS_CLASS()? 2. Base class subobjects are in some applications treated equivalently to member subobject; this is why I found it surprising that I cannot get the names of base class subobjects. But I guess there are implementation difficulties. Bases can be qualified names. 3. As with enums, _public_member_descriptor_fn in global namespace is UB or invalid program as per http://eel.is/c++draft/lex.name#3.2. 4. As others pointed out, the part of the interface that uses enum modifiers is not intuitive. I think that after a while it starts to make sense: you decide on your use case (like doing RPC), form your enum bitmask, and then pass it everywhere. It became more-less clear to me only after I had a look at the implementation of member_filter: https://github.com/pdimov/describe/blob/develop/include/boost/describe/memb… Maybe it makes sense to expose this in the docs. 5. Modifier mod_inherited is great for flattening the inheritance structure: struct X { int a; }; struct Y : X { int b; }; struct Z : Y { int c; }; BOOST_DESCRIBE_STRUCT(X, (), (a)); BOOST_DESCRIBE_STRUCT(Y, (X), (b)); BOOST_DESCRIBE_STRUCT(Z, (Y), (c)); int main() { namespace desc = boost::describe; using namespace std::literals::string_literals; constexpr auto mod = static_cast<desc::modifiers>(desc::mod_public | desc::mod_inherited); using L = desc::describe_members<Z, mod>; assert((boost::mp11::mp_at_c<L, 0>::name == "a"s)); assert((boost::mp11::mp_at_c<L, 1>::name == "b"s)); assert((boost::mp11::mp_at_c<L, 2>::name == "c"s)); } But it is not obvious at first. I recommend that the docs provide an example like this. It even works when base classes have members with same names: struct X { int a; }; struct Y { int a; }; struct Z : X, Y { int b; }; BOOST_DESCRIBE_STRUCT(X, (), (a)); BOOST_DESCRIBE_STRUCT(Y, (), (a)); BOOST_DESCRIBE_STRUCT(Z, (X, Y), (b)); int main() { constexpr auto mod = static_cast<describe::modifiers>(describe::mod_public | describe::mod_inherited); using L = describe::describe_members<Z, mod>; Z z = {{{3}}, {{6}}, {9}}; assert((z.*mp_at_c<L, 0>::pointer == 3)); assert((z.*mp_at_c<L, 1>::pointer == 6)); assert((z.*mp_at_c<L, 2>::pointer == 9)); } 5. What is the use case for modifier mod_hidden? I cannot think of any situation where I would need it. 6. Regarding the overloaded functions, I am no expert in preprocessor metaprogramming, but maybe if there was a way to provide function signatures along the name, you would have enough information to form the pointers. Something like: struct X { void f(int){} void f(void*){} }; BOOST_DESCRIBE_STRUCT(X, (), ( SIGNATURE(void f(int)), SIGNATURE(void f(void*)) ); 7. Modifier mod_virtual works unintuitively. It does not affect the filtering in describe_bases<>. It is only used for decorating the list elements. Maybe the docs should be more explicit about what it is used for. Again, is there a use case for this? Regards, &rzej;

4 4

GSoC'21 boostorg timeline
by Krushnal Patel 15 Mar '21

15 Mar '21

Hi, I wanted to inquire about the GSoC'21 timeline specific to boostorg. I have gone over the GSoC'21 timeline but are there any specifics decided by boost regarding project selection, pre-proposal submission, proposal overview, programming competency test submission, etc? I am asking this question because as I was going over last years' mailing list I found a post where 'pre-proposal submission' was discussed so I started researching more about any timeline released specifically by boost but did not find any. Thanks in advance. Krushnal Patel, http://krushnal.me/

2 1

Requirement of mentorship for Generic Image Library project
by Aditya Tiwari 15 Mar '21

15 Mar '21

Hello there, I am Aditya Tiwari, a GSoC aspirant. I am interested in contributing to the Boost C++ library on the project "*Generic Image Library*". The knowledge requirement for this project is C++ and understanding of basic image processing algorithms, and I have a good knowledge of these two. I have been coding in C++ for over two years, with prior experience working with Boost libraries and working on projects related to image processing for over 1 year. I have read the problem statement and under GIL there's a project 2 about implementing image processing algorithms and in that list I know quite a bunch of algorithms. Also the project 1 under GIL, is quite a confusing task for me like do we have to add more and efficient algorithms here or something else? It would be very helpful if you can guide me through this project. I am open to any suggestions and I shall proceed with the task upon your acknowledgement. Regards, Aditya

2 1

Re: [boost] [release] Boost 1.76.0 Beta 1 Release Candidate 1: fixed std::allocator deprecation-warning
by Löw, Tobias (STEAG Energy Services GmbH) 15 Mar '21

15 Mar '21

Hi, I've made a fix for the deprecation-warning: boost\unordered\detail\implementation.hpp(1452,7): warning C4996: 'std::allocator<T>::is_always_equal': warning STL4010: Various members of std::allocator are deprecated in C++17. Use std::allocator_traits instead of accessing these members directly. You can define _SILENCE_CXX17_OLD_ALLOCATOR_MEMBERS_DEPRECATION_WARNING or _SILENCE_ALL_CXX17_DEPRECATION_WARNINGS to acknowledge that you have received this warning. The PR is here: https://github.com/boostorg/unordered/pull/21 Tobias

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

2 2

Master branch now closed for 1.76.0 beta release
by Marshall Clow 13 Mar '21

13 Mar '21

Please do not make any commits to the master branch. — Marshall

2 2

Re: [boost] FFT proposal for gsoc 2021
by Janek Kozicki 13 Mar '21

13 Mar '21

> Strongly and beneficially Influence that. But we still need > To adhere to all formal application Steps A note regarding these formal steps: https://github.com/boostorg/wiki/wiki/Google-Summer-of-Code%3A-2021 https://lists.boost.org/Archives/boost/2021/02/250876.php https://www.boost.org/users/faq.html > On the board. I can do 1 mentor of Either quad double or FFT. Yeah, both of them are very useful for me. If we make FFT this year, we can hope for quad-double next year :-) best regards Janek Christopher Kormanyos said: (by the date of Fri, 12 Mar 2021 16:00:38 +0100) > We still need to adhere to the > Formal application process > And we should have our dialog > On the board. I can do 1 mentor of > Either quad double or FFT. > > Having your own idea and a > Working model is a tremendous > Advantage in the application > Process and is likely to very > Strongly and beneficially > Influence that. But we still need > To adhere to all formal application > Steps > > Kindest regards, Chris > > Sent from my iPhone > > > On 12. Mar 2021, at 07:26, Eduardo Quintana <eduardo.quintana(a)pm.me> wrote: > > > > Dear Christopher, > > > > I am thrilled to hear from you! Thank you for offering mentorship for this > > project. I look forward to start working on it. > > > > Best regards, > > Eduardo > > > >> On Thu, Mar 11, 2021 at 06:55:37PM +0000, Christopher Kormanyos wrote: > >> > >> <html><head></head><body><div class="ydpad5c413ayahoo-style-wrap" style="font-family:Helvetica Neue, Helvetica, Arial, sans-serif;font-size:16px;"><div></div> > >> <div dir="ltr" data-setdir="false"><div>> Hi Boost community,<br><div>> I've been working on a C++ templated library</div><div>> for Fast Fourier Transforms</div><div><br></div><div>> ...<br></div></div><div dir="ltr" data-setdir="false"><span>> Is there anyone interested in supervising this</span></div><div dir="ltr" data-setdir="false"><span>> project? Any opinions?</span></div><div dir="ltr" data-setdir="false"><span><br></span></div><div dir="ltr" data-setdir="false"><span>Thank you for your interest and query.<br></span></div><div dir="ltr" data-setdir="false"><span><br></span></div><div dir="ltr" data-setdir="false"><span>Yes. I think I am interested and potentially qualified</span></div><div dir="ltr" data-setdir="false"><span>as 5 time GSoC mentor in Multiprecision and Math.</span></div><div dir="ltr" data-setdir="false"><span><br></span></div><div dir="ltr" data-setdir="false"><span>The plan seems good, start with header only</span></div><div dir="ltr" data-setdir="false"><span>simple implementation and increase complexity</span></div><div dir="ltr" data-setdir="false"><span>and efficiency as time allows.</span></div><div dir="ltr" data-setdir="false"><span><br></span></div><div dir="ltr" data-setdir="false"><span>This project would fill a present gap and wish list</span></div><div dir="ltr" data-setdir="false"><span>entry in Math/Multirpecision for those unable/unwilling</span></div><div dir="ltr" data-setdir="false"><span>to include FFTW.</span></div><div dir="ltr" data-setdir="false"><span><br></span></div><div dir="ltr" data-setdir="false"><span>I will write a little project description at rthe relevant</span></div><div dir="ltr" data-setdir="false"><span>page, link will follow...<br></span></div><div dir="ltr" data-setdir="false"><span><br></span></div><div dir="ltr" data-setdir="false"><span>Feel free to continue this thread, at the moment, i'm</span></div><div dir="ltr" data-setdir="false"><span>too busy to put down all my thoughts...<br></span></div><div dir="ltr" data-setdir="false"><span><br></span></div><div dir="ltr" data-setdir="false"><span>Kind regards, Christopher</span><br></div></div><div><br></div> > >> > >> </div><div id="yahoo_quoted_5520563993" class="yahoo_quoted"> > >> <div style="font-family:'Helvetica Neue', Helvetica, Arial, sans-serif;font-size:13px;color:#26282a;"> > >> > >> <div> > >> On Thursday, March 11, 2021, 10:55:29 AM GMT+1, Eduardo Quintana via Boost <boost(a)lists.boost.org> wrote: > >> </div> > >> <div><br></div> > >> <div><br></div> > >> <div>Hi Boost community,<br><br>I've been working on a C++ templated library for Fast Fourier Transforms,<br>https://github.com/Lagrang3/fftx.<br>Templated because some FFT algorithms are algebraic-field independent, eg. you<br>could FFT an array of N matrices provided a Nth matrix-root-of-unity is given.<br>As a result you could have a single algorithm for a variety of underlying, eg.<br>`std::complex<float>`, `std::complex<double>`, `std::complex<long double>`,<br>`boost::math::quaternion`, finite field types (this would yield the "Number<br>theoretic transform" <a href="https://cp-algorithms.com/algebra/fft.html#toc-tgt-6" target="_blank">https://cp-algorithms.com/algebra/fft.html#toc-tgt-6</a>).<br><br>I would like to improve this library during the GSOC 2021, as a proposal for<br>inclusion inside Boost.Math or Boost.Algorithms.<br><br>Is there anyone interested in supervising this project? Any opinions?<br><br>Best regards,<br>Eduardo Quintana<br><br>_______________________________________________<br>Unsubscribe & other changes: <a href="http://lists.boost.org/mailman/listinfo.cgi/boost" target="_blank">http://lists.boost.org/mailman/listinfo.cgi/boost</a><br></div> > >> </div> > >> </div></body></html> > > <publickey - eduardo.quintana(a)pm.me - 341e5416.asc> > -- -- Janek Kozicki, PhD. DSc. Arch. Assoc. Prof. Gdańsk University of Technology Faculty of Applied Physics and Mathematics Department of Theoretical Physics and Quantum Information -- http://yade-dem.org/ http://pg.edu.pl/jkozicki (click English flag on top right)

1 0

[GIL] 2D Convolution/Correlation Proposal for gsoc 2021
by Gaurav kumar 12 Mar '21

12 Mar '21

Hi, I am Gaurav Kumar; I have been working on the Boost.GIL library for the past month. I would like to work on the 2D convolution/Correlation project. The ideas for the project are as follows: 1. Separable Kernels <http://www.dspguide.com/ch24/3.htm>: Most of the standard kernels (e.g. Gaussian, Sobel) can be separated into 2 or more 1D filters. For a N x N kernel, separating it into two 1D filters, the number of computations required would now be proportional to 2*N instead of N*N for the naive implementation. This implementation would also favor code reusability as this would only require a kernel separating function and driver code for a group of 1D filters. 2. Generic Implementation for 2D convolution: There are more generic kernels that are non-separable (e.g. Laplacian operator). In this case, the naive approach has already been implemented. The main task would be to provide the same set of functions as in the 1D convolution/correlation implementation. One potential idea for optimization of 2D convolution is to use the Im2col <https://www.programmersought.com/article/6306124604/> operation, in which the input image is converted into a row of column vectors, where each column vector represents an image block for which convolution/correlation operation is to be performed. The kernel can also be flattened out in a similar manner, resulting in a 1D array. This results in the convolution operation being reduced to matrix multiplication, which can be handled efficiently by BLAS libraries <https://en.wikipedia.org/wiki/Basic_Linear_Algebra_Subprograms> ( Boost.uBLAS ). Please share any suggestions you would have, related to the ideas presented above, or regarding 2D convolutions in general. I am looking for a mentor to guide me through this project. Best Regards, Gaurav Kumar Github handle: https://github.com/gkumar28

2 1

[release] Boost 1.76.0 Beta 1 Release Candidate 1
by Marshall Clow 12 Mar '21

12 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

7 10

Endorsement, review manager sought for Boost.Mysql
by Ruben Perez 12 Mar '21

12 Mar '21

Hi all, I would like to propose a MySQL client library for Boost (under the original name of Boost.Mysql). It is a full implementation of the MySQL client protocol, based on Boost.Asio. It requires C++11. The library is at https://github.com/anarthal/mysql and the documentation is at https://anarthal.github.io/mysql/. Examples under https://anarthal.github.io/mysql/mysql/examples.html. The purpose of this library is to provide a low-level building block for applications or other libraries to interact with MySQL, in the same way Boost.Beast provides a way to interact with HTTP. It complies with Boost.Asio universal asynchronous model, and provides the usual sync and async overloads for every network operation. Some notes: - The scope of this library is limited to MySQL. Its value proposition is implementing the client protocol in an Asio-compliant way. Supporting any database other than MySQL is not in scope of this library. - This library does NOT make use of MySQL libmysqlclient C API. It provides a from-the-ground-up implementation of the MySQL client protocol. Features: - Text queries and server-side prepared statements. - Sync and async functions, following Boost.Asio's universal async model. You may use callbacks, Boost coroutines, futures, C++20 coroutines, or any completion handler that Asio adds support for. - Can be used with any Stream including TCP sockets, UNIX sockets and Boost.Beast TCP streams. - Supports MySQL 5.x, MySQL 8.x and MariaDB.

10 17

[Boost][Describe] Has been ACCEPTED into Boost
by Richard Hodges 12 Mar '21

12 Mar '21

Dear all, I am pleased to announce that we have received 13 high quality reviews. There has been no dissent, with every reviewer recommending that Describe be accepted. Reviews that were sent to me privately have been forward to Peter for consideration. If you have submitted a review and I have not responded privately to thank you, then please accept my apology for this oversight. Thank you everyone for taking some of your valuable time to contribute. -- Richard Hodges hodges.r(a)gmail.com office: +442032898513 home: +376841522 mobile: +376380212

3 2

[interprocess][managed_shared_memory] Memory allocation of managed shared memories
by Grimm, Matthias 12 Mar '21

12 Mar '21

Hi, I have a question regarding the interprocess library and the use of shared memories. When creating a boost::interprocess::managed_shared_memory it seems to be necessary to take some additional space into account. In my case the following approach works well: managed_shm = new ip::managed_shared_memory(ip::create_only, "shm_id", (vec_elems + 110) * (number_of_samples + 1)); Following this it seems to be necessary to always have one additional element. If I remove the additional element (vec_elems + 110) * (number_of_samples) an exception is thrown: boost::interprocess::bad_alloc. This is also the case if I change to (vec_elems) * (number_of_samples + 1) Does anybody know why it is necessary to have this additional space allocated? What is the exact minimum size to avoid the exception? The additional memory may become a problem if the size of the vector elements is large. Attached you'll find some example code. Any help on this topic would be appreciated.

1 0

GSoC'21
by Manan Sharma 12 Mar '21

12 Mar '21

Hey, My name is Manan Sharma, I went through the project ideas for the GSoC'21 and the Multiprecision project really caught my eye. So I would like to contribute to this project but do not know where to start. I have basic knowledge of C++ like Template Programming. So I would appreciate it if anyone could tell me how to get started. Looking forward to contributing to the project. Yours sincerely, Manan Sharma Phone No.: +91 9711306818 Email Id.: manan180796(a)gmail.com

2 1

Queries regarding Contributing to boost open source library
by Tirtharaj Sen 12 Mar '21

12 Mar '21

Hello, I'm Tirtharaj Sen I wanted to know that I will start to contribute to boost open source library from today , so will can I make proposals for GSOC 2021 to the organisation or am I a bit late to start to contribute. I would also like to mention that I want to be associated with the organisation even after the GSOC is over. So does it require a 3 months of contribution history? Will be obliged if I get help from yours's side Thank you

2 1

Does anyone use mp11 with VS2013?
by Peter Dimov 11 Mar '21

11 Mar '21

Does anyone here use mp11 with Visual Studio 2013? (msvc-12.0) 2013 kind of supports C++11 but only barely, and I keep bumping into its bugs and limitations, so I'm considering dropping it and making 2015 the minimum requirement.

1 0