August 2022 - Boost - lists.boost.org

Is there an analogue of `boost::reference_wrapper`, that can also work with rvalue references?
by Денис Михайлов 20 Aug '22

20 Aug '22

I find an wrapper like `boost::reference_wrapper`, but with more abilities, like this: ``` int value = 0; auto rref = boost::ref(std::move(value)); auto prref = boost::ref(int{}); f(rref); // pass rref into f by ordinary reference f(std::move(rref)); // move rref into f f(std::move(prref)); // move prref into f ``` Is there such functionality on the Boost side? If not, is it allowed to discuss the possibility of contributing it?

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Is there a way to get ctype facet with boost::locale::generator?
by Gleb Igumnov 19 Aug '22

19 Aug '22

Hello. I have a problem. I need to get std::locale object for my locale (ru_RU.UTF-8) on a systems that don't have one. I decided to take a look at boost::locale::generator, as it has ICU as a backend and there must be full locale info in it. But to my surprise generator do not generate only locale facet that I really need - ctype one. For example following code will go "oops" branch: #include <iostream> #include <boost/locale.hpp> #include <boost/locale/localization_backend.hpp> using namespace std; int main() { using namespace boost::locale; localization_backend_manager my = localization_backend_manager::global(); my.select("icu"); // I know that icu is default backend but I select it explicitly to be sure. boost::locale::generator gen(my); std::locale loc( gen.generate( "ru_RU.UTF-8" ) ); if( !std::isalpha( L'ф', loc ) ) std::cout<< "Oops\n"; else std::cout << "Ok\n"; return 0; } But if I will do std::locale loc( gen.generate( std::locale( "en_US.UTF-8" ), "ru_RU.UTF-8" ) ); It will work, as it will have ctype facet from en_US.UTF-8 locale, but that is not a solution as I may not have en_US.UTF-8 locale either, and on some systems, (for example iOS) I won't have any UTF-8 locale available for std::locale constructor. So I'm curious, why generator won't generate ctype locale? Is there any reason behind it? Or maybe I'm doing something wrong? Is there any way to generate locale with proper ctype facet from ICU using boost::locale::generator? -- -- With respect Gleb "Crazy Sage" Igumnov mailto:crazy.sage@gmail.com

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TSAN SEGFAULT in Boost.Beast CI
by Richard Hodges 16 Aug '22

16 Aug '22

Dear all, You may have noticed that one of the Beast CI checks fails on the master and develop branches. The failure is a segfault in thread sanitizer. Running on my local machine I get the stack trace embedded below. This does not happen if Asio is reverted back to version 1.79.0 Chris has confirmed that the change in Asio that caused this is in asio::spawn. Note that at this stage there is no reason to suspect that Asio is actually at fault. I believe it to be a false positive. However, I am an absolute noob when it comes to the Dark Arts of thread sanitizer. I have no idea what to blacklist. This email has two aims: 1. To prevent multiple people wasting their time trying to get to the bottom of this, 2. To encourage some sage TSAN-maester to emerge who may guide me to enlightenment. Here is the error and stack trace: testing.capture-output bin.v2/libs/beast/test/beast/http/read.test/gcc-12/debug/link-static/thread-sanitizer-norecover/threading-multi/visibility-hidden/read.run ====== BEGIN OUTPUT ====== beast.http.read ThreadSanitizer:DEADLYSIGNAL ==1761540==ERROR: ThreadSanitizer: SEGV on unknown address 0x7f6ea78ff000 (pc 0x7f6eaaaba0d0 bp 0x000000000000 sp 0x7f6ea783d910 T1761542) ==1761540==The signal is caused by a READ memory access. #0 __sanitizer::StackDepotBase<__sanitizer::StackDepotNode, 1, 20>::Put(__sanitizer::StackTrace, bool*) <null> (libtsan.so.2+0xba0d0) #1 __tsan::CurrentStackId(__tsan::ThreadState*, unsigned long) <null> (libtsan.so.2+0x8c48f) #2 __sanitizer::DD::MutexInit(__sanitizer::DDCallback*, __sanitizer::DDMutex*) <null> (libtsan.so.2+0xac534) #3 __tsan::DDMutexInit(__tsan::ThreadState*, unsigned long, __tsan::SyncVar*) <null> (libtsan.so.2+0x9a3f8) #4 __tsan::MetaMap::GetSync(__tsan::ThreadState*, unsigned long, unsigned long, bool, bool) <null> (libtsan.so.2+0xa85dc) #5 __tsan_atomic32_fetch_add <null> (libtsan.so.2+0x783e9) #6 __gnu_cxx::__exchange_and_add(int volatile*, int) /usr/include/c++/12/ext/atomicity.h:66 (read+0x41ad46) #7 __gnu_cxx::__exchange_and_add_dispatch(int*, int) /usr/include/c++/12/ext/atomicity.h:101 (read+0x41ad46) #8 std::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_release_last_use() /usr/include/c++/12/bits/shared_ptr_base.h:187 (read+0x41ad46) #9 std::_Sp_counted_base<(__gnu_cxx::_Lock_policy)2>::_M_release() /usr/include/c++/12/bits/shared_ptr_base.h:361 (read+0x40d87c) #10 std::__shared_count<(__gnu_cxx::_Lock_policy)2>::~__shared_count() /usr/include/c++/12/bits/shared_ptr_base.h:1071 (read+0x41b43c) #11 std::__shared_ptr<boost::asio::detail::strand_executor_service::strand_impl, (__gnu_cxx::_Lock_policy)2>::~__shared_ptr() /usr/include/c++/12/bits/shared_ptr_base.h:1524 (read+0x424db7) #12 std::shared_ptr<boost::asio::detail::strand_executor_service::strand_impl>::~shared_ptr() /usr/include/c++/12/bits/shared_ptr.h:175 (read+0x424de3) #13 boost::asio::detail::strand_executor_service::invoker<boost::asio::io_context::basic_executor_type<std::allocator<void>, 0ul> const, void>::~invoker() <null> (read+0x486f4d) #14 boost::asio::detail::executor_op<boost::asio::detail::strand_executor_service::invoker<boost::asio::io_context::basic_executor_type<std::allocator<void>, 0ul> const, void>, boost::asio::detail::recycling_allocator<void, boost::asio::detail::thread_info_base::default_tag>, boost::asio::detail::scheduler_operation>::do_complete(void*, boost::asio::detail::scheduler_operation*, boost::system::error_code const&, unsigned long) <null> (read+0x49ff36) #15 boost::asio::detail::scheduler_operation::complete(void*, boost::system::error_code const&, unsigned long) boost/asio/detail/scheduler_operation.hpp:40 (read+0x513742) #16 boost::asio::detail::scheduler::do_run_one(boost::asio::detail::conditionally_enabled_mutex::scoped_lock&, boost::asio::detail::scheduler_thread_info&, boost::system::error_code const&) boost/asio/detail/impl/scheduler.ipp:492 (read+0x501be9) #17 boost::asio::detail::scheduler::run(boost::system::error_code&) boost/asio/detail/impl/scheduler.ipp:210 (read+0x5008af) #18 boost::asio::io_context::run() boost/asio/impl/io_context.ipp:63 (read+0x4f54d6) #19 boost::beast::test::enable_yield_to::enable_yield_to(unsigned long)::{lambda()#1}::operator()() const <null> (read+0x41480d) #20 void std::__invoke_impl<void, boost::beast::test::enable_yield_to::enable_yield_to(unsigned long)::{lambda()#1}>(std::__invoke_other, boost::beast::test::enable_yield_to::enable_yield_to(unsigned long)::{lambda()#1}&&) <null> (read+0x4bb4bc) #21 std::__invoke_result<boost::beast::test::enable_yield_to::enable_yield_to(unsigned long)::{lambda()#1}>::type std::__invoke<boost::beast::test::enable_yield_to::enable_yield_to(unsigned long)::{lambda()#1}>(boost::beast::test::enable_yield_to::enable_yield_to(unsigned long)::{lambda()#1}&&) <null> (read+0x4b8c78) #22 void std::thread::_Invoker<std::tuple<boost::beast::test::enable_yield_to::enable_yield_to(unsigned long)::{lambda()#1}> >::_M_invoke<0ul>(std::_Index_tuple<0ul>) <null> (read+0x4b5b00) #23 std::thread::_Invoker<std::tuple<boost::beast::test::enable_yield_to::enable_yield_to(unsigned long)::{lambda()#1}> >::operator()() <null> (read+0x4b1f74) #24 std::thread::_State_impl<std::thread::_Invoker<std::tuple<boost::beast::test::enable_yield_to::enable_yield_to(unsigned long)::{lambda()#1}> > >::_M_run() <null> (read+0x4ab02e) #25 execute_native_thread_routine <null> (libstdc++.so.6+0xdbb72) #26 __tsan_thread_start_func <null> (libtsan.so.2+0x393ef) #27 start_thread <null> (libc.so.6+0x8ce2c) #28 clone3 <null> (libc.so.6+0x1121af) ThreadSanitizer can not provide additional info. SUMMARY: ThreadSanitizer: SEGV (/lib64/libtsan.so.2+0xba0d0) in __sanitizer::StackDepotBase<__sanitizer::StackDepotNode, 1, 20>::Put(__sanitizer::StackTrace, bool*) ==1761540==ABORTING EXIT STATUS: 66 ====== END OUTPUT ====== -- Richard Hodges hodges.r(a)gmail.com office: +44 2032 898 513 home: +376 861 195 mobile: +376 380 212

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stream operators for number
by Gero Peterhoff 15 Aug '22

15 Aug '22

Hello, can you please provide the << and >> operators for boost::multiprecision::number as a stream template? currently (fixed ostream) template <class Backend, expression_template_option ExpressionTemplates> std::ostream& operator<<(std::ostream& os, const number<Backend, ExpressionTemplates>&) useful template <typename Char, typename Traits, typename Backend, expression_template_option ExpressionTemplates> std::basic_ostream<Char, Traits>& operator<<(std::basic_ostream<Char, Traits>& stream, const number<Backend, ExpressionTemplates>&) thx Gero

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Tested Compilers
by Eduardo Quintana 15 Aug '22

15 Aug '22

Hi! I would like to suggest that Boost is also tested on compilers like Intel OneAPI 2022 and Visual Studio 2022. Regards, Eduardo Quintana SFTWY CDI Ltda. 5511-2157-6800 / 5511-2251-8181- / 5511-95025-3705

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numeric_cast
by Gero Peterhoff 15 Aug '22

15 Aug '22

Hallo, can you improve numeric_cast 1) constexpr 2) vectorisable The problem is that the compilers on x86 without hardware support (AVX512DQ) do not vectorize the conversions u/int64_t -> float64/32_t. This may also apply to other architectures. But that can be solved manually. My patch requires C++20 (std::bit_cast), but you can probably work around that. Modifications: - add #include <boost/predef.h> - improve raw_converter For a better understanding see https://godbolt.org/z/j58rW411s regards Gero

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Boostbook doesn't not work with libxslt 1.1.35
by Giovanni Mascellani 13 Aug '22

13 Aug '22

Hi, it seems that Boost fails building boostbook docs if xsltproc and libxslt1 version 1.1.35 is installed (it works with version up to 1.1.34). Specifically, I can reproduce the failure following these steps: * recursively clone git@github.com:boostorg/boost.git * ./bootstrap.sh * echo "using boostbook ;" > user-config-doc.jam * ./b2 -j32 -q -d2 --ignore-site-config --enable-index --user-config=user-config-doc.jam --build-dir=build-doc * ./b2 -j32 -q -d2 --ignore-site-config --enable-index --user-config=user-config-doc.jam --build-dir=build-doc doc On my Debian unstable system this works when xsltproc and libxslt1.1 version 1.1.34 are installed, but fails when 1.1.35 is installed, with the following error: "xsltproc" --stringparam boost.defaults "Boost" --stringparam boost.root "../../../.." --path "build-doc/boost/bin.v2/libs/logic/doc/docbook" --xinclude -o "build-doc/boost/bin.v2/libs/logic/doc/docbook/tribool.docbook" "/<<PKGBUILDDIR>>/tools/boostbook/xsl/docbook.xsl" "/<<PKGBUILDDIR>>/libs/logic/doc/tribool.boostbook" runtime error: file /<<PKGBUILDDIR>>/tools/boostbook/xsl/annotation.xsl line 432 element element xsl:element: The effective name '' is not a valid QName. runtime error: file /<<PKGBUILDDIR>>/tools/boostbook/xsl/annotation.xsl line 432 element element xsl:element: The effective name '' is not a valid QName.runtime error: file /<<PKGBUILDDIR>>/tools/boostbook/xsl/annotation.xsl line 432 element element xsl:element: The effective name '' is not a valid QName. [repeated many times] Many different libraries are failing in the same way, so I guess that the real problem is in boostbook. However I don't know enough of XSLT and xsltproc to give a proper diagnosis. For the context, this bug was discovered during a test rebuild of the Debian package for Boost[1]. However it can be reproduced with master doing the steps above. [1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1016321 Thanks in advance for any help you can provide, Giovanni.

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Superproject is taking a nap
by Vinnie Falco 12 Aug '22

12 Aug '22

The Boost superproject is not updating submodules on master, that switch needs to be flipped back on if Boost.URL is going to work. -- Regards, Vinnie Follow me on GitHub: https://github.com/vinniefalco

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Questions about incorporating my library into a new library within Boost
by Jooseong Lee 11 Aug '22

11 Aug '22

I recently wrote a general-purpose STL-like ordered associative B-Tree based container in C++. . Its API and usage is very similar to std::set, std::map, std::multiset, std::multimap, and when the number of elements is relatively large, my benchmark shows that it is 2.5~3 times faster than std::set and its friends. Repo link: https://github.com/frozenca/BTree This was better than I thought, so I'd like to contribute to the Boost community by incorporating it within the list of Boost libraries. I'd like to know if it's possible or if you think it's worth it. Best Regards, Jooseong Lee

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beep sound from buzzer
by Daggumati, Rajesh 11 Aug '22

11 Aug '22

Hi Team, I am working on an instrument which is not having any speaker. It is having buzzer only. We use C++ BEEP() function to generate beep sound by using provided frequency number. Ex: Beep(1000,1000); This function is producing sound but its not audible as we don't have speakers. Can we have any specific function in boost so if we call that function then it will interact with buzzer and give sound . Regards, Rajesh D Confidential - Company Proprietary 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.

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Master is open for merges
by Glen Fernandes 11 Aug '22

11 Aug '22

Master is open again, with no restrictions. Boost version numbers bumped (boost, config, more), and new release notes stubbed (website). Next milestone: October 26, Boost 1.81.0 closed for new libraries and breaking changes Release calendar: https://boost.org/development Glen

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[release] Boost 1.80.0
by Glen Fernandes 11 Aug '22

11 Aug '22

Release 1.80.0 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 numerous enhancements and bug fixes for existing libraries. For details, including download links, see <http://www.boost.org/users/news/version_1.80.0> You can also download directly from: <https://boostorg.jfrog.io/artifactory/main/release/1.80.0/> 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. -- The Boost Release Team Marshall Clow, Glen Fernandes, Michael Caisse

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[release] Boost 1.80.0 Release Candidate 1 is available
by Marshall Clow 09 Aug '22

09 Aug '22

The first release candidates for the 1.80.0 release are now available at: <https://boostorg.jfrog.io/artifactory/main/release/1.80.0/source/> The SHA256 checksums are as follows: 4b2136f98bdd1f5857f1c3dea9ac2018effe65286cf251534b6ae20cc45e1847 boost_1_80_0_rc1.tar.gz 1e19565d82e43bc59209a168f5ac899d3ba471d55c7610c677d4ccf2c9c500c0 boost_1_80_0_rc1.tar.bz2 d12a2af721e22dbfb984ef061ee4c4ab2387f1904f6d65bc5acebaa34d6366ec boost_1_80_0_rc1.7z e34756f63abe8ac34b35352743f17d061fcc825969a2dd8458264edb38781782 boost_1_80_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

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[review][JSON] Review of JSON starts today: Sept 14 - Sept 23
by Pranam Lashkari 09 Aug '22

09 Aug '22

Boost formal review of Vinnie Falco and Krystian Stasiowski's library JSON starts today and will run for 10 days ending on 23 Sept 2020. Both of these authors have already developed a couple of libraries which are accepted in Boost(boost beast and Static String) This library focuses on a common and popular use-case for JSON. It provides a container to hold parsed and serialised JSON types. It provides more flexibility and better benchmark performance than its competitors. JSON highlights the following features in the documentation: - Fast compilation - Require only C++11 - Fast streaming parser and serializer - Easy and safe API with allocator support - Constant-time key lookup for objects - Options to allow non-standard JSON - Compile without Boost, define BOOST_JSON_STANDALONE - Optional header-only, without linking to a library (a point I would like to add in highlight: it has cool Jason logo 😝) To quickly understand and get the flavour of the library take a look at "Quick Look" <http://master.json.cpp.al/json/usage/quick_look.html> You can find the source code to be reviewed here: <https://github.com/CPPAlliance/json/tree/master> You can find the latest documentation here: <http://master.json.cpp.al/> Benchmarks are also given in the document which can be found here: <http://master.json.cpp.al/json/benchmarks.html> Some people have also given the early reviews, the thread can be found here: <https://lists.boost.org/Archives/boost/2020/09/249745.php> Please provide in your review information you think is valuable to understand your choice to ACCEPT or REJECT including JSON 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 here: <http://www.boost.org/community/reviews.html> Thank you for your effort in the Boost community. -- Thank you, Pranam Lashkari, https://lpranam.github.io/

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Potentially include xproc library in boost?
by Samuel Venable 08 Aug '22

08 Aug '22

Hi, I've tried sending an email about this already and no one responded from what I can tell. I guess because I was saying way too much. I was wondering if this code of mine could potentially be added to boost. xproc/process.cpp at main · time-killer-games/xproc (github.com)<https://github.com/time-killer-games/xproc/blob/main/apiprocess/process.cpp> It lets you get process information from foreign processes on a lot of platforms. Thanks. Samuel [https://opengraph.githubassets.com/b27d922324c973dacc517314510a40f1739ffa17…]<https://github.com/time-killer-games/xproc/blob/main/apiprocess/process.cpp> xproc/process.cpp at main · time-killer-games/xproc<https://github.com/time-killer-games/xproc/blob/main/apiprocess/process.cpp> Contribute to time-killer-games/xproc development by creating an account on GitHub. github.com

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Upcoming Boost.URL review
by Klemens Morgenstern 06 Aug '22

06 Aug '22

This is a reminder that the boost.url review will start in a week on the 13th. The source code can be found here https://github.com/CPPAlliance/url and the documentation here https://master.url.cpp.al/ . I am looking forward to plenty of reviews.

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Boost 1.80.0 closed for all changes
by Glen Fernandes 04 Aug '22

04 Aug '22

The master branch is closed for all changes. Release expected on 2022-08-10. - Release Managers

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Boost 1.80.0 master open for bug fixes
by Glen Fernandes 03 Aug '22

03 Aug '22

Now open for bug fixes and documentation changes. Other changes by release manager permission. The next deadline: On August 3rd, master closes for all changes. Glen

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Binary Serialization
by Benedict Bede McNamara 02 Aug '22

02 Aug '22

It appears that the main fact determining collection build speed is the heap you use. I++ now uses its own binary heap to perform allocations for the collection forward_list (which is what oarchive uses). So binary serialization goes even faster now. Here are some figures for collections with a million elements: stl list build time is: 0:0:0:0:27 stl list sort time is: 0:0:0:0:21 stl forward_list build time is: 0:0:0:0:20 stl forward_list sort time is: 0:0:0:0:20 stl set build time is: 0:0:0:0:111 I++ set build time is: 0:0:0:0:61 stl unordered_set build time is: 0:0:0:0:149 stl map build time is: 0:0:0:0:118 I++ dictionary build time is: 0:0:0:0:60 Linked list build time is: 0:0:0:0:23 Linked list sort time is: 0:0:0:0:23 Forward list build time is: 0:0:0:0:16 Forward list sort time is: 0:0:0:0:17 I++ serialization/deserialization time is: 0:0:0:0:150 list build time is: 0:0:0:0:74 stl vector build time is: 0:0:0:0:5 Vector sort time is: 0:0:0:0:12 Quick Sort time is: 0:0:0:0:10 heap allocations: 12000007 heap allocations: 0 >From this we see that in general binary serialization/deserialization takes a bit longer than collection allocation. For example the serialization/deserialization time is 150 milliseconds for a million elements whereas forward_list only takes 16 milliseconds to build. I would be interested to see what the equivalent figures are for Boosts text based serialization. Yours Sincerely, Benedict Bede McNamara P.S. The program that produced these figures is attached. Sent from Mail for Windows

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Why was the boostorg/sort master branch deleted
by Glen Fernandes 02 Aug '22

02 Aug '22

Why was the boostorg/sort master branch deleted? The repository has only a develop branch now. I'm going to recreate the master branch and reset its head to before the recent commits, but - I'd like to know why the branch was removed. Glen

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