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[multiprecision] Getting the best performance on windows for uint128_t etc
by Neill Clift 14 Jul '19

14 Jul '19

Hi, I develop a program for generating optimal addition chains. I normally use 64 bit integers but in order to attack some conjectures I compile up my program with boost using uint128_t. In order to get some functionality I need I used the backend access to limbs. For example I need population count/hamming weight/binary digit count. I did this like this: static LPTYPER bits(NTYPE n) /*++ Calculates the number of 1 bits in a number. --*/ { LPTYPER b = 0; std::size_t size = n.backend().size(); boost::multiprecision::limb_type* p = n.backend().limbs(); for (std::size_t i = 0; i < size; i++) { b += (LPTYPER)__popcnt64(p[i]); } return b; } I use the same sort of logic to calculate Floor(Log2(n)) (number of largest bit set), to clear the bottom say b bits of an integer. Is this a reasonable (though probably not idea) way to go? I noted that the limbs are 32 bits on Windows and this leads me to my second question. How can I get the internals of boost using bigger chunks like 64 bit? It seems I need a compiler supporting __int64. I have access to the intel compiler (19) and MSVC but neither seem to change this. I tried LLVM but that seemed quite slow. I may not have put enough effort into investigating LLVM up to this point. Various bit operations seem overly slow in boost. For example I use sequences like this: Control &= Control + 1; Mask = ((Control - 1) ^ Control) >> 1; Control |= Mask; These seem to be bottlenecks under boost. That sequence above is meant to generate masks that straddle the first run of zero bits in control so 1010100000111111_2 produces a mask of 11111111111_2. Thanks. Neill. Sent from Mail<https://go.microsoft.com/fwlink/?LinkId=550986> for Windows 10

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A question regarding gregorian week_iterator
by Bill Moo 12 Jul '19

12 Jul '19

I can’t understand what, if indeed anything, I am doing wrong here. Using boost 1.69 on Arch Linux I am trying to use a gregorian::week_iterator to iterate a gregorian date_period that has a length of 365 which produces this output: Starts 2018-07-10 Ends 2019-07-10 true false true 365 >From this code: boost::gregorian::date_period dp{ m_Start, m_Ends } ; BOOST_LOG(lg) << "Starts " << boost::gregorian::to_iso_extended_string(dp.begin()) << " Ends " << boost::gregorian::to_iso_extended_string(dp.end()) << " " << isYear << " " << isMonth << " " << isWeek << " " << dp.length() ; The following is the code I am using to iterate the date_period: for(boost::gregorian::week_iterator wi = dp.begin(); wi != dp.end(); ++wi) { items.push_back(formatParams(pi, (*wi))) ; } However, when this code executes it eventually fails with the following error: Year is out of valid range: 1400..9999 In my formatParams method the code generates the correct strings, but it doesn’t stop at Jun 2019 as I’d expect but continues to run out to 2375! I would appreciate some feedback on this as I have identical code that uses a gregorian::month_iterator and this generates the 12 items from the same date_period range as I’d expect. -- Bill

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The out_ptr review is now over
by Zach Laine 11 Jul '19

11 Jul '19

Thanks to all that participated. A review result with be posted sometime in the next couple of weeks (the upcoming C++ standards meeting next week will delay it a bit). Zach

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boost interprocess data structure operating when process killed
by 吴昊 09 Jul '19

09 Jul '19

Hello, as I haven’t read the source code deeply, I doubt about what will happen when boost interprocess is handling data structure such as map (e.g. rbtree rotating) while the process is killed (whether or not -9) or the machine is shutdown. Will the inner structure like the rbtree be broken ? Or will interprocess library detect this and fix it ?

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[release] 1.71.0 closed for major changes
by Marshall Clow 04 Jul '19

04 Jul '19

The master branch is now closed for new libraries and breaking changes, and will be closing for the beta in one week. Also, if you're ready, you can also add your libraries' changes to the release notes at: < https://github.com/boostorg/website/blob/master/feed/history/boost_1_71_0.q… > After editing the release notes, you should get a form to create a pull request, remember to submit it, otherwise I won't see your change. As always, the calendar for the release cycle is available at: https://www.boost.org/development/ Thanks, -- The Boost Release Team

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out_ptr review is extended until Wednesday, July 10
by Zach Laine 26 Jun '19

26 Jun '19

We don't have enough reviews yet, so we're extending the review by two weeks. Please review this small and useful library! >From the original announcement: The formal review of JeanHeyd Meneide's out_ptr library starts Sunday, June 16th and ends on Wednesday, June 26th. out_ptr is a library for making it easy to interoperate between smart pointers and traditional C-style initialization and allocation interfaces. It also enables doing so in a way that allows library authors to opt into speed optimizations for their smart pointers that give them performance equivalent to typical C pointers (see benchmarks ( https://github.com/ThePhD/out_ptr/blob/master/docs/out_ptr/benchmarks.adoc) and the Standard C++ proposal for more details). Online docs can be found here: https://github.com/ThePhD/out_ptr/blob/master/docs/out_ptr.adoc The GitHub repository is available here: https://github.com/ThePhD/out_ptr Also, there is an associated standards proposal: https://thephd.github.io/vendor/future_cxx/papers/d1132.html We encourage your participation in this review. At a minimum, please state: - Whether you believe the library should be accepted into Boost - Your name - Your knowledge of the problem domain You are strongly encouraged to also provide additional information: - What is your evaluation of the library's: * Design * Implementation * Documentation * Tests * Usefulness - Did you attempt to use the library? If so: * Which compiler(s)? * What was the experience? Any problems? - How much effort did you put into your evaluation of the review? All issues discussed during this review will be tracked on the library's GitHub issue tracker at https://github.com/ThePhD/out_ptr/issues. Zach

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out_ptr's formal review starts now!
by Zach Laine 25 Jun '19

25 Jun '19

Dear Boost community, The formal review of JeanHeyd Meneide's out_ptr library starts Sunday, June 16th and ends on Wednesday, June 26th. out_ptr is a library for making it easy to interoperate between smart pointers and traditional C-style initialization and allocation interfaces. It also enables doing so in a way that allows library authors to opt into speed optimizations for their smart pointers that give them performance equivalent to typical C pointers (see benchmarks ( https://github.com/ThePhD/out_ptr/blob/master/docs/out_ptr/benchmarks.adoc) and the Standard C++ proposal for more details). Online docs can be found here: https://github.com/ThePhD/out_ptr/blob/master/docs/out_ptr.adoc The GitHub repository is available here: https://github.com/ThePhD/out_ptr Also, there is an associated standards proposal: https://thephd.github.io/vendor/future_cxx/papers/d1132.html We encourage your participation in this review. At a minimum, please state: - Whether you believe the library should be accepted into Boost - Your name - Your knowledge of the problem domain You are strongly encouraged to also provide additional information: - What is your evaluation of the library's: * Design * Implementation * Documentation * Tests * Usefulness - Did you attempt to use the library? If so: * Which compiler(s)? * What was the experience? Any problems? - How much effort did you put into your evaluation of the review? All issues discussed during this review will be tracked on the library's GitHub issue tracker at https://github.com/ThePhD/out_ptr/issues. Regards, Zach Laine

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[boost-users][asio] Make asio::strand using tcp::socket
by Fiver Dev 24 Jun '19

24 Jun '19

Hello everyone, How do I create this strand using the io_context of the socket in boost 1.70. asio::ip::tcp::socket socket; asio::io_context::strand strand( socket.get_executor().context() ); Thanks Tom

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[boost-users] [compiler] Boost VC++ 14.2 test compiler
by Alex J 23 Jun '19

23 Jun '19

Hi, Does anybody know when boost will add VC++ 14.2 as a 'primary compiler tested' ?. At the moment they only have 14.1. Thanks

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B2 release 4.0.0
by Rene Rivera 23 Jun '19

23 Jun '19

After even more years of development the landscape of build systems has changed considerably, and so has the landscape of compilers. This version marks the start of B2 transitioning to a C++ implementation. Initially this means that the engine will be compiled as C++ source but that source is still the base C implementation. Over time it will transform to a C++ code base in both the engine and build system. Some changes in this start: - Requires C++ 11 to build engine. - Simplified build scripts to make it easier to maintain. - Building with C++ optimizations gives an immediate performance improvement. *Other changes in this release:* - Add support for using prebuilt OpenSSL. -- *Damian Jarek* - Define the riscv architecture feature. -- *Andreas Schwab* - Add ARM64 as a valid architecture for MSVC. -- *Marc Sweetgall* - Set coverage flags, from coverage feature, for gcc and clang. -- *Damian Jarek* - Add s390x CPU and support in gcc/clang. -- *Neale Ferguson* - Support importing pkg-config packages. -- *Dmitry Arkhipov* - Support for leak sanitizer. -- *Damian Jarek* - Fix missing /manifest option in clang-win to fix admin elevation for exes - with "update" in the name. -- *Peter Dimov* - Add freertos to os feature. -- *tee3* - Default parallel jobs (-jX) to the available CPU threads. -- *Rene Rivera* - Simpler coverage feature. -- *Hans Dembinski* - Better stacks for sanitizers. -- *James E. King III* *WARNING*: The default number of parallel jobs has changed in this release from "1" to the number of cores. There are circumstances when that default can be larger than the allocated cpu resources, for instance in some virtualized container installs. *Continuously tested on:* - Linux Clang 3.5, 3.6, 3.7, 3.8, 3.9, 4, 5, 6, 7, 8 - Linux GCC 4.7, 4.8, 4.9, 5, 6, 7, 8, 9 - macOS Xcode 8.3.3, 9.0, 9.0.1, 9.1, 9.2, 9.3, 9.3.1, 9.4, 9.4.1, 10.0, 10.1, 10.2, 10.2.1 - Windows MinGW 8.1.0 - Windows VS 2013, 2015, 2017, 2019 Documentation and more at <https://boostorg.github.io/build/> -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net

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