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[system] The new Boost.System is now ready
by Peter Dimov 09 Oct '18

09 Oct '18

The new Boost.System is now complete, on the develop branch: https://www.boost.org/doc/libs/develop/libs/system/ - header-only - even more constexpr than 1.68 - identifier-based category comparison - message() into a caller-supplied buffer - failed() The plan is to merge it to master at some point if no breakage is encountered on develop, so that it can go into the next release.

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Export control classification number for boost
by DEMIAN, Beatrice (SOPRA STERIA GROUP SA) 08 Oct '18

08 Oct '18

Hi, We are using boost in one of our products, and are now in the process of collecting the information needed to export it. Can you tell me what the U.S. Export Control Classification Number (ECCN) for boost is, and whether a license exception may be used for it? Béatrice Demian On behalf of SOPRA STERIA Subcontractor for EYYW6 (AIRBUS France) The information in this e-mail is confidential. The contents may not be disclosed or used by anyone other than the addressee. Access to this e-mail by anyone else is unauthorised. If you are not the intended recipient, please notify Airbus immediately and delete this e-mail. Airbus cannot accept any responsibility for the accuracy or completeness of this e-mail as it has been sent over public networks. If you have any concerns over the content of this message or its Accuracy or Integrity, please contact Airbus immediately. All outgoing e-mails from Airbus are checked using regularly updated virus scanning software but you should take whatever measures you deem to be appropriate to ensure that this message and any attachments are virus free.

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[graph_parallel] property_serialize.hpp
by Peter Dimov 06 Oct '18

06 Oct '18

I'm looking at boost/pending/property_serialize.hpp, with the intent of moving it from Graph Parallel to Graph as it's included from a Graph header, and I see this: https://github.com/boostorg/graph_parallel/blob/develop/include/boost/pendi… #ifdef BOOST_GRAPH_USE_MPI namespace boost { namespace mpi { template<> struct is_mpi_datatype<boost::no_property> : mpl::true_ { }; } } // end namespace boost::mpi BOOST_IS_BITWISE_SERIALIZABLE(boost::no_property) BOOST_CLASS_IMPLEMENTATION(boost::no_property,object_serializable) BOOST_CLASS_TRACKING(boost::no_property,track_never) #endif // BOOST_GRAPH_USE_MPI What this does is, when BOOST_GRAPH_MPI is defined, it sets certain serialization properties for boost::no_property (is bitwise serializable, use object level versioning, never track address), but when BOOST_GRAPH_MPI is not defined, it doesn't. That is, the serialization format of boost::no_property changes on the basis of whether BOOST_GRAPH_MPI is defined. (It's the same for boost::property<>, above in the same file.) This does not seem correct to me. I would expect these serialization properties to be applied consistently regardless of whether MPI is used or not. But fixing this could conceivably break existing code that serializes and deserializes non-parallel graphs and relies on a certain format on disk. So... should we fix this or not?

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Cycle between Graph and GraphParallel
by Peter Dimov 06 Oct '18

06 Oct '18

Currently we have a dependency cycle between `graph` and `graph_parallel`. It's not the only one, but it's notable with the fact that both libraries are buildable and we therefore can't ignore it as we can ignore cycles between header-only libraries that at release time become a single directory. In the particular, this impedes efforts to generate CMake config files. Under one scheme I'm currently working on, for instance, Boost.Python can't be installed because it tries to install Graph, which tries to install GraphParallel, which tries to install Graph. The cycle between these two is an interesting one. boost/graph/breadth_first_search.hpp does: #ifdef BOOST_GRAPH_USE_MPI # include <boost/graph/distributed/breadth_first_search.hpp> #endif at its end, and boost/graph/distributed/breadth_first_search.hpp does: #ifndef BOOST_GRAPH_USE_MPI #error "Parallel BGL files should not be included unless <boost/graph/use_mpi.hpp> has been included" #endif #include <boost/graph/breadth_first_search.hpp> at its very start. So these headers include each other. One would naively think that only the parallel header should include the normal one, but one is not well versed in graph library architectures, so one might quite possibly be missing something, or a lot. Comments?

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Formal Review of Proposed Boost.Histogram Library is FINISHED
by Mateusz Loskot 05 Oct '18

05 Oct '18

Dear Boost Community, The formal review of Hans Dembinski's Histogram library has been completed. Here is the quantitative summary of feedback received: * Reviews: 1. Klemens David Morgenstern 2. Jim Pivarski (off-list via e-mail to Hans) 3. Björn Reese 4. Steven Watanabe 5. Alex Hagen-Zanker * Non-review participations: 1. degski 2. Gavin Lambert 3. Seth 4. Mateusz Loskot I believe I've collected the names/numbers right, but please let me know ASAP if you think otherwise. I'd like to thank all the participants for their time and efforts. I'm sure Hans received lots of valuable comments and suggestions. FYI, the discussion threads are still open for new posts. Those won't be taken into consideration towards the review result though. I will do my best to announce the review results next week. Mateusz Review Manager for the proposed Boost.Histogram -- Mateusz Loskot, http://mateusz.loskot.net

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Twenty years and time to retire
by Beman Dawes 04 Oct '18

04 Oct '18

The idea behind Boost was hatched in March, 1998, and the proposal document <https://www.boost.org/users/proposal.pdf> was released May 6, 1998. That makes Boost twenty years old, and makes me twenty years older. It is high time I retire from Boost; I haven't been able to contribute for some time now. Thanks to all of you who made Boost such an overwhelming success in the past and will drive Boost forward into a bright future! --Beman

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Release notes for release 1.69
by Paul A. Bristow 02 Oct '18

02 Oct '18

To avoid forgetting to do it when release time comes, I would like to add some Math and Multiprecision library release notes for the next release 1.69 Is providing a PR for this file that way to do this? ( I speak Quickbook ;-) ) https://github.com/boostorg/website/blob/master/feed/history/boost_1_69_0.q… (but it doesn't exist yet!) Thanks. Paul --- Paul A. Bristow Prizet Farmhouse Kendal UK LA8 8AB +44 (0) 1539 561830

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[histogram] Variance
by Bjorn Reese 02 Oct '18

02 Oct '18

The variance of individual bins can be obtained when using the adaptive_storage (via h.at(i).variance().) I am trying to understand the overhead of this feature. If I interpret the code correctly, there is a space overhead because each counter has to keep track of both the count and the sum of squares. The computational overhead is that the sum of squares has to be calculated for each insertion. Is this correct? If so, is there any way to use the adaptive storage policy without variance? Furthermore, why does variance() return the sum of squares? Should this not be divided by the sample size?

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[asio] Order of asynchronous messages
by Florian Lindner 01 Oct '18

01 Oct '18

Hello, in a distributed application (only local are network) we are experiencing issues which *may* stem from the order of asychronous messages sent over sockets. We create a send buffer: auto buffer = std::make_shared<std::vector<double>>(); and fill it: buffer.push_back(some_data). This buffer is then given to our communication routine request = aSend(*buffer, recipient); to keep the send buffer alive we place it in a class attribute: bufferedRequests.emplace_back(request, buffer); The aSend method from above works like (asio is boost asio, of course) PtrRequest aSend(std::vector<double> const & itemsToSend, int recipient) { PtrRequest request(new SocketRequest); asio::async_write(*_sockets[recipient], asio::buffer(itemsToSend), [request](boost::system::error_code const &, std::size_t) { std::static_pointer_cast<SocketRequest>(request)->complete(); }); return request; } This way, we can check for completion using request->test(), which is set from the callback request->complete(). For checking of completed requests we have a loop, which is called reqularly void checkBufferedRequests(bool blocking) { do { for (auto it = bufferedRequests.begin(); it != bufferedRequests.end();) { if (it->first->test()) it = bufferedRequests.erase(it); else ++it; } if (bufferedRequests.empty()) return; if (blocking) std::this_thread::yield(); // give up our time slice, so communication way work } while (blocking); } which operates on bufferedRequests, that is a list<pair<PtrRequest, PtrBuffer>>. We use that, so that the sending peer is not blocked by a slow receiving peer. The sockets are created like tcp::acceptor acceptor(*_ioService); { tcp::endpoint endpoint(tcp::v4(), _portNumber); acceptor.open(endpoint.protocol()); acceptor.set_option(tcp::acceptor::reuse_address(_reuseAddress)); acceptor.bind(endpoint); acceptor.listen(); } Now we are having problems with mangled data that are unexplainable right now. - Is the order of requests guaranteed to be preserved? I think so, based that asio works on TCP. - What happens if there is another read or write performed on the socket. I think that there is no way to guarantee that this does not interfere with the order of the asynchronous send or queued requests. Last but not least: Do you see any potential problems with that code? Thanks a lot! Florian

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[container][interprocess][intrusive][move] Removing support for old compilers
by Ion Gaztañaga 01 Oct '18

01 Oct '18

Hi, My libraries have supported quite old compilers, starting from Visual 2003 and GCC 3.4 and I'm asking for feedback before I start dropping old compilers. The number of supported plus locally+regression tested versions has increased a lot these years and that's a lot of work with reduced benefits. I run locally for: - From Mingw GCC 3.4 to GCC 8.1, all released minor versions (combining C++03-C++11-C++14-C++14). - From MSVC 7.1 to MSVC 14.1, all released versions (default language standard). I also run boost regression tests for many of those compilers (see "igaztanaga-*" runners in https://www.boost.org/development/tests/master/developer/summary.html) The number of supported and tested compilers is now unmanageable for me as many of those have specific warnings/bugs that I try to fix. So I was thinking about reducing that list a bit dropping support for the oldest ones and replacing them with recent GCC/Clang from WSL (Windows Subsystem for Linux). My first idea is to drop anything older than 10 years, which means that the minimum will be MSVC 9.0 and GCC 4.3 (both released in 2008). I've reviewed some popular long support Linux distributions: -> RHEL 6 uses GCC 4.4. -> SUSE Linux Enterprise Server 11 Service Pack 4 (SP4) uses GCC 4.3 Microsoft no longer supports Visual 2008 (support ended on April 2018) but I can continue compiling and testing it at least for another year. Note that my libraries will continue support for -std=C++03, but I will not find workarounds or fixes for old GCC and MSVC versions. Thoughts, problems, comments? Best, Ion

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