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[filesystem] and C++17 std::filesystem
by Egor Pugin 07 May '18

07 May '18

Hi! gcc8.1 and VS15.7 (2017) are now shipped with std::filesystem. I'd like to raise a discussion about pure c++ interoperability with boost(::filesystem). With boost-1.67 it's not possible to do such things: #if __has_include(<filesystem>) #include <filesystem> namespace fs = std::filesystem; #else #include <boost/filesystem.hpp> namespace fs = boost::filesystem; #endif Because of boost::filesystem::copy_option::overwrite_if_exists != std::filesystem::copy_options::overwrite_existing, std::fs::path() / boost::fs::unique_path(), directory iterators etc. Next, if we take boost::process, for example, we see that it currently operates only on boost::filesystem. If my application uses c++17 fs, I have to write something like this: fs::path f(fs::path in) { bp::search_path(in.u8string()).wstring(); } So, mixing pure c++ and boost becomes more complex. Any ideas how to deal better with such issues on the user side? What are directions of proper fixing this in boost::process (in case I'll try to prepare a PR)? What are boost policies in adopting standard features in general? -- Egor Pugin

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Boost Graph Library(biconnected_components) issue
by Meghana.M Reddy 06 May '18

06 May '18

Hi, I am working on the Boost Graph Library, currently trying to create an interface of the biconnected_components method to a Python code. I used the example code available here <https://www.boost.org/doc/libs/1_67_0/libs/graph/example/biconnected_compon…> for the method and modified it for my purpose. The template of the method is here <https://www.boost.org/doc/libs/1_67_0/libs/graph/doc/biconnected_components…>. The final code seems fine but I get an error while compiling it. And the errors are related to adjacency.hpp which I have not changed so I'm confused as to what the exact problem is. Hoping someone can help me out. My code: class BoostGraph { private: typedef typename boost::adjacency_list< OutEdgeListS, VertexListS, DirectedS, boost::property<boost::vertex_index_t, v_index>, EdgeProperty, boost::no_property, EdgeListS> adjacency_list; typedef typename boost::property_map<adjacency_list, boost::edge_index_t>::type components; public: adjacency_list graph; std::vector<v_index> bc_tree() { components components_bc = get(boost::edge_index, graph); std::size_t num_comps = biconnected_components(graph, components_bc); std::cerr << "Found " << num_comps << " biconnected components.\n"; std::vector<vertex_descriptor> art_points; articulation_points(graph, std::back_inserter(art_points)); std::cerr << "Found " << art_points.size() << " articulation points.\n"; std::vector<v_index> to_return; return to_return; } The error I'm getting: build/cythonized/sage/graphs/base/boost_graph.cpp:3730:26: required from here /home/meghana/Documents/sage_gsoc/sage_may/sage/local/include/boost/graph/detail/adjacency_list.hpp:2696:29: error: forming reference to void typedef value_type& reference; ^ /home/meghana/Documents/sage_gsoc/sage_may/sage/local/include/boost/graph/detail/adjacency_list.hpp:2697:35: error: forming reference to void typedef const value_type& const_reference; ^ /home/meghana/Documents/sage_gsoc/sage_may/sage/local/include/boost/graph/detail/adjacency_list.hpp:2701:61: error: forming reference to void typename Graph::vertex_descriptor,Property,Tag> type; ^ /home/meghana/Documents/sage_gsoc/sage_may/sage/local/include/boost/graph/detail/adjacency_list.hpp:2704:68: error: forming reference to void typename Graph::vertex_descriptor,const Property, Tag> const_type; ^ error: command 'gcc' failed with exit status 1 Makefile:33: recipe for target 'sage' failed make: *** [sage] Error 1 Thank you, Meghana

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Fw: Mysterious Boost.System-related errors when running Beast tests
by Peter Dimov 05 May '18

05 May '18

The story starts with https://travis-ci.org/vinniefalco/beast/jobs/375049193 which gives the error dyld: Symbol not found: __ZN5boost6system6detail19system_category_ncxEv Referenced from: /Users/travis/build/vinniefalco/boost-root/bin.v2/libs/beast/test/beast/core/clang-darwin-4.2.1/debug/threadapi-pthread/threading-multi/fat-tests Expected in: /usr/local/lib/libboost_system.dylib boost::system::detail::system_category_ncx is a new function (in develop), and careful reading of the above reveals that the compiler is trying to link to a preinstalled libboost_system.dylib, in /usr/local/lib. Looking at the log, Boost.System is not even being built. This is odd; the Beast root Jamfile contains <library>/boost/system//boost_system (at https://github.com/boostorg/beast/blob/develop/Jamfile#L78) but even if it didn't, it also links to Filesystem, which _is_ being built, and Filesystem also depends on System in its build/Jamfile: https://github.com/boostorg/filesystem/blob/develop/build/Jamfile.v2#L29 So Boost.System should be built, but it isn't. Its Jamfile hasn't been touched in 10 years: https://github.com/boostorg/system/blob/develop/build/Jamfile.v2 In addition, there's not even a `mklink-or-dir boost/system` in the log, even though the link must be created because the new headers are being used (this could be a separate issue). The Linux/g++ job, https://travis-ci.org/vinniefalco/beast/jobs/375049187, also doesn't seem to build Boost.System, but it works for some reason. When I try `b2 libs/beast/test` on Windows, with msvc-14.1, Boost.System is being built, in the very beginning: ...patience... ...patience... ...patience... ...found 6992 targets... ...updating 1090 targets... link.hardlink ..\..\boost\utility\string_view.hpp Hardlink created for ..\..\boost\utility\string_view.hpp <<===>> ..\utility\include\boost\utility\string_view.hpp compile-c-c++ ..\..\bin.v2\libs\beast\test\beast\core\type_traits.test\msvc-14.1\debug\threadapi-win32\threading-multi\type_traits.obj type_traits.cpp compile-c-c++ ..\..\bin.v2\libs\beast\test\beast\core\type_traits.test\msvc-14.1\debug\threadapi-win32\threading-multi\main.obj main.cpp compile-c-c++ ..\..\bin.v2\libs\system\build\msvc-14.1\debug\threading-multi\error_code.obj error_code.cpp msvc.link.dll ..\..\bin.v2\libs\system\build\msvc-14.1\debug\threading-multi\boost_system-vc141-mt-gd-x32-1_66.dll (The 1.66 version instead of 1.68 was caused by a typo in the superproject which is now fixed.) When I try the same on Ubuntu Trusty, the result is the same as on Travis; no `mklink-or-dir boost/system`, no building of Boost.System, yet everything compiles and works, and I don't have a preinstalled Boost on my VM. It makes no sense at all. Does anyone have any ideas what might be happening here?

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[release][website] Help wanted
by Daniel James 01 May '18

01 May '18

Hello all, For the last couple of releases, I've been handling the releases mostly on my own, but I'm starting a new job and I'm going to have a lot less time, or maybe even no time, for Boost. So we really need more people helping with release management and updating the website. The main release manager responsibilities are described here: https://svn.boost.org/trac10/wiki/ReleasePractices/ManagerCheckList It's probably best if there are a few people involved. I don't think all of them will need admin permissions. For updating the website, you mainly need to occasionally edit html/quickbook files, accept pull requests to the release notes, and use the php scripts to updates the site at release time (I should be able to help a little there). thanks, Daniel

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Showstopper: Build broken on predef module
by Vicente J. Botet Escriba 30 Apr '18

30 Apr '18

Hi Rene, I've needed -to update to the last boost version and I'm experimenting the same issue as the one reported in https://github.com/boostorg/build/issues/299 but in my Mac. /Users/viboes/github/m_boost/libs/predef/check/../tools/check/predef.jam:46: Unescaped special character in argument $(language)::$(expression) /Users/viboes/github/m_boost/tools/build/src/build/configure.jam:288: in try-find-build *** argument error * rule log-check-result ( result ) * called with: ( ) * missing argument result Do you have an idea of what is wrong? Best, Vicente

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Need help with adding tests
by fady esam 30 Apr '18

30 Apr '18

Hi, i was working on a new opencl api for ublas and i need to add the tests and benchmarks to the ublas library. Amy help would be appreciated :) I am adding my file to the test-suite numeric/uBLAS but i want to add include directories and link 2 libraries with compiling the code.. Can anybody help me with that? Thanks in advance

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[doc] Libraries Listed by C++ standard
by Mateusz Loskot 27 Apr '18

27 Apr '18

Hi, Since each Boost library seems/is free to decide about which C++ standard they require, would it be useful to start tagging each library with standard in the release notes and docs? Perhaps new "by by C++ standard" listing could be added in here https://www.boost.org/libs/ Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

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[GSoC] My proposal with Boost C++ was accepted!!
by Laouen Belloli 27 Apr '18

27 Apr '18

Hi, Boost community, I was notified some days ago that my proposal for the Boost.Real project was accepted in the Google Summer of Code 2018 program. I'm currently in contact with my mentor (Damian Vicino) talking about how to start the project and how to properly work to get a clean and performant code. Any suggestion about common working methodologies in boost projects are welcome, and if there is a tutorial on the boost programming style please let me know so I can achieve a cleaner coding style that fits better with the rest of the library projects and facilitate the review process. Regarding where to store the project: I have received an invitation to join the BoostGSoC18 GitHub organization from David Bellot. Is this a good place where to create the Boost.Real project? I suppose that the organization was created for this purpose, but because I only got the invitation I don't want to create my project within the organization without asking first. Best, -- Laouen Mayal Louan Belloli. LIAA - DC - FCEyN - UBA. C.A.B.A. - Buenos Aires - Argentina. https://liaa.dc.uba.ar +54 9 11 38675694

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[config] Macro for "using" type alias defects
by Raffi Enficiaud 26 Apr '18

26 Apr '18

Hi all, I was wondering if there is any macro in Boost.Config for advertising the defect of the "using" support from the compiler. I was reported this: https://github.com/boostorg/test/pull/140 and at the time I wrote the thing, I thought that those guards would have been enough: https://github.com/boostorg/test/blob/35c9acf5bd38d625ebd45cf940c5b9a19aa22… (auto, tuple and variadic template sounds to me more difficult to support than "using" template alias). Would it make sense to have BOOST_NO_CXX11_TYPE_ALIAS? Thanks, Raffi

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Boost issue or no?
by Joshua Alexander 26 Apr '18

26 Apr '18

Hi all, I am trying to build pCloudCC and not sure if this is a Boost issue or a pCloud issue: # make [ 10%] Building C object CMakeFiles/sqlite3.dir/lib/sqlite/sqlite3.c.o [ 20%] *Linking C static library libsqlite3.a* [ 20%] Built target sqlite3 [ 30%] Building CXX object CMakeFiles/pcloudcc_lib.dir/pclsync_lib_c.cpp.o [ 40%] Building CXX object CMakeFiles/pcloudcc_lib.dir/pclsync_lib.cpp.o In file included from */root/build/console-client-master/pCloudCC/pclsync_lib.cpp:30:0*: */root/build/console-client-master/pCloudCC/lib/pclsync/pcompat.h:95:0:* *warning:*"_GNU_SOURCE" redefined [enabled by default] #define _GNU_SOURCE * ^* *<command-line>:0:0:* *note: *this is the location of the previous definition In file included from */usr/local/include/boost/smart_ptr/detail/local_sp_deleter.hpp:20:0*, from */usr/local/include/boost/smart_ptr/shared_ptr.hpp:1158*, from */usr/local/include/boost/shared_ptr.hpp:17*, from */root/build/console-client-master/pCloudCC/pclsync_lib.cpp:45*: */usr/local/include/boost/smart_ptr/detail/local_counted_base.hpp:* In member function ‘*void boost::detail::local_counted_base::add_ref()*’: */usr/local/include/boost/smart_ptr/detail/local_counted_base.hpp:67:49:* *error: **__builtin_assume*’ was not declared in this scope __builtin_assume( local_use_count_ >= 1 ); * ^* In file included from */usr/local/include/boost/smart_ptr/detail/sp_counted_impl.hpp:29:0*, from */usr/local/include/boost/smart_ptr/detail/shared_count.hpp:30*, from */usr/local/include/boost/smart_ptr/shared_ptr.hpp:28* , from */usr/local/include/boost/shared_ptr.hpp:17*, from */root/build/console-client-master/pCloudCC/pclsync_lib.cpp:45*: /usr/local/include/boost/core/addressof.hpp: In instantiation of ‘*T* boost::addressof(T&) [with T = int (*)(_IO_FILE*)]*’: */usr/local/include/boost/smart_ptr/detail/sp_counted_impl.hpp:182:98:* required from ‘*void* boost::detail::sp_counted_impl_pd<P, D>::get_local_deleter(const sp_typeinfo&) [with P = _IO_FILE*; D = int (*)(_IO_FILE*); boost::detail::sp_typeinfo = std::type_info]*’ */root/build/console-client-master/pCloudCC/pclsync_lib.cpp:304:1:* required from here */usr/local/include/boost/core/addressof.hpp:40:33:* *error: *‘ *__builtin_addressof*’ was not declared in this scope return __builtin_addressof(o); * ^* make[2]: *** [CMakeFiles/pcloudcc_lib.dir/pclsync_lib.cpp.o] Error 1 make[1]: *** [CMakeFiles/pcloudcc_lib.dir/all] Error 2 make: *** [all] Error 2

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