April 2018 - Boost - lists.boost.org

CMake Announcement from Boost Steering Committee
by Jon Kalb 13 Aug '24

13 Aug '24

The libraries produced by the Boost community have had a greater impact on the way that the C++ community writes code than any other library implementation. The focus of the Boost community will always be on the libraries, but it is undeniable that we are dependent on and often limited by the infrastructure of our trade. Years ago, the move to Git was contentious; yet, it was required to improve development. In a similar vein our build system has become an impediment for many developers and users, existing and prospective. Therefore, we, the Steering Committee, announce to the Boost community our desire and intent to move Boost’s build system to CMake for users and developers alike. We are soliciting comments and proposals from the community to guide the process and the goals. Our desire is that the community can come to consensus by the end of the calendar year with a vision of supporting users and developers. We understand that the actual process of achieving the end goal will be long, time consuming, and not without its share of conflict. We also recognize that the Boost community is comprised of bright and passionate individuals that are eager to get involved and help get work done. The members of the Steering Committee have been encouraged by the discussions and activity surrounding CMake on the mailing lists over the years and know that many people have voiced visions. We hope that each of you rejoins the discussion to support this initiative and contributes to the common goal of improving Boost’s integration into the broader C++ ecosystem. For the Boost Steering Committee, Jon Kalb, Chair jonkalb(a)boost.org

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[RFC] unique_val (handles, IDs, descriptors...)
by Miguel Ojeda 15 Oct '18

15 Oct '18

Hi all, While working on a medium-sized project, I had to wrap quite some handles, IDs, descriptors, etc. into RAII classes. Somehow, writing those and making them movable seemed more verbose than needed. I searched in the STL and Boost for something already implemented, but nothing seemed to come up. I decided to write my own prototype to see whether I was missing something important; but actually using it in my project felt quite natural and simple. At this point, I asked for a second opinion from a well-known expert (thanks Scott!) and he agreed that it seemed like a reasonable idea but, of course, he would also be surprised if others haven't come up with something similar. So I polished it up a bit and uploaded it to: https://github.com/ojeda/unique_val Below you have the introduction inlined [1]. If you have the time, please take a look (specially to the Rationale) and let me know your comments. The code itself is very short and straightforward. If you already have this class/template in Boost somewhere that I missed, please let me know! Otherwise, if you think this could be interesting to put into Boost in some existing library (not sure which) or as a new tiny library, I would be glad to make the effort to expand it, clean it up, etc. Thank you! Miguel [1] """ A single-header header-only library for representing unique values (handles, IDs, descriptors...) that default to a value on move for C++11, C++14 and C++17. It simplifies writing resource-owning classes (RAII) with move semantics support for resources with handles, IDs or descriptors that are supposed to be used as unique values, not as unique pointers. For instance, it can be used with non-pointer handlers (like the `int` file/socket descriptors in POSIX) and with opaque pointer handlers (like the `HWND` handles in the Win32 API). As such, it can be used as an alternative to `std::unique_ptr` with or without custom deleter, specially for resources that use a non-pointer type or resources that are not simply heap-allocated. It does not have any overhead compared to using the original type. It supports booleans, integers, pointers and enumerations. The default value can be different than the default-constructed value (i.e. different than 0, nullptr, etc.). """

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Original STL Library Documentation has been recovered and is now safe forever.
by Robert Ramey 03 Sep '18

03 Sep '18

The Standard Template Library is the foundation of modern C++. The creation and publication of this code and its documentation set a new standard for the formal specification of what a computer program should do, how it should be designed and how it should be formally documented. These pages were maintained first by Silicon Graphics and then later by Hewett-Packard. In January of 2018 these pages were removed by H-P. This is a historic blunder. I have recovered the original STL Library Document and hosted them here: http://www.rrsd.com/software_development/stl/index.htm Robert Ramey

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[outcome] v2.1 progress report
by Niall Douglas 04 Jun '18

04 Jun '18

Dear Boost, Two months after you accepted Outcome into Boost, I am pleased to say that I believe that all the known bugs and very substantial source refactoring recommended by the peer review have been implemented (detailed changelog is appended below). What remains is a few months of maturing in real world use as all this severe refactoring needs to be tested outside a test suite, and of course the documentation which I don't intend to start work on until the autumn. The Boost edition has, obviously, received a major upgrade and it is now 100% "Boost native" in that it uses Boost.System and Boost.Exception now. The test suite for the Boost edition exclusively tests the Boost native edition, and it all passes. Outcome (both standalone and Boost editions) now can handle both Boost and std types freely intermixed as you see fit. A new "lite" single header edition exists which drags in virtually no system headers, and is hideously low impact on compile times as a result. ABI and API stability have been dumped to git repo with scripting to check the current library against the frozen dumps. This edition should make the corporate crowd very pleased. Very little should appear to have changed from the outside. Code written for v2.0 ought to, more or less, compile and work as before with v2.1. I would appreciate whatever help the Boost community can give in helping to test this edition. I expect new bugs to have been introduced given the severe source code refactoring, and new dual support for Boost and std as equals. My gratitude in advance. Niall --- ## v2.1 in progress [[project]](https://github.com/ned14/outcome/projects/1) - Boost edition is now 100% Boost, so defaults for `result` and `outcome` are `boost::system::error_code::errc_t` and `boost::exception_ptr`. Moreover, the test suite in the Boost edition now exclusively tests the Boost edition. One can, of course, freely use the standalone edition with Boost, and the Boost edition with `std` types. - Renamed ADL discovered customisation point `throw_as_system_error_with_payload()` to `outcome_throw_as_system_error_with_payload()`. - [#135](https://github.com/ned14/outcome/issues/135) - Added much clearer compile failure when user tries `result<T, T>` or `outcome` where two or more types are identical. Thanks to Andrzej Krzemieński for suggesting a technique which combines SFINAE correctness with the remaining ability for `result<T, T>` etc to be a valid type, but not constructible. - [#67](https://github.com/ned14/outcome/issues/67) - Fixed one of the oldest long open bugs in Outcome, that the noexcept unit tests failed on OS X for an unknown reason. - [#115](https://github.com/ned14/outcome/issues/115) - Outcome did not construct correctly from `failure_type`. - Inexplicably outcome's error + exception constructor had been removed. Nobody noticed during the Boost peer review, which is worrying seeing as that constructor is needed for one of the main advertised features to Boost! - [#107](https://github.com/ned14/outcome/issues/107) and [#116](https://github.com/ned14/outcome/issues/116) - `operator==` and `operator!=` now become disabled if the value, error and exception types do not implement the same operator. - Relatedly, both comparison operators simply didn't work right. Fixed. - [#109](https://github.com/ned14/outcome/issues/109) - `swap()` now has correct `noexcept` calculation and now correctly orders the swaps to be whichever is the throwing swap first. - Added reference dump of v2.1 ABI so we can check if ABI breakage detection works in the next set of changes, plus Travis job to check ABI and API compatibility per commit. - [#124](https://github.com/ned14/outcome/issues/124) - `OUTCOME_TRY` is now overloaded and selects `void` or `auto` edition according to input parameter count. - [#120](https://github.com/ned14/outcome/issues/120) - Fix generation of double underscored temporary variables in `OUTCOME_UNIQUE_NAME`, which is UB. - [#110](https://github.com/ned14/outcome/issues/110) - Separated `result` from its hard coded dependency on the `<system_error>` header. - Renamed `result` and `outcome` to `basic_result` and `basic_outcome`. - Renamed `result.hpp` into `basic_result.hpp`. - Moved `<system_error>` and `<exception>` dependent code into new `std_result.hpp` and `std_outcome.hpp` header files. - Added `boost_result.hpp` and `boost_outcome.hpp` which use Boost.System and Boost.Exception (these are `result.hpp` and `outcome.hpp` in the Boost edition). -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/

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Proposal for a thread synchronisation primitive: future_queue
by Martin Hierholzer 21 May '18

21 May '18

Dear boost developers, I want to propose a thread synchronisation primitive, which works like a mixture of (lockfree) queues and futures. Therefore I gave it the name "future_queue". It is basically a lockfree queue which can be waited on for new values (without busy waiting), but it has some nice extra features like when_any() and continuations. The github project can be found here: https://github.com/mhier/future_queue It already contains a README file with a short description, an example and results of a first performance measurement. Further documentation so far exists only inside the code: https://github.com/mhier/future_queue/blob/master/include/future_queue.hpp My first question is, whether this is really something new (I might have overlooked something in the many boost libraries) and if it makes sense to integrate it into the boost libraries. Another question would be whether this should really be its own library, since it is basically a single class (with a few helper classes) and a single non-member function. Maybe it would be better to make it part of an existing library? I am happy to receive some first feedback! Cheers, Martin -- Martin Hierholzer DESY Notkestrasse 85 22607 Hamburg Office 55a / 123 Tel: +49 40 8998 1897 Mob: +49 176 992 46 476 Skype: mhier48 This e-mail may contain confidential and/or privileged information and is intended only for the use of the individual or entity named above. If you received it in error, please advise the sender immediately by reply e-mail and delete the original. Any further use - especially any form of publication - of this e-mail without explicit authorisation is strictly prohibited.

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[type_traits] revisiting is_virtual_base_of
by John Maddock 10 May '18

10 May '18

There is a problem with is_virtual_base_of in that it doesn't work especially well - most of the time it works OK, but can be made to fail catastrophically in a few situations, see for example: https://svn.boost.org/trac10/ticket/11323 Now... it turns out that with C++14 and later we now have is_detected which can test the validity of almost any expression... and I'm wondering if there's a cunning way to press this into action to create a more accurate is_virtual_base_of, but I'm having trouble coming up with anything. Any bright ideas? Note that an explicit static_cast can't be tested for, though we can use is_constructible if required. Thanks in advance, John. --- This email has been checked for viruses by AVG. http://www.avg.com

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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 01 May '18

01 May '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 27 Apr '18

27 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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[range] master broken in latest MSVC
by Vinnie Falco 26 Apr '18

26 Apr '18

I'm using the latest release of Visual Studio and I get these errors from the master superproject: 8>c:\users\vinnie\src\boost\boost\range\concepts.hpp(257): error C3646: 'n': unknown override specifier 8>c:\users\vinnie\src\boost\boost\range\concepts.hpp(264): note: see reference to class template instantiation 'boost::range_detail::RandomAccessIteratorConcept<Iterator>' being compiled 8>c:\users\vinnie\src\boost\boost\range\concepts.hpp(257): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int This issue exactly describes the problem: <https://github.com/boostorg/range/issues/68> Thanks

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[lexical_cast] calling virtual function in constructor of `boost::detail::basic_pointerbuf`
by Andrzej Krzemienski 25 Apr '18

25 Apr '18

Hi everyone, Following the recommendation, I am posting a note about the filed issue in lexical_cast: https://svn.boost.org/trac10/ticket/13540#ticket clang-tidy reports (while checking the code that uses boost::lexical_cast) a virtual function is called in the default constructor of class template boost::detail::basic_pointerbuf. (Function setbuf() is declared virtual in base class.) This might be an indication of a bug. If not, I would recommend using a different construct that avoids confusion, for instance declaring the function override final in newer versions of C++, or providing another function with different name but with the same semantics as the overriding setbuf(). Here's the link to the offending call: https://github.com/boostorg/lexical_cast/blob/develop/include/boost/detail/… Regards, &rzej;

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Fornux C++ Superset
by Phil Bouchard 25 Apr '18

25 Apr '18

Greetings, Because there was a conflict of interests in the past then I feel obliged to give an update regarding the status of the "Fornux C++ Superset" (formerly "Fornux C Leak Detector"). This way corporations will not claim ownership of the idea. - Fornux C++ Superset harnesses the power of Clang. - It now supports, as you have guessed, C++98 syntax. - It's deterministic so it will not slow down your application randomly like with Java. - You can see attached examples memory leaks in C & C++ with cyclic references which are correctly handled and the memory usage never increases. Like I mentioned previously, I am working hard on a free version I will be able to share in a month or two. Regards, Phil Bouchard www.fornux.com

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[interprocess] Enhancment for Boost.Interprocess on Windows
by Aliaksandr Zaitsau 23 Apr '18

23 Apr '18

Hello, My colleague at work suggests an enchancement for Boost.Interprocess for detecting unique boot on Windows. Currently in Boost.Interprocess we have 3 implementations: 1. Using COM. It is marked as incorrect in case of hibernation. 2. Current default implementation using system events log is incorrect since lots of computers will not have expected event in system event log. 3. There is some new for me implementation using reading Windows registry. It is disabled by default. Question 1 What Windows versions are expected to be supported by current library version? What about Windows XP? Earlier Windows? Question 2 What is the status of third implementation via registry? Question 3 It seems strange for him third implementation needs 2 registry values for creating unique id. First of them looks enough for this purpose. And another one may be not present on some Windows. Who may he speak to get technical details why this implementation looks like this? He has an idea how to implement unique boot id better than first and second implementations. He tried to email Ion Gaztanaga directly, but without any responce. Is it good idea to create PR on GitHub before getting any details from Ion? Best regards, Alexander Zaitsev

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UUID broken with Boost 1.67 and VS2015?
by rleigh＠codelibre.net 23 Apr '18

23 Apr '18

In a source file including: #include <boost/uuid/uuid.hpp> #include <boost/uuid/uuid_io.hpp> #include <boost/uuid/uuid_generators.hpp> and then calling boost::uuids::to_string(boost::uuids::random_generator()()) I'm getting: [15/26] Linking CXX executable test\ome-files\ometiffwriter.exe FAILED: test/ome-files/ometiffwriter.exe cmd.exe /C "cd . && "C:\Program Files\CMake\bin\cmake.exe" -E vs_link_exe --intdir=test\ome-files\CMakeFiles\ometiffwriter.dir --manifests -- C:\PROGRA~2\MICROS~1.0\VC\bin\amd64\link.exe /nologo test\ome-files\CMakeFiles\ometiffwriter.dir\ometiffwriter.cpp.obj test\ome-files\CMakeFiles\ometiffwriter.dir\tiffsamples.cpp.obj /out:test\ome-files\ometiffwriter.exe /implib:test\ome-files\ometiffwriter.lib /pdb:test\ome-files\ometiffwriter.pdb /version:0.0 /machine:x64 /debug /INCREMENTAL /subsystem:console lib\ome\files\ome-filesd.lib lib\ome\test\ome-testd.lib C:\build\b\stage\lib\ome-xmld.lib C:\build\b\stage\lib\boost_random-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\tiffd.lib C:\build\b\stage\lib\ome-commond.lib C:\build\b\stage\lib\boost_iostreams-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\boost_log-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\boost_filesystem-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\boost_regex-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\boost_log_setup-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\boost_thread-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\boost_date_time-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\boost_chrono-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\boost_system-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\boost_atomic-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\Xalan-C_1D.lib C:\build\b\stage\lib\xerces-c_3D.lib C:\build\b\tools\lib\gtest.lib kernel32.lib user32.lib gdi32.lib winspool.lib shell32.lib ole32.lib oleaut32.lib uuid.lib comdlg32.lib advapi32.lib && cd ." LINK Pass 1: command "C:\PROGRA~2\MICROS~1.0\VC\bin\amd64\link.exe /nologo test\ome-files\CMakeFiles\ometiffwriter.dir\ometiffwriter.cpp.obj test\ome-files\CMakeFiles\ometiffwriter.dir\tiffsamples.cpp.obj /out:test\ome-files\ometiffwriter.exe /implib:test\ome-files\ometiffwriter.lib /pdb:test\ome-files\ometiffwriter.pdb /version:0.0 /machine:x64 /debug /INCREMENTAL /subsystem:console lib\ome\files\ome-filesd.lib lib\ome\test\ome-testd.lib C:\build\b\stage\lib\ome-xmld.lib C:\build\b\stage\lib\boost_random-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\tiffd.lib C:\build\b\stage\lib\ome-commond.lib C:\build\b\stage\lib\boost_iostreams-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\boost_log-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\boost_filesystem-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\boost_regex-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\boost_log_setup-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\boost_thread-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\boost_date_time-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\boost_chrono-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\boost_system-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\boost_atomic-vc140-mt-gd-x64-1_67.lib C:\build\b\stage\lib\Xalan-C_1D.lib C:\build\b\stage\lib\xerces-c_3D.lib C:\build\b\tools\lib\gtest.lib kernel32.lib user32.lib gdi32.lib winspool.lib shell32.lib ole32.lib oleaut32.lib uuid.lib comdlg32.lib advapi32.lib /MANIFEST /MANIFESTFILE:test\ome-files\CMakeFiles\ometiffwriter.dir/intermediate.manifest test\ome-files\CMakeFiles\ometiffwriter.dir/manifest.res" failed (exit code 1120) with the following output: Creating library test\ome-files\ometiffwriter.lib and object test\ome-files\ometiffwriter.exp ome-filesd.lib(OMETIFFWriter.cpp.obj) : error LNK2019: unresolved external symbol BCryptCloseAlgorithmProvider referenced in function "public: __cdecl boost::uuids::detail::random_provider_base::~random_provider_base(void)" (??1random_provider_base@detail@uuids@boost@@QEAA@XZ) ome-filesd.lib(OMETIFFWriter.cpp.obj) : error LNK2019: unresolved external symbol BCryptGenRandom referenced in function "public: void __cdecl boost::uuids::detail::random_provider_base::get_random_bytes(void *,unsigned __int64)" (?get_random_bytes@random_provider_base@detail@uuids@boost@@QEAAXPEAX_K@Z) ome-filesd.lib(OMETIFFWriter.cpp.obj) : error LNK2019: unresolved external symbol BCryptOpenAlgorithmProvider referenced in function "public: __cdecl boost::uuids::detail::random_provider_base::random_provider_base(void)" (??0random_provider_base@detail@uuids@boost@@QEAA@XZ) test\ome-files\ometiffwriter.exe : fatal error LNK1120: 3 unresolved externals Looking at boost/winapi/bcrypt.hpp from the 1.67.0 source tar.bz2, I see these symbols prototyped, but not defined anywhere. Is this header broken, missing the implementation? Thanks, Roger

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Seeking help to build GitHub forks on AppVeyor and Travis
by Cromwell Enage 22 Apr '18

22 Apr '18

Hi, all! 1. Is this the right mailing list to seek help for building forks of Boost library modules on GitHub? If not, which mailing list should I bring the next questions to? 2. On my Boost.Parameter fork, one of the AppVeyor jobs gets cut off after 1 hour. How do I split the job into several jobs, one for each compiler or smaller set of compilers? 3. The Boost.MultiArray project on GitHub doesn't have AppVeyor or Travis configuration files, so I created a couple for my fork based on the ones that exist in Boost.Parameter. The AppVeyor jobs error out because they don't recognize the compile-fail rule when running the Jamfile script. Any clues as to what I'm missing? 4. On my Boost.MultiArray fork, one of the Travis jobs builds fine, but the other fails because <boost/array.hpp> is not found. Has anyone else run into this issue? If so, what was your workaround? My GitHub account is GitHub.com/CromwellEnage, in case anyone wants to peruse. Thanks in advance! Cromwell D. Enage

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[graph][graph_parallel][disjoint_sets] Of dependencies and "pending" libraries.
by Rene Rivera 21 Apr '18

21 Apr '18

In the process of creating Conan packages I ran into the rather strange "disjoint_sets" library. It's a library that has been "pending" for 18 years, AFAICT. I don't know what a pending status means for this. But for creating modular packages it means it's a giant PITA to deal with the the interdependencies of "disjoint_sets", "graph", and "graph_parallel". What I want to know is: 1. What is this hidden "disjoint_sets" library/module that only has two headers? 2. Why isn't "disjoint_sets" in the "graph" library tree, especially given that it's not an official library (AFAICT)? 3. Why is "graph_parallel" not in the "graph" library also? -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net

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[release] Boost 1.67.0 Release Candidate 2
by Daniel James 20 Apr '18

20 Apr '18

The second release candidates for the 1.67.0 release are now available at: <https://dl.bintray.com/boostorg/release/1.67.0/source/> The SHA256 checksums are as follows: 1cd94f03a71334a67d36f5161b57f5931e0cd6ecf726d7aca8bd82a3be720b74 boost_1_67_0_rc2.7z 2684c972994ee57fc5632e03bf044746f6eb45d4920c343937a465fd67a5adba boost_1_67_0_rc2.tar.bz2 8aa4e330c870ef50a896634c931adf468b21f8a69b77007e45c444151229f665 boost_1_67_0_rc2.tar.gz 7e37372d8cedd0fd6b7529e9dd67c2cb1c60e6c607aed721f5894d704945a7ec boost_1_67_0_rc2.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.

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Bug or change behavior in Fusion at_c in boost 1.66 and 1.67
by Pietro Incardona 18 Apr '18

18 Apr '18

Dear boost developers I used to use boost vector container with arrays like in the code below #include <boost/fusion/sequence/intrinsic/at.hpp> #include <boost/fusion/include/at.hpp> #include <boost/fusion/container/vector.hpp> int main() { boost::fusion::vector<int[3], int, int> v; boost::fusion::at_c<1>(v) = 2; boost::fusion::at_c<0>(v)[0] = 1; //// <----- Broken on newer boost version } Compiled with g++ --std=c++11 -I/home/i-bird/BOOST_166/include -o out main.cpp Unfortunately while this code was working under BOOST 1.63, on Boost 1.66 and Boost 1.67 it does not compile and it produce this error below. It seem that include/boost/fusion/container/vector/detail/value_at_impl.hpp went under some "modernization" process that broke the code above Regards Pietro /////////////////////////// Error ///////////////////////////////////////////// In file included from /home/i-bird/BOOST_166/include/boost/fusion/container/vector/detail/at_impl.hpp:12:0, from /home/i-bird/BOOST_166/include/boost/fusion/container/vector/vector.hpp:29, from /home/i-bird/BOOST_166/include/boost/fusion/container/vector.hpp:12, from main.cpp:3: /home/i-bird/BOOST_166/include/boost/fusion/container/vector/detail/value_at_impl.hpp: In instantiation of ‘struct boost::fusion::extension::value_at_impl<boost::fusion::vector_tag>::apply<boost::fusion::vector<int [3], int, int>, mpl_::int_<0> >’: /home/i-bird/BOOST_166/include/boost/fusion/container/vector/detail/at_impl.hpp:45:95: required from ‘struct boost::fusion::extension::at_impl<boost::fusion::vector_tag>::apply<const boost::fusion::vector<int [3], int, int>, mpl_::int_<0> >’ /home/i-bird/BOOST_166/include/boost/fusion/sequence/intrinsic/at.hpp:66:16: required from ‘struct boost::fusion::detail::at_impl<const boost::fusion::vector<int [3], int, int>, mpl_::int_<0>, boost::fusion::vector_tag>’ /home/i-bird/BOOST_166/include/boost/fusion/sequence/intrinsic/at.hpp:81:16: required from ‘struct boost::fusion::result_of::at<const boost::fusion::vector<int [3], int, int>, mpl_::int_<0> >’ /home/i-bird/BOOST_166/include/boost/fusion/sequence/intrinsic/at.hpp:86:16: required from ‘struct boost::fusion::result_of::at_c<const boost::fusion::vector<int [3], int, int>, 0>’ /home/i-bird/BOOST_166/include/boost/fusion/sequence/intrinsic/at.hpp:127:5: required by substitution of ‘template<int N, class Sequence> constexpr typename boost::fusion::result_of::at_c<const Sequence, N>::type boost::fusion::at_c(const Sequence&) [with int N = 0; Sequence = boost::fusion::vector<int [3], int, int>]’ main.cpp:9:26: required from here /home/i-bird/BOOST_166/include/boost/fusion/container/vector/detail/value_at_impl.hpp:53:68: error: no matching function for call to ‘value_at_impl<mpl_::int_<0>::value>(boost::fusion::vector<int [3], int, int>*)’ decltype(vector_detail::value_at_impl<N::value>(boost::declval<Sequence*>())) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /home/i-bird/BOOST_166/include/boost/fusion/container/vector/detail/value_at_impl.hpp:38:11: note: candidate: template<long unsigned int N, class U> U boost::fusion::vector_detail::value_at_impl(const volatile boost::fusion::vector_detail::store<N, U>*) U value_at_impl(store<N, U> const volatile*); ^~~~~~~~~~~~~ /home/i-bird/BOOST_166/include/boost/fusion/container/vector/detail/value_at_impl.hpp:38:11: note: template argument deduction/substitution failed: /home/i-bird/BOOST_166/include/boost/fusion/container/vector/detail/value_at_impl.hpp:53:68: note: template argument ‘1’ does not match ‘0’ decltype(vector_detail::value_at_impl<N::value>(boost::declval<Sequence*>())) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /home/i-bird/BOOST_166/include/boost/fusion/container/vector/detail/value_at_impl.hpp:53:68: note: template argument ‘2’ does not match ‘0’ /home/i-bird/BOOST_166/include/boost/fusion/container/vector/detail/value_at_impl.hpp: In substitution of ‘template<long unsigned int N, class U> U boost::fusion::vector_detail::value_at_impl(const volatile boost::fusion::vector_detail::store<N, U>*) [with long unsigned int N = 0; U = int [3]]’: /home/i-bird/BOOST_166/include/boost/fusion/container/vector/detail/value_at_impl.hpp:53:68: required from ‘struct boost::fusion::extension::value_at_impl<boost::fusion::vector_tag>::apply<boost::fusion::vector<int [3], int, int>, mpl_::int_<0> >’ /home/i-bird/BOOST_166/include/boost/fusion/container/vector/detail/at_impl.hpp:45:95: required from ‘struct boost::fusion::extension::at_impl<boost::fusion::vector_tag>::apply<const boost::fusion::vector<int [3], int, int>, mpl_::int_<0> >’ /home/i-bird/BOOST_166/include/boost/fusion/sequence/intrinsic/at.hpp:66:16: required from ‘struct boost::fusion::detail::at_impl<const boost::fusion::vector<int [3], int, int>, mpl_::int_<0>, boost::fusion::vector_tag>’ /home/i-bird/BOOST_166/include/boost/fusion/sequence/intrinsic/at.hpp:81:16: required from ‘struct boost::fusion::result_of::at<const boost::fusion::vector<int [3], int, int>, mpl_::int_<0> >’ /home/i-bird/BOOST_166/include/boost/fusion/sequence/intrinsic/at.hpp:86:16: required from ‘struct boost::fusion::result_of::at_c<const boost::fusion::vector<int [3], int, int>, 0>’ /home/i-bird/BOOST_166/include/boost/fusion/sequence/intrinsic/at.hpp:127:5: required by substitution of ‘template<int N, class Sequence> constexpr typename boost::fusion::result_of::at_c<const Sequence, N>::type boost::fusion::at_c(const Sequence&) [with int N = 0; Sequence = boost::fusion::vector<int [3], int, int>]’ main.cpp:9:26: required from here /home/i-bird/BOOST_166/include/boost/fusion/container/vector/detail/value_at_impl.hpp:38:11: error: function returning an array U value_at_impl(store<N, U> const volatile*); ^~~~~~~~~~~~~ main.cpp: In function ‘int main()’: main.cpp:9:26: error: no matching function for call to ‘at_c<0>(boost::fusion::vector<int [3], int, int>&)’ boost::fusion::at_c<0>(v)[0] = 1; ^ In file included from main.cpp:1:0: /home/i-bird/BOOST_166/include/boost/fusion/sequence/intrinsic/at.hpp:119:5: note: candidate: template<int N, class Sequence> constexpr typename boost::lazy_disable_if<boost::is_const<Sequence>, boost::fusion::result_of::at_c<Sequence, N> >::type boost::fusion::at_c(Sequence&) at_c(Sequence& seq) ^~~~ /home/i-bird/BOOST_166/include/boost/fusion/sequence/intrinsic/at.hpp:119:5: note: template argument deduction/substitution failed: /home/i-bird/BOOST_166/include/boost/fusion/sequence/intrinsic/at.hpp:127:5: note: candidate: template<int N, class Sequence> constexpr typename boost::fusion::result_of::at_c<const Sequence, N>::type boost::fusion::at_c(const Sequence&) at_c(Sequence const& seq) ^~~~ /home/i-bird/BOOST_166/include/boost/fusion/sequence/intrinsic/at.hpp:127:5: note: substitution of deduced template arguments resulted in errors seen above [i-bird@localhost boost_bug_test]$ [i-bird@localhost boost_bug_test]$ [i-bird@localhost boost_bug_test]$ [i-bird@localhost boost_bug_test]$ g++ --std=c++11 -I/home/i-bird/BOOST_167/include -o out main.cpp In file included from /home/i-bird/BOOST_167/include/boost/fusion/container/vector/detail/at_impl.hpp:12:0, from /home/i-bird/BOOST_167/include/boost/fusion/container/vector/vector.hpp:29, from /home/i-bird/BOOST_167/include/boost/fusion/container/vector.hpp:12, from main.cpp:3: /home/i-bird/BOOST_167/include/boost/fusion/container/vector/detail/value_at_impl.hpp: In instantiation of ‘struct boost::fusion::extension::value_at_impl<boost::fusion::vector_tag>::apply<boost::fusion::vector<int [3], int, int>, mpl_::int_<0> >’: /home/i-bird/BOOST_167/include/boost/fusion/container/vector/detail/at_impl.hpp:45:95: required from ‘struct boost::fusion::extension::at_impl<boost::fusion::vector_tag>::apply<const boost::fusion::vector<int [3], int, int>, mpl_::int_<0> >’ /home/i-bird/BOOST_167/include/boost/fusion/sequence/intrinsic/at.hpp:66:16: required from ‘struct boost::fusion::detail::at_impl<const boost::fusion::vector<int [3], int, int>, mpl_::int_<0>, boost::fusion::vector_tag>’ /home/i-bird/BOOST_167/include/boost/fusion/sequence/intrinsic/at.hpp:81:16: required from ‘struct boost::fusion::result_of::at<const boost::fusion::vector<int [3], int, int>, mpl_::int_<0> >’ /home/i-bird/BOOST_167/include/boost/fusion/sequence/intrinsic/at.hpp:86:16: required from ‘struct boost::fusion::result_of::at_c<const boost::fusion::vector<int [3], int, int>, 0>’ /home/i-bird/BOOST_167/include/boost/fusion/sequence/intrinsic/at.hpp:127:5: required by substitution of ‘template<int N, class Sequence> constexpr typename boost::fusion::result_of::at_c<const Sequence, N>::type boost::fusion::at_c(const Sequence&) [with int N = 0; Sequence = boost::fusion::vector<int [3], int, int>]’ main.cpp:9:26: required from here /home/i-bird/BOOST_167/include/boost/fusion/container/vector/detail/value_at_impl.hpp:53:68: error: no matching function for call to ‘value_at_impl<mpl_::int_<0>::value>(boost::fusion::vector<int [3], int, int>*)’ decltype(vector_detail::value_at_impl<N::value>(boost::declval<Sequence*>())) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /home/i-bird/BOOST_167/include/boost/fusion/container/vector/detail/value_at_impl.hpp:38:11: note: candidate: template<long unsigned int N, class U> U boost::fusion::vector_detail::value_at_impl(const volatile boost::fusion::vector_detail::store<N, U>*) U value_at_impl(store<N, U> const volatile*); ^~~~~~~~~~~~~ /home/i-bird/BOOST_167/include/boost/fusion/container/vector/detail/value_at_impl.hpp:38:11: note: template argument deduction/substitution failed: /home/i-bird/BOOST_167/include/boost/fusion/container/vector/detail/value_at_impl.hpp:53:68: note: template argument ‘1’ does not match ‘0’ decltype(vector_detail::value_at_impl<N::value>(boost::declval<Sequence*>())) ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~ /home/i-bird/BOOST_167/include/boost/fusion/container/vector/detail/value_at_impl.hpp:53:68: note: template argument ‘2’ does not match ‘0’ /home/i-bird/BOOST_167/include/boost/fusion/container/vector/detail/value_at_impl.hpp: In substitution of ‘template<long unsigned int N, class U> U boost::fusion::vector_detail::value_at_impl(const volatile boost::fusion::vector_detail::store<N, U>*) [with long unsigned int N = 0; U = int [3]]’: /home/i-bird/BOOST_167/include/boost/fusion/container/vector/detail/value_at_impl.hpp:53:68: required from ‘struct boost::fusion::extension::value_at_impl<boost::fusion::vector_tag>::apply<boost::fusion::vector<int [3], int, int>, mpl_::int_<0> >’ /home/i-bird/BOOST_167/include/boost/fusion/container/vector/detail/at_impl.hpp:45:95: required from ‘struct boost::fusion::extension::at_impl<boost::fusion::vector_tag>::apply<const boost::fusion::vector<int [3], int, int>, mpl_::int_<0> >’ /home/i-bird/BOOST_167/include/boost/fusion/sequence/intrinsic/at.hpp:66:16: required from ‘struct boost::fusion::detail::at_impl<const boost::fusion::vector<int [3], int, int>, mpl_::int_<0>, boost::fusion::vector_tag>’ /home/i-bird/BOOST_167/include/boost/fusion/sequence/intrinsic/at.hpp:81:16: required from ‘struct boost::fusion::result_of::at<const boost::fusion::vector<int [3], int, int>, mpl_::int_<0> >’ /home/i-bird/BOOST_167/include/boost/fusion/sequence/intrinsic/at.hpp:86:16: required from ‘struct boost::fusion::result_of::at_c<const boost::fusion::vector<int [3], int, int>, 0>’ /home/i-bird/BOOST_167/include/boost/fusion/sequence/intrinsic/at.hpp:127:5: required by substitution of ‘template<int N, class Sequence> constexpr typename boost::fusion::result_of::at_c<const Sequence, N>::type boost::fusion::at_c(const Sequence&) [with int N = 0; Sequence = boost::fusion::vector<int [3], int, int>]’ main.cpp:9:26: required from here /home/i-bird/BOOST_167/include/boost/fusion/container/vector/detail/value_at_impl.hpp:38:11: error: function returning an array U value_at_impl(store<N, U> const volatile*); ^~~~~~~~~~~~~ main.cpp: In function ‘int main()’: main.cpp:9:26: error: no matching function for call to ‘at_c<0>(boost::fusion::vector<int [3], int, int>&)’ boost::fusion::at_c<0>(v)[0] = 1; ^ In file included from main.cpp:1:0: /home/i-bird/BOOST_167/include/boost/fusion/sequence/intrinsic/at.hpp:119:5: note: candidate: template<int N, class Sequence> constexpr typename boost::lazy_disable_if<boost::is_const<Sequence>, boost::fusion::result_of::at_c<Sequence, N> >::type boost::fusion::at_c(Sequence&) at_c(Sequence& seq) ^~~~ /home/i-bird/BOOST_167/include/boost/fusion/sequence/intrinsic/at.hpp:119:5: note: template argument deduction/substitution failed: /home/i-bird/BOOST_167/include/boost/fusion/sequence/intrinsic/at.hpp:127:5: note: candidate: template<int N, class Sequence> constexpr typename boost::fusion::result_of::at_c<const Sequence, N>::type boost::fusion::at_c(const Sequence&) at_c(Sequence const& seq) ^~~~ /home/i-bird/BOOST_167/include/boost/fusion/sequence/intrinsic/at.hpp:127:5: note: substitution of deduced template arguments resulted in errors seen above

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Proposal of a new container
by Vanand Gasparyan 16 Apr '18

16 Apr '18

Hi everyone, First, a short introduction of me. My name is Vanand, I'm from Armenia, 23 yo, C++ software Engineer. I'm new in the community and I've come with a proposal. I've implemented a prefix tree and tried to make it as STL compatible as possible. After a short investigation I found out that boost libraries don't provide one and here I am with a proposal. Here is the link to the repository: https://github.com/vgasparyan1995/prefix_tree It's a header only implementation, all source files are in "include" directory. I also have unit and performance tests. If the proposal (of having prefix tree container in boost) is accepted, I will ask for mentorship and support to make it "boost friendly" , create a proper documentation, meet the coding style and other guidelines. In the end I want to mention that I am new to this, so if I'm already doing something wrong or this is not the proper way to propose something, please kindly let me know and help to do it right. Looking forward to hearing from anyone :) Best Regards, Vanand

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[release] 1.68.0 open for merging
by Daniel James 15 Apr '18

15 Apr '18

The master branch is open for merging all stable changes from develop, including bug fixes and major upgrades to existing libraries. Breaking changes should be coordinated via the mailing list with the developers of the other libraries affected. New libraries may be added, but require permission of a release manager. In other words, merging does not require permission from a release manager, except for new libraries. Boost Calendar with the release schedule: http://www.boost.org/development/index.html Release schedule explanation: https://github.com/boostorg/boost/wiki/Release-Schedule Release practices for developers: http://svn.boost.org/trac/boost/wiki/ImprovingPractices -- The Boost Release Team

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[release] Boost 1.67.0
by Daniel James 15 Apr '18

15 Apr '18

Release 1.67.0 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 2 new libraries and numerous enhancements and bug fixes for existing libraries. For details, including download links, see <https://www.boost.org/users/news/version_1.67.0> You can also download directly from: <https://dl.bintray.com/boostorg/release/1.67.0/> To install this release on your system, see <https://www.boost.org/doc/libs/release/more/getting_started/index.html> Thanks to everyone who participated in this release. Thanks, -- The Boost Release Team

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