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Problems building Boost libraries for Windows Store when C++/CX is involved
by Mikael Olenfalk 04 Jan '16

04 Jan '16

Hi, I am working on porting the boost libraries we depend on to winrt, most porting is rather straightforward (basically switch from win32 apis which are 20 years old to apis which are 15 years old :D ). However I have hit a bit of a problem when compiling Boost.Log. Boost.Log depends on Boost.Asio which uses C++/CX to call some of the newer Store APIs (Windows::Networking and friends). When I build I get these errors: compile-c-c++ ..\..\..\bin.v2\libs\log\build\msvc-14.0\debug\log-api-winnt\threading-multi\windows-api-store\dump_ssse3.obj dump_ssse3.cpp ..\..\..\libs\log\src\dump_ssse3.cpp: fatal error C1107: could not find assembly 'platform.winmd': please specify the assembly search path using /AI or by setting the LIBPATH environment variable call "C:\Program Files (x86)\Microsoft Visual Studio 14.0\VC\vcvarsall.bat" x86 store >nul cl /Zm800 /ZW /EHsc -nologo @"..\..\..\bin.v2\libs\log\build\msvc-14.0\debug\log-api-winnt\threading-multi\windows-api-store\dump_ssse3.obj.rsp" (As you can see I have monkey-patched msvc.jam to append the "store" argument to vcvarsall.bat - to no avail :( -- the monkey-patch is here if you want to look at it: https://github.com/mauve/build/commits/universal-windows-boost-1.59.0 ) The @response file looks like this: "..\..\..\libs\log\src\dump_ssse3.cpp" -Fo"..\..\..\bin.v2\libs\log\build\msvc-14.0\debug\log-api-winnt\threading-multi\windows-api-store\dump_ssse3.obj" -TP /Z7 /Od /Ob0 /W3 /GR /MDd /Zc:forScope /Zc:wchar_t /wd4675 /EHs /arch:SSE2 /bigobj /wd4003 /wd4456 /wd4459 /wd4503 -c -DBOOST_ALL_NO_LIB=1 -DBOOST_CHRONO_DYN_LINK=1 -DBOOST_DATE_TIME_DYN_LINK=1 -DBOOST_FILESYSTEM_DYN_LINK=1 -DBOOST_LOG_BUILDING_THE_LIB=1 -DBOOST_LOG_DLL -DBOOST_SPIRIT_USE_PHOENIX_V3=1 -DBOOST_SYSTEM_DYN_LINK=1 -DBOOST_SYSTEM_NO_DEPRECATED -DBOOST_THREAD_BUILD_DLL=1 -DBOOST_THREAD_DONT_USE_CHRONO=1 -DBOOST_THREAD_USE_DLL=1 -DDATE_TIME_INLINE -DWINAPI_FAMILY=WINAPI_FAMILY_APP -D_CRT_SECURE_NO_DEPRECATE -D_CRT_SECURE_NO_WARNINGS -D_SCL_SECURE_NO_DEPRECATE -D_SCL_SECURE_NO_WARNINGS -D_WIN32_WINNT=0x0603 "-I..\..\.." Regards, Mikael

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Generic type inferencer function?
by Nat Goodspeed 04 Jan '16

04 Jan '16

Our code has any number of instances of this pattern: template <typename T, typename U> class SomeTemplate { SomeTemplate(const T& t, const U& u); ... }; template <typename T, typename U> SomeTemplate<T, U> make_SomeTemplate(const T& t, const U& u) { return SomeTemplate<T, U>(t, u); } Am I overlooking a generic boost::make<something>() of this general form? template <template<typename...> class CLASS_TEMPLATE, typename... ARGS> CLASS_TEMPLATE<ARGS...> make(ARGS && ... args) { return CLASS_TEMPLATE<ARGS...>(std::forward<ARGS>(args)...); } If that doesn't already exist... would it be useful to add (a less naive version) somewhere?

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[multiprecision] uses boost::math::gcd without including the header
by Peter Dimov 04 Jan '16

04 Jan '16

include/boost/multiprecision/cpp_int/misc.hpp uses boost::math::gcd (and lcm), but does not include common_factor_rt.hpp.

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Potential contribution scenarios?
by Miguel Coimbra 04 Jan '16

04 Jan '16

Dear Community, This is my first post, apologies if I am breaking any rule with this. I've wanted to learn and improve my C++ skills for some time now. Learning more about Boost's usage and contributing to it has been on my mind. As a Ph.D student (Instituto Superior Técnico, Portugal), I became aware of Boost's participation in Google's Summer of Code and read up on some of Boost's past projects. Two ideas of GSoC2015 in particular caught my attention: - Concurrent Hash Tables - Mentor: Niall Douglas - Boost Document Library development - Mentor: Antony Polukhin I have been looking for direct contacts to learn about some of these ideas (Niall Douglas and Antony Polukhin, respectively) from 2015's Google Summer of Code to find out more, but was unsuccessful so far. While the first idea was not put into practice, the second one was undertaken (by Anurag Ghosh if I am not mistaken). Would anyone be able to point me in a direction to learn more about the state of work on these two ideas (specially the Document Library) and (if possible) if they are available for me to pick up and look into ways of contributing? Perhaps querying the mentors of those ideas for feedback? Thank you very much for your time, Kind regards, Miguel E. Coimbra

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How to start Contributing !
by Yuvraj Singh 03 Jan '16

03 Jan '16

I am new to boost C++ libraries. I want to contribute to org and Participate in GSOC'2016 can someone please guide me through it. I have looked through the page https://svn.boost.org/trac/boost/wiki/SoC2016 . Can someone please help me about *C++ programming aptitude test *mentioned on the page. How and when it is organised and what type of questions are asked ?. *Thanks !*

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Status of the CMake-ification
by Louis Dionne 02 Jan '16

02 Jan '16

Dear Boost, I'd like to inquire about the status of the CMake-ification of Boost that had been started a while ago. AFAICT, the effort is completely stopped now; is this correct? Also, I'd like to poll the community to gauge interest in the rebirth of such an effort. __I'm not proposing myself to work on such a rebirth__, but I'm just curious to know what the community thinks about it. I, for one, would love to see it happen. Regards, Louis -- View this message in context: http://boost.2283326.n4.nabble.com/Status-of-the-CMake-ification-tp4681599.… Sent from the Boost - Dev mailing list archive at Nabble.com.

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[winapi] [thread] Conflicting declarations on MinGW
by Antony Polukhin 01 Jan '16

01 Jan '16

Hi, Some of the Boost.DLL tests produce following warnings: ../boost/thread/win32/thread_primitives.hpp:175:83: warning: declaration of 'void* boost::detail::win32::GetModuleHandleA(const char*)' with C language linkage ../boost/detail/winapi/dll.hpp:47:1: warning: conflicts with previous declaration 'HINSTANCE__* GetModuleHandleA(boost::detail::winapi::LPCSTR_)' ../boost/thread/win32/thread_primitives.hpp:195:94: warning: declaration of 'int (__attribute__((__stdcall__)) * boost::detail::win32::GetProcAddress(void*, const char*))()' with C language linkage ../boost/detail/winapi/dll.hpp:82:1: warning: conflicts with previous declaration 'int (__attribute__((__stdcall__)) * GetProcAddress(boost::detail::winapi::HMODULE_, boost::detail::winapi::LPCSTR_))()' Andrey, Vicente what's the best way to resolve such issues? -- Best regards, Antony Polukhin

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[qvm] deduce_xx traits wouldn't introduce ODR issues.
by Vicente J. Botet Escriba 31 Dec '15

31 Dec '15

Hi, I wonder if the deduce_xx traits wouldn't introduce ODR issues. Remember the TBoost.Conversion library where conversion between two types was customizable. The fact that deduce_xx traits have two types would promote ODR as there is no one type that is expected to do the customization. I believe that changing the default to something depending on the first argument will be better than using the specific qvm type as result. If this is not enough, you could add symbolic operations taken the result type as parameter, e.g. if a+b is not something specified by A, the user could use sum<C>(a,b) Forget my comment if there is no ODR issue. Best, Vicente

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[dll] ready for master branch. Please merge
by Antony Polukhin 29 Dec '15

29 Dec '15

Hi, Boost.DLL is ready to appear in next release of Boost. Please, merge the DLL related changes into the master branch of boostorg/boost (changes for the develop branch were merged here: https://github.com/boostorg/boost/pull/94) Thanks! -- Best regards, Antony Polukhin

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[qvm] Today is the last day of QVM formal review extended period
by Adam Wulkiewicz 23 Dec '15

23 Dec '15

Dear Boost Community! Today is the last day of the extended period of QVM library formal review. Since now we received 4 reviews. I encourage you to send more, there is still some time left. I'd like to thank all of you who have sent reviews as well as those who have taken part in the discussions. I'm going to wait for additional reviews a few days in case someone wanted to send one after the end of the review period. Does any of you plan to do it? Regards, Adam

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Broken Link
by Mudit Sharma 23 Dec '15

23 Dec '15

All, The boost.python link provided on this page is broken: http://www.boost.org/doc/libs/1_60_0/more/getting_started/windows.html (See Boost.Python in section 3) Can anyone fix this? Thanks M

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[autoindex] Default building with an Index
by Edward Diener 22 Dec '15

22 Dec '15

The documentation for VMD supports building with an index but I had not made this the default situation. This is my mistake. Can I assume the official build of the docs for a release supports building with an index via autoindex ? If so I will change the jamfile to support this as the default for the future and assume any end-user wishing to regenerate the docs has autoindex support also as part of the distribution as long as my jamfile is setup correctly for autoindex.

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[doc] Releases 1.59 and 1.60 missing some tools documentation
by Edward Diener 22 Dec '15

22 Dec '15

In the 1.60 release, and I also just noticed in at least the 1.59 release also, the documentation links to the Release and Regression tools go to an invalid URL. Also while the documentation link to Boost.Build goes to a general explanation page the subsequent documentation link to Documentation goes to an invalid URL. Is this what we want, and that the end-user should have to "build" the documentation ? It seems doubtful, considering what a trial it often is for developers themselves to build the documentation given the tools available to do so. I think that this needs to be corrected in upcoming releases.

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[regression] run.py merge option
by Antony Polukhin 22 Dec '15

22 Dec '15

Hi, How hard would it be to add a --merge option to run.py? Motivation: I'm experimenting with running all the regression tests on TravisCI https://github.com/apolukhin/boost_indirect_testing. Unfortunately, it has some hard limits, so a task can not work more than 2 hours. I've ended up splitting all the Boost tests by libraries and running tests on per library basis. Unfortunately, when the test results are send to server, only one library result is displayed in resulting matrix (search http://www.boost.org/development/tests/develop/developer/summary.html for indirect_travisci_tests) So I'd like to get a --merge option, that will allow merge of all the results by tester_name+revision. For example if results for 'geometry' and 'any' are sent with tester name `indirect_travisci_tests` and revision 74f85d, then show them in a single column. This may be also useful for those test runners that run tests on embedded or emulated devices (running all the Boost tests on emulated MIPS device may take a few weeks; running the tests on multiple emulated MIPS devices will speed up things) -- Best regards, Antony Polukhin

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Software Freedom Conservancy Support
by Jon Kalb 22 Dec '15

22 Dec '15

This is not a technical message, but instead focuses on Boost Administration. Software Freedom Conservancy in a Financial Fight for its Life Software Freedom Conservancy, the non-profit home of Boost is facing an existential threat. Historically, Conservancy has been funded by corporate donations. This works great when it works, but a management shake-up, change in priorities, or a bad quarter at a large donor can derail the organization¹s programs. It has become obvious that Conservancy must move to a Supporter-driven funding model, where individuals who believe in Conservancy¹s mission of supporting open source projects, such as Boost, make a personal commitment to support that effort. Conservancy's fundraiser, found at https://sfconservancy.org/supporter/, is centered around asking individuals who care about the work that Conservancy does to donate $120/year, or just $10/month, to support the organization. Conservancy seeks about 2,500 Supporters to continue its current work, and 750 Supporters to continue a ³bare minimum² of services to its projects. What does this mean to Boost? Boost receives a myriad of important services (see https://sfconservancy.org/members/services/ ) from Conservancy. We¹ve relied on Conservancy since 2007 to provide them. Here are some of the things that Conservancy does for Boost that are in the ³bare minimum² category: * Dealing with all the financial and contractual details regarding our annual C++ Now conference. It was BoostCon that brought Boost and Conservancy together. C++Now 2016 will the the tenth annual BoostCon and it is a tribute to what we¹ve accomplished working together. * Handle our Google Summer of Code payments and travel, including handling all financial transactions with Google to receive and then disperse the money. * Coordinating travel reimbursements for Boost contributors (both developers and students) to attend conferences. * Receiving and tracking all donations to Boost. * Keeping the non-profit status for us so that we don't have to form our own org and file our own paperwork. As the Chair of the Boost Steering Committee, I cannot overstate how important this is to our existence as an organization. Here are some of the services Boost has received in the wider category: * Dealing with questions from the community (including license-governing bodies like OSI) about Boost's license. * Discussing the issue of copyright governance and contributions with large corporations who want their employees to contribute to Boost but need legal assurances or have questions relating to Boost's license or contribution policies. * Reviewing and handling licensing terms of third-party software that relate to Boost in some way, and giving us feedback and answers about issues related to it. * General legal consulting on issues that we run into as an open source non-profit. As you can see, Boost really relies on the important work of Conservancy. Support from Boost Boost, like all of Conservancy¹s projects, contributes 10% of our revenue to Conservancy¹s general fund. (The other 90% is maintained and administered by Conservancy at the direction of the Boost Steering Committee to advance the Boost project.) But that 10% of revenue from all Conservancy¹s member projects doesn¹t add up to enough to even employee one full time person, let alone the already overworked staff of three that Conservancy has. Donors must make up the difference. When Conservancy launched its fundraising effort, I sent out a request to past BoostCon/C++Now attendees asking for support and I¹m proud and delighted to say that a number of Boost community members have already stepped up. One told me that her company will be matching her support. Boost is one of Conservancy¹s oldest and largest projects, so it is right that Boost community members make up a fair proportion of its supporters. I encourage you to choose Conservancy as one of your charitable gifts this holiday season. (Conservancy is a 501(c)(3) charity incorporated in New York, and donations are typically deductible on U.S. taxes.) Please visit: https://sfconservancy.org/supporter/ If you are able to join the others from the Boost community that are making this gift, please let me know. I¹d like to personally thank you. Jon Kalb Chair, Boost Steering Committee

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Becoming Maintainer of the Iterator Library
by Nathan Wilson 21 Dec '15

21 Dec '15

Hi all, There was talk on the mailing list a few months back, and was apparently discussed at CppCon in September, about becoming a Library Maintainer. This was pertaining to Libraries which are either being maintained by the CMT, or as Edward Diener mentioned, Libraries which aren't in the CMT's hands but the current maintainer(s) don't have time to devote to maintaining the particular library. That said, after having discussed it with a few people outside the mailing list, I would like to volunteer to become a Maintainer of Boost's Iterator Library. I have not been active on Boost's mailing list, but have participated in the C++ Standardization Process with the paper Delimited Iterators (http://open-std.org/jtc1/sc22/wg21/docs/papers/2014/n4257.html) which will be in the Library Technical Specification 2. I have also submitted/committed some Patches in Clang as well. I just wanted to mention those couple of things as a point of reference so this didn't seem entirely random. Anyway, I'd be really excited to help contribute and help Boost by becoming a Maintainer of the Iterator Library. I do have some concern about compiling on various versions of Windows/OSX though. I have a Windows 8.1 machine and could obviously use Visual Studio, but I'm not too sure about verification of older Windows/OSX versions. On Linux I can certainly create VMs for various distros. If anyone has some best practices or advice about handling different OS distros/versions, that would be great. Please let me know if there are any questions. Thank you, Nathan

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[smart_ptr] Moving cast for unique_ptr
by Karolin Varner 21 Dec '15

21 Dec '15

Hi all! There is the family of boost pointer cast (boost::static_pointer_cast, boost::dynamic_pointer_cast, ...) that allow a developer to write generic code by casting pointers regardless of whether they are some smart pointer (e.g. shared_ptr) or plain pointers. However, those functions have not been implemented for unique_ptr, because they create a copy of their pointer and unique_pointers can not be copied. In my case I still needed to cast some unique_ptr and since it's ok to move unique_ptrs I wrote a function that does exactly that. The code is below – Comments are very, very welcome. It works for my case, but I am sure it is not as generic and safe as it should be ;) . Specifically, for a library, it should be made to work on any kind of smart/plain pointer. Not just unique_ptr. Is there any interest to include a boost::static_moving_pointer_cast and the other types of casts in boost? Best, Karolin /// Dynamic cast a unique_ptr. /// /// This function shall move the pointer in in_ptr, into /// a new unique_pointer of the desire type, dynamic_casting /// it in the process. /// In given pointer shall contain a NULL pointer afterwards. /// /// If unsuccessful, function shall throw an error and leave /// in_ptr unmodified. /// /// This behaviour contrasts a bit with the behaviour of the /// normal dynamic_cast: /// 1. dynamic_cast copies objects, this moves them since /// unique_pointers can not be copied. /// 2. dynamic_cast returns a NULL pointer if the pointer to /// cast is of an incomplete type, this throws /// incomplete_cast instead, to ease error handling. /// /// @tparam T The type to convert to (as non-pointer) /// @tparam F The type to convert from (as non-pointer) /// @param in_ptr The unique_ptr to cast /// @return in_ptr, cast to the desired type template<typename T, typename F> std::unique_ptr<T> dynamic_moving_pointer_cast(std::unique_ptr<F> &in_ptr) { // Exception safety: If The dynamic cast throws an error, // or of we throw incomplete_cast, in_ptr will still be // unmodified T *plain_out_ptr = dynamic_cast<F*>(in_ptr.get()); if (plain_out_ptr == NULL && in_ptr.get() != NULL) throw incomplete_cast(); // Exception safety: Both operations are noexcept in_ptr.release(); return std::unique_ptr<T>(plain_out_ptr); }

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safe::map
by Karen Pease 21 Dec '15

21 Dec '15

Hi everyone - I'm new to boost-devel, and am a bit intimidated ;) I recently finished a project and I don't know if the boost community would have any interest in it, whether it's really "boost material" or not: https://github.com/KarenRei/safe-map The page goes into more detail, but the short of it is: after searching and a long conversation on StackExchange, I discovered that while there are threadsafe ordered-map containers out there, the threadsafety was a bit weak. For example, if you have Thread A iterating across the map and Thread B thread just happens to delete an element as A is passing by, A's iterator becomes invalidated and the program crashes - even in a supposedly "threadsafe" map. For the type of multithreaded cache that I needed, I needed a structure that had the thread safety level of a filesystem - you know, where multiple processes can have file descriptors open at a time and one process might even potentially delete a file that another is accessing, without leading to a system crash. And that's basically what I implemented: safe::map, which not only ensures that basic operations on the container itself are threadsafe, but that everything you do with the iterators - even deleting elements out of the map that other iterators are pointing to - is also threadsafe. It does this by implementing reference counting on the elements in the map and flagging elements for deletion rather than deleting them immediately. A more detailed description of usage, performance, implementation, use cases, etc is on the project page. The project comes with a test suite which launches a number of threads that endlessly randomly tweak and iterate around the map with every function available to them. Does this sound like something that might be useful in boost (after whatever changes would be required)? If there's no interest, no harm done :) - kv, Karen

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[Travis] All boostorg builds stalled?
by Louis Dionne 20 Dec '15

20 Dec '15

Hi, All of Hana's builds are currently stalled [1]. It has been like this for 2 or 3 days. I tried contacting Travis' support, but they are in vacation until January 4th. It also seems like the builds for Predef have been stalled for a while [2]. Perhaps other libraries are also touched. Strangely, builds for non-Boost repositories are not stalled, since I can build personal projects just fine. Does anyone know what might be happening? Louis [1]: https://travis-ci.org/boostorg/hana/builds [2]: https://travis-ci.org/boostorg/predef/builds/97532851

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[gsoc]Seeking Guidance
by Ibrahim Dalal 20 Dec '15

20 Dec '15

Hi I am a sophomore, majoring in Computer Science. I am also a GSoC'16 aspirant. Its the first time I would be contributing to an open source project. Can someone please guide to a small project/patch suitable for a beginner? I have familiarity with C++ programming language along with basic understanding of C and Python. Also have some elementary knowledge of Git. Thanks

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Boost 1.60.0 has been released
by Marshall Clow 18 Dec '15

18 Dec '15

Release 1.60.0 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 one new library and numerous enhancements and bug fixes for existing libraries. New Libraries * VMD: Variadic Macro Data library, from Edward Diener For details, including download links, see http://www.boost.org/users/news/version_1.60.0 You can also download directly from SourceForge: http://sourceforge.net/projects/boost/files/boost/1.60.0/ Tom Kent has made pre-built windows binaries, and they are available at: https://sourceforge.net/projects/boost/files/boost-binaries/1.60.0/ To install this release on your system, see http://www.boost.org/doc/libs/release/more/getting_started/index.html Thanks, --The Boost release team Vladimir Prus Rene Rivera Marshall Clow Eric Niebler Daniel James Beman Dawes

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[variant] Opinion on boost::safe_get<> and default boost::get<> behavior
by Antony Polukhin 18 Dec '15

18 Dec '15

Hi all, I'm in doubt and would like to hear opinions on the following issue. boost::get for boost::variant was not making any compile time checks, resulting in runtime errors where a compile time error must be: boost::variant<int, string> v(100); boost::get<bool>(&v); // returns NULL instead of compile time error boost::get<bool>(v); // throws exception on runtime instead of compile time error Now we have an implementation of compile time checked get in a separate branch at git: boost::variant<int, string> v(100); boost::safe_get<bool>(&v); // compile time error boost::safe_get<bool>(v); // compile time error boost::unsafe_get<bool>(&v); // returns NULL instead of compile time error boost::unsafe_get<bool>(v); // throws exception on runtime instead of compile time error I'm in doubt, what the default behavior of boost::get must be: * safe_get behavior is much closer to Standard Library behavior (just like std::get for tuples) and allows to avoid errors in user code * unsafe_get behavior is same as behavior of old boost::get and won't break user's code if boost::get is used in some generic contexs What's your opinion? -- Best regards, Antony Polukhin

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[QVM] Boost.QVM formal review is ongoing
by Adam Wulkiewicz 18 Dec '15

18 Dec '15

Dear Boost community, It seems that there are some problems with gmane.org related to handling of messages sent to many mailing lists at once. Therefore I'm reposting the information about the formal review. I appologize those of you who recieve this message for the second time. The formal review of Emil Dotchevski's QVM library begined on 7th Dec and it ends on 16th Dec. Boost QVM defines a set of generic functions and operator overloads for working with quaternions, vectors and matrices of static size with the emphasis on 2, 3 and 4-dimensional operations needed in graphics, video games and simulation applications. While it provides its own quaternion, matrix and vector types, it is designed to work primarily with user-defined types through user specializations of the q_traits, v_traits and m_traits templates. QVM's source code is available on Github: https://github.com/zajo/boost-qvm Full documentation is also viewable on Github: http://zajo.github.io/boost-qvm/ We encourage your participation in this review. At a minimum, kindly state: - Whether you believe the library should be accepted into Boost * Conditions for acceptance - 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? More information about the review process can be found here: http://www.boost.org/community/reviews.html We await your feedback! Best regards, Adam Wulkiewicz

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[qvm] Formal review for QVM
by Adam Wulkiewicz 18 Dec '15

18 Dec '15

Dear Boost community, The formal review of Emil Dotchevski's QVM library begins on 7th Dec and ends on 16th Dec. Boost QVM defines a set of generic functions and operator overloads for working with quaternions, vectors and matrices of static size with the emphasis on 2, 3 and 4-dimensional operations needed in graphics, video games and simulation applications. While it provides its own quaternion, matrix and vector types, it is designed to work primarily with user-defined types through user specializations of the q_traits, v_traits and m_traits templates. QVM's source code is available on Github: https://github.com/zajo/boost-qvm Full documentation is also viewable on Github: http://zajo.github.io/boost-qvm/ We encourage your participation in this review. At a minimum, kindly state: - Whether you believe the library should be accepted into Boost * Conditions for acceptance - 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? More information about the review process can be found here: http://www.boost.org/community/reviews.html We await your feedback! Best regards, Adam Wulkiewicz

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QVM Review
by Phil Endecott 17 Dec '15

17 Dec '15

Dear All, This is my review of Emil Dotchevski's QVM library. Thank you to Emil for offering this code. I believe that Boost and/or the standard library would benefit from vectors and matrices. Unfortunately I don't think that this proposal is what is needed, and I feel it should not be accepted. I have previously posted my thoughts about the terseness of the identifiers used and the use of operator,; I won't repeat the details here but in summary I find the syntax not to my taste, and not suitable for "public" code. Boost should aim to promote best practice, and I think this library falls short. Now, it's not unusual to find libraries that have interfaces that we don't like. Often we'll use them anyway because the features that the libraries provide outweigh the pain of using them. Does this apply in the case of QVM? Actually since first looking I've found that it does have more functionality than I thought - for example, I've only just found that it has functions to create matrices representing rotations (but not any other affine transformations) and to compute the inverse of a matrix (but not the determinant). But there's still not enough meat here for me to think it's worth using. If this were a comprehensive matrix algebra library, or a computational geometry library, or a SIMD library, then it might be worth putting up with the syntax. But it isn't, it's just a medium-size collection of operators and functions for quaternions, vectors and matrices that many projects will already having amongst their own local utilities. What it does offer is the ability to wrap existing matrix and vector classes and use a single unified syntax for all of them. It's just a shame that the single unified syntax is not the one I want to use! It is interesting to contrast QVM with Boost.Polygon and Boost. Geometry. The similarity is that both of these also wrap existing classes (for e.g. points) by traits class specialisations. When these were reviewed we discussed extensively how support for this compromised the friendliness of the syntax, i.e. the need to write get<0>(p) rather than p.x. What we ended up with there was I think the best that we could do, and it was probably worthwhile because of the substantial core functionality of each of those libraries. In my opinion, QVM doesn't reach that threshold. To address some of the "standard questions": I've not looked at the code, only the docs; I've spent a couple of hours this time and also looked when it was first proposed; and yes I do use vectors and matrices in my own code, for various graphics and cartographic purposes. Regards, Phil.

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