March 2017 - Boost - lists.preview.boost.org

[Convert] std::isspace requires unsigned #28
by Olaf van der Spek 21 Mar '17

21 Mar '17

Hi, > boost\convert\base.hpp(112): warning C6330: 'const char' passed as _Param_(1) when 'unsigned char' is required in call to 'isspace'. > boost\convert\base.hpp(115): warning C6330: 'const char' passed as _Param_(1) when 'unsigned char' is required in call to 'isspace'. https://github.com/boostorg/convert/issues/28 IMO the code should be fixed and it's not a documentation issue. What do you think? -- Olaf

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Re: [boost] [release] 1.64.0 Delayed because of Microsoft (version numbers)
by Tom Kent 20 Mar '17

20 Mar '17

Sorry all, I meant to send this to the list but only replied to Daniel. This adds an option 4 and 5. On Sun, Mar 19, 2017 at 3:58 PM, Tom Kent <lists(a)teeks99.com> wrote: > > > On Sun, Mar 19, 2017 at 10:17 AM, Daniel James <dnljms(a)gmail.com> wrote: > >> On 19 March 2017 at 13:10, Tom Kent via Boost <boost(a)lists.boost.org> >> wrote: >> > >> > Option 1 - 14.10 Use microsoft toolset version based on cl.exe version >> -5. >> > This is the official version of the c++ toolset that microsoft has been >> > pushing (somewhere). The new $(VCToolsVersion) macro is "14.10.25017", >> this >> > macro is not available in previous versions of visual studio. >> > >> > build bootstrap would use bootstrap.bat vc1410 >> >> [snip] >> >> > Option 2 - 14.1 Use the abbreviated toolset version that microsoft uses >> for >> > their toolset version. The $(PlatformToolsetVersion) macro is "141". In >> > VS2015 this was "140". >> >> [snip] >> >> > I *think* that is all the reasonable options. Let the consensus form! >> >> I disagree, I think we should limit ourselves to values that Microsoft >> actually uses. As far as I'm aware, they don't use 1410, and they >> don't use 14.1. There are already too many ways of writing the version >> number, adding more will just add to the confusion. >> > > So 2-a would meet these requirements. However, I did overlook the mixed > options: > > Option 4 (141 and 14.10) - > build bootstrap would use bootstrap.bat vc141 > build of source would use b2 toolset=msvc-14.10 > build would generat libraries of the format libboost_NAME_vc141-OPTIONS-1_ > 64.lib > config would auto-link libraries of the same format > (4-a is the same as 2-a) > > Option 5 (1410 and 14.1) - > build bootstrap would use bootstrap.bat vc1410 > build of source would use b2 toolset=msvc-14.1 > build would generat libraries of the format libboost_NAME_vc1410-OPTIONS- > 1_64.lib > config would auto-link libraries of the same format > (5-a is the same as 1-a) > > Tom > >

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About all these metaprogramming libraries
by Louis Dionne 20 Mar '17

20 Mar '17

Dear Boost, We've seen two metaprogramming libraries ask for a formal review on the list recently. I expect a third (Brigand) might join the party soon, and maybe even a fourth (Eric Niebler's meta). I think it would be wise to have a plan for how we're going to deal with this. Before going further, I'd also like to clear something out. Some people have asked whether "classic" metaprogramming libraries still had their place given that we now have Hana. As the author of Hana, I think the answer is yes. While Hana is (IMHO) easier to use and more powerful, it also has an important shortcoming. Hana is too slow when dealing with very large inputs. This is due to the fact that it can also handle values, which is much heavier than dealing with types only. This can be alleviated to some extent, but the truth is that our execution model (the compiler) simply has to do more work when handling values. Hence, I think Boost does need a modern classic TMP library to handle these cases where a library writer needs to handle gigantic type lists. I think marketing such a library as an advanced tool for library writers would be a service to the overall C++ community, but that's an orthogonal concern. However, Boost needs one such library, not four. I think we can't just do 4 reviews and include all the libraries that pass in Boost; that would be a huge disservice to our users, who will be left with the burden of choosing. Heck, if we can't even make our mind, how can they? So, how do we pick? Have we ever been in a similar situation where we have multiple competing libraries solving _exactly_ the same problem? Louis -- View this message in context: http://boost.2283326.n4.nabble.com/About-all-these-metaprogramming-librarie… Sent from the Boost - Dev mailing list archive at Nabble.com.

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Newcomer Contributor to Boost C++ Libraries
by Aman Gupta 20 Mar '17

20 Mar '17

Hello everyone, I am Aman Kumar Gupta, an undergraduate 1st year student from International Institute of Information Technology, Bhubaneswar, India. I'm a newcomer to Boost C++ community. I have ,what i think, medium to good C++ coding background as i've been coding in C++ since past 5-6 years and have won some coding competitions as well. I have a good C++ STL knowledge and am very keen and interested in contributing to Boost's STL libraries. But as i'm a newbie to this community, i'm little confused where and how to start. I would be very glad and thankful if anyone would please help me and guide me through.

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Re: [boost] [gsoc17]The implement of Programming competency test From Ruoyun Jing
by Ruoyun Jing 20 Mar '17

20 Mar '17

Hi Vissarion, 2017-03-20 20:29 GMT+08:00 Vissarion Fisikopoulos <fisikop(a)gmail.com>: > Hi Ruoyun, > > > - The main work I should do during GSoC about project 1 is just to > improve > > the algorithms of compare two distances of two point pairs or try to > > consider different situations which used compare distance predicates to > > avoid calculation? > > the project is about algorithms that does not compute the actual distance > but an approximation (as rough as possible) that suffices to accurately > compare the lengths of two geodesic segments on the ellipsoid > > Thanks for your answer, I have the correct point of these project and will continue to write my proposal. > > - Do "In some algorithms there is the need to compare two distances of > two > > point pairs" this means compare two points distances on Earth? Or on > every > > ellipsoid model? > > the later (see answer above) > > > - Do I need to find the approaches of filter by myself? Could you please > > help me get more information about these? Like the implement detail about > > the predicate compare_distance function, mathematical calculation papers > > about compare distance on ellipsoid? > > Well we give one approach on the website (there is another proposal of > another > candidate on the list). My opinion is that if you understand these > approaches > (pos and cons, differences etc) that will help you towards a solid > application. > Having another idea for an approach will definitely strengthen you > application. > Thanks for your help. I can get the point of those approaches and will try to have new ideas. :) > > - In my view, just like compute the shortest distance between two given > > points on Earth, the background approach can be used. And I used > cartisian > > coordinate to avoid many trigonometric function calculation, but I can > not > > find more improve with my lacking knowledge, could you give me some > aspects > > to get more approaches? > > Please see answer above > > At this point I think it is better to jump to boost list because our > discussion > could interest more people. I will not copy anything of our private > conversation > there but feel free to do the jump and I will continue answering there. > > Btw, any news from you test and comparison with Boost.Geometry. > > I reply you and jump to boost with your advice. Hope this will help more people. :) Vissarion > > ps. you can send questions whenever you want, I will answer them a.s.a.p. > my zone is UTC+2 > > Thanks for your answer. Best regards. Ruoyun -- Northwest University of China Software Engineering jingry0321(a)gmail.com <jingry0321(a)163.com>

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Re: [boost] [geometry] [gsoc17] boost.geometry
by Vissarion Fisikopoulos 20 Mar '17

20 Mar '17

Hi Aman, thanks for your interest in Boost.Geometry and projects 1, 3 in particular. Do you have particular preference between 1 and 3? I think you should specify in your application. Regarding you idea, indeed that could be an option. Do you expect that would be faster or more accurate than the one proposed in the boost GSoC ideas webpage? How would you compare the two approaches? To be clear, I am not testing you but answering that questions could lead to a stronger application. Regarding application there are two options, either you do the competency test or you send a link of a project of you. Please read https://svn.boost.org/trac/boost/wiki/SoC2017 (and links therein) also for details on how to proceed, that is on how to write your proposal. Best, Vissarion. ps. I copy to the boost list for potential feedback from the community On 20 March 2017 at 13:07, Aman Gupta via Geometry <geometry(a)lists.boost.org > wrote: > Respected sir/ma'am > I, Aman Gupta, want to contribute in Boost.Geometry; mainly in Project 1(Filtering > of compare distance predicates) and Project 3( Nearly antipodal points > distance accuracy improvement) . > I have good knowledge in geometry and want to learn more . > > For the problem given in Project 1, another approach I can suggest is to > get 2 intersections of plane (which would be ellipse) with the help given > points and compute the respective distances using those ellipses. > > I hope to get selected for the project work. > > Thanking You. > AMAN GUPTA > resume: https://drive.google.com/open?id=0B9HCqOWnVVvDcm9PQkYtczFjVmM > > _______________________________________________ > Geometry mailing list > Geometry(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/geometry > >

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[gsoc17] boost.geometry
by Aman Gupta 20 Mar '17

20 Mar '17

Respected sir/ma'am I, Aman Gupta, want to contribute in Boost.Geometry; mainly in Project 1(Filtering of compare distance predicates) and Project 3( Nearly antipodal points distance accuracy improvement) . I have good knowledge in geometry and want to learn more . For the problem given in Project 1, another approach I can suggest is to get 2 intersections of plane (which would be ellipse) with the help given points and compute the respective distances using those ellipses. I hope to get selected for the project work. Thanking You. AMAN GUPTA resume: https://drive.google.com/open?id=0B9HCqOWnVVvDcm9PQkYtczFjVmM

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Formal Review Request: mp11
by Peter Dimov 19 Mar '17

19 Mar '17

I'd like to request a review for mp11, a simple C++11 metaprogramming library. The library implements the approach outlined in my two articles http://pdimov.com/cpp2/simple_cxx11_metaprogramming.html http://pdimov.com/cpp2/simple_cxx11_metaprogramming_2.html and is available at https://github.com/pdimov/mp11/ It supports g++ 4.9 and above, clang 3.6 and above, msvc-12.0, 14.0, 14.1. The library is in Boost format and is intended to be placed in libs/mp11 in a Git clone of Boost. There is documentation in doc/html/mp11.html, it can be viewed locally, or with https://htmlpreview.github.io/?https://github.com/pdimov/mp11/master/doc/ht… Please excuse the lack of .css in that link. Thanks in advance for any interest, comments or suggestions.

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[safe_numerics] review results
by Andrzej Krzemienski 19 Mar '17

19 Mar '17

Hi Everyone, This is to inform you that safe_numerics library by Robert Ramey is *CONDITIONALLY ACCEPTED* to Boost. The list of conditions can be found down below. I would like to congratulate Robert for getting the library into Boost, and thank him for the effort to develop a useful library for the community. I also would like to thank everyone who participated in the review and shared their useful feedback. I recorded five reviews with a yes/no vote: - Paul A. Bristow (yes with conditions) - Steven Watanabe (yes with conditions) - John Maddock (yes with conditions) - Antony Polukhin (yes) - Barrett Adair (yes) And three without a vote: - Vicente J. Botet Escriba - John McFarlane - Peter Dimov We also got some feedback from an individual nicknamed "scatters" at Reddit (https://www.reddit.com/r/cpp/comments/5x1z67/boostsafe_ numerics_formal_review_starts_today/deew1kq/), and from Tomasz Kaminski in private conversation. There was a general consensus that the problem of surprises with C++ ints deserves a solution. Some people observed that there are other ways to approach the same problem, but it was agreed that the approach taken by safe_numerics is sound. The acceptance conditions mostly revolve around documenting micro-decisions made by the library, and fixing bugs. They apply to the reviewed GIT commit 3bcfabe1cafb8ef6edf08d3bd8730a1555b1c45d, but I know Robert is already working on fixing them, and has most of them fixed locally. *Acceptance conditions:* - Comply with Boost formal requirements: 1. index.html in root directory that redirects to doc/. 2. all headers in folder include/boost/numeric/. 3. Macro safe_literal: either remove it or let it follow Boost macro naming conventions: BOOST_NUMERIC_SAFE_LITERAL(). - Automatic promotion policy: either just remove it, or fix it so that: - it can see the range of safe_base in order to allow for slower increase in sizeof(), - it is clear from documentation how the promotion mechanism works. - in particular, what type gets selected for bit-wise operators &, | - The division bug (see below) is fixed. - Decide and document up front how the library addresses each of the following different situations: - overflow upon arithmetical operation, - unexpected promotion to unsigned when comparing signed with unsigned number, - arithmetic operation on unsigned int with negative value versus a signed value (-1 + 1u). - bit-wise operation on negative signed integers (unless they are removed), or that would produce one as the result. - division by zero, - operations upon default-constructed int type with indeterminate value, - conversion from float to int, when float contains non-integral value. - conversion from float to int, when float contains an integral value that would overflow upon native conversion - operator% where one operand is negative (for native ints it is implementaiton-defined) - leftshift by 32 bits (on 32-bit int) - Decide and document what safe's default constructor does. - Document upon which operations safe<> throws exceptions (or, signals arithmetic error at run-time). IOW, document in which cases safe<> never throws exceptions (signals run-time failure) because it is able to say that the operation will always succeed. - Document what happens when you invoke an operation on two instances of safe<> with different policies. - Resolve name conflict with interval, which already exists in namespace boost::numeric::interval. Either use a different namespace or a different name. - Remove anonymous namespaces from the header files. Use namespace detail and inline functions instead. - Improve test cases, so that they also check if numeric values of computations are correct (not only whether an operation throws or not). - Use enable_if (or similar) tricks to constrain the overload resolution for your arithmetical operations, so that they only work for numeric types rather than "any type T". - Fix the division bug: safe<signed, automatic> a {-1}; safe<unsigned, automatic> b {2}; auto c = a / b; // this returns 2147483647 <%28214%29%20748-3647> - Either document that safe<T> only works for scalar types (rather than any T that models concept Integer<T>), or provide alternate implementation of safe_base, as described in https://github.com/robertramey /safe_numerics/issues/44 - Fix linker errors when building a program from two cpp files that include safe_numerics headers. The error is caused by non-inline full specializations of operator<<. - Either entirely remove the support for bit-wise ops on signed types (make it a compiler error), or provide a consistent implementation that detects any UB or surprising results. - `++i` should return by reference; `i--` should return by value. *Other important issues* The following are *not *conditions for library acceptance, but I still recommend addressing them before the initial release. - Concepts: what do you need them for? Any other type except built-in scalars does not work anyway. Do you want to show how close safe<T> resembles T? In this case, they need to be changed. If you want to extend safe<T> to other T's, they need to be fixed: https://github.com/robertramey/safe_numerics/issues/46 <https://github.com/robertramey/safe_numerics/issues/46> - IOStreams interoperability needs fixes: - Move to a separate header, so that it does not affect compilation times when not needed (but provide forward declarations, so that implicit conversions to int do not make IOStreams work with unintended semantics) - Fix other problems as per https://github.com/robertramey /safe_numerics/pull/35 - safe<>'s interface is not documented - Make the library compile with -fno-exceptions: https://github.com/robertramey/safe_numerics/pull/31 <https://github.com/robertramey/safe_numerics/pull/31> - Some people fail to see how this library is better than just using rar ints but compiling with a UB-sanitizer. Address this in the documentation. - Prevent inadvertent ADL by putting safe into a nested namespace boost::numeric::save_types, and then in boost::numeric import: `using boost::numeric::save_types::safe`. This way boost::numeric::safe still works, but inadvertent ADL of everything inside namespace boost::numeric is prevented. - Does it make sense to apply bitwise operations on two different types? If so, document the semantics. - Fix header names and paths in documentation. - Consider adding support for saturation policy upon overflow. - Expression `safe<int>{4} ^ 1` does not compile due to overload resolution ambiguity. - Fix constexpr usages. - If possible, make workarounds in order to make the library work with MSVC. - Document that operations on safe<> do not thorw exceptions other than these thrown by exception policy. *Suggestions* The following summarizes other useful suggestions for improving the library in the future. - operation `safe<signed>{INT_MIN} + safe<unsigned>{UINT_MAX}` throws even though the mathematical result would fit in either signed or unsigned int. This is correct according to what policies describe, but is at the same time surprising, given that comparison `safe<signed>{INT_MIN} < safe<unsigned>{UINT_MAX}` just gives a mathematically correct answer rather than throwing an exception. Document this behavior explicitly. - Remove underflow_error from the policies: it sends the wrong message, that som form of an underflow is checked in this library. - Expose functions like add(), divide() in public interface, they might be useful on their own. - Expose the constructor with check disabled in the public interface, like `safe<int>{1, checks_sisabled{}}` this helps to locally disable the checks where the user knows that certain chain of operaitons will not overflow, and checks are redundant, but the library cannot see it. - Issues reported with bit-shift operators - unary operator- on unsigned type with pormotion policy `automatic` could return a signed type. - Use BOOST_NORETURN wherever possible, e.g. in throwing policies. - Use BOOST_LIKELY, BOOST_UNLIKELY for the policy tests. - Add support for statful policies. - Maybe drop the support for automatic type widening, to simplify the interface and the scope of the library, and let some other library handle the widening, maybe BigInt. Regards, Andrzej Krzemienski

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[release] 1.64.0 Decision on VS2017 version number?
by Rene Rivera 19 Mar '17

19 Mar '17

> (B) The community decides what version number we should be using and the > appropriate PRs are filed and applied and tested for all the repos > involved. Which means: > 1. The community has until 12:00 CDT US March 18 to decide on what the vc > version number and tag should be. > It's now past that time.. Is there consensus on what version number Boost should use for identifying the VS2017 toolset? If there is.. People need to start submitting PRs for the changes ASAP.. > 2. The community must post PRs for the places where we reference VS2017 > version numbers to the new number. Those are at least: > <https://github.com/boostorg/config> > <https://github.com/boostorg/build> > <https://github.com/boostorg/boost> > <https://github.com/boostorg/website> > People have until 17:00 CDT Monday March 20 to submit those PRs. Thanks. -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net -- rrivera/acm.org (msn) - grafikrobot/aim,yahoo,skype,efnet,gmail

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Project R-tree Serialisation
by Kabir Sahni 19 Mar '17

19 Mar '17

Hi everyone, I am midway through my competency test.I wanted to know whether working of serialisatjon for n dimensional point is the only thing to be demonstrated in main.cpp file. Thanks

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Re: [boost] Advanced find() for associative containers
by Bjorn Reese 19 Mar '17

19 Mar '17

On 03/16/2017 06:18 PM, Boris Rasin via Boost wrote: > 2. Where exactly should it fit in the boost? The most appropriate place would be Boost.Algorithm, so that is Marshall's domain. > Public interface consists of a single free function template: > > template <typename C> > auto find(C& c, const typename C::key_type& key); Your find() function deviates on several accounts from std::find() so it should probably be renamed, e.g. to find_key. Can you elaborate on why you have a specialization that uses lower_bound()? What is the minimal C++ version required? Looks like C++14 from the auto return type.

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Visual Studio multi-toolset support (was: [release] 1.64.0 please test master snapshot)
by Mateusz Loskot 18 Mar '17

18 Mar '17

On 18 March 2017 at 14:27, Peter Dimov via Boost <boost(a)lists.boost.org> wrote: > Mateusz Loskot wrote: > >>> No, VS 2015 can build with v140, v120, v110, v100, v90, as long as you >>> have the earlier versions installed. (VS 2017 can build with v140 even if >>> you don't have VS 2015 installed.) >> >> >> I understood VS2017 is first version with multi-toolset support. > > > The first version with multi-toolset support is VS 2012, although the only > two toolsets supported are v110 and v110_xp, which share the same version. > VS 2013 supports v90 - v120. VS 2015 supports v90 - v140. I always used the 'default' toolset of particular VS version, hence fostered ignorance about that multi-toolset support. > Wait, no, VS 2010 supports v100 and v90. :-) :-) Thank you for the enlightenment. Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

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[release] 1.64.0 please test master snapshot..
by Rene Rivera 18 Mar '17

18 Mar '17

After help from various sources to get the VS2017 building working the latest master snapshot should at least try and build with VS2017. Assuming nothing horrible shows up today we will release the first beta tonight. Hence, please smoke test the latest master snapshot found at: <https://dl.bintray.com/boostorg/master/> -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net -- rrivera/acm.org (msn) - grafikrobot/aim,yahoo,skype,efnet,gmail

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[review process] candidate library maintenance disturbs the review
by Andrzej Krzemienski 17 Mar '17

17 Mar '17

Hi Everyone, In the context of the discussion around review process improvements, I wanted to report another problem that I do not know how to solve. But maybe you do. Extending the review period by allowing the review on the BLIncubator looks like a good idea, but it also comes with a problem. The review applies to a particular commit (if we use GItHub terms), that is, to the state of the library on a particular branch at a particular point in time. If I see a review on BLIncubator (not that I see many of them), how do I know what commit it applies to and if it is even irrelevant. It might be partially relevant, but it puts me in an uncomfortable situation, that I will be investing my time in something that is likely to turn out to be useless. Also, I might consider submitting a review into BLIncubator, but what chances I have that it will be considered in the formal review, given that the formal review may work on a different commit: possibly on a quite different library by now? Regards, &rzej;

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[gsoc2017] Apply for static_map
by Dobra Gábor 17 Mar '17

17 Mar '17

Hi all, I'm planning to participate to Boost GSOC, about static_map proposal. I'm Gábor Dobra, third-year student of Budapest University of Technology, Hungary, software engineering BSc. I've contributed to a few open-source libraries, I'm working as a C++ developer at a finance company. I'd like to contact a mentor of static_map (possibly Niall Douglas?) about my competency test. Thanks, Gábor

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[gsoc17] Apply for the ticket to Project static_map
by John Lee 17 Mar '17

17 Mar '17

Hello all, I’m John Lee from China, learning at BUPT, Beijing. I love coding, especially in C++. I am willing to contribute to Boost Community and applying for developing cool things with the community in GSOC 2017. As described in the requirement section, I suppose that I am well prepared :-) - I spent my 2016 in learning and practicing my Modern C++ (up to C++ 14, not 17 so far due to the poor support of compilers...) on both coursework and real products. - I’ve been contributing to some projects in C++ open-source communities in China, such as http://purecpp.org/ . - I’ve developed an open-source Header-Only, Strong-Typed, Compile-time Object Relation Mapping (ORM) in Modern C++, available at https://github.com/BOT-Man-JL/ORM-Lite (over-1000-line non-coursework library, first committed 5 months ago and iterated over time) (surprisingly meeting the requirements) lol - I also developed an toy Graphics Library on both Windows and X Window, but no longer maintain it. :-( It’s available at https://github.com/BOT-Man-JL/EggAche-GL/tree/x11 I’m a bit confused on some items on the main page of Boost GSOC 2017, and I will appreciate it very much if anyone could answer these questions: - I am very interested in generic/meta programming and willing to apply for Project static map. My question is should I still post a solution of the competency test of this project? - There are 3 suggested proposals on the main page. Are they the project we should do in GSOC 2017, or we can do other projects if applying for the ticket to a certain project of three? - How could I find a mentor if I have the ticket? Posting something like this or contact one on the email list? It’s my first year to attending GSOC, and the first time to work with the community internationally. Thanks for your help. ;-) Best Regards, John Lee Feel free to contact me :-) https://BOT-Man-JL.github.io/ -- View this message in context: http://boost.2283326.n4.nabble.com/gsoc17-Apply-for-the-ticket-to-Project-s… Sent from the Boost - Dev mailing list archive at Nabble.com.

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[release} 1.64.0 additional merge required
by Oliver Kowalke 17 Mar '17

17 Mar '17

Unforutnately I got an andditional pull reqeuest taht fixes an segmentation fault on ARM - https://github.com/boostorg/context/pull/47/files Do I get permission to merge to master? ty, Oliver

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Feedback request for Invariant Library idea
by Attila Szenczi 17 Mar '17

17 Mar '17

Hello! I am asking for some feedback if my library idea is good enough to be part of boost if it will meet the requirements. When i started this small utility lib i had 3 goals in my mind: - Write cleaner interfaces - Be safer with pre and post conditions - Eliminate redundant checks whenever possible at compile time The goal is to solve this problem for primitive types. *Example "bad" code:* void set_red_color(int red) { //Why the precondition is not visible on the interface? assert(red >= 0 && red <= 255); } *Example "good" code:* void set_red_color(bounded_i<0, 255> red) {} *Example "bad" code:* void foo(int bar) { assert(bar >= 0); } *Example "good" code:* void foo(positive_i bar) {} or void foo(lower_bounded_i<0> bar) {} Basically the main idea is to have an invariant_host class, which is customizable via policies: -* Invariant policy:* Define a static check() function which ensure the invariant. - *Fail policy: *Define a static trigger_assert function which is called when the invariant policy::check is failed. If the fail policy is disabled (constexpr bool flag), then the checks doesn't happen. Defining your own class looks like this: template<typename PrimitiveType> using my_type = invariant_host<PrimitiveType, default_fail, my_invariant<PrimitiveType>>; *Optimizations:* bounded_i<0, 50> bi (30); //trigger check bounded_i<0, 100> bi2(bi); //range check happens at compile time bounded_i<51, 52> bi3(bi1); //should be compile error bounded_i<0, 50> bi4(integral_constant<int, 10>); //check should happen compile time Things like operator+,-,*,/, bitwise operators etc can trigger checks. Tho alot of times it can be optimized away. For example adding 2 positive number should stay positive. C++20(?) contracts will be great, it will allow us to write cleaner interfaces, but i don't feel like it solve every issue i would like to solve. Do you think it would be a good addition to boost? I appreciate any feedback! Thank you very much! Attila Szenczi

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Advanced find() for associative containers
by Boris Rasin 16 Mar '17

16 Mar '17

I've written an improved version of find() for associative containers (in the form of a free function), and I need your help answering these two questions: 1. Will it be a useful addition to boost? 2. Where exactly should it fit in the boost? Public interface consists of a single free function template: template <typename C> auto find(C& c, const typename C::key_type& key); If element is found, return value evaluates to true and contains iterator to found element. If element is not found, return value evaluates to false and contains hint iterator for insert/emplace. Allowing one to do this: if (auto i = find(container, key)) { i->value_member(); container.erase(i); } And this: if (auto i = !find(container, key)) { container.insert(i, expensive_value_construction()); } The code is here: https://github.com/Boris-Rasin/find I've tested it with the following containers: std::map std::multimap std::unordered_map std::set std::multiset std::unordered_set boost::container::map boost::container::set boost::container::flat_map boost::container::flat_set boost::multi_index::ordered_unique boost::multi_index::ordered_non_unique boost::multi_index::hashed_unique boost::multi_index::hashed_non_unique boost::multi_index::ranked_unique boost::multi_index::ranked_non_unique Thanks for your comments and help.

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Fwd: Google Summer of Code
by Georgios Samaras 16 Mar '17

16 Mar '17

Dear all, my name is Georgios Samaras, a Masters student from NKUA, Greece. I am interested in the distance predicates <https://svn.boost.org/trac/boost/wiki/SoC2017#PROJECT1.Filteringofcomparedi….> of Boost Geometry, but I am flexible. I am attaching my CV in case anyone is interested. Here is my GitHub <https://github.com/gsamaras>, which demonstrates that I have experience in C++. Good luck with all your projects, Georgios Samaras

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Issue Tracker for Boost organization?
by Olaf van der Spek 16 Mar '17

16 Mar '17

Hi, Do we have an issue tracker for Boost 'organization' itself? I know we've got mailing lists and the steering committee but it's hard to track issues like that. -- Olaf

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[gsoc17] boost.uBLAS
by Leandro Raffo 16 Mar '17

16 Mar '17

Hi My name is Leandro, I'm a CS student at the University of Buenos Aires, and I'm interested in the uBLAS projects. I've already done the competency test and I was wondering who I should talk/send it to and who could be a possible mentor. Thanks

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Libc++ failures on linux
by Tom Kent 16 Mar '17

16 Mar '17

So I tried to add my first linux regression runner using libc++ with clang, and I'm seeing the following error saying it can't find <cstddef>: http://www.boost.org/development/tests/develop/developer/output/teeks99-02-… "clang++-3.9" -c -x c++ -Wno-c99-extensions -std=c++1z -stdlib=libc++ -O0 -g -fno-inline -Wall -g -m64 -DBOOST_ALL_NO_LIB=1 -DBOOST_CHRONO_STATIC_LINK=1 -DBOOST_CHRONO_THREAD_DISABLED -DBOOST_SYSTEM_NO_DEPRECATED -DBOOST_SYSTEM_STATIC_LINK=1 -DBOOST_TEST_NO_AUTO_LINK=1 -DBOOST_TIMER_STATIC_LINK=1 -I".." -o "/var/boost/run/results/boost/bin.v2/libs/accumulators/test/count.test/clang-linux-3.9~c++1z~lc/debug/link-static/count.o" "../libs/accumulators/test/count.cpp" In file included from ../libs/accumulators/test/count.cpp:6: In file included from ../boost/test/unit_test.hpp:18: In file included from ../boost/test/test_tools.hpp:17: In file included from ../boost/config.hpp:44: ../boost/config/select_stdlib_config.hpp:18:12: fatal error: 'cstddef' file not found # include <cstddef> ^ 1 error generated. However when I try to compile the following program on the same docker image (teeks99/boost-build:clang-3.9) // basic.cpp #include <cstddef> int main(int argc, char* argv[]) { size_t three = 3; return three; } with: $ clang++-3.9 -stdlib=libc++ -std=c++1z basic.cpp It works fine $ ./a.out $ echo $? 3 I can build this sample file fine with the whole command line shown above, so it doesn't seem to be one of the other options conflicting. Any thoughts on why boost code wouldn't be able to find this but some basic stuff would? One relevant detail, I'm building with clang 3.9, however the libc++ version that I'm using (ubuntu default) is the one that shipped with clang 3.7. That shouldn't preclude including a file! I also found a couple old threads with the same error, but never any good resolution. http://lists.boost.org/boost-testing/2012/07/7075.php http://lists.boost.org/boost-users/2012/11/76659.php Tom

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Re: [boost] [release] 1.64.0 closed for Beta
by Rene Rivera 15 Mar '17

15 Mar '17

On Tue, Mar 14, 2017 at 9:50 PM, Tom Kent <lists(a)teeks99.com> wrote: > > > On Tue, Mar 14, 2017 at 9:23 PM, Rene Rivera <grafikrobot(a)gmail.com> > wrote: > >> On Tue, Mar 14, 2017 at 6:09 PM, Tom Kent via Boost < >> boost(a)lists.boost.org> wrote: >> >>> >>> I tried building the latest snapshot from bintray, but it doesn't find >>> any >>> compiler when running `bootstrap.bat`. However running `boootstrap.bat >>> vc14.0` works, so something in bootstrap's lookup logic? >>> >> >> Which VSs did you have installed when you tried that? >> > > Everything from VS 2005 to VS2017. > In my Win10 setup I have VS 11, 12, 14, and 14.10.. And it seems to work for me. -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net -- rrivera/acm.org (msn) - grafikrobot/aim,yahoo,skype,efnet,gmail

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