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Regression test relying on undefined compiler behavior (c++11)
by Chris Cooper 24 Apr '14

24 Apr '14

libs/utility/numeric_traits_test.cpp generates values complement_traits<Number>::min using a clever recursive template, but that template relies on left-shifting a negative value, and according to the C++11 standard that’s a no-no (“the behavior is undefined”) which means it’s not a constant expression, which means it can’t be calculated at compile time, which means the BOOST_STATIC_ASSERT in line 332 won’t compile, saying “static_assert expression is not an integral constant expression” (I’m using clang++). See discussion here: http://stackoverflow.com/questions/23250651/strange-behavior-with-c-recursi… In addition, it looks like the existing code also relies on the compiler filling the vacated bits with one’s, which I don’t think is what actually happens. The solution I’ve come up with, is to do the shifting using unsigned values, thus avoiding the compiler no-no, and then putting the result back in the specified type. In other words, replacing line 73 BOOST_STATIC_CONSTANT(Number, min = Number(Number(prev::min) << CHAR_BIT)); With BOOST_STATIC_CONSTANT(Number, min = boost::detail::is_signed<Number>::value ? (Number)(((unsigned long)(prev::min) << 8) | 0x00FF) : Number(Number(prev::min) << CHAR_BIT) ); I’m using constants ‘8’ and ‘0x00FF’ rather than CHAR_BIT since the code would get really ugly if CHAR_BIT != 8. Thoughts? Thanks, Chris

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Fwd: [Boost-users] [typeindex v3.0] Peer review begins Mon 21st ends Wed 30th
by Antony Polukhin 24 Apr '14

24 Apr '14

2014-04-23 17:33 GMT+04:00 Paul A. Bristow <pbristow(a)hetp.u-net.com>: <...> > > 2. What is your evaluation of the implementation? > OK. > > Though I'm not enthusiastic about the name of namespace boost::typeind:: > but I > don't have any much better ideas. Perhaps someone else has? > > Nor am I clear that this namespace bti helps the reader. > > "Through all the examples, we'll assume that the following namespace alias > is in > effect: > > namespace bti = boost::typeind; > > " > > IMO, the frequency of use of the namespace bti is probably so low that > spelling > it out is clearer, for example: > > boost::typeind::type_id<T>().pretty_name() // human readable > Agreed: boost::typeindex would be more user friendly. It suggests to the reader which library to look for. Other notes will be also addressed. Thanks for the review! -- Best regards, Antony Polukhin

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Re: [boost] Application need a Review Manager. Anyone is interested?
by Brian Wood 24 Apr '14

24 Apr '14

Niall Douglas: > Yeah, I'd definitely redouble my advice to break up Application into > smaller, standalone, reusable bits. The problem with any overarching > framework is that it's a vision (i.e. your vision), and other > people's visions never peer review well, whether in academia, here in > Boost, or anywhere. Also, unless you're a member of Boost's steering > committee and/or on the C++ standards committee, any vision you > propose probably won't be given any benefit of the doubt > unfortunately. Some might think: If you can't beat 'em, join 'em. My motto though is: If you can't join 'em, beat 'em. -- Brian Ebenezer Enterprises - "A fool with a plan can beat a genius with no plan." T. Boone Pickens http://webEbenezer.net

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Can't compile valarray.cpp - any ideas why?
by Chris Cooper 23 Apr '14

23 Apr '14

On my Mac (OSX 10.9.2, running clang++ "Apple LLVM version 5.1 (clang-503.0.38) (based on LLVM 3.4svn)”), I can’t get the libs/accumulators/test/valarray.cpp regression test to compile. The error it gives is of course lengthy, but goes something like this: In file included from valarray.cpp:18: ../../../boost/accumulators/statistics/weighted_mean.hpp:73:13: error: no matching constructor for initialization of 'result_type' (aka 'valarray<typename divides<left_value_type, const double>::result_type>') : mean( ../../../boost/accumulators/framework/depends_on.hpp:319:17: note: in instantiation of function template specialization 'boost::accumulators::impl::immediate_weighted_mean_impl<SNIP>' requested here : Accumulator(args) ../../../boost/accumulators/framework/depends_on.hpp:252:29: note: in instantiation of function template specialization 'boost::accumulators::detail::accumulator_wrapper<SNIP>' requested here return type(args, next_build_acc_list::call(args, fusion::next(f), l)); ../../../boost/accumulators/framework/depends_on.hpp:252:56: note: in instantiation of function template specialization 'boost::accumulators::detail::build_acc_list<SNIP>' requested here return type(args, next_build_acc_list::call(args, fusion::next(f), l)); ../../../boost/accumulators/framework/depends_on.hpp:271:51: note: in instantiation of function template specialization 'boost::accumulators::detail::build_acc_list<SNIP>' requested here return meta::make_acc_list<Sequence>::call(args, fusion::begin(seq), fusion::end(seq)); ../../../boost/accumulators/framework/accumulator_set.hpp:159:21: note: in instantiation of function template specialization 'boost::accumulators::detail::make_acc_list<SNIP>' requested here detail::make_acc_list( valarray.cpp:150:78: note: in instantiation of function template specialization 'boost::accumulators::accumulator_set<SNIP>' requested here /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/c++/v1/valarray:806:5: note: candidate constructor not viable: no known conversion from 'typename result<SNIP>' to 'const std::__1::valarray<double>' for 1st argument valarray(const valarray& __v); That last little bit makes it look like “result_type mean” is of type valarray<double> and boost is trying to pass a valarray<int> into its copy constructor and not succeeding. I’ve narrowed down the offending code (in valarray.cpp) and this is the code that won’t compile: typedef std::valarray<int> sample_t; typedef boost::accumulators::stats<boost::accumulators::tag::weighted_mean(boost::accumulators::immediate)> mystats; boost::accumulators::accumulator_set<sample_t, mystats, int> acc2; Which is basically the same as: sample_t s; typedef boost::numeric::functional::multiplies<sample_t, int>::result_type weighted_sample; typedef boost::numeric::functional::fdiv<weighted_sample, int>::result_type result_type; result_type mean(s); which also doesn’t compile and gives a pretty-much-identical error message. I’m completely unfamiliar with the boost accumulators code, any suggestions on why this is failing, and what I can do to patch valarray.cpp so the regression test will compile? Thanks, Chris

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[Git] Are past releases tagged somehow?
by John Maddock 23 Apr '14

23 Apr '14

Is there a way to identify and checkout past releases from Git? I couldn't find anything on the Wiki? Thanks, John.

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[container] pull request for fixing propagate_on_container_move_assignment (add ::value)
by Ben Pope 23 Apr '14

23 Apr '14

I noticed that this was only just changed, but hey ho. https://github.com/boostorg/container/pull/1 Ben

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[GSoC] A C++11 enabled TMP library (accepted)
by Louis Dionne 23 Apr '14

23 Apr '14

Dear community, I am pleased to announce that my proposal named "A C++11 template metaprogramming library"[1] was accepted for GSoC 2014. I want to thank the community for putting trust in the proposal, and I am committed to do everything I can to make this project succeed. As explained in my proposal, the goal of the project is to build a high quality template metaprogramming library using modern techniques to achieve both higher expressiveness and lower compilation times. Since the ultimate goal is to make such a library part of the Boost distribution, I will try to involve the community and maintain a tight feedback loop. With your support, I am confident that we can achieve a lot in the direction of better template metaprogramming. This is also a good time to mention (advertise?) that I will be presenting the project at the upcoming C++Now conference. :-) I am knee-deep in my finals right now, but updates should come shortly. Stay tuned! Louis Dionne [1]: http://goo.gl/ZlYeFi

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[assign] [tokenizer] Please pull two trivial patches
by Gregor Jasny 23 Apr '14

23 Apr '14

Hello, since four months two trivial patches to replace a plain throw with BOOST_THROW_EXCEPTION sit in the trac and github (as pull requests). Could anyone please review and submit them? I'd like to see them in the next release or the one after. #9504 - https://github.com/boostorg/assign/pull/1 #9505 - https://github.com/boostorg/tokenizer/pull/1 Thanks, Gregor

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[utility] Pull request: Use an unsigned type as an intermediate result instead of left shifting a negative integral constant
by Ben Pope 22 Apr '14

22 Apr '14

https://github.com/boostorg/utility/pull/4 No maintainer listed in maintainers.txt so cross posting this one. Ben

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[gsoc2014] This year's students announced
by Niall Douglas 22 Apr '14

22 Apr '14

Dear Boost, We are pleased to announce that the following eight students will be this year's Google Summer of Code for 2014: 1. Anton Bikineev Mentor: Christopher Kormanyos Topic:Boost.Math Generalized Hypergeometric Functions 2. Ian Forbes Mentor: Tim Blechmann Topic: Boost.Thread Scheduled Executors 3. Louis Dionne Mentor: Joel Falcou Topic: A C++11 template metaprogramming library 4. Mark Lingle Mentor: David Bellot Topic: Boost.uBlas: Optimization via Smart Templating and a Tree Optimizer class 5. Roshan Mentor: Kyle Lutz Topic: Expand and Improve Boost.Compute 6. Saksham Maheshwari Mentor: Stefan Seefeld Topic: Boost.XML - A Standard XML Library 7. Thaler Benedek Mentor: Vicente J. Botet Escriba Topic: Boost.Pipeline 8. Vinícius dos Santos Oliveira Mentor: Bjorn Reese Topic: HTTP server on Boost At US$5,000 funding per student, this represents an investment of US$40,000 into Boost by Google this year, for which we are extremely grateful. Our thanks to everyone in Google who makes this happen every year. With so few slots available from Google some very good candidates and proposals could not be selected, so if you were not selected this year, better luck next year (remember to come early!). Congratulations to the students who did make it, and our collective thanks go to the primary mentors above for taking the time this summer, as well to the secondary mentors not listed above as well as everyone who helped out with the proposal review and the ranking and voting this year. Niall & Boris --- Boost C++ Libraries Google Summer of Code 2014 admin https://svn.boost.org/trac/boost/wiki/SoC2014

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