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[release] Boost 1.72.0 has been released
by Marshall Clow 11 Dec '19

11 Dec '19

Release 1.72.0 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 new libraries and numerous enhancements and bug fixes for existing libraries. For details, including download links, see < http://www.boost.org/users/news/version_1.72.0> You can also download directly from: < https://dl.bintray.com/boostorg/release/1.72.0/> To install this release on your system, see < http://www.boost.org/doc/libs/release/more/getting_started/index.html> Thanks to everyone who participated in this release. Thanks, -- The Boost Release Team Marshall Clow, Michael Caisse

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[release] Boost 1.72.0 Release Candidate 2
by Marshall Clow 10 Dec '19

10 Dec '19

The second release candidates for the 1.72.0 release are now available at: <https://dl.bintray.com/boostorg/release/1.72.0/source/> The SHA256 checksums are as follows: 247a91dd7e4d9dd3c4b954b532fbc167ba62dc15ab834e5ad893d7c3f9eb5f0f ./boost_1_72_0_rc2.7z 59c9b274bc451cf91a9ba1dd2c7fdcaf5d60b1b3aa83f2c9fa143417cc660722 ./boost_1_72_0_rc2.tar.bz2 c66e88d5786f2ca4dbebb14e06b566fb642a1a6947ad8cc9091f9f445134143f ./boost_1_72_0_rc2.tar.gz 8c20440aaba21dd963c0f7149517445f50c62ce4eb689df2b5544cc89e6e621e ./boost_1_72_0_rc2.zip Changes since RC1: * A change to Boost.Proto that would cause compilation failures on the latest MS compiler. 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. -- The Boost Release Managers

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Interest in a C++20 Unit Testing Framework?
by Krzysztof Jusiak 10 Dec '19

10 Dec '19

Hi, I was wondering whether there is any interest in exploring a C++20 single header/single module, macro-free Unit Testing Framework with no dependencies? Github: https://github.com/boost-experimental/ut Additional links: - Try it online: https://godbolt.org/z/uVDxkW - Benchmarks: https://github.com/boost-experimental/ut#benchmarks - How it works?: https://github.com/boost-experimental/ut#how-it-works Thanks, Kris

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Re: [boost] [STLInterfaces] only three operations?
by Zach Laine 09 Dec '19

09 Dec '19

On Mon, Dec 9, 2019 at 12:55 PM Andrzej Krzemienski <akrzemi1(a)gmail.com> wrote: > > > pon., 9 gru 2019 o 17:32 Zach Laine <whatwasthataddress(a)gmail.com> > napisał(a): > >> >> >> >>> Same with the iterator in the flight map: >>> >>> >>>> https://github.com/tzlaine/flat_map/blob/master/implementation/flat_map#L266 >>>> >>> >>> According to C++17 requirements this shouldn't have been a >>> random_access_iterator. >>> >>> Also, std::ranges::sort() will not work with it. But this is not >>> directly related to `iterator_interface` >>> >> >> I don't know why you think that. ranges::sort() is designed to work with >> std::random_access_iterator, which is designed explicitly to support proxy >> iterators. Casey and Eric have assured me that this "just works". Do you >> know of a reason why it does not? If so, you've spotted a defect, and we >> should file an LWG issue immediately. >> > > Not sure if it is a defect. An iterator that returns a proxy as > ::reference can be a valid random_access_iterator. However, > std::ranges::sort(), apart from a random_access_iterator requirement, has > one more requirement: sortable<>: (http://eel.is/c++draft/sort) which > boils down to indirectly_writable ( > http://eel.is/c++draft/iterator.concept.writable) This last concepts > puts severe restrictions on proxy types. For instance you should be able to > assign to them when they are const-qualified. So a type like std::tuple<> > of references will not work. But you will be able to design a sufficiently > bizarre proxy type that will work with std::ranges::sort(), So in a way it > will work with *some* reference proxies. > Ok, I just realized this somehow drifted off-list. Re-adding the list... This is the definition of indirectly_writable: template<class Out, class T> concept indirectly_writable = requires(Out&& o, T&& t) { *o = std::forward<T>(t); // not required to be equality-preserving *std::forward<Out>(o) = std::forward<T>(t); // not required to be equality-preserving const_cast<const iter_reference_t<Out>&&>(*o) = std::forward<T>(t); // not required to be equality-preserving const_cast<const iter_reference_t<Out>&&>(*std::forward<Out>(o)) = std::forward<T>(t); // not required to be equality-preserving }; All you need to make this work is a reference type for which all those are well-formed. If you pick std::tuple, it all just works. If you pick std::pair, only the first two expressions in the requires expression work. You can easily define UDTs for which this concept works too, of course. Zach

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Interest in an audio filtering / algorithm Library?
by Vinnie Falco 09 Dec '19

09 Dec '19

Is there any interest in having a new libraries for Boost that is focused on the audio domain (but with portions applicable generically)? I'm thinking about a library that does stuff like: * finite impulse response filtering * infinite impulse response filtering * time stretching, resampling * audio synthesis * audio algorithms * mixing * plenty of ready-to-run filters: - low pass, high pass, band pass - echo, reverb, flanger, phaser and the like This is a pure math library, no actual audio. To get an idea of the algorithms and use-cases check out my DSPFiltersDemo program (press Download Now): <https://github.com/vinniefalco/DSPFiltersDemo> Please note, my library is not what is being proposed, this would be a new library from a domain expert (not me). Thanks

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[review][fixed_string] review period finishes today Dec 8
by Joaquin M López Muñoz 08 Dec '19

08 Dec '19

The review period of candidate Boost.FixedString finishes today, Dec 8. Many interesting subjects have been discussed about during these two weeks and I have quite a bit of material to digest before publishing the final review result plus further action points. I expect to be able to do so during the following week. Thank you to all the people who have contributed their reviews and comments and to Krystian and Vinnie for submitting their work and enduring the famously severe review ordeal. Best regards, Joaquín M López Muñoz Review manager for candidate Boost.FixedString

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Re: [boost] Boost GIL
by Siddhartha Sen 08 Dec '19

08 Dec '19

Thanks a lot for forwarding my email to the boost GIL list. I will check it out. What I meant by conversion, however was primarily converting an image to negative and greyscale. As you may already know, the two pf them are pretty similar and OpenMP has shown how incredibly fast the process can be using more threads. I just feel GIL would benefit a lot from using parallel programming. On Sun, 8 Dec, 2019, 5:30 PM , <boost-request(a)lists.boost.org> wrote: > Send Boost mailing list submissions to > boost(a)lists.boost.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.boost.org/mailman/listinfo.cgi/boost > or, via email, send a message with subject or body 'help' to > boost-request(a)lists.boost.org > > You can reach the person managing the list at > boost-owner(a)lists.boost.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Boost digest..." > > > The boost archives may be found at: http://lists.boost.org/Archives/boost/ > > > Today's Topics: > > 1. Re: [fixed_string][review] Review of fixed_string (Rob Stewart) > 2. Re: Extending GIL (Mateusz Loskot) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Sat, 07 Dec 2019 13:23:51 -0500 > From: Rob Stewart <rstewart(a)ptd.net> > To: boost(a)lists.boost.org,Phil Endecott via Boost > <boost(a)lists.boost.org> > Cc: Phil Endecott <spam_from_boost_dev(a)chezphil.org> > Subject: Re: [boost] [fixed_string][review] Review of fixed_string > Message-ID: <142EED34-B802-4381-9FF9-C9FE999BA0F9(a)ptd.net> > Content-Type: text/plain; charset=utf-8 > > > > On December 5, 2019 9:35:35 AM EST, Phil Endecott via Boost < > boost(a)lists.boost.org> wrote: > > Peter Dimov wrote: > > > - a function that checks whether the remaining capacity is at least > > n should > > > be added. I suggest the name > > > > > > bool can_fit( std::size_t n ) const noexcept; > > > > > > although my previous choice of "has_capacity_for" has merit too. > > I suggest the simpler "fits". > > > Make this a free function template and you can use it with other > > containers: > > > > template <typename CONTAINER> > > bool can_fit( const CONTAINER& C, typename CONTAINER::size_type n ) > > noexcept > > { > > return C.capacity() - C.size() >= n; > > } > > That's a nice idea, especially with the name "fits". :) However, if you > reverse the parameters, "fits_in" would be a better name as it indicates > the argument order. > -- > Rob > > (Sent from my portable computation device.) > > > ------------------------------ > > Message: 2 > Date: Sun, 8 Dec 2019 01:25:04 +0100 > From: Mateusz Loskot <mateusz(a)loskot.net> > To: boost(a)lists.boost.org > Subject: Re: [boost] Extending GIL > Message-ID: > < > CABUeae_cupOMOhCNvvHaeruX2ksycHhVKkHJbtCSCLr-kW-XkA(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > On Sat, 7 Dec 2019 at 01:12, Siddhartha Sen via Boost > <boost(a)lists.boost.org> wrote: > > > > Having looked up this repository : > https://github.com/boost-gil/gil_threaded, > > I feel the idea was the same, but a lot of improvement can be made. > > Good, sounds like you may have a plan in mind > > > Also, there was no provision for image conversion, which I feel > > Please, you need to be more specific here. > What kind of conversion do you mean: color, channel/pixel type, format,...? > > p.s. I forwarded your post to the GIL mailing list > https://lists.boost.org/boost-gil/2019/12/0362.php > > Best regards, > -- > Mateusz Loskot, http://mateusz.loskot.net > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Unsubscribe & other changes: > http://lists.boost.org/mailman/listinfo.cgi/boost > > > ------------------------------ > > End of Boost Digest, Vol 6271, Issue 1 > ************************************** >

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[release] 1.72.0 post-beta merges
by Michael Caisse 08 Dec '19

08 Dec '19

The master branch is is now open for post-beta merges, but only as described in the Post-Beta Merge Policy. See <https://github.com/boostorg/boost/wiki/Releases%3A-Beta-Merge-Policy>

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[range] Trying to extend boost::range::combine to std::tuples
by Andres Llopis 08 Dec '19

08 Dec '19

Hi everyone, I am trying to make my own version of combine so that it works also with std::tuples. Someone on slack suggested that the zip iterator should be able to handle it properly. My attempt however fails when trying to use the metafunction tuple_of_references::type for the std::tuple of iterators. This is what I tried (https://godbolt.org/z/Ymjtvn) (Please excuse any style problems, this is my first post) namespace myns { using boost::iterators::zip_iterator; using boost::iterator_range; template<typename IterTuple> class combined_range : public iterator_range<zip_iterator<IterTuple> > { typedef iterator_range<zip_iterator<IterTuple> > base; public: combined_range(IterTuple first, IterTuple last) : base(first, last) { } }; template<typename... Ranges> auto combine(Ranges&&... rngs) -> combined_range<decltype(std::make_tuple(std::begin(rngs)...))> { return combined_range<decltype(std::make_tuple(std::begin(rngs)...))>( std::make_tuple(std::begin(rngs)...), std::make_tuple(std::end(rngs)...)); } }

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Extending GIL
by Siddhartha Sen 08 Dec '19

08 Dec '19

Having looked up this repository : https://github.com/boost-gil/gil_threaded, I feel the idea was the same, but a lot of improvement can be made. For example, by using OpenMP, I feel the computational performance can be massively improved and that too, not requiring any extremely sophisticated hardware. Also, there was no provision for image conversion, which I feel is a very good extension. What do you all think?

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