April 2020 - Boost - lists.preview.boost.org

Adding my sorting algorithm, ska_sort, to boost, attempt 2
by Malte Skarupke 24 Nov '21

24 Nov '21

Hi everyone, I started a discussion about this in October, but at the time the maintainer of the sort library was busy, then I was busy, so now it's January... I wrote a generalized version of radix sort a couple years ago and gave a talk about it here: https://www.youtube.com/watch?v=zqs87a_7zxw I would like to get a new version of that sorting algorithm into boost. It's faster than what I showed several years ago. It's also even more general and has a new interface that should be easier to extend. I uploaded the code here: https://github.com/skarupke/sort/tree/master The documentation is also already updated with new benchmark results. Let me know what's required to get this into boost. Would you like this in the form of a pull request? One of the big things that probably needs review is the interface, since radix sorting works differently than comparison based sorting. For most normal uses you just need to provide a sort key, but more complicated cases can get more complicated. I tried very hard to make everything easy, but I'd also be curious if others can come up with better ways of doing the interface. Thanks, Malte -- Malte Skarupke malteskarupke(a)fastmail.fm

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Optional library
by anshu khare 27 May '20

27 May '20

Hi mentors I was going through the optional library of boost. I was facing some problem in understanding the code base. In lines from 94 to 97 in optional.hpp, the code is as follows: struct in_place_init_if_t { Struct init_tag{}; explicit in_place_init_if_t(init_tag) {} //not able to understand this line }; I understand that we are creating a structure in_place_init_if_t and inside that we are creating another structure init_tag and then we are calling the constructor of in_place_init_if_t. But I am not able to understand that what does it the constructor do when we pass init_tag as an argument to it. Is it same as we are creating a structure Car and then creating another structure wheels inside it and passing wheels as an argument to the constructor of car as follows: struct car { Struct wheels{}; explicit car(wheels) {} //not able to understand this line }; Could you please tell what is the significance of passing wheels as an argument in this counter example?

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[Filesystem] Directory entry caching
by Chris Glover 13 May '20

13 May '20

Hi All, Whatever happened to the work in this branch https://github.com/boostorg/filesystem/tree/feature/directory-entry-cache-r… that looks to implement this paper? http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0317r1.html Wondering if it's planned, dead, or looking for someone to do the work. I ran into the problem today by chance. -- chris

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[Range] Transform in place
by Frederick Gotham 11 May '20

11 May '20

Earlier today I wrote the following two lines of code: auto const my_range = v | boost::adaptors::sliced(1,15) | boost::adaptors::strided(2); boost::range::transform( my_range, my_range.begin(), std::bit_not<uint8_t>() ); However it would have been nice as a one-liner: boost::range::transform( v | boost::adaptors::sliced(1,15) | boost::adaptors::strided(2), std::bit_not<uint8_t>() ); Why isn't there a form of "range::transform" that can transform in place (and therefore takes exactly two arguments)?

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Embarcadero C++ and Boost libraries
by Edward Diener 01 May '20

01 May '20

Embarcardero ( formerly Codegear, formerly Borland ) has had for about five years C++ compilers based on clang, along with the venerable bcc32, which is the Borland compiler of old through a number of transformations. The clang-based Windows compilers are bcc32c/bcc32x for 32-bit development and bcc64 for 64-bit development. The only difference between bcc32c and bcc32x is that the former takes the same command line flags as their legacy bcc32 compiler while the latter, like bcc64, takes clang command line flags. The clang-based C++ compilers are based on clang-5.0, and use the Dinkumware library. The clang based compilers still predefine __BORLANDC__ and __CODEGEARC__ but also predefine __clang__. The latter is the way to distinguish in preprocessor code between the bcc32 compiler and the clang-based compilers. Despite numerous workarounds in Boost code based on the predefined macros __BORLANDC__ and __CODEGEARC__ the bcc32 compiler, not being very C++ compliant even at the C++98/C++03 level at which it operates, has not really worked for Boost since about Boost 1.39. It is useless for modern day Boost. Therefore I have made efforts, in contact with some Embarcadero C++ representatives, to integrate the clang-based compilers into Boost, especially since there is a free non-commercial offering by Embarcadero called C++ Builder Community Edition at https://www.embarcadero.com/products/cbuilder/starter which any Boost developer could use to test these compilers if they wished. I am doing this in the hopes that this may become effective for Boost 1.74.0. Doing this involves: 1) Creating an embarcadero.jam toolset, based on the clang-linux.jam toolset, which supports bcc32x and bcc64. Updating the borland.jam toolset to also support bcc32c. I have done these and the PR has been merged to 'develop' on Boost Build. 2) Updating Boost Config to support the clang-based compilers. I have done this and the PR has been merged to 'develop' on Boost Config. 3) In the update to Boost Config, I have created these macros: a) BOOST_BORLANDC = __BORLANDC__ with __clang__ not defined b) BOOST_CODEGEARC = __CODEGEARC__ with __clang__ not defined c) BOOST_EMBTC = Embarcadero C++ compilers with __clang__ defined Therefore what is really needed in Boost libraries is to change all the code which currently uses __BORLANDC__ to BOOST_BORLANDC and all the code which uses __CODEGEARC__ to BOOST_CODEGEARC when Boost config has been included. When in the rarer case that Boost config has not been included, then __BORLANDC__ logic becomes __BORLANDC__ and !__clang__ and __CODEGEARC__ logic becomes __CODEGEARC__ and !__clang__. I am workiog on doing this for the numerous Boost libraries with workarounds nased on __BORLANDC__ and __CODEGEARC__ in Boost code, and will create PRs for those libraries. I only ask that library maintainers will merge the PRs I create once they have passed their CI tests, since the PRs are almost all just simple transformations regarding the __BORLANDC__ and __CODEGEARC__ in the code. If any library maintainer wants to so this on their own in the 'develop' branch it would be appreciated. Further points: The Embarcadero C++ clang-based compilers are not as good as clang itself, which is at release 9, gcc, or vc++. But they are good enough for the majority of Boost code. The Embarcadero C++ clang-based compilers support only C++17. The documentation implies that they also support C++11 and C++14 but that is not so. But since Boost libraries written for a C++ standard level are supposed to work flawlessly at a higher level this is no impediment for C++ Builder programmers using the Embarcadero C++ compilers in current Boost. I have reported a number of bugs, based on my Boost testing, for the Embarcadero C++ compilers to Embarcadero themselves in their bug reporting system. I believe that any registered user of their free community edition can report bugs to Embarcadero C++ at their bug reporting system at https://quality.embarcadero.com. Hopefully these reports will improve the compilers. It would really be nice, once the Embarcadero C++ clang-based compilers are integrated into current Boost, if regression testers could test their compilers. I will try to do so myself if I have the time and resources. I have discussed this with some Embarcadero C++ representatives about adding the Embarcadero clang-based C++ compilers to one or more CI testing services, but currently there are not any which support them of which I know. Besides the clang-based Windows compiler Embarcadero also has clang-based C++ compilers for 32-bit and 64-bit iOS ( Apple ) and for Android ( Google ). The code in Boost Config distinguishes between these environments, if necessary, with further macros based off of the mnemonic BOOST_EMBTC. It would be nice to add these configurations to embarcadero.jam once the rest of the work is done. But I have no idea how to test any of these other compilers as they are not part of the Windows based Embarcardero C++ Builder Community Edition.

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Re: [boost] [review][STLInterfaces] STLInterfaces review results (ready for merge)
by Barrett Adair 30 Apr '20

30 Apr '20

On Thu, Dec 26, 2019 at 2:31 AM Barrett Adair <barrettellisadair(a)gmail.com> wrote: > > Many thanks are owed to all who participated in the formal review of Zach Laine's STLInterfaces library, especially during this busy holiday season: > > * Hadriel Kaplan - ACCEPT > * Andreas Wass - ACCEPT > * Rainer Deyke - ACCEPT > * Arthur Gruzauskas - ACCEPT > * Krystian Stasiowski - ACCEPT > * Daniela Engert - CONDITIONALLY ACCEPT > * Gavin Lambert - Technical comments > > (snip) > > The reviews clearly demonstrate a consensus. Accordingly, I'm pleased to announce that STLInterfaces is CONDITIONALLY ACCEPTED as a Boost library. > > Conditions for acceptance: > 1. Remove optional dependency on cmcstl2 (issue #27) > 2. Add Boost license comments to all files, including appveyor.yml, .travis.yml, README.md, */CMakeLists.txt (issue #26) > 3. Support Boost.Build (issue #25) > 4. Replace googletest with Boost equivalent (issue #24) > 5. Remove usage of non-existent v2_dtl members in container_interface.hpp (issue #22) > 6. Include <tuple> for std::tie usage in C++14 mode (issue #21) > 7. Fix dangling parens in container_inteface.hpp:731 (issue #20) > 8. Make Concepts usage C++20-conformant (issue #13) > 9. Remove the destructor in container_interface (issue #12) > 10. Add tests for non-copyable value types (issue #30) > > (snip) I've confirmed that STLInterfaces (https://github.com/tzlaine/stl_interfaces) has met the conditions for acceptance. Review wizards, please reply with any objections. Merge ticket here: https://github.com/boostorg/admin/issues/174 Thanks, Barrett

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GSoC 2020 proposal review and GSoD
by Tom Kwok 29 Apr '20

29 Apr '20

Hi David (and other potential mentors), I updated my repository hosting my little project of C++ matrix classes for the GSoC competency test. Also, is there any editing needed for my proposal? I am sure you and other mentors are busy reviewing so I am sorry for bothering you with this message. If I don’t receive further feedback I would take it as no changes are needed (yet). Also, I read that Boost community is interested in participating GSoD (Google Season of Docs) as well. I would like to express my interest in GSoD participation and I look forward to hearing updates on specific requirements on GSoD participants and/or projects that Boost community may have. Best regards, Tom > On 23 Apr 2020, at 3:51 PM, boost-request(a)lists.boost.org <mailto:boost-request@lists.boost.org> wrote: > > Message: 8 > Date: Thu, 23 Apr 2020 08:25:22 +1000 > From: David Bellot <david.bellot(a)gmail.com <mailto:david.bellot@gmail.com>> > To: Boost <boost(a)lists.boost.org <mailto:boost@lists.boost.org>>, Boost users list > <boost-users(a)lists.boost.org <mailto:boost-users@lists.boost.org>> > Subject: [boost] 10 slots for the Google Summer of Code 2020 > Message-ID: > <CAOE6ZJGh_rM_Dg=h8SYktYoMqux2g+eAt7FiTaShJSs9UkeVMA(a)mail.gmail.com <mailto:CAOE6ZJGh_rM_Dg=h8SYktYoMqux2g+eAt7FiTaShJSs9UkeVMA@mail.gmail.com>> > Content-Type: text/plain; charset="UTF-8" > > Hi Boost community, > > this year Google allocated 10 slots for the Google Summer of Code. It's > again a great achievement thanks to the hard work of our team of dedicated > mentors. > > We are now selecting the best students among all the proposals we receive. > We received 79 proposals this year. 10 of them will be selected. > > This year, a lot of proposals if not all are targeting a finalization of > the work which has been done in the previous GSoCs and we should see a lot > of code being pushed in production. It's a very exciting time for all of us. > > The mentors are now hard at work to choose the students. We'll keep you > informed when it's official. > > Best regards, > David

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[release] Boost 1.73.0 Release Candidate 1
by Marshall Clow 28 Apr '20

28 Apr '20

The first release candidates for the 1.73.0 release are now available at: <https://dl.bintray.com/boostorg/release/1.73.0/source/> The SHA256 checksums are as follows: d2e7501bb04fe7abc09aa93f013ae997604286a882da1bd36ddd96ea1163ea71 boost_1_73_0_rc1.7z 4eb3b8d442b426dc35346235c8733b5ae35ba431690e38c6a8263dce9fcbb402 boost_1_73_0_rc1.tar.bz2 9995e192e68528793755692917f9eb6422f3052a53c5e13ba278a228af6c7acf boost_1_73_0_rc1.tar.gz 0909a79524f857ef54570ceef8f397cc0629202532cc997785479c7c08bbc2a4 boost_1_73_0_rc1.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. -- The Release managers

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Emails from Travis CI not coming?
by Andrey Semashev 28 Apr '20

28 Apr '20

Hi, Does anyone else have a problem with build result notifications from Travis CI not coming? I haven't received emails from Travis for about a month, although I can see the completed builds in the web UI. I checked spam, they aren't there.

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CI Testing and failures
by Edward Diener 28 Apr '20

28 Apr '20

Sometimes CI testing fails because of a bug in a compiler. It is possible to designate in a jam file that a particular test should not be done for a particular compiler version so that CI testing succeeds, and therefore a PR can be more easily merged because the CI tests "succeed". But then the fact that the compiler has a bug is masked by such a change to the jam file. Is there a solution to such a problem, or maybe this is really not a problem at all ? What do others think about this ?

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