July 2015 - Boost - lists.preview.boost.org

Boost.DLL Review is finished
by Vladimir Prus 14 Jul '15

14 Jul '15

Boosters, the formal review of the Boost.DLL library by Antony Polukhin is now finished. The preliminary results are as follows: The following people have provided reviews: - Ralf Globisch - Yes - Klaim - Joël Lamotte - Yes (*) - Niall Douglas - Yes, conditionally - John P Fletcher - Yes - Bjorn Reese - Yes - Edward Diener - Yes Klaim - Joël has asked that his vote is not counted until he's done trying the library for real, and there was no confirmation it's done yet. The following people have contributed, but did not provide a review - Rodrigo Madera - Thomas Trummer - Rob Stewart - Ion Gaztañaga If anybody would like to amend or clarify anything, or plans to provide additional comments during this week, please contact me off-list. I will post final review result after that. Thanks, Volodya

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Boost.DLL formal review
by Vladimir Prus 14 Jul '15

14 Jul '15

The formal review of Boost.DLL library by Antony Polukhin starts today. Boost.DLL is a C++98 library for comfortable work with DLL and DSO. Library provides a portable across platforms way to: - load libraries at runtime - import and export any native functions and variables - make alias names for C++ mangled functions and symbols - query libraries/objects and executables for sections and exported symbols - self loading and self querying - getting program and module location by exported symbol The documentation can be found at: http://apolukhin.github.io/Boost.DLL/index.html and the source can be obtained at: https://github.com/apolukhin/Boost.DLL Please post your reviews on the mailing list and if possible, answer the following questions: - Should the library be accepted? - How useful is it? - What's your evaluation of - Design - Implementation - Documentations - Tests - How much effort did you put into your evaluation? - Did you attempt to use the library? On what systems and compilers? This formal review has a couple of adjustments in place: - It will run for two calendar weeks, not for 10 days, as a number of people said 10 days is too little. That said, please try to submit a review during first week, so that necessary discussion can happen conveniently. - The documentation site has Google Analytics enabled, which will allow us to see which pages and navigation paths are most useful for reviewers. No personally identifiable information will be collected. I will post the data after the review is over. Thanks, Volodya

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[1.59] [locale] Merge PR to fix build failures
by Andrey Semashev 13 Jul '15

13 Jul '15

Hi, I've created this pull request [1] a while ago, but it's still not merged. The PR fixes compilation on MSVC and GCC (Ubuntu) and IMO is essential for 1.59. Could someone take a look and merge it? [1] https://github.com/boostorg/locale/pull/9

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[threads] Problem with lambda and tls
by Fu ji 13 Jul '15

13 Jul '15

Hello, I have a problem when I use lambda in lambda and I want to obtain thread local storage. Here is simple example: auto late_connect = wakeup_signal_notify_to_connect.connect([this](){ auto* alias_to_this = this; this->OnInvokeUpdate(); //here I can obtain thread local storage from boost auto wakeup = wakeup_signal_ptr->connect([alias_to_this]() { alias_to_this->OnInvokeUpdate(); //here I cannot obtain thread local storage from boost } });}); Between first and second of invoke OnInvokeUpdate function there was no destructor call. Someone have idei why ? If I don't use alias for this in capture list there is the same effet. Best regards

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[Boost-announce] [review] Metaparse Review Result
by Christophe Henry 13 Jul '15

13 Jul '15

Hi all, First of all, the final result. Metaparse is formally unconditionally accepted into Boost. We had 11 reviews, all "Yes" votes. 2 "No" reviews based on formality were later reversed to a "Yes". The review was lively, with a general agreement that the library is very useful, the design of high quality and the documentation great. Here are some noticeable quotes which helped me take my decision: - "thank you Abel for submitting such an amazing library. The quality of the documentation and code is wonderful and it has been a pleasure to review Metaparse." (Michael Caisse) - (Design) "Of high quality. Based on the MPL paradigm, but I don't view this as a problem." (Peter Dimov) - "Part of the role of boost is to push compilers to the limit (and sometimes beyond). This library certainly has the capabilities to do so." (Roland Bock) Worth noticing is the review of Gordon Woodhull. I myself wrote a new front-end for MSM using Metaparse, and other use cases were very welcome and Gordon managed to produce one for his compile-time graph library by the end of the review, which I found impressive (for both the reviewer and the library). Thank you for investing time in this review. Another important factor for me for acceptance is how well the author is going to maintain his library. We have too many abandoned libraries. Abel went out of his way to oblige remarks and demands made by reviewers. Long before the reviews he also had obliged my many critics and demands. He also showed himself open for experiments. All this while keeping a very calm and professional tone. This is for me a very good sign of a library which will be well-maintained. Finally, there were some repeated important comments which I see as adressed to the rest of Boost that the library is targeted towards library writers. >From Peter Dimov: > - Are you knowledgeable about the problem domain? "I'm not sure if anybody is. :-)" It all depends on us, library and potential library writers to become knowledgeable about this domain and make this library move from potentially useful to very useful. We need to use it to write more cool libraries. I notice a recurring theme where Boost would be dead or on the way to doom etc etc. Some very popular Boost libraries are now part of the Standard, and so what? We need to make new ones. Metaparse is one of them. Let's build more, using it! Yes Reviews(11): Andrzej Krzemienski Bjorn Reese Gordon Woodhull Lee Clagett Louis Dionne Michael Caisse Paul A. Bristow Peter Dimov Roland Bock Edward Diener Niall Douglas I want to thank all the reviewers who invested their time in this review and those who provided some usefuls comments. I also want to thank Abel for presenting this great library. Christophe Henry Metaparse Review Manager

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Re: [boost] [Boost-users] Boost.DLL formal review is ending soon - submit your reviews
by Klaim - Joël Lamotte 12 Jul '15

12 Jul '15

On 12 July 2015 at 21:24, Edward Diener <eldiener(a)tropicsoft.com> wrote: > The name of the library seems Windows specific, since DLL is the term that > Windows uses for shared libraries. Would not Boost DLM ( for dynamic > loadable modules ) or Boost Loadable Library be clearer ? If I remember correctly, there was a long discussion about the naming of the library before the majority seemed ok with DLL because it's explicitely only about loading libraries, not "modules"(which is misleading) nor "plugins" (which would require a lot more features). The name, if my memory is correct, was not particularly thought to be about the Windows context. Other libraries also already took the other names like Boost.SharedObject so it was not an option.

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[msm][eUML2][metaparse] Compile time
by Christophe Henry 12 Jul '15

12 Jul '15

Michael Caisse wrote: >> >> Boost.Msm v3 also implements a new compile-time strings based front-end >> called eUML2 to demonstrate the power of the library and the conciseness >> and expressiveness it allows. >> Please have a look at the documentation: >> >> https://htmlpreview.github.io/?https://raw.githubusercontent.com/boostorg/m… >> >> > >Christophe, this is wonderful work and a great example of the usefulness >of Metaparse. Can you comment on the compile time compared to eUML? Hi Michael, sorry, I had completely forgotten this post and saw it while preparing the review results (which will be done soon). Please allow me to answer this question, with my apologies. I added in the msm3 branch a CompareFrontEnds.cpp example. It is a simple fsm with 12 transitions. I tried with gcc-4.9 and clang-3.5, using -O2 on a i7-5960X processor, suse linux 13.2. Here are the results. eUML clang 4s g++ 5s eUML2 clang 9s g++ 14s Clang is clearly much faster than g++, with about 0.5s added compile-time per transition. With g++ it does not look so good. I already noticed that compile times of most production code at work with g++ is much higher than with clang. Regards, Christophe

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[Better Enums] Maps between enums and other types
by Anton Bachin 12 Jul '15

12 Jul '15

Hello, In past exchanges on this list, several people expressed a desire for bidirectional maps on enums. I've made a simple implementation [1] that relies on constexpr functions containing a switch. The switch forces case exhaustiveness checking. This method therefore requires C++14 to be truly useful. Usage is: ENUM(Channel, int, Red, Green, Blue) constexpr const char* describe(Channel channel) { switch(channel) { case Channel::Red: return "the red channel"; case Channel::Green: return "the green channel"; case Channel::Blue: return "the blue channel"; } } constexpr auto descriptions = better_enums::make_map(describe); int main() { std::cout << descriptions.from_enum(Channel::Red) << std::endl; std::cout << descriptions.to_enum("the green channel") << std::endl; } This prints the red channel Green In principle, make_map should enumerate the function by passing every possible value of Channel, and use the results to build up some lookup data structure. I am not doing that right now because I haven't found a compile-time data structure with fast enough generation to be practical. I suppose with reflective information, there are other ways to check for exhaustiveness besides using a switch. The implementation is currently inefficient (it uses a linear scan to do the reverse mapping). There is also no support for multimaps or partial maps. I could probably support the latter easily by having the function return an option type. I am not sure multimaps are a good idea at all. The only point of them would be to do a reverse mapping from multiple values to the same enum. Interested to hear any opinions. Anton [1] http://aantron.github.io/better-enums/tutorial/Maps.html

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Another Problem (was RE: [type_traits] Another big update in develop)
by Fletcher, John P 11 Jul '15

11 Jul '15

A recent change on develop is breaking something in boost function: _In file included from ../../../boost/function/function_base.hpp:22:0, from ../../../boost/function/detail/prologue.hpp:17, from ../../../boost/function.hpp:24, from ../../../boost/thread/future.hpp:52, from ../../../libs/thread/src/pthread/thread.cpp:19: ../../../boost/type_traits/has_trivial_copy.hpp:47:47: error: template argument 1 is invalid This was not there yesterday. John Fletcher

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Boost.Hana
by Glen Fernandes 11 Jul '15

11 Jul '15

Dear Ron, Louis, and Boost developers, The review period for Hana has concluded. 18 reviews were submitted: - 17 votes for acceptance. (1 of these was conditional upon Hana wholly supporting a second C++ implementation however). - 1 vote for rejection; for lack of compiler support. I submit that Hana be accepted into Boost. I want to congratulate Louis: the Boost community wants Hana to become an official Boost library. Thank you again, Louis, for your work on Hana and for contributing it to Boost. I propose we require, prior to Hana's inclusion in a Boost release, only that: 1. Hana's unit tests to be integrated into Boost's regression tests. If this requires maintaining both CMakeLists.txt and .b2 files, it is still worth it. I am willing to assist with this effort (and the invitation extends to anyone in the community to also contribute to the task). For release managers, potential Hana contributors, or just the general developer community in Boost, to see Hana's test cases in http://boost.org/development/tests/master/developer/summary.html will be useful. I trust, but do not mandate before Hana is officially accepted into Boost, that: 1. All GitHub issues pertaining to implementation and documentation that were opened by Louis in response to review feedback (or by others, such as Vincente, that were approved by Louis) will be addressed eventually (as long as they remain relevant). I personally would ask for, but do not require for Hana's acceptance, that: 1. That Hana's non-reference documentation live outside of the source code. The presentation of Hana's documentation is great; it looks modern, is easy to browse. I am not a fan of the prose living inside hana.hpp though (API reference documentation is the only exception). 2. Louis to investigate further the possibility of a Hana core library if such can be achieved with zero overhead (instead of focusing that effort onto a separate library that provides only a subset of Hana's functionality). On the note of Hana's current support in existing C++ implementations: - While Hana is wholly only supported by clang at present, gcc is not far behind. Given the trend of language conformance, it is reasonable to expect Hana will be entirely supported in a future gcc release. - Hana targets the C++ standard (i.e. This isn't a case of targeting any compiler-vendor specific extensions) and any highly-contentious C++ language features within (e.g. This isn't something like a pre-C++11 library that uses 'export' that only builds with an EDG compiler). - The community now has expressed sufficient interest in both kinds of libraries being part of Boost: Highly portable libraries that target implementation-specific features, and maintain compatibility with even legacy compilers; standard conforming, modern, libraries that are free of the maintenance debt of ancient compiler support. - We need more libraries taking advantage of C++14 language features to drive vendor conformance. A standard may only be as potent as the C++ implementations that support support it, but when one (such as clang does) does, others will be more driven to follow suit when real (and highly desired) projects take advantage of it. My thanks to everyone that participated in Hana's review with a review (Edouard, John Fletcher, John Bytheway, Niall, Krzysztof, Manuel, Roland, Christophe, David Stone, David Sankel, Lorenzo, John, Paul, Zach, Kohei, Charley, Vincente, Abel) as well as discussion and bug reports. Best, Glen

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