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Boost.Build requirements to exclude GCC 5
by Niall Douglas 14 Jan '19

14 Jan '19

Outcome is now into Boost, and is being tested nightly: Docs in BoostDoc theme: https://www.boost.org/doc/libs/develop/libs/outcome/doc/html/index.html Regression matrix: https://www.boost.org/development/tests/develop/developer/outcome.html One problem is how to exclude from testing GCC 5 which Outcome cannot support due to GCC 5's incorrect parsing of variable templates in nested template classes [1], so I need some sort of Boost.Build project requirement which explicitly excludes GCC 5. Unfortunately, GCC 5 appears to Boost.Config as fully implementing C++ 14, so this is not straightforward. What might work is to specify a requirement for one of the library items at https://github.com/boostorg/config/blob/develop/checks/Jamfile.v2 which we know for a fact libstdc++ 5 does not implement, but libstdc++ 6 does. However, clang with libstdc++ 5 would then be excluded incorrectly, as clang does not have this parsing bug. I guess ideally speaking Boost.Config gains a new test testing for this specific compiler parsing bug. But it seems a bit much to ask for this just for Outcome. Guidance is sought! Niall [1]: https://www.boost.org/development/tests/develop/developer/output/teeks99-02…

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C++Now 2019 Submission Deadline
by Jon Kalb 14 Jan '19

14 Jan '19

The deadline for submitting to C++Now 2019 is just a few days away. If you’ve been thinking of submitting, please do not delay: http://cppnow.org/announcements/2018/12/2019-call-for-submissions/ <http://cppnow.org/announcements/2018/12/2019-call-for-submissions/> Thanks. Jon

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High number of integer_sequence/index_sequence implementations
by Nikita Kniazev 14 Jan '19

14 Jan '19

Bunch of Boost libraries have their own integer_sequence/index_sequence implementation. Wouldn’t it be better if there was boost::integer_sequence/boost::index_sequence? boost\beast\core\detail\integer_sequence.hpp boost\callable_traits\detail\polyfills\make_index_sequence.hpp boost\context\detail\index_sequence.hpp boost\fusion\support\detail\index_sequence.hpp boost\mp11\integer_sequence.hpp boost\phoenix\core\detail\index_sequence.hpp (alias of fusion one) boost\poly_collection\detail\functional.hpp (uses mp11 one) boost\test\data\index_sequence.hpp boost\variant\detail\multivisitors_cpp11_based.hpp

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(no subject)
by Siddhartha Sen 14 Jan '19

14 Jan '19

Hey, This is Siddhartha. I have been interested in contributing to boost and hopefully work with boost in GSOC 2019. I apologise for the delay as my exams were going on and I hope it is not too late to start. I have looked in to the ideas list as well as last year's projects. Currently, I am proficient in c and c++,especially algorithms,data structures and maths. Any help regarding how to get started would be appreciated. I myself have some ideas about implementation of a few libraries which I would like to discuss as well. Thank You

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Regression matrix stopped updating
by Nikita Kniazev 13 Jan '19

13 Jan '19

For past month or two regression matrix update frequency was fluctuating in a big range, sometimes not updating for two-three days. As for now master is not updated for 7 days and develop for 5 days. https://www.boost.org/development/tests/master/developer/summary.html Summary: Master Report Time: Tue, 11 Dec 2018 01:44:54 +0000 https://www.boost.org/development/tests/develop/developer/summary.html Summary: Develop Report Time: Thu, 13 Dec 2018 06:05:04 +0000 Is it down for maintenance or what is going on?

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Safe numerics at Meeting C++
by Robert Ramey 12 Jan '19

12 Jan '19

News Flash for both of you interested in the Boost Safe Numerics Library. Checkout https://www.youtube.com/watch?time_continue=942&v=tcyb1lpEHm0 at 1 hour in. The whole rest of the talk is about a safe integer implementation written D. He uses it to illustrate his concept of "Introspective Programming". ALL the features and techniques he mentions (and more) are implemented in the safe numerics library. The Safe Numerics library is the Next Big thing! Robert Ramey

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question/guidence regarding merge to master
by Robert Ramey 12 Jan '19

12 Jan '19

I'm looking to merge my develop branch into the master so that they will be in sync. I'm thinking that this the changed in develop should be squashed so that the master branch doesn't included all the the intermediate changes made during the develop phase. Is there any boost rule/practice/guidence regarding this?. Ideally, I'd like to see the master have only one set of consolidated changes for each release. But I'm not the person who decides these things or does the work. Any insight by other parties would be appreciated. Robert Ramey

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Re: [boost] A class for embedded friendly callbacks.
by Bjorn Reese 12 Jan '19

12 Jan '19

On 1/4/19 1:30 PM, Mikael Rosbacke via Boost wrote: > I'm Mikael Rosbacke and new to this list. The last couple of months I've > been writing on a class for storing callbacks to different forms of > callables (member functions, functors, free functions). The main focus A while back, a somewhat similar library underwent a formal review. You may want to read the review report to see if any of the comments applies to your library: https://lists.boost.org/boost-announce/2016/12/0484.php

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Re: [boost] Feedback desired for reflective enum library
by Nir Friedman 12 Jan '19

12 Jan '19

I had to fill in the subject for this manually, because of settings for the mailing list. I really hope it ends up on the right thread. Apologies if it doesn't. Hi Geert, There is an ADAPT macro, which is similar to your concept of CONVERT_TO_WISE_ENUM. However, it does require listing the enumerators; after all there's no way to find them out after the fact or else this library wouldn't exist in the first place. That said, I'm not quite sure what you mean by "changing your whole codebase". To take advantage of wise enums, all you'd need to do is change the original enum declaration to the wise enum macro. Everything else in your codebase will continue to work exactly as before. No typedef shenangians are necessary. Changing the original enum declaration is exactly the same amount of work as writing an adapt macro, but you don't have to maintain the list of enumerators twice. So I can't imagine a reason to write things the way you have (unless you want a conditional build dependency on WISE_ENUM but that seems unnecessary). The ADAPT macro is designed to be use wise_enum functionality generically with enumerators whose source you don't control, and therefore cannot change the declaration. Hope that clarifies things. Cheers, Nir

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boost log to display source code name and lines
by hh h 11 Jan '19

11 Jan '19

Hi, I am looking for good log library to replace google log, my plan is to use boost log, but I am not sure if it is mature or it has been used seriously. It lacks some simple basic features such as display source code name and lines in log file, I've searched on line discussion, there are many suggestion to fix it in piece of code, but I could not get that work, difficult to use it may be overstated. Are there any good examples to display source program name and lines similar to asio socket examples on line? What is your opinion about boost log? Should I still pursue it? Thank you. - jhh

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GSoC19
by Pranam Lashkari 10 Jan '19

10 Jan '19

Hello, Organization application date is going to start soon. I was trying to find our idea page for this year but couldn't find it. can anyone help!? Thank you, Pranam Lashkari

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Requesting formal review for (Boost) LEAF
by Emil Dotchevski 10 Jan '19

10 Jan '19

LEAF is a small C++11 error handling library (the acronym stands for Low-latency Error Augmentation Framework). Features: - Header-only, NO dependencies. - No dynamic memory allocations. - Associate objects of arbitrary types with any failure — when it is initially reported or at a later time. - Compatible with std::error_code, errno and any other error handling API. - Use with or without exception handling. - Support for multi-thread programming. Official documentation: https://zajo.github.io/leaf. LEAF is designed for use in low-latency environments without exception handling, but it also works with exception handling; in that case it is a better, more optimal replacement for Boost Exception. This link can be helpful for refactoring existing Boost Exception code: https://zajo.github.io/leaf/#boost_exception.

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async_read SEGFAULT
by hh h 09 Jan '19

09 Jan '19

I use one io_service in one process to run two servers A and B each has its own port, own context and SSL configuration to accept inbound connections. Although both A and B have boost::asio::deadline_timer, but I think there is only one thread is running: (gdb) info threads Id Target Id Frame * 1 Thread 0x7ffff7fe0bc0 (LWP 31204) "ssl_connection" 0x00007ffff4a690a3 in __epoll_wait_nocancel () at ../sysdeps/unix/syscall-template.S:84 The problem I got: - If I started only one server A, it worked just fine for both async_read and async_write. - If I started both servers A and B, even B was in idle, server A could sometime be crashed after receiving and responding just one message, then crashed at next async_read in the first second, it was more stable if it did not call async_write. SEGFAULT: Fault address=0x55b3700d00cf, #4 0x000055555557f98a in boost::asio::detail::task_io_service_operation::complete (this=0x55555584adc0, owner=..., ec=..., bytes_transferred=0) at /usr/include/boost/asio/detail/task_io_service_operation.hpp:38 #5 0x0000555555581f82 in boost::asio::detail::task_io_service::do_run_one ( this=0x555555814710, lock=..., this_thread=..., ec=...) at /usr/include/boost/asio/detail/impl/task_io_service.ipp:372 #6 0x0000555555581ab4 in boost::asio::detail::task_io_service::run ( this=0x555555814710, ec=...) at /usr/include/boost/asio/detail/impl/task_io_service.ipp:149 #7 0x000055555558221f in boost::asio::io_service::run (this=0x7fffffffe150) at /usr/include/boost/asio/impl/io_service.ipp:59 It seems that async_write and async_read messed up, but that problem was intermittent, especially when the server A passed first second, it could be running for hours for doing consequent many async_read and async_write simultaneously. It was only one thread, what could cause that problem? Thank you.

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b2 --exec-prefix=...
by Peter Dimov 09 Jan '19

09 Jan '19

Our "b2 --help" documentation says --exec-prefix=<EPREFIX> Install architecture dependent files here. Default: <PREFIX> --libdir=<LIBDIR> Install library files here. Default: <EPREFIX>/lib and bootstrap.sh also supports --exec-prefix and when given, records it in project-config.jam. But it doesn't work and has never worked. Only --prefix is honored, --exec-prefix is simply ignored. I think that we should bring the documentation and the actual behavior in sync, either by making --exec-prefix work as documented, or removing it from the documentation. Which one should we do? Comments?

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Boost wiki - revised Boost guidance for authors on Warnings - RFC
by Paul A. Bristow 08 Jan '19

08 Jan '19

As promised at the end of a long (hijacked!) thread on 'Warnings' http://boost.2283326.n4.nabble.com/Current-Guidance-on-Compiler-Warnings-td… starting from a query by Brian Kuhl of Wind River on Boost's policy on compiler warnings, I have spent some time revising the previous guidance document on Trac that I edited many years ago. This was a long and tedious task as Markdown, as most conveniently used on Github, is rather different from the mark-up language on Trac, leaving me slightly in fumble mode :-( I have made some updates en passant, but there is still much to do updating for the much improved granularity of warning suppression and perhaps more about other code improvement tools like Lint, UBSan. The overall structure leaves a lot to be desired, but I don't want to put any more work into this without some encouragement that it will prove useful. I have posted the result of my efforts on https://github.com/boostorg/boost/wiki/Guidelines:-Warnings and I am as promised I am starting this new thread on warning for your comments, corrections, condemnations etc. HTH Paul --- Paul A. Bristow Prizet Farmhouse Kendal UK LA8 8AB +44 (0) 1539 561830

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[cmake] Pull request announcement - update
by mike.dev＠gmx.de 07 Jan '19

07 Jan '19

I think it is time for an update on this issue. #################################################### # TLDR: There are now ~25 boost libraries that can be directly used in a cmake project via the add_subdirectory & target_link_library - workflow. And I want to encourage library maintainers to comment/merge outstanding PRs or make similar additions to their libraries themselves. ################################################### # A summary what that thread was about: In September last year I was informing the mailing list that I was about to make a bunch of PRs adding a set of minimal CMake files to various boost libraries. Their sole purpose was to enable the following workflow from within a cmake project: add_subdirectory( <path-to-boost-libfoo-directory> ) target_link_library( my_app Boost::libfoo ) Without needing b2 or the boost super project for that matter (although support in the super project would be very welcomed) For that, the cmake file in libfoo has to - provide the target Boost::libfoo - attach the dependency information for Boost::libfoo - attach the proper include directory for Boost::libfoo - if necessary, build libfoo with whatever toolchain and compile flags the parent cmake project defines - if necessary, attach any necessary compile definitions to Boost::libfoo Although things like running the unit-tests or provide and install target can be added by any library maintainer (and some have done just that) it is not part of my PRs. ################################################### # What is the current state. For a quick overview, I uploaded a picture of the boost dependency graph (code based on boostdep) that shows which libraries Have a cmake file in their root and which don't [1]. So far, about 25 libraries have gained cmake files as part of this effort (not all from me). And of course there are a couple of libraries that Already used cmake before I started my efforts, but AFAIK, most of them can not be used in the above mentioned work-flow. Of course, there remains a lot to do, but at least progress is happening and we now have fitted almost all "foundational" libraries , so from here on out, the pace should increase. Currently, I have 7 outstanding PRs and I would ask the Respective maintainers to comment on them as soon as they can find some spare time, as further PRs are blocked on them. Even if the PRs get completely rejected, I at least know for which part of boost I should no longer pursue this quest and/or find a workaround. Finally a big thanks to all maintainers that added such cmake files on their own. Best Mike [1] https://gist.github.com/Mike-Devel/46d04409d6ae6053861706e3ad91e4dc Explanation for the linked picture: It shows the boost dependency graph (generating code based on boostdep). - Green libs already have a cmake file in their root directory - Yellow libraries don't have such a cmake file, but all their dependencies have one, so one could be added and most likely there is already a PR for that - Red libraries have at least one direct or indirect Dependency that lacks a cmake file, so I consider Them "blocked" for now.

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A class for embedded friendly callbacks.
by Mikael Rosbacke 07 Jan '19

07 Jan '19

Greetings. I'm Mikael Rosbacke and new to this list. The last couple of months I've been writing on a class for storing callbacks to different forms of callables (member functions, functors, free functions). The main focus has been to make it suitable for embedded work with small footprint and dependable exception and heap behavior. The code can be found on github: https://github.com/rosbacke/delegate It has reached a stage where I'm getting sort of 'done'. I feel it could be useful to a wider audience so I would like to get some feedback about if this is suitable for that and if it is worth starting a new branch for possibly adapting it to boost for inclusion in some future version of boost. Any feedback is appreciated. Cheers, --- Mikael Rosbacke

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Should pass boost::asio::io_service by raw pointer or smart pointer?
by hh h 07 Jan '19

07 Jan '19

Hi, In many examples and even implementations, programmers like to pass boost::asio::io_service by raw pointer: MyClass::MyClass(boost::asio::io_service &io_service) : myRawIoService(io_service) {} Will this cause issues to pass raw pointer for large size of classes, should it be replaced by passing smart pointer: MyClass::MyClass(const std::shared_ptr<boost::asio::io_service> &io_service) : myIoService(io_service) {} Thank you.

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Is there interest in an "iofiber" library?
by Vinícius dos Santos Oliveira 06 Jan '19

06 Jan '19

I have written a completion token for Boost.Asio that is a little more advanced than plain ASIO's spawn featuring abstractions such as join(), detach() and even interrupt(). I'd like to know if there is interest in seeing this library merged as part of Boost. https://vinipsmaker.github.io/iofiber/ (there is also a mutex and a semaphore, but these are undocumented as of now and were poorly ported from the previous token supporting abstractions and need rework) Boost.Fiber integration with ASIO is problematic: https://github.com/boostorg/fiber/issues/102#issuecomment-263558882 Default Boost.Asio yield token will do as long as you don't need communication between fibers. When primitive communication is necessary, you can work around it by exploiting the completion token protocol. In fact, after having rolled my own solution, I eventually was made aware of Peter's solution (which he rolled on his own independently) which was incredibly similar to my solution: https://github.com/equalitie/ouinet/blob/a2afaf9932c8a23434d1f0a10be06fc407… If you need anything more advanced such as careful strand integration, join, or interruption API, you'll just have to roll your own token. That's what I end up doing after working around ASIO's token for many months. There was also a recent request by Vinnie to turn Boost.Coroutine 1 deprecation warning off. This separate library would be an alternative (although it is still a far from review-ready). -- Vinícius dos Santos Oliveira https://vinipsmaker.github.io/

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Re: [boost] Skipping regression builds for unsupported toolsets
by Nikita Kniazev 05 Jan '19

05 Jan '19

> > How can I 'tell' regression builders to skip building GIL > where required C++ version is not supported? Add requirements to you tests Jamfile, something like: import config : requires ; project /boost/gil/test : requirements [ requires cxx11_constexpr cxx11_decltype cxx11_template_aliases cxx11_variadic_templates ] (those checks come from Config library which most likely you are pulling already in your CI builds). I noticed that some libraris specify "std" in libraries.json, for example: > - Any: "std": [ "c++17" ] > - Ratio: "std": [ "proposal" ] > What is the purpose of these? > Is this respected by regression builds? I doubt those do anything. IIUC `libraries.json` is used only for https://www.boost.org/doc/libs/ list generation.

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Skipping regression builds for unsupported toolsets
by Mateusz Loskot 05 Jan '19

05 Jan '19

Hi, The regression builds report unreloved issues for number of libraries: https://www.boost.org/development/tests/develop/developer/issues.html In particular, for Geometry and GIL those issues happen on msvc-8.0. For GIL, specifically, this is due to the fact GIL now requires C++11. How can I 'tell' regression builders to skip building GIL where required C++ version is not supported? I noticed that some libraris specify "std" in libraries.json, for example: - Any: "std": [ "c++17" ] - Ratio: "std": [ "proposal" ] What is the purpose of these? Is this respected by regression builds? Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

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iround() and itrunc() in Conceptual Requirements for Real Number Types
by Matt Pulver 04 Jan '19

04 Jan '19

Hello, Regarding the page Conceptual Requirements for Real Number Types https://www.boost.org/doc/libs/1_69_0/libs/math/doc/html/math_toolkit/real_… Is it still accurate to list these 2 rows under Standard Library Support Requirements? - iround(cr1) | int - itrunc(cr1) | int The motivation in asking this is two-fold: 1. I don't see either of these functions listed in the Standard Library. Perhaps this is just old documentation, or I am not looking in the right place. Instead, I do find lround() and truncl(). 2. One of the design goals of Boost.Autodiff (WIP) is to satisfy all of the requirements on this page, and these are the only two which I am unable to satisfy for the above reason. If someone were to update this page, or otherwise advise on how to reconcile, it would be appreciated so that the Boost.Autodiff <https://github.com/pulver/autodiff> library could accurately claim to satisfy 100% of Boost's Real Number Type requirements. Best regards, Matt

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Could shared_ptr cause memory leak?
by hh h 04 Jan '19

04 Jan '19

Suppose I have a session object A, the shared_ptr<A> is created and stored in a global connection list after a connection is accepted by async_accept, when the connection is terminated, the reference in connection list is removed, but since A has a member B still holds A reference, that session object is never deleted, is it memory leak? class A : public boost::enable_shared_from_this<A> { public: A(); ~A(); void Start() {b = make_shared<B>(shared_from_this());} void Stop(); private: shared_ptr<B> b; };

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Re: [boost] [multi_index] problem with Travis integration
by Nikita Kniazev 31 Dec '18

31 Dec '18

Aah, you repository has both Travis enabled. Formerly Travis had two separated sites, one (.org) served for open source project and other (.com) for private projects. A while ago they opened .com for open sources and announced that they will merge .org to .com, but actually nothing changed. https://docs.travis-ci.com/user/open-source-on-travis-ci-com/ > Looking closer, there is a duplication. In commit 1af32b3, the "Travis > CI - Branch" link redirects > (indirectly) to > > https://travis-ci.com/boostorg/multi_index/builds/95957238 > > while the "continuous-integration/travis-ci/push" points to > > https://travis-ci.org/boostorg/multi_index/builds/473601408 > > Note the most surprising fact that *the first link is **to travis-ci.com > and the second **to > travis-ci.org*. These two domains don't see each other (If i try to see > 473601408 in > travis-ci.com or 95957238 in travis-ci.org I get a "we couldn't find > that build" screen). > > Joaqu?n M L?pez Mu?oz

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[multi_index] problem with Travis integration
by Joaquin M López Muñoz 30 Dec '18

30 Dec '18

Sorry to be such a noob when it comes to Travis integration, but for the life of me I just can't see how to fix the following: Travis was activated for boostorg/multi_index yesterday, and, in addition, I've been given admin privileges to boostorg/multi_index so I can, in theory, control how the Github/Travis communication happens. Evreything is working OK except that, when I push something to develop, *two* Travis tasks are created, named "Travis CI - Branch"and "continuous-integration/travis-ci/push": whereas in all the other boostorg libs I've examined, only "continuous-integration/travis-ci/push" appears (example with smart_ptr): I've walked all over the settings pages for both Travis and Github, looked up on the Internet and didn't come to any conclusion as to what this "Travis CI - Branch" thing is and how it can be turned off so that integration looks the same way as for any other Boost lib. Any clue much appreciated. Joaquín M López Muñoz

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