June 2019 - Boost - lists.preview.boost.org

[regression tests] Regression test pages not updating since June 4th
by Joaquin M López Muñoz 11 Jun '19

11 Jun '19

Thank you, Joaquín M López Muñoz

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[out_ptr] Review scheduled for June 16 to June 26
by Zach Laine 10 Jun '19

10 Jun '19

This is a heads-up that out_ptr has been scheduled for review, starting next Sunday, June 16. From JenHeyd's earlier post about the library: " Documentation: https://github.com/ThePhD/out_ptr/blob/master/docs/out_ptr.adoc Repository: https://github.com/ThePhD/out_ptr <https://github.com/ThePhD/out_ptr/blob/master/docs/out_ptr.adoc> Standards Proposal: https://thephd.github.io/vendor/future_cxx/papers/d1132.html boost.out_ptr is a library for making it easy to interoperate between smart pointers and traditional C-style initialization and allocation interfaces. It also enables doing so in a way that allows library authors to opt into speed optimizations for their smart pointers that give them performance equivalent to typical C pointers (see benchmarks ( https://github.com/ThePhD/out_ptr/blob/master/docs/out_ptr/benchmarks.adoc) and the Standard C++ proposal for more details). " Please consider checking out the library now, and doing a review next week. It's a pretty small library; reviews should be pretty quick to do. Zach

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Re: [boost] [Boost.Stringify] Yet another formatting library.
by Roberto Hinz 09 Jun '19

09 Jun '19

On Sat, Jun 8, 2019 at 9:53 AM Helmut Zeisel <HZ2012(a)gmx.at> wrote: > Actually I did not check your library, but I would be interested in a > formatting library that is not based on functions, but on function objects. > > The usage would not be something like > > std::string s1 = to_string("base10", 15); > std::string s2 = to_string("base16", 42); > > but > > stringifier dec; > dec.set_base(10); > std::string s1=hex(15); > stringifier hex; > hex.set_base(16); > std::string s2=hex(42); > > To format values in Boost.Stringify, one does like this, for example: namespace strf = boost::stringify; int v = 255; std::string s = strf::to_string(v, " in hexadecimal is ", strf::hex(v)); assert(s == "255 in hexadecimal is ff"); So could maybe lambdas solve your need ? auto hex = [](int v){return strf::to_string(strf::hex(v)); }; auto dec = [](int v){return strf::to_string(v); }; auto s1 = hex(15); auto s2 = dec(42); assert(s1 == "f"); assert(s2 == "42"); > With a function object based interface, one could easily store and reuse > different formating options in parallel. > Not clear to me what you mean by that. Could you explain better ?

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[Boost.Stringify] Yet another formatting library.
by Roberto Hinz 08 Jun '19

08 Jun '19

Dear Boost Community, Naturally, any interest in a new formatting library must be lower now that fmtlib is approved into C++20. Still, I'm confident that the library I'm working on has great potential, so I would like to know your opinions. https://github.com/robhz786/stringify This is a locale-independent formatting library that: - has great performance ( almost twice as fast as fmtlib ) - can do things that others can't, like encoding conversion. - is highly customizable. Through "facets" you can specify things like numeric punctuation, encoding error handling, and the width calculation algorithm. - is highly extensible. Not only you can add new input types with own formatting options and facets, but also easily add new output types. The doc has an example of how to extend the library to write to QString ( from Qt ). Actually, I did announce this library about two years ago. But the design is much enhanced now. I believe it will be ready for review by the end of this year. But it may take longer. I much appreciate any feedback. Thank you. Roberto

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Setting up linter for boost library development
by Sagnik Dey 07 Jun '19

07 Jun '19

If someone has a linter setup with appropriate settings, can you please share details? I'm working on Boost.Real and would like to have a linter to help with coding style consistency. Help is appreciated. Thank You

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Re: [boost] [Boost.Config] Detect compiler support for std::current_exception
by dariomt＠gmail.com 06 Jun '19

06 Jun '19

> > >Are there instructions for developers that I've missed? > > There are some instructions here: > > > https://www.boost.org/doc/libs/1_70_0/libs/config/doc/html/boost_config/gui… > > Thanks! I was expecting developer guidelines in the github readme, not in the actual library docs! doh! I have made a PR #285 and after some trial and error (I only have VS2015 and VS2017 available to test locally) I think I have something. However, in my test I throw and catch exceptions: int test() { std::exception_ptr ep; try { throw 42; } catch(...) { ep = std::current_exception(); } try { std::rethrow_exception(ep); } catch(int i) { // return zero on success return i == 42 ? 0 : 1; } return 1; } But the CI jobs have gcc and clang configured to compile without exception support! And I get errors like: libs/config/test/boost_no_cxx11_hdr_exception.ipp:22:5: error: cannot use 'throw' with exceptions disabled throw 42; ^ libs/config/test/boost_no_cxx11_hdr_exception.ipp:20:3: error: cannot use 'try' with exceptions disabled try ^ I have two questions: 1) Where are exceptions disabled in the CI jobs? I can't find it in the .travis.yml, but I can see e.g. clang being invoked with -fno-exceptions 2) How can I test proper support for std::current_exception() and std::rethrow_exception() if exceptions are disabled for the test? Thanks!

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[ boost.out_ptr ] [ Review Endorsement ] New Library targeting C++11
by JeanHeyd Meneide 04 Jun '19

04 Jun '19

Dear Boost Community, After a lot of work and discussion in-person, via e-mail, and on the Slack, I would like to ask for the library boost.out_ptr <https://github.com/ThePhD/out_ptr/blob/master/docs/out_ptr.adoc> -- targeting C++11 -- to be endorsed for review. Documentation: ascii doc-ready and readable on GitHub <https://github.com/ThePhD/out_ptr/blob/master/docs/out_ptr.adoc> Repository: GitHub <https://github.com/ThePhD/out_ptr> Standards Proposal: p1132 <https://thephd.github.io/vendor/future_cxx/papers/d1132.html> (accepted for and targeting C++20) boost.out_ptr is a library for making it easy to interoperate between smart pointers and traditional C-style initialization and allocation interfaces. It also enables doing so in a way that allows library authors to opt-into speed optimizations for their smart pointers that give them performance equivalent to typical C pointers (see benchmarks <https://github.com/ThePhD/out_ptr/blob/master/docs/out_ptr/benchmarks.adoc> and the Standard C++ proposal <https://thephd.github.io/vendor/future_cxx/papers/d1132.html#perf> for more details). Many thanks to the in-person discussion during Library in a Week at C++Now, which helped shape the implementation and yield the final Rationale <https://github.com/ThePhD/out_ptr/blob/master/docs/out_ptr/rationale.adoc>. Many thanks to Ezra (eracpp) for a lot of the quick, easy-to-read examples that became part of the documentation. Sincerely, JeanHeyd Meneide

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Re: [boost] [Boost.Config] Detect compiler support for std::current_exception
by dariomt＠gmail.com 03 Jun '19

03 Jun '19

> > >>> Hi all, > >>> > >>> I'm working on a Boost.Exception issue [1] and I need to detect > compiler > >>> support of std::current_exception. In the issue there is a suggestion > to > >>> use #if __cplusplus > 199711L but that does not work for my use case > >>> (VS2015 reports __cplusplus = 199711L). > >> > >> MSVC defines _MSVC_LANG for this[1]. At least, it used to. However, it > >> would be cleaner to have a dedicated macro in Boost.Config for this. > >> > > Totally agree. > > > >> > >>> Is it possible to add a config macro for this? > >>> Or is there a good enough existing macro I can use? > >> > >> I don't think there is. Something like BOOST_NO_CXX11_HDR_EXCEPTION > >> would be useful. > > > > I would need to detect support for std::current_exception, not the > presence > > of header <exception>, so I would think that > > BOOST_NO_CXX11_CURRENT_EXCEPTION is what I need, right? > > BOOST_NO_CXX11_HDR_EXCEPTION, as all BOOST_NO_CXX11_HDR_* macros, detect > that the header not only exists, but is usable and contains all major > components described by the standard. In case of > BOOST_NO_CXX11_HDR_EXCEPTION, that would mean std::exception_ptr, > std::current_exception, std::rethrow_exception, std::make_exception_ptr, > etc. You need at least std::exception_ptr and std::current_exception. > Thanks, that makes sense! > > Should I open an issue in github for Boost.Config? > > Yes, or better yet - make a PR. > Added github Issue #284 [1], I'll try to come up with a PR. Wondering how deep the rabbit hole goes... ^_^ Regards [1] https://github.com/boostorg/config/issues/284

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