April 2016 - Boost - lists.preview.boost.org

[boot] using the boost name on unofficial libraries
by Sam Kellett 23 Apr '16

23 Apr '16

i see a *lot* of rejected / unfinished libraries that use the boost name with the intentions of one day becoming a boost library. doesn't this affect the brand strength associated with the boost name? i would have thought that it wouldn't be ok to name your library a boost library before it is officially accepted, but that doesn't seem to be the case? or is it the case but it isn't / can't be enforced?

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[gsoc16] Summer of Code 2016 shall proceed after all
by Niall Douglas 23 Apr '16

23 Apr '16

Dear Boost, We are very glad to announce that non-Google funding has been found to continue the Summer of Code for the following veteran student projects in Summer 2016: A. Boost Document, mentored by Antony Polukhin. Veteran student: Anurag Ghosh https://anuragxel.github.io/boost-document/ B. Boost.Compute, mentored by Kyle Lutz. Veteran student: Jakub Szuppe https://boostorg.github.io/compute/ C. Boost.Http, mentored by Bjorn Reese. Veteran student: Vinícius dos Santos Oliveira https://boostgsoc14.github.io/boost.http/ All three of these projects shall see a Summer of Code as if it were Google Summer of Code following the same timeline, mentor and student stipends, and progress acceptance criteria. Our thanks to the students and mentors for being so patient during the organisation of this funding. This all happened very quickly and much faster than Boost org processes normally happen - it would not have been possible without the efforts of Jon Kalb and Bryce Adelstein Lelbach, the latter of whom wrote up a great funding request worth reading at https://goo.gl/7v3VMK. Thanks are also due to the Boost Steering Committee for moving so quickly to vote on this, and to Boris Schäling for finding sponsorship for this effort. And finally congratulations to the veteran students! Niall and Bryce --- Boost C++ Libraries Google Summer of Code 2016 admin https://svn.boost.org/trac/boost/wiki/SoC2016

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Interest in a "concepts lite" library?
by Juan Pedro Bolivar Puente 22 Apr '16

22 Apr '16

Hi! With concepts lite not getting into C++17, the need for library-based alternatives becomes more apparent. With this regard, the current Boost.ConceptCheck library is outdated, as it emulates an too old proposal for concepts, and it does not leverage more modern techniques (e.g. expression sfinae). Eric Niebler proposed in his Range-V3 library a technique to simulate concept checking using C++11 [1]. I myself implemented a variation of such technique in the Atria library [2]. Atria's implementation differs in two ways with Range-V3 concepts: - It is simpler, because it has no special support for refinements. A concept refines another just by checking the refined concept in the normal `requires` definition. The downside is that refinement information can not be used for dispatch. - It wants to be future-proof. Concepts defined with the `ABL_CONCEPT_SPEC` macro can be automatically upgraded to a Concepts Lite concept by redefining `ABL_CONCEPT` as `constexpr concept`. There are few reasons though why Atria's implementation could not be directly included in Boost. I would like to work on a more formal proposal, but first I'd like to know if there is interest in it, and if there are any obvious concerns or questionmarks. Thanks! JP [1] http://ericniebler.com/2013/11/23/concept-checking-in-c11/ [2] https://github.com/Ableton/atria/blob/master/src/atria/meta/concept.hpp https://github.com/Ableton/atria/blob/master/src/atria/meta/tst_concepts.cpp

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Ordering the header files in the library's doxygen reference
by Edward Diener 22 Apr '16

22 Apr '16

I use quickbook and doxygen to create the doc for my library. In my jamfile for building the docs I have the header files in my doxygen reference listed in the particular order I would like to see them in the reference when the documentation is built. But for some reason I cannot discern the order of the header files in the reference section of my final HTML documentation is not the same as the order in which I have the header files listed. Does anybody know how I can control the order of the header files listed in the reference section of my library's HTML documentation ?

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[function] Placement new warnings from gcc 6
by Andrey Semashev 22 Apr '16

22 Apr '16

Hi, In my tests on gcc 6 I'm seeing these warnings which stem from Boost.Function: ../boost/function/function_template.hpp:572:11: warning: placement new constructing an object of type 'boost::spirit::qi::detail::parser_binder<boost::spirit::qi::sequence<boost::fusion::cons<boost::spirit::qi::any_uint_parser<unsigned int, 10u, 1u, -1>, boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::standard, true, false>, boost::fusion::cons<boost::spirit::qi::any_uint_parser<unsigned int, 10u, 1u, -1>, boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::standard, true, false>, boost::fusion::cons<boost::spirit::qi::any_uint_parser<unsigned int, 10u, 1u, -1>, boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::standard, true, false>, boost::fusion::cons<boost::spirit::qi::any_uint_parser<unsigned int, 10u, 1u, -1>, boost::fusion::nil_> > > > > > > >, mpl_::bool_<false> >' and size '8' in a region of type 'char' and size '1' [-Wplacement-new=] ../boost/function/function_base.hpp:308:13: warning: placement new constructing an object of type 'boost::detail::function::functor_manager_common<boost::spirit::qi::detail::parser_binder<boost::spirit::qi::sequence<boost::fusion::cons<boost::spirit::qi::any_uint_parser<unsigned int, 10u, 1u, -1>, boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::standard, true, false>, boost::fusion::cons<boost::spirit::qi::any_uint_parser<unsigned int, 10u, 1u, -1>, boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::standard, true, false>, boost::fusion::cons<boost::spirit::qi::any_uint_parser<unsigned int, 10u, 1u, -1>, boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::standard, true, false>, boost::fusion::cons<boost::spirit::qi::any_uint_parser<unsigned int, 10u, 1u, -1>, boost::fusion::nil_> > > > > > > >, mpl_::bool_<false> > >::functor_type {aka boost::spirit::qi::detail::parser_binder<boost::spirit::qi::sequence<boost::fusion::cons<boost::spirit::qi::any_uint_parser<unsigned int, 10u, 1u, -1>, boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::standard, true, false>, boost::fusion::cons<boost::spirit::qi::any_uint_parser<unsigned int, 10u, 1u, -1>, boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::standard, true, false>, boost::fusion::cons<boost::spirit::qi::any_uint_parser<unsigned int, 10u, 1u, -1>, boost::fusion::cons<boost::spirit::qi::literal_char<boost::spirit::char_encoding::standard, true, false>, boost::fusion::cons<boost::spirit::qi::any_uint_parser<unsigned int, 10u, 1u, -1>, boost::fusion::nil_> > > > > > > >, mpl_::bool_<false> >}' and size '8' in a region of type 'char' and size '1' [-Wplacement-new=] I'm not familiar with boost::function internals, but the warning looks serious enough to do something about it. I.e. if it's actually benign, it would be nice to silence it to avoid causing panic.

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[graph] Many outstanding pull requests
by Jared Grubb 22 Apr '16

22 Apr '16

I just wanted to ping the list, since the graph repo hasn't gotten much love lately. There are 22 open pull requests, and some (like mine) have been pending for over a year now. is there an active maintainer? https://github.com/boostorg/graph/pulls Jared

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[quickbook] Template problems
by Edward Diener 21 Apr '16

21 Apr '16

I am seeing these template problems with quickbook using the 'develop' branch: 1) I have a cxxd_templates.qbk file which has this template: [template power[x y] '''[x]<superscript>[y]</superscript>'''] I include it first in my main .qbk file as: [include cxxd_templates.qbk] In another .qbk file, which is also included in my main .qbk file after the cxxd_templates.qbk I have: "Despite the fact that there are [power 2..n] possible ..." etc. but this shows up as is: "Despite the fact that there are [power 2..n] possible ..." etc. If I just put the template at the top of that other .qbk file instead the expansion actually takes place. Why is this ? Is not the template global to all sections of the doc after it is defined somewhere ? 2) The template above when expanded via [power 2..n] shows x with y superscripted rather than 2 with n superscripted. Why is this and how do I get it to work properly ?

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[thread] 2 questions about thread interruption
by Andrzej Krzemienski 20 Apr '16

20 Apr '16

Hi, I have two questions connected to thread interruption in Boost.Thread. *1.* The docs say that interrupt_and_join_if_joinable is defined as follows: ``` struct interrupt_and_join_if_joinable{ void operator()(thread& t) { t.interrupt(); if (t.joinable()) { t.join(); } }}; ```

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Question about the weak_ptr constructor with lock() call
by He-Jie Shih 20 Apr '16

20 Apr '16

Hi all, I have question about this line: https://github.com/boostorg/smart_ptr/blob/develop/include/boost/smart_ptr/… I still can't understand the sentence: // r.px may already have been invalidated. The px(r.px) // conversion may require access to *r.px (virtual inheritance). The px is just a scalar. Why assigning the scalar will require the de-reference operator? The comment says it's in virtual inheritance, but I still have not idea about it. Thanks, Jerry

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[boost.process] 0.6 Redesign
by Klemens Morgenstern 20 Apr '16

20 Apr '16

Hi, I am currently working on a new version (0.6) of boost.process which mainly provides a new interface. Most of the underlying features have be derived from the older boost.process version. By doing all this, I tried to hide basically all platform-specifics, so that no #ifdefs are required as in 0.5. It is somewhat inspired by python and std::thread. I really hope this can help to make boost.process an official library. At the current state, I have all functionality in the library that I want, but it's not polished at all. Also it of course needs more tests and documentation. But I think it sufficient to get the basic idea. You can check it out here: https://github.com/klemens-morgenstern/boost-process/tree/develop And the little documentation it has is found here: http://klemens-morgenstern.github.io/process/ Additionally here are the development notes: https://github.com/klemens-morgenstern/boost-process/issues/2 At the current state, the tests pass on linux as well as windows (gcc-5 & MSVC-14). Requirements are C++, boost.fusion, boost.asio, boost.iostreams, boost.filesystem and boost.system. I really could use some feedback and hope you're interested. Sincerely, Klemens Here's some sample code: child c = execute("program", "param1", std_err > "error.log"); And to show off a little: Or you can modify the environment read the output into a future, write the input via pipe and redirect stderr to null. std::future<std::string> fut; process::pipe p; asio::io_service io_service; auto c = execute("other-prog", std_out > fut, std_in < p; std_err > null; env["PATH"]+="/tmp", env["BOOST_VERSION"]="1.61", io_service); iostreams::streams<iostreams::file_descriptor_sink> str(p.sink()); The child class binds the subprocess analogue to an std::thread, i.e. it will wait for the process to finished. It can be detached, terminated and waited for.

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