March 2016 - Boost - lists.boost.org

A GUI Library
by jinhao 09 Nov '17

09 Nov '17

Hi, all I am developing a GUI library, it takes aim at easy-to-use and portable library for modern C++ methods. The project at http://stdex.sourceforge.net A git repository at http://nanapro.codeplex.com A brief at http://nanaproject.wordpress.com/2011/12/16/preliminary-study-of-nana-c-lib… Is there any interest in this library? Regards Jinhao

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Re: [boost] Boost CRC maintainer (Daryle Walker) missing in action?
by Olaf van der Spek 19 Jun '17

19 Jun '17

Hi Daryle, Any luck on your new setup? Gr, Olaf On Mon, Nov 28, 2011 at 1:11 AM, Daryle Walker <darylew(a)gmail.com> wrote: > I can look at it once I've finished my new setup. > > I had to reset my computer after a partial crash years ago. I never > got around to recreating my programming setup. My computer had been > at its maximum Operating System level back then, which is now 3 > versions behind. For the past few months, I've had my sister's old > laptop, with Windows Vista, and am trying to add a programming setup > to it now. > > > On Tue, Nov 22, 2011 at 7:18 AM, Beman Dawes <bdawes(a)acm.org> wrote: >> Hi Daryle, >> >> This guy has volunteered to take over maintenance of Boost CRC. Should >> we take him up on his offer? > >> ---------- Forwarded message ---------- >> From: >> Date: Wed, Nov 2, 2011 at 7:51 AM >> Subject: [boost] Boost CRC maintainer (Daryle Walker) missing in action? >> To: boost(a)lists.boost.org >> >> >> Hi, >> >> It looks like the Boost CRC maintainer (Daryle Walker) is missing in action? >> >> No response to tickets from the past 3 years. What's the procedure in this case? >> >> https://svn.boost.org/trac/boost/ticket/2492 >> https://svn.boost.org/trac/boost/query?component=crc&col=id&col=summary&col… > > -- > Daryle Walker > Mac, Internet, and Video Game Junkie > darylew AT gmail DOT com -- Olaf

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[msm] [statechart] unmerged PRs
by András Kucsma 23 May '17

23 May '17

Hi Everyone, There are a couple of PRs for msm and statechart by me and others, which didn't get any attention for many months now. Can the maintainers please take a look at them? https://github.com/boostorg/msm/pulls https://github.com/boostorg/statechart/pulls Thank you, Andras

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[container] moving a pre-built vector into a flat_set
by Sam Kellett 12 Mar '17

12 Mar '17

a common problem i encounter is that i have two stage's w/r/t to a large collection of data: building and querying. vector is obviously the king of building. flat_set is the king of querying. so what i often tend to do is build up a very large vector, sort it then create a flat_set using the flat_set(ordered_unique_t) constructor. however this still copies the entire vector into the flat_set, right? what i would like to be able to do is move the vector straight into the flat_set, something like: std::vector<T> data; flat_set data_set1(std::move(data)) // move vector in and sort it // or: std::sort(data.begin(), data.end()); // sort vector flat_set data_set2(ordered_unique_t, std::move(data)) // and move it in is this doable (am i just being blind?) or is there plans/interest for this?

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[nowide] Library Updates
by Artyom Beilis 04 Mar '17

04 Mar '17

Hello, Disclaimer: --------------- I recently discovered that virtually all e-mails sent from Yahoo account to any mailing lists go to user's spam due to recent Yahoo's DMARC policy. So I'm sending some important stuff from GMail account that almost certainly was missed: What is Boost.Nowide: -------------------------------- Boost.Nowide is a library that make cross platform Unicode aware programming easier. The library provides an implementation of standard C and C++ library functions, such that their inputs are UTF-8 aware on Windows without requiring to use Wide API. It was inspiration and inspired by http://utf8everywhere.org/ development ideas and policy. Some updates regarding Boost.Nowide ------------------------------- 1. Library moved to github and its format is converted to modular boost layout: https://github.com/artyom-beilis/nowide 2. Fixed unsupported std::ios::ate flag by boost::nowide::fstream 3. Added some C++11 interfaces to boost::nowide::fstream 4. Added integration functionality with boost::filesystem: https://github.com/artyom-beilis/nowide/blob/master/include/boost/nowide/in… Note: that the links to the source code on review schedule aren't relevant, it should be: - Code: https://github.com/artyom-beilis/nowide - Documentation: http://cppcms.com/files/nowide/html/ Also the library is still looking for review manager. Artyom Beilis P.S.: I'm sorry if you are getting this as "duplicate"

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bad include guards
by Steven Watanabe 26 Jan '17

26 Jan '17

AMDG The following pairs of files have identical include guards ./boost/concept_check/general.hpp ./boost/concept/detail/msvc.hpp ./boost/concept_check/msvc.hpp ./boost/concept/detail/msvc.hpp ./boost/filesystem/cerrno.hpp ./boost/cerrno.hpp ./boost/interprocess/containers/tree.hpp ./boost/interprocess/containers/detail/tree.hpp ./boost/mpl/min_max.hpp ./boost/mpl/max.hpp ./boost/mpl/vector/aux_/front.hpp ./boost/mpl/list/aux_/front.hpp ./boost/multi_index/identity_fwd.hpp ./boost/multi_index/identity.hpp ./boost/python/pointee.hpp ./boost/python/detail/pointee.hpp ./boost/spirit/phoenix/closures.hpp ./boost/lambda/closures.hpp ./boost/xpressive/proto/v1_/proto_typeof.hpp ./boost/xpressive/proto/proto_typeof.hpp ./libs/config/test/boost_no_dep_nested_class.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/config/test/boost_no_mem_templates.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/config/test/boost_no_std_allocator.ipp ./libs/config/test/boost_has_vc6_mem_templ.ipp ./libs/conversion/test.hpp ./libs/any/test.hpp ./libs/interprocess/example/print_container.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/interprocess/test/expand_bwd_test_template.hpp ./libs/interprocess/test/allocation_test_template.hpp ./libs/interprocess/test/printcontainer.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/interprocess/test/print_container.hpp ./libs/interprocess/example/printcontainer.hpp ./libs/iostreams/test/detail/utf8_codecvt_facet.hpp ./boost/detail/utf8_codecvt_facet.hpp ./libs/regex/test/regress/test_regex_search.hpp ./libs/regex/test/regress/test_partial_match.hpp ./libs/serialization/test/C.hpp ./libs/serialization/test/A.hpp ./libs/xpressive/perf/regex_comparison.hpp ./libs/regex/performance/regex_comparison.hpp ./tools/inspect/time_string.hpp ./tools/common/time_string.hpp In Christ, Steven Watanabe

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[MPL] A Proposal
by Bruno Dutra 16 Nov '16

16 Nov '16

Dear Community, About a year ago today, there was a proliferation of threads [1][2][3] in this mailing list concerning the future of Boost.MPL, or even whether it had a future at all, and opinions diverged widely on the matter. Many have expressed concerns about the fact Boost.MPL was long outdated and proposed major changes to open path for modernization, while some others argued against it, fearing unexpected and disastrous side-effects could propagate throughout the rest of Boost. A few questioned if it was worth it at all to spend any further resources on Boost.MPL given the fact new alternatives were coming up, such as Boost.Hana, which departed entirely from template metaprogramming, yet some argued TMP remained a competitive alternative for type computations in C++14 as it has been demonstrated by Peter Dimov in his impressive articles [4] on modern TMP. Amidst all this, a proposal by Robert Ramey [5] caught my attention and inspired me to develop what I call Metal [6], a template metaprogramming library designed on the same core principles as Boost.MPL, but written from the very beginning to take full advantage of C++11. Metal was not designed to be a strict drop in replacement for Boost.MPL though, it was rather meant to be regarded as a modern version of Boost.MPL's original API, diverging only where it could really benefit from modern C++ and that essentially means gains of several orders of magnitude in performance** and lower memory consumption. At this point Metal is very close to where I originally intended to bring it and I think it's time I gauge interest from the community on a modest proposal I've been maturing along the past year. As a modern approach to the same task that Boost.MPL was meant to address, I don't believe Boost would benefit at all from yet another TMP library that would essentially compete with Boost.MPL and even Boost.Hana in some cases, specially as maintainers of older code that depends on Boost.MPL would have to go through major refactoring efforts in order to benefit from such an addition to Boost. I would like to propose something different instead. My proposal is to make Metal officially into a new revision of Boost.MPL's API, essentially MPL2 as the original proposal by Robert Ramey put it, merging both into one single TMP library. The idea would be to provide a thin proxy for the current Boost.MPL API which would have two backends configurable by preprocessor switches: the original implementation and a another one based on Metal. This way older code using Boost.MPL could see immediate gains on performance by selecting the newer backend on supported compilers, while at the same time legacy code maintained on older compilers could still rely on Boost.MPL's impressive ability to run virtually anywhere. On the other hand, newer projects interested on pure type computations would have the newer API entirely available to them. This proposal also overcomes the problem of dealing with the maintainability of Boost.MPL, since it provides a way for smooth transition from legacy hacks required by ancient compilers into a cleaner and easier to maintain C++11 codebase, besides avoiding any breaking changes within existing code in the process. Furthermore, should this proposal make it into Boost, I would be naturally willing to take responsibility for the maintenance of Boost.MPL, which AFAIK has been maintained by the CMT for quite some time now, often with limited resources. Comparing Metal and Boost.MPL there are a few noteworthy differences. Metafunction Classes have proven themselves entirely unnecessary and have thus been removed altogether in favour of pure Lambdas (in the Boost.MPL sense). Moreover, iterators make little sense in a functional world, so these too have been removed despite the fact they may easily be emulated in the new design. Moreover Metal develops the concept of optionals, that is, its metafunctions only have a nested ::type defined when they may be successfully computed, what may be safely tested using metal::is_just and may also be used to SFINAE out of miscomputations. Finally I'd like to point out that Metal was designed to be portable across as many compilers as possible and three of the most popular ones are continuously tested using Travis and Appveyor: Clang 3.5+, GCC 4.8+ and MSVC 14 (2015). I hope this is a reasonable proposal and I look forward into your opinions about it. ** Even though I haven't published any benchmarks yet, an example follows just to back my claims regarding performance (just tested on my personal laptop running linux): //Generate a list containing 10 thousand instances of std::integral_constant, from 0 to 9999 using l = metal::enumerate_t<metal::integer<10000>>; // GCC 5.3 ~0.4 s // Clang 3.7 ~0.5 s //Transform a list containing 5 thousand numbers by squaring each element using l1 = metal::enumerate_t<metal::number<long long, 5000>>; using l2 = metal::transform_t<metal::pow<metal::_1, metal::integer<2>>, l1>; // GCC 5.3 ~5.6 s // Clang 3.7 ~3.0 s [1]: http://thread.gmane.org/gmane.comp.lib.boost.devel/257680 [2]: http://thread.gmane.org/gmane.comp.lib.boost.devel/257983 [3]: http://thread.gmane.org/gmane.comp.lib.boost.devel/258843 [4]: http://pdimov.com/cpp2/simple_cxx11_metaprogramming.html [5]: http://rrsd.com/blincubator.com/bi_suggestion/mpl-lite-or-mpl2/ [6]: http://brunocodutra.github.io/metal/ Regards, Bruno Dutra

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[config] RFC PR 82
by Domagoj Saric 01 Aug '16

01 Aug '16

Hi everyone, I am finally getting back to (trying to) contributing some of my personal projects to Boost. For two of those, Err (https://github.com/psiha/err) and especially Functonoid (a C++11 generalization and rewrite of my previous Boost.Function related work) I need some lower level codegen and/or optimiser control functionality (i.e. portable macros wrapping toolset specific attributes and pragmas) that I've added to my personal fork of Boost.Config and which I've now submitted in the subject PR (https://github.com/boostorg/config/pull/82) I don't expect this PR to be accepted as is/'just like that' so I'm opening this thread where we can discuss which of those changes/macros are welcome, which need more work and which, for some reason, should not be part of Boost.Config (and which, in turn then, I have to move to some 'internal implementation headers' in libraries that will need them). To avoid 'spamming' (and save time;) I'll skip the explanation of the individual macros as I expect them to mostly be self-explanatory (if not from their name then from the minimal Boost.Config documentation additions that are part of th PR). ps. I'll be on the (off) road for the next three weeks so I don't know when I'll be able to respond until I get back... -- "What Huxley teaches is that in the age of advanced technology, spiritual devastation is more likely to come from an enemy with a smiling face than from one whose countenance exudes suspicion and hate." Neil Postman

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[clang][preprocessor] Testing of clang emualting the VC++ preprocessor on Windows
by Edward Diener 07 Apr '16

07 Apr '16

I have made local changes in the Boost preprocessor config.hpp on the 'develop' branch to have clang's emulation of the non-standard VC++ preprocessor act like the VC++ preprocessor as far as Boost PP is concerned. Boost PP has a large number of workarounds for VC++ without which Boost PP preprocessor code would not work when compiling using any version of VC++. I have tested the usual compilers extensively to make sure they are unaffected by these changes as well as the normal clang-linux implementation. Everything remains the same for these compilers with my changes so I am assured the changes will not affect any other compiler implementation. I was able to test both clang-3.8 and the latest build of clang, which is clang-3.9, by invoking clang-cl. My user-config.jam file for these entries looks like: using clang-win : 3.8 : SomePath/clang-cl : <compatibility>vc12 using clang-win : 3.9 : SomePath/clang-cl : <compatibility>vc14 By passing toolset=clang-win-3.8 or toolset=clang-win-3.9 I was able to successfully test these implementations against the Boost PP test code. There are quite a few failures in this clang emulation of the VC++ preprocessor when tested against the preprocessor test code. In fact testing clang emulation of VC++ preprocessor when I don't treat clang as VC++ in Boost PP, but as its normal C++ standard conforming preprocessor, still fails a few cases but far less than when clang is treated as VC++ in Boost PP. Needless to say when invoking clang-linux, which tests the normal clang implementation whether on Windows or Linux, there are no failures in the Boost PP tests. I am perfectly willing to push my changes to 'develop' for the preprocessor. The changes are essentially just in the Boost PP config.hpp file, which sets macros which control the compiler workarounds in Boost PP. As I have previously stated I am not personally willing to try to figure out or report to clang why their VC++ preprocessor emulation in Boost PP is failing, but others who are interested can do so if they wish. My personal reasons for this is that I think it is a very bad thing to attempt to replicate an already flawed C++ preprocessor in another compiler in general code. I also have spent enough time working with the VC++ preprocessor trying to find workarounds for its non-standard behavior that I do not want to do so for another preprocessor which attempts to be non-standard. I posted this to alert others to my plans to update Boost PP on 'develop' with this change, in case anybody is greatly opposed to it or wants to discuss it further. The change will not affect any other compiler but clang in VC++ preprocessor emulation mode. Unless I hear objections etc. I plan to push my update within the next day although I will wait awhile for any replies to this post.

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Nasty compile time reflection and iteration for POD types using C++14 without macro
by Antony Polukhin 07 Apr '16

07 Apr '16

Hello, I've come up with a trick that may be useful in Boost.Hana, Boost.Serialization or some other libraries. Here's a small motivating example: #include <cstdio> #include <boost/type_index.hpp> #include "magic.hpp" struct foo { unsigned char i0; unsigned int i1; unsigned short i2; unsigned long long i3; unsigned char ar[2]; int q; std::size_t w; int* p1; const void* p2; int const**const**** p_crazy; const double d; }; template <std::size_t I, class T> void print(T& f) { printf( "%lu\t\t%s\n", (std::size_t)get(f), boost::typeindex::type_id<decltype(get(f))>().pretty_name().c_str() ); } int main() { foo f {10, 11, 12, 13, {14, 15}, 16, 17, 0, 0, 0, 30.0}; print<0>(f); print<1>(f); print<2>(f); print<3>(f); print<4>(f); print<5>(f); print<6>(f); print<7>(f); print<8>(f); print<9>(f); print<10>(f); print<11>(f); static_assert(tuple_size<foo>() == 12, "failed tuple size check"); } That example will output: 10 unsigned char 11 unsigned int 12 unsigned short 13 unsigned long long 14 unsigned char 15 unsigned char 16 int 17 unsigned long 0 int* 0 void const* 0 int const** const**** 30 double Core ideas: 1) We may detect the POD structure fields by the POD's constructor: template <std::size_t I> struct ubiq { std::size_t* ref_; template <class Type> constexpr operator Type() const noexcept { ref_[I] = type_to_id(identity<Type>{}); return Type{}; } }; template <class T, std::size_t... I> constexpr auto type_to_array_of_type_ids(std::size_t* types) noexcept -> decltype(T{ ubiq{types}... }) { return T{ ubiq{types}... }; } Here type_to_array_of_type_ids will return array with types via `types`, each element of array encodes some basic type. 2) Then we convert that array into an std::index_sequence<I...> and create a type with same layout as our POD type: template <std::size_t... I> constexpr auto as_tuple_impl(std::index_sequence<I...>) noexcept { return std::tuple< decltype( id_to_type(std::integral_constant<std::size_t, I>{}) )... >{}; } 3) Now we have a type with same layout, and we cast the structure to that type: template <std::size_t I, class T> decltype(auto) get(const T& val) noexcept { auto t = reinterpret_cast<const decltype(detail::as_tuple<T>())*>( std::addressof(val) ); return get(*t); } Drawbacks: * works for POD types only (could be possibly extended to trivial constructible type) * structures with non-default alignment are not supported * step 3) contains an UB, but even without that step we're still able to get field types of the POD type and fields count * current draft implementation does no support nested PODs (could be fixed easily) * current draft implementation works only on libc++ (could be fixed easily, requires reimplementing std::tuple) * there's no known to me way to make get<>() method constexpr * does not detect constness (because of that get<>() always returns const reference) Is there any interest in this feature? Sources https://github.com/apolukhin/magic_get/blob/master/magic2.cpp Online experiments can be done here: http://coliru.stacked-crooked.com/a/c33857e566e76ce2 -- Best regards, Antony Polukhin

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Boost 1.61.0 Beta 1
by Vladimir Prus 06 Apr '16

06 Apr '16

The first beta packages for 1.61.0 beta 1 are now available: http://boost.cowic.de/rc/boost_1_61_0_b1.zip http://boost.cowic.de/rc/boost_1_61_0_b1.7z http://boost.cowic.de/rc/boost_1_61_0_b1.tar.bz2 http://boost.cowic.de/rc/boost_1_61_0_b1.tar.gz There are no changes compared to RC2, expect for different names of the archives and different name of the top-level directory in the archives. The SHA256 checksums are as follows: 3f8888099ee6f62b412a13be916dead2bacbdd6d69e5afd5b6fea4bb738e5df4 boost_1_61_0_b1.7z 866941f0038b27fcc69ced1490b2dc5fa8d20f505d66b939a92a68ef194d1a6c boost_1_61_0_b1.tar.bz2 0b92c5fb5b91641409b9675b2fd11d3b3fa5f71dd986d3b5fb03da201bf55474 boost_1_61_0_b1.tar.gz 9dffe5ee7f5f7bf7695f5738c686e44bd266933e3ca68732b0de5520c3c82615 boost_1_61_0_b1.zip Signed list of checksums should be posted within 24 hours. 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. It was discovered that the .zip and .7z archives actually have LF line endings, at least in some places. Fixing this is not quite trivial, as Travis uses ancient version of Ubuntu and Git, and is not deemed critical, as most Windows editors handle LF just fine. We might do something for the final release, or might not. Thanks! -- The release managers

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[build] How to use with clang on windows?
by John Maddock 03 Apr '16

03 Apr '16

What's the correct way to configure clang on windows with current Boost.Build? If I use: using clang-win : 3.7 : "C:/Progra~2/MICROS~4.0/VC/Clang 3.7/bin/x86/clang.exe" : <cxxflags>-std=c++11 <compatibility>vc14 ; to configure the clang that ships with VC14 I see: compile-c-c++ ..\..\..\bin.v2\libs\smart_ptr\test\shared_ptr_basic_test.test\clang-vc14-win-3.7\debug\shared_ptr_basic_test.obj clang.exe: error: no such file or directory: '/Od' clang.exe: error: no such file or directory: '/Ob0' clang.exe: error: no such file or directory: '/W3' clang.exe: error: no such file or directory: '/GR' clang.exe: error: no such file or directory: '/MDd' clang.exe: error: no such file or directory: '/Zc:forScope' clang.exe: error: no such file or directory: '/Zc:wchar_t' clang.exe: error: no such file or directory: '/wd4675' clang.exe: error: no such file or directory: '/EHs' Same errors with the llvm clang-3.9. On the other hand if I initialize with: using clang : : "C:/Progra~2/LLVM/bin/clang.exe" : <cxxflags>-std=c++14 <compatibility>vc14 <cxxflags>-fms-compatibility-version=19.00.22609 ; Then this sort of works for llvm clang, but not the msvc one (can't find c2.exe), but the compiler is identified as "clang-linux" and I see: LINK : warning LNK4044: unrecognized option '/-start-group'; ignored LINK : warning LNK4044: unrecognized option '/Bstatic'; ignored LINK : warning LNK4044: unrecognized option '/Bdynamic'; ignored LINK : warning LNK4044: unrecognized option '/-end-group'; ignored Plus some linker errors such as: yield_k_test.obj : error LNK2019: unresolved external symbol __mm_pause referenced in function "void __cdecl boost::detail::yield(unsigned int)" (?yield@detail@boost@@YAXI@Z) Ideas? Thanks, John.

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Boost 1.61.0 open for fixes
by Vladimir Prus 02 Apr '16

02 Apr '16

The master branch is now open for bugfixes for 1.61.0. Please make sure that develop tests are healthy prior to merging. We're two weeks late relative to the plan, so further dates were also moved by two weeks in the calendar. -- The release managers

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[Trac][convert] Associate Vladimir as author of Boost.Convert
by Vicente J. Botet Escriba 01 Apr '16

01 Apr '16

Hi, I requested sometime ago to add convert to the Trac system. It was done, but it was associated to me as maintainer. Please, could someone assign it to Vladimir Batov Vladimir, I guess you need to give your use in name. Best, Vicente Convert <http://www.boost.org/doc/libs/1_60_0/libs/convert/> An extendible and configurable type-conversion framework. Author(s) Vladimir Batov First Release 1.59.0

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Coroutine2 examples - Cannot link properly.
by Carlos Ferreira 01 Apr '16

01 Apr '16

Hello to all. I'm having trouble in compiling the coroutine2 examples. For the fibonacci example, the following linking error occurs: /usr/include/boost/coroutine2/detail/pull_control_block.ipp:62: undefined reference to `boost::context::execution_context::current()' Now, I know that I have to link against boost context, something that I'm already doing, but for some reason, it is not enough. Can anyone help me with this? Thank you. -- Carlos Miguel Ferreira Researcher at Telecommunications Institute Aveiro - Portugal Work E-mail - cmf(a)av.it.pt Skype & GTalk -> carlosmf.pt(a)gmail.com LinkedIn -> http://www.linkedin.com/in/carlosmferreira

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[boost 1.61] authorization to merge to master
by Raffi Enficiaud 31 Mar '16

31 Mar '16

Dear Boost, I would like to merge a boost.test bugfix to master. Those changes are running on develop for a week. I haven't done my PR for the website change log update because of that (would change the content of the PR). According to the schedule, boost 1.61 is open for bugfixes since 10 days now, but as I understood, we are still waiting for post RC2 go. - do I still have time for the website PR? - would the opening 1.61 for bugfixes be announced on the ML? - Am I allowed to merge those changes, so that I can reopen develop for post 1.61 developments? Thanks, Raffi Enficiaud

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[boost 1.61 - [thread] Request for permission to merge
by Vicente J. Botet Escriba 31 Mar '16

31 Mar '16

Hi, I would like to merge once it is announced that the release branch is open for fixes a minor fix https://svn.boost.org/trac/boost/ticket/11562 - (condition_variable_any::wait_until + recursive_mutex + steady_clock) timer expires after computer time is set forward on Ubuntu 64-bit add missing template parameter in wait_until. https://github.com/boostorg/thread/commit/9db70b803d8f45632cd92cd61ab019c1f… and the rollback of something that resulted in a regression https://svn.boost.org/trac/boost/ticket/12049 - Assertion failure from detached threads during shutdown rollback BOOST_THREAD_PATCH. https://github.com/boostorg/thread/commit/47357de276fe4fc01469f34c1dbf8b26f… Best, Vicente

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Re: [boost] [filesystem] Horrible documentation
by Tatsuyuki Ishi 31 Mar '16

31 Mar '16

> From: Edward Diener <eldiener(a)tropicsoft.com> > Date: Wed, 30 Mar 2016 00:06:00 -0400 > Subject: Re: [boost] [filesystem] Horrible documentation > > What sort of documentation unification with other libraries do you mean ? By saying unification, I'm talking about the green-background header. It's in most documentation and also on the homepage. > Can you not increase the font size, if it is too small for you to read, in your preferred browser since the doc is HTML ? The layout is quite problematic. Not only the font, text breaks border, and the page is too tall(long). I noticed it's created with FrontPage 2002. Come on, this is 2016.

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[release] Download data
by Daniel James 31 Mar '16

31 Mar '16

Hi, Currently the download details for a release are included in the quickbook source file for the release notes, which is a bit wonky, and makes it tricky to add extra data, so I'm thinking about storing it separately. This should make it easier to add things like hash signatures and links to third party downloads, such as the windows binaries. So I'm thinking about how to make it easy for people to add the details of their downloads. Could possibly create an extra file for each release, and then people can add data using pull requests, much as we've been using pull requests on the quickbook files, which seems to work fairly well. Another possibility is that we could pull in the details from the server's API, although I don't really fancy having to support multiple data sources with different APIs. Any other ideas? Also, is there any way in which you'd like me to make this kinds of information available for your scripts, packaging etc. Here's a rough version of how the internal data might be stored in a JSON file (other file formats are possible): { 'version': '1.61.0', 'status': 'beta', 'release-notes': '/feed/history/boost_1_61_0.qbk', 'documentation': '/doc/libs/1_61_0/', 'downloads': [ { 'url': 'http://..../boost_1_61_0_beta1.tar.bz2', 'hash': '484c635.....' }, { 'url': 'http://..../boost_1_61_0_beta1.7z', 'hash': 'f93de8.....' }, // ... ], 'third-party': [ { 'url': 'http://...', 'title': 'Windows binaries', 'whatever_else': '' } ] }

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[filesystem] Horrible documentation
by Tatsuyuki Ishi 30 Mar '16

30 Mar '16

Sorry for complaining. Is there any plan to use any documentation tool to regenerate this? It's not unified with other libraries, and too horrible due to the small font size. I really can't read that.

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[Root Pointer] Benchmark w/ Threading = 124% faster
by Phil Bouchard 30 Mar '16

30 Mar '16

I just noticed that if I do not define the BOOST_DISABLE_THREADS macro, root_ptr is faster than allocate_shared_noinit by 124%: unique_ptr (new): 42.1397 unique_ptr (make_unique): 43.4631 shared_ptr (new): 76.4543 shared_ptr (make_shared): 76.6611 shared_ptr (allocate_shared_noinit): 81.9926 root_ptr (new): 66.3417 Thanks, -Phil

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Fwd: [sort parallel] New Parallel Sort Algorithm
by Francisco José Tapia 29 Mar '16

29 Mar '16

This message is for to announce the new version of the Boost Sort Parallel algorithms. You can find in http://github.com/fjtapia/sort_parallel. In the documentation, you can see the description of the algorithms, examples of invocations, and the graphs of the benchmark of the algorithms. The benchmark was not include in the library. I created other repository https://github.com/fjtapia/sort_parallel_benchmark, where you can find the code of the benchmark, the library, and the external code of the TBB parallel stable sort. It was not logic, include external code inside the library. The most significant of this version is the new parallel sort algorithm (internally named Block Indirect Sort) In the Parallel Sort Algorithms, we can find two groups. - Algorithms very fast with many threads (GCC Parallel Sort, Microsoft Parallel Buffered Sort), but use an additional memory as the data. - Algorithms without additional memory, but slower with many threads (TBB Parallel Sort, Microsoft Parallel Sort) The new algorithm *invented, designed and implemented by the author, provide the speed of GCC Parallel Sort and a memory usage similar to TBB. With the additional advantage that don't need any library ( Open MP , TBB, Microsoft PPL …). Only need a C++11 compiler. An example shows you this : Sorting 100 000 000 random numbers of 64 bits. In a server with 32 threads. The results obtained was *Time spent* *Memory used (MB)* *GCC Parallel Sort* 1.05 secs 1560 MB *TBB Parallel Sort* 1.76 secs 783 MB *Block Indirect Sort* 0.97 secs 790 MB In the repository with the benchmark code you can find the benchmark results with several machines https://github.com/fjtapia/sort_parallel_benchmark/tree/master/Linux64_GCC/… <https://github.com/fjtapia/sort_parallel_benchmark/tree/master/Linux64_GCC/…>In these files, you can see the rival is GCC. TBB is clearly surpassed, due to their internal algorithm. GCC divide the data, sorted independently by all the threads. And after for to merge do an easy process, and copy in an auxiliary memory, of the same size than the used by the data. All the threads are fed, but need the double of memory. The new algorithm, do the division, and sort independently, but for the merge, have a small buffer of 1024 elements, and when a part is moved to the buffer, must calculate which part must be copied in that place. Do the same but without the additional memory. Due this, need more CPU for to do the process. The hyper threading (HT) provide around a 30% more power to the processor, and usually in the machines with HT activate, the new algorithm is a bit faster than GCC, and with the HT deactivate is slower, and TBB is slower except when very big objects. But then the bottleneck is not the algorithm, is the data bus The new algorithm is a collection of bad algorithms when you have only 1 thread. But they are easily subdivided. This permit parallelize all the process and have fed all the threads. The new algorithm is documented in two articles - block_indirect_sort_brief_en.*:* (Introduction and graph benchmarks) - block_indirect_sort_en.pdf: (Introduction, detailed description of the algorithm and benchmarks.) If you want to test the benchmark in your machine it's easy. In the benchmark repository, you have the code used, and shell scripts for to compile and run, saving the results in a Results.txt file, for Linux GCC and CLANG and Windows Visual Studio 15 If you see any problem, mistake, something to improve or need any other information, please, say me. Yours Francisco * Invented: The algorithm had been ideate, designed and implemented beginning from zero from an old idea. After read hundreds of articles and books, I didn't find any similar. If you know something, please say me. But the important is not the author, is provide a fast, robust, and easy to use algorithm to the community of programmers.

1 0

[Boost 1.61] Open for bugfixes?
by Louis Dionne 29 Mar '16

29 Mar '16

Hi, On the release calendar [1], it is written that Boost 1.61 is currently open for bug fixes (since March 17). Some previous discussion left me under the impression that authors still had to ask a permission for pushing to their master branches. So, can I push (bugfixes) to Hana's master branch? Do I have to ask the permission when the calendar says it's open? Can I always rely exclusively on the official calendar at [1]? Thank you, Louis Dionne [1]: http://www.boost.org/community/index.html

2 2

[move][sort] Asymptotically optimal stable and in-place merging and sorting with no auxiliary memory
by Ion Gaztañaga 27 Mar '16

27 Mar '16

[Disclaimer, long e-mail, thank you for your attention] Hi to all, Some months ago I tried to gain interest from sorting experts about implementing stable and inplace merge [O(N)] or sort [O(NlongN)] algorithms that don't need additional memory. My main use case for these algorithms was lowering the complexity guarantees of range insertion functions offered by flat associative containers without any temporary allocation (the programmer does not expect allocations when capacity() is big enough to hold the new elements). On the other hand, I wanted those algorithms to be adaptive so as to take advantage of the extra capacity already allocated by flat containers. Of course, if a good implementation is available in Boost, it could be used as existing practice to change the worst-case complexities of some STL algorithms when no additional memory (e.g. get_temporary_buffer()) is available. After reviewing several algorithms from papers and some open source implementations, I decided to implement one of those algorithms. The implemented algorithm is based on the GrailSort algorithm developed by Andrey Astrelin. The main idea of the my adaptive_sort algorithm is explained by Andrey in an article published by the russian collaborative blog Habrahabr (http://habrahabr.ru/post/205290/) The algorithm is based on ideas explained by Huang and Langston in their paper "Fast Stable Merging and Sorting in Constant Extra Space (1989-1992" (http://comjnl.oxfordjournals.org/content/35/6/643.full.pdf) Since the implementation from (https://github.com/Mrrl/GrailSort) is macro-based, does not support non-memcopyable types and has a MIT license (which seems to be problematic for Boost), I implemented the algorithm from scratch following the article and taking ideas from Andrey's implementation. I added some new ideas and optimizations in order to reduce comparisons and elements moves. I must say that the implementation was really hard for someone like me without experience in sorting algorithms, the complexity is huge when compared with a classic mergesort algorithm. The implementation is already in develop and master branches but the develop branch contains more tests and a refactored and more documented code. So please check the code from the develop branch if interested. The implementation is still experimental and not production ready. What about benchmarks? I've only experimented in the oldest Visual compilers to make sure it correctly supports Boost.Move emulation and complexity guarantees were correct. Note that the STL algorithms tested in the benchmark might not be as fast as current implementations. In general, the new algorithms need much more elements moves than algorithms that allocate O(n) memory, but they are still quite fast when data movement is cheap (e.g. when a move constructor just copies a couple of pointers). These are the numbers for A VERY LIGHTWEIGHT object (a struct holding two integers, one for the key, another one to test the stability, don't take times very seriously, just pay attention to the number of comparisons/moves). ////////////////////////// ////////////////////////// STABLE MERGING ////////////////////////// ////////////////////////// - N: number of elements - NK: number of keys (0 means all keys different) - InplaceMerge: std::inplace_merge - Sqrt2AdaptMerge: adaptive_merge with an auxiliary buffer of 2*sqrt(N) elements - SqrtAdaptMerge: adaptive_merge with an auxiliary buffer of sqrt(N) elements - AdaptMerge: adaptive_merge with no external buffer - Cmp: number of comparisons / N - Cpy: number of move constructor/assignments / N - (ratio): time of execution / time needed by InplaceMerge ---------------------------------------------- Numbers produced by the bench_merge.cpp test in Boost.Move: ---------------------------------------------- - - N: 100001, NK: 511 - - InplaceMerge Cmp: 0.9989 Cpy: 1.5000 633.65us ( 1.00) Sqrt2AdaptMerge Cmp: 1.2429 Cpy: 4.4209 910.16us ( 1.44) SqrtAdaptMerge Cmp: 4.2708 Cpy: 5.6712 1.63ms ( 2.57) AdaptMerge Cmp: 5.6014 Cpy: 8.7573 3.11ms ( 4.91) - - N: 100001, NK: 2047 - - InplaceMerge Cmp: 0.9998 Cpy: 1.5000 604.77us ( 1.00) Sqrt2AdaptMerge Cmp: 1.2449 Cpy: 4.4483 934.83us ( 1.55) SqrtAdaptMerge Cmp: 2.0131 Cpy: 4.7609 1.12ms ( 1.85) AdaptMerge Cmp: 2.7608 Cpy: 11.1419 2.83ms ( 4.67) - - N: 100001, NK: 8191 - - InplaceMerge Cmp: 0.9999 Cpy: 1.5000 653.51us ( 1.00) Sqrt2AdaptMerge Cmp: 1.2443 Cpy: 4.3179 943.86us ( 1.44) SqrtAdaptMerge Cmp: 1.4661 Cpy: 4.4348 998.62us ( 1.53) AdaptMerge Cmp: 1.7692 Cpy: 10.6292 2.54ms ( 3.89) - - N: 100001, NK: 32767 - - InplaceMerge Cmp: 1.0000 Cpy: 1.5000 772.06us ( 1.00) Sqrt2AdaptMerge Cmp: 1.2417 Cpy: 4.4317 1.03ms ( 1.33) SqrtAdaptMerge Cmp: 1.3320 Cpy: 4.4758 1.06ms ( 1.38) AdaptMerge Cmp: 1.5295 Cpy: 10.1233 2.44ms ( 3.16) - - N: 100001, NK: 0 - - InplaceMerge Cmp: 1.0000 Cpy: 1.5000 881.88us ( 1.00) Sqrt2AdaptMerge Cmp: 1.2387 Cpy: 4.4124 1.16ms ( 1.31) SqrtAdaptMerge Cmp: 1.2933 Cpy: 4.4412 1.20ms ( 1.36) AdaptMerge Cmp: 1.4110 Cpy: 7.5794 1.93ms ( 2.19) In general, with no memory and enough keys, the algorithm needs 7,5*N data moves and 1,5*N comparisons. Data locality is quite high and with cheap-moving types the overall time can be just two-three times slower. With fewer keys, the algorithm might need upt to 5xN comparisons and 11xN moves. Number are improved if an auxiliary buffer of sqrt(N) elements is available. The number of comparisons and moves are even better than those shown in experimental results from several papers, but I still find them quite high. The algorithm needs some initial steps (e.g. unique key extraction) that are not amortized during the merge (adaptive_sort amortizes the initial steps much better ). I've derived the merge algorithm from the sorting algorithm so maybe there is room for improvement (I've invested much more time in the sorting algorithm). ////////////////////////// ////////////////////////// STABLE SORTING ////////////////////////// ////////////////////////// Numbers when sorting: - N: number of elements - NK: number of keys (0 means all keys different) - MergeSort: A half-copying mergesort (it only needs N/2 auxiliary memory) implemented in boost/move/algo/detail/merge_sort.hpp. Based on the paper "Fast mergesort implementation based on half-copying merge algorithm" by Cezary Juszczak (http://kicia.ift.uni.wroc.pl/algorytmy/mergesortpaper.pdf) Usually faster than std implementations with less auxiliary memory. - StableSort: std::stable_sort - HeapSort: std::heap_sort - QuartAdaptSort: adaptive_sort with N/4 auxiliary memory - Sqrt2AdaptSort: adaptive_sort with 2*sqrt(N) auxiliary memory - SqrtAdaptSort: adaptive_sort with sqrt(N) auxiliary memory - SqrtHAdaptSor: adaptive_sort with sqrt(N)/2 auxiliary memory - AdaptSort: adaptive_sort with no auxiliary memory - Cmp: number of comparisons / N - Cpy: number of move constructor/assignments / N - (ratio): time of execution / time needed by MergeSort [numbers produced by the bench_sort.cpp test in Boost.Move] - - N: 100001, NK: 511 - - MergeSort Cmp: 16.379 Cpy: 16.707 6.49ms ( 1.00) StableSort Cmp: 20.594 Cpy: 22.978 10.85ms ( 1.67) HeapSort Cmp: 16.992 Cpy: 22.098 10.98ms ( 1.69) QuartAdaptSort Cmp: 17.659 Cpy: 26.314 8.34ms ( 1.29) Sqrt2AdaptSort Cmp: 17.829 Cpy: 35.340 9.90ms ( 1.53) SqrtAdaptSort Cmp: 27.805 Cpy: 56.059 19.48ms ( 3.00) SqrtHAdaptSort Cmp: 27.356 Cpy: 60.375 20.35ms ( 3.14) AdaptSort Cmp: 27.352 Cpy: 67.889 21.83ms ( 3.36) - - N: 100001, NK: 8191 - - MergeSort Cmp: 16.394 Cpy: 16.725 7.47ms ( 1.00) StableSort Cmp: 20.578 Cpy: 22.978 11.92ms ( 1.60) HeapSort Cmp: 16.992 Cpy: 22.099 11.91ms ( 1.59) QuartAdaptSort Cmp: 17.676 Cpy: 26.362 9.26ms ( 1.24) Sqrt2AdaptSort Cmp: 17.847 Cpy: 35.747 10.93ms ( 1.46) SqrtAdaptSort Cmp: 18.977 Cpy: 41.641 12.19ms ( 1.63) SqrtHAdaptSort Cmp: 17.076 Cpy: 57.799 15.47ms ( 2.07) AdaptSort Cmp: 17.090 Cpy: 67.179 17.37ms ( 2.33) - - N: 100001, NK: 32767 - - MergeSort Cmp: 16.395 Cpy: 16.727 7.66ms ( 1.00) StableSort Cmp: 20.581 Cpy: 22.986 12.16ms ( 1.59) HeapSort Cmp: 16.994 Cpy: 22.099 11.96ms ( 1.56) QuartAdaptSort Cmp: 17.674 Cpy: 26.319 9.47ms ( 1.24) Sqrt2AdaptSort Cmp: 17.833 Cpy: 35.792 11.16ms ( 1.46) SqrtAdaptSort Cmp: 18.967 Cpy: 41.604 12.42ms ( 1.62) SqrtHAdaptSort Cmp: 17.065 Cpy: 57.756 15.71ms ( 2.05) AdaptSort Cmp: 17.081 Cpy: 67.131 18.32ms ( 2.39) - - N: 100001, NK: 0 - - MergeSort Cmp: 16.399 Cpy: 16.731 7.76ms ( 1.00) StableSort Cmp: 20.521 Cpy: 22.920 12.23ms ( 1.58) HeapSort Cmp: 16.991 Cpy: 22.094 11.85ms ( 1.53) QuartAdaptSort Cmp: 17.671 Cpy: 26.380 9.50ms ( 1.22) Sqrt2AdaptSort Cmp: 17.825 Cpy: 35.653 11.17ms ( 1.44) SqrtAdaptSort Cmp: 18.954 Cpy: 41.545 12.42ms ( 1.60) SqrtHAdaptSort Cmp: 17.058 Cpy: 57.694 15.66ms ( 2.02) AdaptSort Cmp: 17.072 Cpy: 67.072 17.57ms ( 2.26) In general, with no memory and enough keys, the algorithm needs nearly optimal comparisons and significantly more (4x) data movements. Data locality is quite high and with cheap-moving types the overall time can be just two-three times slower. With fewer keys, the algorithm performs worse but it's quite competitive. When extra memory (e.g. sqrt(N)) is available, the algorithm is quite fast with cheap-moving types. //////////////////////////////////////////// Final words: The effort to implement the algorithms was big and I couldn't fix many open bugs in my libraries, so in the following months I don't expect to invest much time on this. At least I wanted to publicly share the committed implementation so that it can be improved by sorting experts. I don't claim these algorithms are groundbreaking or even useful for many programmers, but they might be a good starting point. I'm not happy with the implementation as the algorithm is complicated and I' haven't found a way to simplify it further without noticeable slowdowns. For those interested in the implementation and the algorithm: please contribute correct benchmarks and testing, as there are very few open source implementations of similar algorithms. Any optimization, patch or bug report is welcome. Best, Ion

4 9

Boost 1.61.0 Beta 1 Release Candidate 2
by Vladimir Prus 26 Mar '16

26 Mar '16

Second set of release candidates for 1.61.0 beta 1 are now available: http://boost.cowic.de/rc/boost_1_61_0_b1_rc2.zip http://boost.cowic.de/rc/boost_1_61_0_b1_rc2.tar.bz2 http://boost.cowic.de/rc/boost_1_61_0_b1_rc2.tar.gz http://boost.cowic.de/rc/boost_1_61_0_b1_rc2.7z 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 changes from RC1 are: * Top-level directory in the archive matches the name * Zip and 7z archives use CRLF line endings The known issues are: * Documentation build has some wrong-location, extra-files and broken-links issues. * There was a report of Boost.Context issue on OSX Release managers believe these issues are not blocking beta 1. The SHA1 checksums are as follows: 4d3c83d3a802d3dd12d4f2d516b3fcf076f6f6ba boost_1_61_0_b1_rc2.7z 8c6ac7326a3cabcabf6c7876052b73e0d41fc36d boost_1_61_0_b1_rc2.tar.bz2 e82b8ff7c3ad5b08c7dbeac1ea85fcf707a1cd4d boost_1_61_0_b1_rc2.tar.gz 7292e8fdac0566fe098a60a197a5722d381842d3 boost_1_61_0_b1_rc2.zip The SHA256 checksums are as follows: bc8341bfb8c6621319ad9eb732179fc7ec4da35c3cefc31b613f83ec3df10361 boost_1_61_0_b1_rc2.7z c0f06c78c195af9079773a2b250674244f1899ec81e84d5455f0761f1d888a16 boost_1_61_0_b1_rc2.tar.bz2 400fa0949aa201d993bf116461365e5d44904a3f8db6412f4f40f2b4ab490405 boost_1_61_0_b1_rc2.tar.gz d75688ecad601303dda2658e9a3d06f406dd4dc8e2c13c36bdadcac0a11dcffa boost_1_61_0_b1_rc2.zip Thanks! -- The release managers

9 15

[Root Pointer] Partial documentation
by Phil Bouchard 26 Mar '16

26 Mar '16

The documentation is not completed yet but an updated overview, a basic tutorial and the rationale are available here: https://htmlpreview.github.io/?https://raw.githubusercontent.com/philippeb8… https://htmlpreview.github.io/?https://raw.githubusercontent.com/philippeb8… https://htmlpreview.github.io/?https://raw.githubusercontent.com/philippeb8… Thanks, -Phil

1 0

[Root Pointer] Ultimate test - Neural Network
by Phil Bouchard 25 Mar '16

25 Mar '16

Hi, I wrote a small utility that reads PDFs over the Internet and converts the text into a tree of regular expressions. The goal here is to test root_ptr<> and see if it will stand up to this complexity. The code is very simple for the moment as you can see: https://github.com/philippeb8/root_ptr/blob/master/example/t100_test1.cpp Because it makes use of Bash utilities. I am also using libpstreams and "indent_facet.hpp". So anyway apparently it works fine and please let me know if you do not think the code is clean enough. Regards, -Phil

3 14

Boost libraries cannot yet be trusted
by Michael Witten 23 Mar '16

23 Mar '16

In short, I request that the maintainers start publishing cryptographically signed, strong hashes of: * downloadable files. * git objects (tags, and even commits). A cryptographic signature should probably be a personal signature of a relevant maintainer (rather than some generic project-level signature for which nobody has a sufficiently strong incentive to maintain the trustworthiness). Perhaps, each repository should include a collection of relevant public keys, so as to compound trustworthiness and ease dissemination. ------------------------------------------------------------------------ I'm new to this community, so forgive my ignorance if I've missed an existing solution. With each release, there should be included conspicuously (and widely) published means by which to check the authenticity of the relevant content. As far as I can tell, this is not yet the case. At the very least, within an email that announces a release, there should be a list of suitably safe (e.g., SHA-256) hashes for the downloadable files in question, including the hash of the relevant git commit object[s]. Now, SourceForge does indeed list SHA-1 and MD5 hashes of each file it offers for download, but they are not conspicuous; the user must know to click on an `i' symbol that sits next to each link (the `i' presumably stands for `information', but I wouldn't be surprised if it actually stood for `ignore me'). To make matters worse, that very icon and its associated functionality is only available when JavaScript is enabled, which is absurd. Furthermore, it's important that this list of hashes appear in as many independent places as possible, so that it becomes increasingly difficult to alter the association; for instance, if Gmane picks up an announcement email that includes such hashes, then an attacker will also have to compromise Gmane's servers in order to forge a new record of the intended payload. That is, widely published integrity information strongly suggests a [reasonable] means by which to calculate authenticity; certainly, the converse is true: Authenticity implies integrity. Of course, it's irritating (and unlikely) for a user to take the time to check multiple publishers for such integrity information every time a new release is made. Thus, it makes more sense to abstract away this process into a one-time dissemination of integrity information with which a user may determine the authenticity of other, related data that is provided by any publisher. Such an abstraction is provided by cryptographic signatures. By widely publishing a public key, a maintainer provides a [reasonable] means by which a user may calculate the authenticity (and thus also the integrity) of any other data that is signed by the associated private key. Now, that calculation is only as trustworthy as the private key itself, so it's important that there be a strong incentive to keep that private key trustworthy; this possibly implies that the private key in question should be intimately associated with the individual who uses it; this suggests that, as a matter of explicit policy, there should not be some generic project-level private key shared by multiple individuals across space or time. The easiest solution is to require that some *individual* maintainer of data be responsible for signing that data with his own personal signature. Of course, not every user has the machinery or desire to work with cryptographic signatures; some people are satisifed with merely checking that the hash of data matches the result provided by a trusted publisher. Fortunately, all parties can be satisfied simultaneously and cheaply: Provide the list of hashes as a cryptographically signed message. Furthermore, the source-control management tool `git' (which this project already uses) provides support for integrating cryptographic signatures; not only can a tag object be cryptographically signed, but every commit object can also be cryptographically signed. It's probably enough just to sign tags (those of releases, at the very least), but perhaps it would be worthwhile to sign a commit object that sits some sufficient number of commits ahead of the object last signed, so as to give users a kind of checkpoint of authenticity. It might be worthwhile to include in every repository the public key of each relevant maintainer (say, one file for each maintainer); this kind of publication would allow for compounding a key's trustworthiness with each new commit, and it would make dissemination of that information both easier and more specialized to its purpose. In any case, something must be done; this project sits at the core of much critical software, and its integrity should be ensured with greater zeal. Sincerely, Michael Witten

10 18

[Fit] formal review ends 20th March.
by Vicente J. Botet Escriba 23 Mar '16

23 Mar '16

Hi, There have been some that would be able to write a review next week-end. Others said that they had not enough time. Maybe having an additional week can help. I have not received confirmation from the review withards, but as there is no planned reviews for this week, I propose to continue with the review until 20th. Please take the time to do a review and share your point of view. Best, Vicente Fit is a header-only C++11/C++14 library that provides utilities for functions and function objects. Fit is: - Modern: Fit takes advantages of modern C++11/C++14 features. It support both `constexpr` initialization and `constexpr` evaluation of functions. It takes advantage of type deduction, varidiac templates, and perfect forwarding to provide a simple and modern interface. - Relevant: Fit provides utilities for functions and does not try to implement a functional language in C++. As such, Fit solves many problems relevant to C++ programmers, including initialization of function objects and lambdas, overloading with ordering, improved return type deduction, and much more. - Lightweight: Fit builds simple lightweight abstraction on top of function objects. It does not require subscribing to an entire framework. Just use the parts you need. Fit is divided into three components: * Function Adaptors and Decorators: These enhance functions with additional capability. * Functions: These return functions that achieve a specific purpose. * Utilities: These are general utilities that are useful when defining or using functions Fit has been tested on gcc 4.6-4.9, clang 3.4-3.7, and Visual Studio 2015. For more information see: Github:https://github.com/pfultz2/Fit/tree/boost Documentation:http://pfultz2.github.io/Fit/doc/html/ We encourage your participation in this review. At a minimum, kindly state: - Whether you believe the library should be accepted into Boost * Conditions for acceptance - Your name - Your knowledge of the problem domain. You are strongly encouraged to also provide additional information: - What is your evaluation of the library's: * Design * Implementation * Documentation * Tests * Usefulness - Did you attempt to use the library? If so: * Which compiler(s) * What was the experience? Any problems? - How much effort did you put into your evaluation of the review? More information about the review process can be found here:http://www.boost.org/community/reviews.html

8 16

[http] Design ideas for a request router
by Vinícius dos Santos Oliveira 23 Mar '16

23 Mar '16

Hi list, I've been designing a HTTP library for Boost inclusion for the last two years. First it was funded as a GSoC 2014 project. Then I continued to polish the implemented bits on my own and the library was peer reviewed (and rejected) last year. I'm currently addressing the requests made during last year's review and one of the requested items was a higher-level interface built on top the current building blocks that would be easier to use. One of such abstractions would be an HTTP request router. I usually do my research and check what others have done (not only in C++), read a lot of spec and do a design on my own (sometimes I ask for feedback of a few chosen ones). I rarely ask for public feedback because I usually can solve the interface issues on my own. However, Boost.Http is a new thing and I'm exploring an unexplored ground. I've been facing an issue for the last months and I'd like to have "open" feedback of anyone interested in this topic. Maybe it'll speed me up. The issue I'm facing is that (1) I haven't found enough diversity of HTTP request routers and (2) Boost.Http is a new thing and problems must be approached differently (what other HTTP library will let you do HTTP over uTP using Boost.Asio threading/async model?). Detailing the problem a little more: I categorize current HTTP request routers into two styles. The "tree style" is the style where you declare some paths to be handled and each request will be routed to at most one handler. You'll find this style usually when the author advertise a ReST support library (e.g.crow[1]). The "chained style" is the style where you declare a chain of <rule,handler> pairs (or anything in these lines) and one handler can "give up" and pass the route to the next in line. Rules in the "chained side" can overlap and an order exists (and must be explicit). You can find this style being used frequently in the Node.JS frameworks (e.g. connectjs[2]). You could reimplement these NodeJS APIs in C++ keeping a lot of the same look'n'feel. For instance, take a look at node.native[3]. I thought I could combine and allow both styles. Actually, Boost.Http don't force you to use any style and both could be used. However I wanted to implement both allowing some kind of interoperability and communication between them. There are a lot of open questions right now and I decided to implement both individually and only then come back trying to unify them. So, for now, my problem is designing the "chained style". Even implementing only "one style" I had open questions and I decided to draft an implementation to maybe give some light to my own mind. One thing that I was trying to address would be the "next" function. If you take a look at the connectjs library[2], you'll see that the "next" function is an argument passed to the handler and, if the handler wants to give up and pass the route to the next handler, it only needs to call "next". This behaviour could be emulated in C++ using std::function<>. An alternative design would be to make the handler return a bool. This is actually the design I've chose in Tufão[4] and I regret this decision to this date. The bad thing about this approach is the too-much-sync minded. If you need to communicate with a database to know whether you'll be able to handle the route then you need to block the whole thread under this approach. Knowing this is Boost and Boost is about serious C++ users I know I must be concerned about performance. Therefore, many may not like the std::function<> approach. It can imply some hidden allocation that you pay even if the handler is not going to give up on the route. Another approach would be to turn the handlers into template functors. However, this would be too much burden on the user. And if I chose this route, what would be the type of "next"? The approach I've chose was to encode the "next" function into the "request object". In Boost.Http, there is no "request object" like you'd be used to when using other APIs. Boost.Http exposes a socket and the socket will fill a message object of your choice (let's call it the input message) and later you pass it another message object to execute the reply (let's call it the output message). So the "next" function is really encoded in the input message. Other APIs use a passive style and constantly check if there is network activity and schedule new socket reads. Boost.Asio is more explicit and Boost.Http follows along. An active style is useful because it'll allow you to defer new operations to later when your server is under heavy load. Anyway, I felt that maybe I'll need a "done" function and I've added an empty one for now. I'll see if I'll really need it later when I integrate everything together. For now, just know that the "done" function does nothing. Anyway, this is my draft and I'd like to know your opinion: https://github.com/vinipsmaker/asiohttpserver/blob/router/example/router.cp… You can see that I'm declaring a static router because most of the time you don't change the rules at runtime. This router is actually more difficult to design and it'll be easier to add a "dynamic router" later on. I also want to mention that I'm aware of another effort by another developer (Uisleandro) trying to add a router to Boost.Http: https://github.com/uisleandro/Router_for_Boost.Http I also want to mention that performance of the implementation isn't really something I care about for the draft. If it were at another place it could mean that I'm not interested in implementation feedback. However it doesn't mean that I know the best way to implement these APIs and I'm still interested in implementation feedback (even more because I don't remember if I ever implemented much TMP before). Some points that I'll tackle LATER will be: - A router is a handler too, then you can have nested routers. - The router doesn't take the rule, only the handler. Later, I'll make algorithms that adapts rules and conditionally call your handler or pass the route to the next handler. This design is more flexible and I wish I could also use it in "tree style too". - How to create Message types more easily? I've read about component-based architectures before, but I never really understood them. Is there any library that was proposed to Boost in these lines that I could take a look at? [1] https://github.com/ipkn/crow [2] https://github.com/senchalabs/connect#mount-middleware [3] https://github.com/d5/node.native [4] http://vinipsmaker.github.io/tufao/ref/1.x/class_tufao_1_1_http_server_requ… -- Vinícius dos Santos Oliveira https://vinipsmaker.github.io/

7 20

Sean Parent to Keynote C++Now 2016
by Jon Kalb 22 Mar '16

22 Mar '16

Boost Developers, C++Now is announcing that the keynote speaker for our tenth conference will be the keynote that started us off, Sean Parent. http://cppnow.org/2016-conference/announcements/2016/03/22/keynote-announced .html Jon

2 1

[Fit] Formal review / Kris
by Krzysztof Jusiak 22 Mar '16

22 Mar '16

Hi, Firstly, sorry for submitting my review so late. > - Whether you believe the library should be accepted into Boost Yes. Although the submission is not perfect, I prefer boolean logic, and, therefore Fit a 1 for me. > - Your name Krzysztof Jusiak > - Your knowledge of the problem domain. I have been implementing similar solutions myself when experimenting with lambdas. I have also checked out functional part of Hana library. > You are strongly encouraged to also provide additional information: > - What is your evaluation of the library's: > * Design IMHO design is decent. Functionality is loosely coupled and really easy to follow. There are a few inconsistencies here and there but there were pointed out already and they don't have a huge impact on the overall solution. > * Implementation Quite a lot of macros but most of these are due to lack of language features or compilers bugs. Besides that, it looks alright. Moreover, I do agree with most issues pointed out already. > * Documentation Motivation could have been much better. Examples showing how much pain might be saved using Fit in comparison to writing the same things by hand would be great. Moreover, ready to copy examples would simplify testing the library. Personally, I would also add disassembled code for these examples showing how well-optimized code Fit can produce. Maybe, it's worth to add try-it-online functionality too? > * Tests Tests are short and easy to follow. I can't see coverage but it seems like most things are tested. Travis addition with each push make me confident that the library is always in a good shape. I would like to see performance tests though for both compilation times and run times. > * Usefulness IMHO Fit is defo a library to have in Boost for modern C++ development. I find the solutions provided by Fit very useful as I have been writing similar functionality myself. Nevertheless, documentation needs improving (as it was stated already) in order to state the purpose more clearly with clean examples. I have been worrying that there will be a clash with Hana. Having 2 modern libraries providing similar functionality would be confusing, however, my concerns were already clarified by Louis. > - Did you attempt to use the library? If so: > * Which compiler(s) Clang 3.7/3.8/HEAD, MSVC 2015 > * What was the experience? Any problems? No issues. > - How much effort did you put into your evaluation of the review? A few hours for the review, however, I have been looking and trying Fit for a while. Cheers, Kris

4 8

[test] Not using Boost.Test for an official Boost library
by Vinícius dos Santos Oliveira 22 Mar '16

22 Mar '16

Hi list, I'd like to know if it's mandatory to use Boost.Test if you intend to contribute a library to Boost. After facing an issue trying to enable compiler santizers on my tests[1] for long enough, I'd like to use a different test library. According to a survey done by Niall concerning new libs[2], everybody avoids Boost.Test, favouring assert/static_assert. I've been interested in using Catch[3], which is header-only and can be embedded, posing no problem to users (it'd be transparent). I've seen Boost.AFIO (which is not an official Boost library) already uses it. I've seen lightweight_test is also used within Boost[4]. If Boost.Test ever fix its integration problem with compiler sanitizers[1], I'd have no problem migrating everything back again to Boost.Test. However, it's more important for me to have this issue solved now so I can jump to the next task (valgrind and fuzz testing). I've also seen that some header-only libraries use a different build system for the test target[5] and using a header-only test library would be a lesser demand that should be okay. [1] https://svn.boost.org/trac/boost/ticket/11425 [2] https://raw.githubusercontent.com/boostcon/cppnow_presentations_2015/master… [3] https://github.com/philsquared/Catch [4] http://www.boost.org/doc/libs/1_60_0/libs/core/doc/html/core/lightweight_te… [5] https://github.com/boostorg/hana/blob/63c5f87dfdadd07e496cefefc63c3ea9968d3… -- Vinícius dos Santos Oliveira https://vinipsmaker.github.io/

6 5

Boost 1.61.0 Beta 1 Release Candidate 1
by Vladimir Prus 22 Mar '16

22 Mar '16

Release candidates for 1.61.0 beta 1 are now available: http://boost.cowic.de/rc/boost_1_61_0_b1_rc1.zip http://boost.cowic.de/rc/boost_1_61_0_b1_rc1.tar.bz2 http://boost.cowic.de/rc/boost_1_61_0_b1_rc1.tar.gz http://boost.cowic.de/rc/boost_1_61_0_b1_rc1.7z 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. These packages were generated by the CI system that Rene has put together, and one user-visible change is that the directory inside archive is named after git commit hash. This will be changed for the final release. Otherwise, these were smoke-tested on Windows and Linux, and should be functionally identical to usual packages. The SHA1 checksums are as follows: b8314cff39908e6d6221bdad01ce1f1468546419 boost_1_61_0_b1_rc1.zip cd916da1aa5ed812e538975171069506ecc4560c boost_1_61_0_b1_rc1.tar.bz2 ca18da298d739ef70145b29e3bd2c8d903067075 boost_1_61_0_b1_rc1.tar.gz 2fb4b8cf9112f59aa1c4b61f2ea0c66cbbe3ffd0 boost_1_61_0_b1_rc1.7z The SHA256 checksums are as follows: 3668b868d3f883327e2ff1324e09899cbb033087147d4dd268424a7729791f94 boost_1_61_0_b1_rc1.zip e07784e9770193ff1e68cfe05c6fd08ca05913afedaedf1aca33f6da30d49b17 boost_1_61_0_b1_rc1.tar.bz2 2344369b6859ed151589286d05b38764a902884c10a4dac9c67b133c6c046130 boost_1_61_0_b1_rc1.tar.gz 9ab80608c9ec70ec7afee25f2213f803ed3d15a71ade2c6ae184c48f33fd9d29 boost_1_61_0_b1_rc1.7z Thanks! -- The release managers

10 18

[Fit] formal review starts today
by Vicente J. Botet Escriba 21 Mar '16

21 Mar '16

Dear Boost community, sorry for the late anounce The formal review of Paul Fultz II's Fit library starts today, 2nd March and ends on 13th March. Fit is a header-only C++11/C++14 library that provides utilities for functions and function objects. Fit is: - Modern: Fit takes advantages of modern C++11/C++14 features. It support both `constexpr` initialization and `constexpr` evaluation of functions. It takes advantage of type deduction, varidiac templates, and perfect forwarding to provide a simple and modern interface. - Relevant: Fit provides utilities for functions and does not try to implement a functional language in C++. As such, Fit solves many problems relevant to C++ programmers, including initialization of function objects and lambdas, overloading with ordering, improved return type deduction, and much more. - Lightweight: Fit builds simple lightweight abstraction on top of function objects. It does not require subscribing to an entire framework. Just use the parts you need. Fit is divided into three components: * Function Adaptors and Decorators: These enhance functions with additional capability. * Functions: These return functions that achieve a specific purpose. * Utilities: These are general utilities that are useful when defining or using functions Fit has been tested on gcc 4.6-4.9, clang 3.4-3.7, and Visual Studio 2015. For more information see: Github:https://github.com/pfultz2/Fit/tree/boost Documentation:http://pfultz2.github.io/Fit/doc/html/ We encourage your participation in this review. At a minimum, kindly state: - Whether you believe the library should be accepted into Boost * Conditions for acceptance - Your name - Your knowledge of the problem domain. You are strongly encouraged to also provide additional information: - What is your evaluation of the library's: * Design * Implementation * Documentation * Tests * Usefulness - Did you attempt to use the library? If so: * Which compiler(s) * What was the experience? Any problems? - How much effort did you put into your evaluation of the review? More information about the review process can be found here:http://www.boost.org/community/reviews.html We await your feedback! Best regards, Vicente J. Botet Escriba

10 64

[Fit] formal review is over
by Vicente J. Botet Escriba 21 Mar '16

21 Mar '16

Hi, The review of the Fit library finished yesterday 20 March. Thanks to all the people who participated in the review, as a reviewer or commenting the threads. I hope to announce the result soon ;-) Best, Vicente P.S. Of course you/we can continue with the discussion and add issues in github that would help to improve the library. For more information see: Github:https://github.com/pfultz2/Fit/tree/boost Documentation:http://pfultz2.github.io/Fit/doc/html/

1 0

[fit] Mini Review (consider 1/2 or 1/4 weight)
by Artyom Beilis 21 Mar '16

21 Mar '16

Disclaimer: please consider my review as partial if at all because of the way I did it (see notes below) > - Whether you believe the library should be accepted into Boost No, I don't think so. I don't feel that library adds any real value to boost: being useful or in other words significantly simplifying rather straight forward tasks can't be done However I understand that there are some cases with template meta-programming that can make library useful shown there: http://article.gmane.org/gmane.comp.lib.boost.devel/265453 So I do think it another major review after significant redesign can be done. > - Your name Artyom Beilis > - Your knowledge of the problem domain. I worked a lot with lambda expressions and various callbacks also mostly in dynamic manner rather implementing functional programming. > - What is your evaluation of the library's: > * Design I did very brief analysis of design. What concerns me is wide use of static objects and declaration of "static functions". There is significant difference between static struct foo_class { void operator()() const;... } foo; and inline void foo() { } Of course two issues: 1. Inline functions are weak symbols and don't violate ODR 2. Static variables in C++ do violate ODR (btw in C they do not) so basically you COPY every instance of the functions across compilation unit. If you define some static function that does something by macro I'd rather expect to see stuff like inline void foo(...) { static foo_instance ... f = ...; f(...) } I don't know if it is implementable but it makes more scene or at least justify use of macro. On the other hand I don't see (with exception of some corner cases) why this is better than BOOST_FIT_STATIC_FUNCTION(foo) = fit:compose(bar1,bar2) // * calls bar1(bar2(...)) inline void foo(...) { bar1(bar2(...)) } or inlined auto foo = fit:compose(bar1,bar2); Is better than auto foo = [](...) { bar1(bar2(...) ) }; I understand (after getting this reply http://article.gmane.org/gmane.comp.lib.boost.devel/265453) That there are some meta-programming cases that the library is really helpful. But this isn't something I see in library documentation or it isn't the major library purpose. And for trivial cases I think direct approach is better as it is just clearer and easier to understand for an average code maintainer. > * Implementation Reviewed barely... no comment > * Documentation This is another major issue it does not clear what library does and how it is useful. This alone would make a condition on the acceptance. > * Tests Didn't reviewed > * Usefulness It is probably the major questions that the library need to ask. What is the purpose of the library and what problem it solves. I didn't find a complete answer to this question. > - Did you attempt to use the library? If so: No > - How much effort did you put into your evaluation of the review? Several hours - mostly reading docs and code. I can't say I reviewed most of the code or most of the docs. I stopped before as I couldn't find the satisfying answers regarding what library does. I understand that if somebody would submit the library regarding astrophysics or bio-modeling I'd had hard time to understand what library does. However regarding FIT I don't think it is the case. So if you (review manager/library designer) feel that I attempted to review a library in a field I don't get - feel free to ignore my review. Artyom Beilis

7 8

[release] New libraries documentation + release notes
by Daniel James 20 Mar '16

20 Mar '16

Hi, I'm starting to compile the release notes, so please add the info for your library. Easy way to do so is to click the pencil icon at the top right of the code at: https://github.com/boostorg/website/blob/master/feed/history/boost_1_61_0.q… Or you can just email me if you don't like quickbook. Also, the documentation for the new libraries in this release is now building okay and I've added links to the release notes, so please can the relevant people take a look: http://www.boost.org/users/history/version_1_61_0.html thanks, Daniel

3 4

[1.61] Two weeks remaining for new libraries and breaking changes
by Vladimir Prus 19 Mar '16

19 Mar '16

I wanted to remind that the master branch is closing for new libraries and breaking changes on Feb 24, about two weeks from now. We'll be closed for major changes on March 2. That's not a lot of time, please make sure any big work is completed. Thanks, -- Vladimir Prus http://vladimirprus.com

10 38

[Spirit X3] move_to
by Mikhail Strelnikov 18 Mar '16

18 Mar '16

Hi, I'm using Boost 1.60 with Spirit X3 from develop branch (because it has this fix <http://boost.2283326.n4.nabble.com/Single-element-attributes-in-X3-quot-sti…> ). If I change the rule from this: auto a2 = rule<class i2, ast::a2>{} = a1 >> a2_v2; to this: auto a2 = rule<class i2, ast::a2>{} = a1 >> '(' >> a2_v2 >> ')'; it stops compiling (both gcc and clang) with error "no matching function for call to 'move_to'". Here is full source code: #include <boost/spirit/home/x3.hpp> #include <boost/spirit/home/x3/support/ast/variant.hpp> #include <boost/fusion/include/define_struct_inline.hpp> #include <string> #include <vector> namespace ast { BOOST_FUSION_DEFINE_STRUCT_INLINE ( a1, (std::string, v) ) BOOST_FUSION_DEFINE_STRUCT_INLINE ( a2, (a1, v1) (std::vector<double>, v2) ) BOOST_FUSION_DEFINE_STRUCT_INLINE ( a3, (std::vector<a2>, v1) ) } using namespace boost::spirit::x3; auto a0 = rule<class i0, std::string>{} = lexeme[+alpha]; auto a1 = rule<class i1, ast::a1>{} = a0; auto a2_v2 = rule<class a2_v2, std::vector<double>>{} = -(double_ % ','); auto a2 = rule<class i2, ast::a2>{} = a1 >> '(' >> a2_v2 >> ')'; //auto a2 = rule<class i2, ast::a2>{} = a1 >> a2_v2; auto a3_v1 = rule<class a3_v1, std::vector<ast::a2>>{} = *(a2 >> ';'); auto a3 = rule<class i3, ast::a3>{} = a3_v1; using data = ast::a3; int main() { std::string script = ""; auto begin = script.begin(); auto end = script.end(); data v; bool ok = (boost::spirit::x3::phrase_parse(begin, end, a3, space, v) && begin == end); } Here is how it is compiled: #!/bin/bash wget --no-clobber http://netcologne.dl.sourceforge.net/project/boost/boost/1.60.0/boost_1_60_… tar -zxvf boost_1_60_0.tar.gz wget --no-clobber https://github.com/boostorg/spirit/archive/develop.zip unzip develop.zip mv ./boost_1_60_0/boost/spirit ./boost_1_60_0/boost/spirit_old g++ -std=c++14 test.cpp -I./spirit-develop/include/ -I./boost_1_60_0/ -o test

1 0

[Root Pointer] Benchmark
by Phil Bouchard 17 Mar '16

17 Mar '16

So I renamed block_ptr<> to root_ptr<> and the code is accessible from here: https://github.com/philippeb8/root_ptr I am sorry but I made a mistake in the benchmark again. root_ptr<> wasn't using the fast allocator. Now it does and the new benchmark is: unique_ptr (new): 42.3736 unique_ptr (make_unique): 59.6104 shared_ptr (new): 69.9175 shared_ptr (make_shared): 46.9994 shared_ptr (allocate_shared_noinit): 31.0648 root_ptr (new): 30.5549 Regards, -Phil

5 36

[ann][offtopic] GSoC with the STE||AR-Group
by Thomas Heller 17 Mar '16

17 Mar '16

Hi list, We are very sad that Boost didn't make it into GSoC this year. However, for students with enthusiasm for C++, Parallelism and Concurrency and looking for an interesting project for this summer, there are other opportunities. The STE||AR-Group (https://summerofcode.withgoogle.com/organizations/5183170693562368/) is looking for prospective students, we have a large variety of projects surrounding the HPX Parallel Runtime System (one of the reference implementations of the upcoming additions to the C++17 standard for parallelism and concurrency). You can find our project ideas list here: https://github.com/STEllAR-GROUP/hpx/wiki/GSoC-2016-Project-Ideas In addition, if you have a project idea you'd like to mentor that would fit into the scope of our organisation, we would be more than happy to welcome you! We are looking forward to your responses at hpx-users(a)stellar.cct.lsu.edu or on our IRC channel #ste||ar on Freenode! Best regards, Thomas -- Thomas Heller Friedrich-Alexander-Universität Erlangen-Nürnberg Department Informatik - Lehrstuhl Rechnerarchitektur Martensstr. 3 91058 Erlangen Tel.: 09131/85-27018 Fax: 09131/85-27912 Email: thomas.heller(a)cs.fau.de

1 0

[Fit] About supported C++ version
by Vicente J. Botet Escriba 16 Mar '16

16 Mar '16

Hi, I was wondering if Boost.Fit shouldn't be a library as Boost.Hana, a library that makes use of the last C++ version and avoids as much portability issues as possible. Which C++14 features will make the library simpler? Which adopted C++17 features will make the library simpler? Which other C++ features would be missing? Paul I guess that you are using a C++11 compiler and want to support this version, could you confirm? Best, Vicente

2 3

Providing means to verify integrity and authenticity for releases
by Daniel Hofmann 16 Mar '16

16 Mar '16

The current download page at > http://www.boost.org/users/download/ redirects the user to SourceForge for downloading sources and / or binary Boost distributions. SourceForge can no longer be trusted as a hosting platform, as you can for example see following this thread > http://lists.boost.org/boost-users/2016/02/85662.php where a user was tricked into downloading some arbitrary binary while downloading a Boost release. Unfortunately there does not seem to be a secure and convenient way to download Boost releases. Although Github's Boost "releases" can be found at > https://github.com/boostorg/boost/releases but those are only repository snapshots, from which you can not even build a Boost distribution. And whereas the Boost 1.60 rc1 announcement mail at least provides checksums > http://lists.boost.org/boost-users/2015/12/85435.php The official 1.60 release announcement mail does not > http://lists.boost.org/boost-users/2015/12/85467.php Correct me if I'm wrong, but there is no way for obtaining a Boost release and verifying its integrity and authenticity. The only option I'm seeing is recursively cloning all Boost repositories from Github and building a release by myself. Can we please change this situation? Here are some options that come to mind ordered by amount of effort: - Providing checksums - Educating users on the Downloads page - Signing releases with a trusted Release Team key - Changing the hosting platform Cheers, Daniel J H

7 8

[ann] C++ Archive Network
by Egor Pugin 16 Mar '16

16 Mar '16

Hi, I'd like to present my project - C++ Archive Network (or simply CPPAN). You can consider it as (yet another) C/C++ package manager. In the beginning it was targeting C++ Modules, but it seems it can handle many current C/C++ projects. You can read more information about idea and motivation from links below (see docs). This is an alpha release (0.1.2). I'm announcing it only here to get initial feedback (but still boost community is large enough). As always the general idea is to create programs faster, to reuse and share your or anyone's code. But specifically here: source only packages (no tools, no tests in distribution pkg - keep all your stuff in your repos), Modules-like paths (org.boost.algorithm), semantic versioning (semver.org) zero-conf. projects, all-or-nothing dependencies (no optional deps.) and some other convenient features. At the moment CPPAN works only with CMake. It generates files that you include to your project (see docs). To be closer to boost and modern C++ community I added some popular projects as demo versions: - boost 1.60.0 - all projects - some core parts work (filesystem, thread, log, asio etc.), did not tried less used libraries. - new boost libs: coroutine2 (added but not set up, so does not works), dll - boost incubator libs: fit, DI - you can try them faster during reviews - gsl, range-v3, mach7, sqlpp11 (and connectors) - some modern libs - concepts libs: cmcstl2, text_view - so users can try and adopt new C++ features faster - google's: gtest,gmock,protobuf, recent 'highwayhash' lib - sqlite3 (3.11.0) - zlib, bzip2 - libressl - image libs: libpng, tiff, gif, webp, some others - libpqxx Most of them just works. Almost all dependencies are met. In boost.* I do not untangle the core dependencies, so base dependency-ball is quite big. I believe that library authors can eliminate unneeded deps better. Links: https://cppan.org/ - website https://github.com/cppan/cppan - client, use issues for feedback https://github.com/cppan/cppan/wiki - docs https://github.com/cppan/demo_project - example project that uses cppan https://github.com/cppan/packages - example packages (config files) https://github.com/cppan/packages/blob/master/boost/boost.cppan - base boost config file (big list of deps, probably can be shorter) --- ps. I'm not writing about pros. and cons. Both are present. Just give CPPAN a try and we'll see how we can improve it. -- Egor Pugin

5 5

Re: [boost] [Block Pointer] Benchmarks
by Glen Fernandes 15 Mar '16

15 Mar '16

On Sun, Mar 13, 2016 at 1:02 PM, Phil Bouchard wrote: > Thanks for your help. > > So block_ptr<> wouldn't be a drop-in replacement for shared_ptr<> but an > add-on for: > - complex containers, > - neural networks, > - C# / Java / Javascript engines, > - etc. > No problem. Also renaming the thread to reflect the current benchmarks (since it doesn't appear that block_ptr is faster than shared_ptr where creation is involved). 1. Gathering these benchmarks is always useful, even if block_ptr was not designed to be a drop-in replacement for share_ptr. So you had the right idea, even if the execution needed some work. It's important to get the execution correct, though, otherwise the results are not meaningful - which is where I (and I believe Rob, also) was trying to steer you. 2. Looking at the numbers you obtained after modifying my benchmark example, they are close enough that at least you could say "Using block_ptr over shared_ptr won't be a significant performance loss": > unique_ptr (new): 47.7686 > unique_ptr (make_unique): 46.8545 > shared_ptr (new): 77.8261 > shared_ptr (make_shared): 50.8072 > shared_ptr (allocate_shared_noinit): 33.021 > block_ptr (new): 69.6554 3. There are more benchmarks beyond just creation (though creation is likely the most meaningfully expensive one). Copying overhead might be one: I haven't looked at what is involved in copying a block_ptr, but some work happens when you copy a shared_ptr. 4. shared_ptr by way of allocate_shared allows creation to not involve 'new' expressions, or even a call to '::operator new(std::size_t)' at all. i.e. For those C++ projects that have a requirement for all dynamic allocation in their project to involve some stateful custom allocator instances of some stateful custom allocator type, they can still use shared_ptr (with allocate_shared). Is this possible with block_ptr? I hope to take a look at the block_ptr motivation, design, and implementation when I have some time next week. The title of the thread caught my attention; "X is 600% faster than Y" always has a high excitement potential. Glen

8 16

[Block Pointer] Update
by Phil Bouchard 14 Mar '16

14 Mar '16

Hi, - So I've restructured all the code in the correct namespaces boost::smart_ptr & boost::smart_ptr::detail: https://github.com/philippeb8/block_ptr/tree/master/include/boost/smart_ptr - I am now using another smart pointer to refer to proxies because it is safer but the code is 15% slower than without it (now ~= shared_ptr<>): make: auto_ptr: 26211292 ns shared_ptr: 27291607 ns block_ptr: 61097868 ns new: auto_ptr: 23240569 ns shared_ptr: 48016207 ns block_ptr: 55554121 ns - Because of the removal of the proxy optimization there is a new caveat; if you assign an rvalue (temporary pointer on the stack) to a pointer on the heap (opposite of normal heap object assigned to stack pointer) then there the behavior will be undefined. I am looking to fix it or throw an exception but for now it's better not to use rvalues when assigning to pointer living on the heap as such: https://github.com/philippeb8/block_ptr/blob/master/example/t100_test1.cpp#… Regards, -Phil

2 13

[Fit] formal review ends today, 13th March.
by Vicente J. Botet Escriba 14 Mar '16

14 Mar '16

Hi, The formal review of Paul Fultz II's Fit library ends today, 13th March. If you had not time to do the review and you plan to do it, please let us know so that we see if the review can be extended. Up to now we had 3 formal review (2 for conditional acceptance and 1 against, not now). I have not done a review myself, but I have created a lot of issues on Github. Best regards, Vicente Fit is a header-only C++11/C++14 library that provides utilities for functions and function objects. Fit is: - Modern: Fit takes advantages of modern C++11/C++14 features. It support both `constexpr` initialization and `constexpr` evaluation of functions. It takes advantage of type deduction, varidiac templates, and perfect forwarding to provide a simple and modern interface. - Relevant: Fit provides utilities for functions and does not try to implement a functional language in C++. As such, Fit solves many problems relevant to C++ programmers, including initialization of function objects and lambdas, overloading with ordering, improved return type deduction, and much more. - Lightweight: Fit builds simple lightweight abstraction on top of function objects. It does not require subscribing to an entire framework. Just use the parts you need. Fit is divided into three components: * Function Adaptors and Decorators: These enhance functions with additional capability. * Functions: These return functions that achieve a specific purpose. * Utilities: These are general utilities that are useful when defining or using functions Fit has been tested on gcc 4.6-4.9, clang 3.4-3.7, and Visual Studio 2015. For more information see: Github:https://github.com/pfultz2/Fit/tree/boost Documentation:http://pfultz2.github.io/Fit/doc/html/ We encourage your participation in this review. At a minimum, kindly state: - Whether you believe the library should be accepted into Boost * Conditions for acceptance - Your name - Your knowledge of the problem domain. You are strongly encouraged to also provide additional information: - What is your evaluation of the library's: * Design * Implementation * Documentation * Tests * Usefulness - Did you attempt to use the library? If so: * Which compiler(s) * What was the experience? Any problems? - How much effort did you put into your evaluation of the review? More information about the review process can be found here:http://www.boost.org/community/reviews.html We await your feedback!

4 6

[Fit] Review
by Zach Laine 13 Mar '16

13 Mar '16

- Whether you believe the library should be accepted into Boost Yes, conditionally. * Conditions for acceptance I think the documentation and naming issues I raise below, and those filed on GitHub by me and others should be addressed before acceptance. Also, the ADL issues that Steven Watanabe alluded to previously need to be fixed. After that, I think it should be re-submitted. - Your name Zach Laine - Your knowledge of the problem domain. I do generic programming regularly, and have done for years. You are strongly encouraged to also provide additional information: - What is your evaluation of the library's: * Design I think it's good. I particularly like the fact that it attempts to keep everything constexpr- and SFINAE-friendly wherever possible. I *really* like reveal() and failure(). Too few TMP-heavy libraries pay attention to providing good error messages. I have no problem with the constness requirements on Callables used throughout Fit, as was discussed previously. I even consider this a feature, allowing me to detect non-const Callables, which are almost always an error on my part. This is especially true since std::ref() and mutable_() let me explicitly choose how to handle mutable Callables, in a way that is also explicit at the call site. There are a number of adaptors that I find have obscure names: by() is a projection; why not call it project()? compress() is defined in terms of "fold", with a link to the Wikipedia page for same; why not call it foldl()? Similarly, reverse_compress() should be foldr(). flow() is a super obscure name! Why is this not reverse_compose() or similar? indirect() could more easily be understood if it were called deref() or dereference(). I don't feel as strongly about partial(), but I think it might be clearer if it were called partial_apply() or curry(). conditional() should be called invoke_first(), call_first_of(), or similar. I find it too easy to confuse with if_(). * Implementation I only briefly looked at the implementation, and only a few adaptors at that. What I saw did not leave me any concerns in particular. However, I *am* concerned by Steven Watanabe's claim that the library is ADL-unsafe. He did not state exactly why that I could tell, but this needs to be addressed if so. * Documentation The Quick Start section is good at showing a compelling motivating case for using the library. The result at the end of the section looks like a very good start on a "Scrap Your Boilerplate" solution for simple, dump-style printing. It's relatively easy to read and write. The documentation is what needs the most work, from what I've seen. The Quick Start is quite nice, but then there are some things that are underexplained in the subsequent Overview and Basic Concepts sections. For instance, why are these macros used everywhere and what do they do? They should be used for the first time after showing what the expanded code looks like. This will justify their use for those users that want them, and show those that don't what they can write instead. Others have written during the review that they don't understand why this library is useful. I think this is simply a documentation failure. I find the printing example from the Quick Start compelling, but perhaps Paul could show how it would have to be done if hand-written (even if only partially). Also, Paul has told me offline that there are a small number of primitive operations on which everything else is built (pack, unpack, and apply, IIRC). Perhaps show how those can be used to implement the other adapters, and how hard they are to write yourself. Showing how at least some of the library can be used as fundamental building blocks would go a long way. Some specifics. I have read the online docs before, and I put several bugs into the GitHub page for what I consider insufficient examples or explanations. Some new points, though: I think alias() is in bad need of a motivating example. I don't understand the distinction between lazy() and protect() just from the descriptions. In particular, this is what protect()'s docs say: '' The protect function adaptor can be used to make a bind expression be treated as a normal function instead. Both bind and lazy eargerly evaluates nested bind expressions. The protect adaptor masks the type so bind or lazy no longer recognizes the function as bind expression and evaluates it. '' I don't know what "masks the type" means here. This really needs an example. * Tests I did not run the tests, and just sort of spot-checked them. They seem a bit thin. In particular, one of the ones I looked at was conditional(). This one seems like it is needs more coverage, including thorny ones that must be kept working when maintenance occurs. There are probably others adapters that need similar treatment. Also, consider this -- Steven pointed out this as a failure case: boost::fit::conditional(identity(), identity())(0); and Paul says that it is supposed to fail, and that this failure is a feature, not a bug. If so, a minimal use like this that fails to compile needs to be added as a fail-compile test (and of course this intention should be documented). * Usefulness I think the library is very useful. There seem to be some things in there that use of which might be deemed a bit clever (not the good kind), like infix(), but then there are things like conditional() that I can see being *extremely* useful. - Did you attempt to use the library? If so: Yes. * Which compiler(s) Clang 3.6 * What was the experience? Any problems? I found I could gin up quick uses of things like conditional() (the most interesting adaptor for my purposes) in a short period of time. It was quite straightforward. - How much effort did you put into your evaluation of the review? About 5 or 6 hours. Zach

9 23

Alternative names to Boost.Fit
by paul Fultz 13 Mar '16

13 Mar '16

Hello All, Boost.Fit is a function utility library, however, the name currently doesn't have anything with this. I originally chose the name because it started with F(for function) and it was short and sounded nice. However, there could be some names(or abbreviations) that more adequately describe the library. Here are some alternatives that are short: - Boost.FP - Boost.FPL - Boost.Fun - Boost.FN Of course, I prefer the Boost.FN name. Names like Boost.FP or Boost.FPL could imply that it provides full functional constructs whereas Boost.Fit does not and is mainly focused on functions. Either way, this is something reviewers could consider as they review the library as I am not strongly tied to the name Boost.Fit. Thanks, Paul

13 27

[Block Pointer] Up to 600% faster than Shared Pointer
by Phil Bouchard 13 Mar '16

13 Mar '16

- I made the proxy explicit. Now it can be used 3 different ways: 1) Clothesline style: block_proxy x; block_ptr<int> v = block_ptr<int>(x, new block<int>(11)); block_ptr<int> w = block_ptr<int>(x, new block<int>(12)); 2) Root style: proxy_ptr<char[9]> u = proxy_ptr<char[9]>(new block<char[9]>()); 3) Container style (very easy to write containers now): struct list : block_proxy { public: list() : root(*this) {} [...] private: block_ptr<node> root; }; - I removed the capacity to unify sets. Why? Because it's faster & cleaner without it. - If we use fastblock<>() then the speedup can go up to 600% compared to shared_ptr<>: new: auto_ptr: 23174753 ns shared_ptr: 49726615 ns block_ptr: 7812659 ns - Once again all the examples can be found here: https://github.com/philippeb8/block_ptr/tree/master/example - And the pointer itself here: https://github.com/philippeb8/block_ptr/blob/master/include/boost/smart_ptr… Regards, -Phil

3 18

32/64 library name conflict under Windows?
by Peter Dimov 12 Mar '16

12 Mar '16

I remember that we discussed this problem before: C:\Projects\boost-git\boost>b2 --with-system toolset=msvc-10.0 address-model=32,64 [...] error: Name clash for '<pstage\lib>libboost_system-vc100-mt-gd-1_61.lib' error: error: Tried to build the target twice, with property sets having error: these incompatible properties: error: error: - <address-model>32 error: - <address-model>64 error: error: Please make sure to have consistent requirements for these error: properties everywhere in your project, especially for install error: targets. but don't remember what we concluded. Will we support building both 32 and 64 bit libraries under Windows? At present if I want to have an IDE project that has both Win32 and x64 configurations I need to build the 32 bit libraries, move them out of stage/lib somewhere, then build the 64 bit libraries, then move them out of stage/lib to somewhere else, and set my library directories in the IDE accordingly. It would be much more convenient if 32/64 were encoded into the name, so that I can leave my library path to point at stage/lib and rely on autolink to choose the right .lib file automatically, like it works today for the other options (debug/release, static/dynamic runtime).

14 25

[Fit] Louis Dionne's formal review
by Louis Dionne 12 Mar '16

12 Mar '16

First of all, sorry for submitting my review so late. > - Whether you believe the library should be accepted into Boost Yes, conditionally. > - Your name Louis Dionne > - Your knowledge of the problem domain. Extensive. In fact, I have implemented something very similar to Fit in parallel to Paul, but in the Hana library. Hence, I understand what Fit can be useful for, and I know many of the challenges Paul must have faced in designing the library. > You are strongly encouraged to also provide additional information: > - What is your evaluation of the library's: > * Design Good. It is simple and quite lean, which is nice. However, - The issue about `capture`'s semantics (and `pack`'s semantics too) ought to be addressed. I created an issue for this: https://github.com/pfultz2/Fit/issues/141. - It would be nice to provide a master header: https://github.com/pfultz2/Fit/issues/143 - I am not sure that `alias` has its place as part of the public interface of the library. I have only looked at it quickly, but it seems to diverge pretty heavily from the purpose of the rest of the library. I know it's used to implement `fit::pack`, but is it necessary to make it part of the public interface? Zach Laine already opened a similar issue here: https://github.com/pfultz2/Fit/issues/95 - I'm not sure about `compress` and `reverse_compress`. I think `fold` and `reverse_fold` (or my favorite `fold_left` and `fold_right`) would be better suited. An issue was already filed by Vicente here: https://github.com/pfultz2/Fit/issues/62 > * Implementation I have not looked at the implementation intensively, but I have to say that the profusion of macros is a bit off-putting. That being said, it's probably difficult to do better while supporting archaic compilers such as GCC 4.6. Hats off to Paul on this one. Also, I think the `fit/detail/ref_tuple.hpp` is unused and should be removed. Finally, why do you use your own `move` function? Is it because it is not marked constexpr in pre-C++14? > * Documentation I submitted pull requests to fix typos, but these are not worth mentioning here. Comments that might be of interest for the purpose of this review were made in the form of GitHub issues: - https://github.com/pfultz2/Fit/issues/131 - https://github.com/pfultz2/Fit/issues/132 - https://github.com/pfultz2/Fit/issues/133 - https://github.com/pfultz2/Fit/issues/135 - https://github.com/pfultz2/Fit/issues/136 - https://github.com/pfultz2/Fit/issues/138 - https://github.com/pfultz2/Fit/issues/139 - https://github.com/pfultz2/Fit/issues/140 - https://github.com/pfultz2/Fit/issues/142 - https://github.com/pfultz2/Fit/issues/144 > * Tests I have looked quickly, and basically all the individual components seem to be tested. It's hard to evaluate the depth in which each component is tested, but it seems OK. Also, the fact that the library is tested on Travis CI on each commit is a blessing, and it makes me much more confident about its quality. > * Usefulness This, I think, is the biggest problem of the library. I personally know very well why the library is useful, but I can also understand that someone with a different background would not feel the same. In my view, the library is mostly useful as a replacement to shortcomings of lambdas in C++11/14. Not only this, but in large part yes. Indeed, let's say I have a function object `f`, and I'd like to get a function object that swaps the arguments and calls `f`. The obvious solution (simplified) is auto g = [f](auto x, auto y) { return f(y, x); }; In other words, the simplest way to express my intent is to use a lambda and to do exactly what I mean. Unfortunately, this has several limitations - The lambda above can't be constexpr - The lambda can't appear in an unevaluated context So I end up using `fit::flip`. In a different situation, I might want to capture many variables in a lambda, but moving them into the capture (not copying). So I write auto f = [x = std::move(x)...](auto const& param) { ... }; but unfortunately there's no way to capture a parameter pack by moving each of its elements in a lambda. So I resort to using `fit::capture`. Examples like this abound, and IMO these limitations are the main (but not the only) reason for using Fit. Actually, this is how I implemented a library similar to Fit inside Hana; I started by using lambdas everywhere and then I wanted to make everything constexpr, capturing by move and things like that. All of this is very useful, but I feel like the documentation completely misses the goal of explaining the problem solved by Fit (the problem I would use it for, at least). This failure of motivating its own existence is the main reason why I think Fit should be accepted conditionally. > - Did you attempt to use the library? If so: > * Which compiler(s) AppleClang 6.1.0.6020053 (shipped with Xcode 6.4) Clang 3.5, 3.6, 3.7 I used both the Makefile and the Ninja generators for CMake, and both worked. > * What was the experience? Any problems? Classic CMake setup, everything works well and the tests compile and run fast. No problem whatsoever, as expected. > - How much effort did you put into your evaluation of the review? A couple of hours for the formal review itself, but I have been looking at Fit's development for a while. Summary ------- Fit should be accepted conditionally and re-submitted for a mini-review before it can be accepted. My conditions are 1. Correctly justify the purpose of the library 2. Resolve the issues on `capture` and `pack`'s semantics I think all the other points I raised are important too, but they shouldn't refrain Fit from being accepted. I also trust that Paul would be willing to continue working on the issues that were raised during this review if Fit were to be accepted. Regards, Louis

4 5

Boost.ASIO SSL examples
by Umit Sami 11 Mar '16

11 Mar '16

Hi All, SSL examples in boost.asio is very limited and not that clear. How can I improve my knowledge of this great network/security library ? what are some of well known online websites and books I can read/buy to better write secure/encrypted client-server applications ? Thank you, U

2 1

[release] Need help to test new release archives.
by Rene Rivera 09 Mar '16

09 Mar '16

As part of my attempt to make the Boost release management less painful, for everyone, I've implemented building of the release archives in Travis-CI. As of yesterday archives of the "boost" super-project master branch are getting uploaded to the bintray.com service at < https://bintray.com/boostorg/snapshots/master/view>. There are still some kinks in how this works but it's automated enough at this point that it might serve the upcoming release needs. I would appreciate it if people download the archives available at the above link and test them out. In particular I'm looking to see if there's anything missing or generally incorrect. For reference the archives are named with the commit SHA that they correspond to. Thank you. -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net -- rrivera/acm.org (msn) - grafikrobot/aim,yahoo,skype,efnet,gmail

6 16

Re: [boost] [Boost-users] [Fit] formal review starts today
by paul Fultz 09 Mar '16

09 Mar '16

>> >> >> >> Quick Start:Function Objects >> >> >> >> "We can make it behave like a regular function if we > construct >> the class >> >> as a global variable." >> >> >> >> What about a non-global >> >> >> >> sum_f sum = sum_f(); >> >> >> >> makes 'sum' not behave like a regular function other > than the >> fact that >> >> the variable 'sum' may eventually go out of scope ? >> >> >> > >> > In C++, a regular function is always global, there is no such >> thing as local >> > function(sans gcc extensions). >> >> My point is that the non-global 'sum' in my example above > behaves just >> as much like a regular function as your global 'sum'. You may > want to >> promote the idea of global function objects but I think that this is >> personally a bad idea. IMO global variables of any kind are to be >> avoided. >> >> It is quite common in several modern C++ libraries to declare functions as >> global objects. There are many advantages to this. Why do you believe it >> should be avoided? Especially since it has the same effect as a free >> function. >> DO you believe free function should be avoided as well? > > Global objects, whether functions or data, increases the chances for > name clashes. Also accessing global data increases the chances for > errors in a multi-threaded environment. > > Free functions can be in a namespace, as the standard library functions > are in the 'std' namespace. This helps greatly in avoiding name > conflicts. By global variables, I mean defined at the namespace level, not solely at the global namespace level. So functions using BOOST_FIT_STATIC_FUNCTION can be defined within a namespace. Also, the function objects are `const` so there isn't an issue from multithreaded environments. > >> >> >> >> > >> > >> >> >> >> Quick Start:Lambdas >> >> >> >> Why do we need both BOOST_FIT_STATIC_LAMBDA and >> >> BOOST_FIT_STATIC_LAMBDA_FUNCTION ? I would seem that >> >> BOOST_FIT_STATIC_LAMBDA_FUNCTION would be adequate and >> >> BOOST_FIT_STATIC_LAMBDA is just redundant, mimicking lambda >> syntax to no >> >> purpose. >> >> >> > >> > BOOST_FIT_STATIC_LAMBDA_FUNCTION and BOOST_FIT_STATIC_FUNCTION >> both define a >> > function at global scope, and can only be used at global scope, >> whereas >> > BOOST_FIT_STATIC_LAMBDA can be used to constexpr initialize local >> variables >> > as >> > well. >> >> It might be good to add that when the end-user first encounters >> BOOST_FIT_STATIC_LAMBDA, because the name does not suggest >> initialization of local objects. Furthermore I cannot imagine why one >> would want to use it to initialize a local object, >> >> >> Really? You just said that you would prefer avoiding global functions. > > I mean that for local objects I do not see the reason why I would ever > use BOOST_FIT_STATIC_LAMBDA instead of initializing local objects in the > normal C++ way(s). If this is not the case you need to explain what > problem(s) BOOST_FIT_STATIC_LAMBDA solve in initializing local data > which ordinary C++ initialization of local data could encounter. If > there aren't any problems BOOST_FIT_STATIC_LAMBDA solves in initializing > local data I see no purpose for its existence. > Well, they can still be passed to constexpr functions, even if they are local, I probably shouldn't discuss BOOST_FIT_STATIC_LAMBDA in the Quick Start guide because its usage is not quite as a common. >> >> so you might want to >> explain the benefit of doing so as opposed to the normal syntax for >> creating a lambda function. >> >> >> Maybe the quick start guide isn't the place for this in the first > place. > > I would hope to convince you that a good Overview of your library should > come first and then all the Quick Start guides, tutorials, examples etc. > would make much more sense once your end-user understands what your > library really does in terms of at least the main general functionality. I usually start with the Quick Start guide with a library in order to get an understanding of what components are in the library and what they can do, then I start delving into the other components from there. Thats what I am showing in the Quick Start guide. I guess people have different ways of learning a library. I wonder what is needed to be explained better in a initial overview of the library. > >> >> >> > In fact, BOOST_FIT_LIFT uses this since it is not always clear > what >> > context the user might call BOOST_FIT_LIFT. >> > >> > >> >> >> >> Quick Start:Overloading >> >> >> >> The overloading adaptors show two or more lambda functions. > Can >> they >> >> also work with function objects ? Or a mix of lambda > functions and >> >> function objects ? In fact all the reamining Quick Start > topics >> show >> >> examples with lambda functions. Do they also work with > function >> objects ? >> >> >> > >> > Yes it can be used with function objects. I probably should show >> an example >> > of >> > that as well. I used the lambdas because of the terseness of > them. >> >> Evidently the adaptors can be used with any Callable. I think you >> should >> make that point very strongly and show that in examples also. >> >> >> Agreed. >> >> >> > >> > >> >> >> >> Quick Start:Variadic >> >> >> >> I do not understand what 'We can also make this print > function >> varidiac, >> >> so it prints every argument passed into it.' means ? >> >> >> > >> > I'll try to explain that better, but basically it will print > each >> argument, >> > so: >> > >> > print("hello", 5); // Will print "hello" and > 5 >> >> I wouldn't associate that with the word 'Variadic' but I do > think you >> need to explain that more clearly. >> >> >> I always understood variadic to mean taking a variable number of >> arguments. What do you understand variadic to mean? > > Your terminology is fine, but I always think of variadic in terms of > variadic templates or variadic macros. After all your not making the > print function variadic in the sense of taking a variable number of > arguments. Yes, I am, so I probably need to make that more clear in the documentation. > The simple_print functionality is any of 3 different lambda > functions, with 'conditional' picking the first one that is callable and > > 'fix' passing in the callable as the first parameter. So I really > don't > understand what 'by' does here in printing each argument irregardless of > > your 'Variadic' terminology. You need invoking examples and then show > what the output would be for each invocation, and then it would be > easier for me and others to understand what 'by' does in this situation. > Yep, that part needs to go into more in-depth. >> >> >> > >> > >> >> >> >> I do not think the Quick Start explains very much since it is >> dealing >> >> with adaptors of which we know almost nothing and the >> explanation for >> >> these adaptors and what they actually do is very terse. >> > >> > >> > Probably can expand the explanation of adaptors a little more. >> >> Good idea. What do adaptors create ? >> >> >> They create a function. >> >> Different function objects I would >> imagine ? In that case how about the explanation that adaptors take >> Callables as input and generate function object types that adapt the >> original functionality of one or more Callables to some other purpose. >> >> >> The examples are already show taking Callables. Are you suggesting I >> show an example taking a member function or something? > > Global/static function, member function, std::function, boost::function, > Boost Phoenix and/or Boost lambda function objects, instantiated > template functions. My point is that you should show your library > functionality working with as many types of Callables as possible. > Instead your doc suggests that function objects and lambda functions are > the only type which can be passed to your library's functionality and > you enforce this view by your examples. I'll try to do that. > >> >> > >> > >> >> >> >> In the 'Signatures' section of the Overview I read: >> >> >> >> "All the functions are global function objects except > where an >> explicit >> >> template parameter is required." I honestly don't > know what this is >> >> supposed to mean. Does this refer to when function objects > are >> referred >> >> to as parameters to the adaptors, functions, and utilities of >> the library >> >> ? >> >> >> > >> > I don't understand what you are asking. It means that the >> function is >> > written >> > like this in the documentation: >> > >> > template<class IntegralConstant> >> > constexpr auto if_(IntegralConstant); >> > >> > But its actually a function object like this in the code: >> > >> > struct if_f >> > { >> > template<class IntegralConstant> >> > constexpr auto operator()(IntegralConstant) const; >> > }; >> > const constexpr if_f if_ = {}; >> > >> > However, `if_c` is written like this in the documentation: >> > >> > template<bool B, class F> >> > constexpr auto if_c(F); >> > >> > It requires the bool `B` template parameter explicity. So in the >> code it is >> > written as a function and not as a function object. >> >> I don't understand to what you are referring when you say > 'function'. >> Are you talking about adaptors in your library, functions in your >> library, or what ? >> >> >> I am talking about all functions that are defined in the library, that >> includes adaptors as well. I am not sure how to make that clearer. >> >> Please try to understand that your use of the word >> 'function' is very broad but that the word 'function' > in C++ has a much >> narrower meaning. >> >> >> By function, I mean something like in the example: >> >> template<class IntegralConstant> >> constexpr auto if_(IntegralConstant); >> >> I think everyone agrees that is a function in C++. > > I call that a function template. Which is a family of functions. > My definition for 'function' is not the > > same as yours. I know you feel differently but please realize that the > term 'function', to mean any and every type of callable in C++, is not a > > universally agreed on terminology. I would bet that for the vast > majority of C++ programmers a function is: > > ReturnType FunctionName(ZeroOrMoreFunctionParameters); Yes, which can happen at class scope or namespace scope, and it can also be templated.

5 7

Re: [boost] 2 regression test failing at under 1.60 (John Maddock)
by Steven Kelso 09 Mar '16

09 Mar '16

On Tue, Mar 8, 2016 at 3:42 AM, <boost-request(a)lists.boost.org> wrote: > Date: Mon, 7 Mar 2016 19:21:26 +0000 > From: John Maddock <jz.maddock(a)googlemail.com> > To: boost(a)lists.boost.org > Subject: Re: [boost] 2 regression test failing at under 1.60 > Message-ID: <56DDD4B6.6030603(a)gmail.com> > Content-Type: text/plain; charset=windows-1252; format=flowed > > > > On 07/03/2016 17:04, Steven Kelso wrote: > > I've just started trying to install version 1.60 of boost using the gcc > > 5.3.0 compiler. With a vanilla download and no chnages it all seems to > > compile correctly, but I have a problem with 2 library regressions tests > > not terminating. They have both run for over 18 hours before I had to > kill > > them. I was using the options and configuration "out of the box" so > > optimization was -O3. > > I'm unable to reproduce on Ubuntu x64, all the Math lib tests pass fine > for me with gcc-5.3.0 in both C++03 and C++11 modes. > > So you'll need to debug and supply a patch if you're able, > > Thanks, John. > I'm trying to find out what exactly is causing the issue here. Would it be possible for you to show me the 'gcc -###' output so that I can compare to my version of gcc. Since the failure occurs only with optimization turned on i'm now leaning towards a compiler issue since I compiled gcc from source for this test. I'm hoping it's something obvious when I look closer. So far this has failed on a RHEL6.5 system running a locally compiler gcc 5.3.0 as well as a RHEL 7.2 based system compiled with the same gcc 5.3.0. Many thanks for your help, S

1 0

Re: [boost] [C++-sig] Trouble building boost with Visual Studio 2010
by Stefan Seefeld 09 Mar '16

09 Mar '16

Hi David, On 09.03.2016 05:04, David Aldrich wrote: > > Hi > > > > I am trying to build Boost 1.60 with Visual Studio 2010 Professional > on Windows 10. > > > > I use the command: > > > > b2 toolset=msvc-10.0 --with-python link=shared > > > > and get the following error: > > > > python34.lib(python34.dll) : fatal error LNK1112: module machine type > 'x64' conflicts with target machine type 'X86' > Just a quick guess: is it possible that your "libpython34.dll" file is a 64-bit binary, when the command really requires it to be a 32-bit binary ? > > > I guess this means I have a conflict of 32-bit and 64-bit libraries. > I want to target 32-bit (X86). > > > > Do I need to install a 32-bit version of Python? I wonder if that can > co-exist with the current version of Python? > I'm unfortunately unable to answer your question, as the question seems more about the build system than Boost.Python itself. Therefore I'm including the Boost mailing list in my reply, hoping that some Boost.Build expert may be able to help. Regards, Stefan > > > Best regards > > > > David > > > > > > _______________________________________________ > Cplusplus-sig mailing list > Cplusplus-sig(a)python.org > https://mail.python.org/mailman/listinfo/cplusplus-sig -- ...ich hab' noch einen Koffer in Berlin...

1 0

Re: [boost] [Boost-users] [Fit] formal review starts today
by paul Fultz 09 Mar '16

09 Mar '16

> On Tuesday, March 8, 2016 11:39 PM, Gavin Lambert <gavinl(a)compacsort.com> wrote: > > On 9/03/2016 10:43, paul Fultz wrote: >>> I would hope to convince you that a good Overview of your library > should >>> come first and then all the Quick Start guides, tutorials, examples > etc. >>> would make much more sense once your end-user understands what your >>> library really does in terms of at least the main general > functionality. >> >> I usually start with the Quick Start guide with a library in order to get > an >> understanding of what components are in the library and what they can do, > then >> I start delving into the other components from there. Thats what I am > showing >> in the Quick Start guide. >> >> I guess people have different ways of learning a library. I wonder what is >> needed to be explained better in a initial overview of the library. > > I suspect part of the problem is that the Introduction appears under the > ToC at the top level instead of on its own page above the Quick Start. > Thus someone not scrolling down is likely to miss the Introduction and > > start with the Quick Start. > > Still, even the Introduction is a little light on the things an Overview > generally needs to cover: "why should I consider using this library and > what types of problems does it solve?" (Sometimes some of this is split > to a separate Motivation section.) Yea, I think adding Motivation section will be helpful. > > Quick Starts / Tutorials are more for answering "now that I've already > decided to (probably) use this library, how do I do XXX?" > > > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users >

2 1

Re: [boost] [Boost-users] [Fit] formal review - should we propose some parts to Boost.Config/Boost.Core
by paul Fultz 09 Mar '16

09 Mar '16

> On Tuesday, March 8, 2016 6:52 PM, Steven Watanabe <watanabesj(a)gmail.com> wrote: > > AMDG > > On 03/06/2016 09:39 PM, Paul Fultz II wrote: >> >> On Sunday, March 6, 2016 at 3:44:31 AM UTC-6, Vicente J. Botet Escriba >> wrote: >>> >>> Le 06/03/2016 06:16, paul Fultz a écrit : >>>> >>>>> On Saturday, March 5, 2016 10:50 PM, Steven Watanabe < >>> watan...(a)gmail.com <javascript:>> wrote: >>>>> >>>>> #ifndef BOOST_FIT_NO_EXPRESSION_SFINAE >>>>> #ifdef _MSC_VER >>>>> #define BOOST_FIT_NO_EXPRESSION_SFINAE 1 >>>>> #else >>>>> #define BOOST_FIT_NO_EXPRESSION_SFINAE 0 >>>>> #endif >>>>> #endif >>>> This is can be configurable, whereas Boost.Config it is not. >>> I'm not sure this is true. >>> >>> > http://www.boost.org/doc/libs/1_60_0/libs/config/doc/html/index.html#boost_… >> >> >> That doesn't seem easily configurable by the user. I think I would > prefer >> to make it configurable by the library and use Boost.Config for the default > >> value. >> > > Why does it need to be easily configurable? > No one is ever going to care about it except > when Boost.Config is wrong. Well, I guess its mainly only useful for development then. I like to use the "no expression sfinae" path on clang as I can get better diagnostics. It seems kind of complicated to change this with Boost.Config, so I would prefer to have it easily configurable, and then use Boost.Config for the default value.

1 0

[property_tree] Two pull requests removing rtti and exception dependencies
by Chris Glover 09 Mar '16

09 Mar '16

Hi, I have two pull requests against property tree that I haven't heard anything about.. The first replaces usage of typeid(Type).name() in exception messages with boost::typeindex::type_id<Type>().pretty_name(). The second uses macros from no_exception_support.hpp to replace try catch blocks. I was hoping these might get into 1.61 so I don't need to carry local changes for too long -- is there any chance of that? Links: https://github.com/boostorg/property_tree/pull/20 https://github.com/boostorg/property_tree/pull/21 Thanks, -- chris

1 0

[Fit] review - ends next 13th Mars
by Vicente J. Botet Escriba 08 Mar '16

08 Mar '16

Hi, we are on the middle of the Fit review stated on 2 Mars and that ends 13th Mars. We have not received a lot of comments, only 4 or 5 people have commented and only a formal review (reject now). I understand that the documentation needs a lot of improvements, nevertheless, this review is the occasion to give as much feedback as possible. If you want to improve this library, please take the time to do a review and share your point of view. Best, Vicente

1 0

[coroutine] Broken on all compilers.
by Rene Rivera 08 Mar '16

08 Mar '16

Coroutine on master branch seems broken across all the master tested compilers in the same way. Would be nice if it gets fixed. -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net -- rrivera/acm.org (msn) - grafikrobot/aim,yahoo,skype,efnet,gmail

2 1

[release] Reminders..
by Rene Rivera 07 Mar '16

07 Mar '16

Boost was closed for "major changes" last Wednesday. Boost will be closed for all change this Wednesday (9th). If all goes well.. Boost will reopen for bug fixes only on the 17th. Please consult the calendar, and subscribe, to the calendar for such dates < http://www.boost.org/development/index.html>. -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net -- rrivera/acm.org (msn) - grafikrobot/aim,yahoo,skype,efnet,gmail

4 6

[BGL] Multiple Start Vertices in Dijkstra Shortest Path
by Matthias Fuchs 07 Mar '16

07 Mar '16

Hi folks, I am interested in adding support for multiple start vertices for the Dijkstra Shortest Path Algorithm. Having such functionality would improve both performance and clarity of code I wrote. In a prove of concept I implemented such functionality using iterators for dijkstra_shortest_paths_no_color_map. Is there interest for such a feature? Or would it be a waste of my time working on that? If there is interest what should be the preferred way? * Using iterators (first_start_vertex, last_start_vertex) * Using ranges What about unit tests? AFAICT there are only few tests, which do not seem to be run automatically. What about documentation? Thanks for reading, Matthias

1 0

2 regression test failing at under 1.60
by Steven Kelso 07 Mar '16

07 Mar '16

I've just started trying to install version 1.60 of boost using the gcc 5.3.0 compiler. With a vanilla download and no chnages it all seems to compile correctly, but I have a problem with 2 library regressions tests not terminating. They have both run for over 18 hours before I had to kill them. I was using the options and configuration "out of the box" so optimization was -O3. I downloaded the regressions tests from https://github.com/boostorg/regression and installed in the boost source tree under 'tools' I then compiled and run them : B=$PWD cd tools/regressions-develop/build $B/b2 --boost-root=$B export PATH=$B:$B/tools/regression-develop/stage/bin:$PATH cd $B/lib/maths/test b2 threading=multi variant=release toolset=gcc-5.3.0 test_binomial_real_concept2 The last few lines of the output file are: test_binomial.cpp(671): error: in "test_main": check x == (RealType)floor(binomial_quantile_data[i][3]) has failed [60 != 61] test_binomial.cpp(673): error: in "test_main": check x == (RealType)floor(binomial_quantile_data[i][4]) has failed [61 != 64] test_binomial.cpp(673): error: in "test_main": check x == (RealType)floor(binomial_quantile_data[i][4]) has failed [60 != 59] test_binomial.cpp(673): error: in "test_main": check x == (RealType)floor(binomial_quantile_data[i][4]) has failed [60 != 59] the same looping forever occurs with test_binomial_real_concept4 as well. However, editing the Jamfile.v2 file to add an entry '<optimization>off' for the test, allows the test to complete successfully and the test_binomial_real_concept2.output having no errors. I've done the same test using gcc 5.2.0 and gcc 5.1.0 as well with the same results. However, boost 1.56 using gcc 5.3.0 completes all of it's tests successfully. Is this a known issue or, if not, is there any more information that I can supply to help diagnose why this isn't working? Many thanks, S

2 2

Recommended Boost file structure?
by Paul A. Bristow 07 Mar '16

07 Mar '16

I've been looking at the structure of Phil Bouchard's prototype block_ptr library and am wondering if the structure of the header files is optimal/Boost_Standard/wrong. http://www.boost.org/doc/libs/1_60_0/more/getting_started/windows.html describes the Boost structure, but looks well out of date to me. (Can/should anyone still update this to reflect Modular Boost?) And looking through libraries, there seems some variation. I'm asking for views on what the best structure should be, (or if it doesn't matter much?) Some libraries have a structure modular_boost/libs/algorithm/include/boost/algorithm which contains algorithm.hpp and string.hpp that one might use directly. Others like asio contain /asio and just a asio.hpp that includes (all?) other headers. Others like multiprecision contain just a single folder modular_boost/libs/algorithm/include/boost/multiprecision but no other header files, not even forwarding header(s). So should the structure be that all headers (except forwarding headers - or a single header) are within modular_boost/libs/some_library/include/boost/some_library/ so the user should include with #include <boost/some_library/some_header.hpp #include <boost/some_library/other_header.hpp ... or to get everything useful #include <boost/some_library/some_library_fwd.hpp> possibly with a /detail folder containing headers that should not be called by users. Just checking... Paul --- Paul A. Bristow Prizet Farmhouse Kendal UK LA8 8AB +44 (0) 1539 561830

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Re: [boost] [Boost-users] [Fit] formal review - should we propose some parts to Boost.Config/Boost.Core
by paul Fultz 07 Mar '16

07 Mar '16

> On Saturday, March 5, 2016 10:50 PM, Steven Watanabe <watanabesj(a)gmail.com> wrote: > > AMDG > > On 03/05/2016 07:21 PM, Vicente J. Botet Escriba wrote: >> >> I want to start a new sub-thread about some of the concerns of Steven >> Watanabe about whether some of the contents of this library fits better >> in Boost.Config. In particular the file boost/fit/returns.hpp. >> > > When I mentioned Boost.Config, I was talking about > things like > > #ifndef BOOST_FIT_NO_EXPRESSION_SFINAE > #ifdef _MSC_VER > #define BOOST_FIT_NO_EXPRESSION_SFINAE 1 > #else > #define BOOST_FIT_NO_EXPRESSION_SFINAE 0 > #endif > #endif This is can be configurable, whereas Boost.Config it is not. > > or > > #ifndef BOOST_FIT_HAS_TEMPLATE_ALIAS > #if (defined(__GNUC__) && !defined (__clang__) && __GNUC__ == 4 > && > __GNUC_MINOR__ < 7) > #define BOOST_FIT_HAS_TEMPLATE_ALIAS 0 > #else > #define BOOST_FIT_HAS_TEMPLATE_ALIAS 1 > #endif > #endif > This could be replaced with Boost.Config, however, I have ran into problems before with template aliases on gcc 4.7, so I wanted to make this configurable as well, although it could fallback onto Boost.Config right now. > In Christ, > > Steven Watanabe > > _______________________________________________ > Boost-users mailing list > Boost-users(a)lists.boost.org > http://lists.boost.org/mailman/listinfo.cgi/boost-users >

3 2

[MMap/VM] RFC
by Domagoj Saric 06 Mar '16

06 Mar '16

Hello everyone, for quite some time I've been working on a portable mmap/virtual memory library and I've finally found enough time to bring it out of the 'my internal litle tool' state into something presentable: https://github.com/psiha/mmap (C++14 currently). I would now kindly ask fellow devs for opinions (on the good, the bad, the ugly and the future;) First let me answer the basic questions (i.e. on motivation and scope)... Q&A: (1) Why? Considering Boost already offers two related solutions * Interprocess: http://www.boost.org/doc/libs/release/doc/html/interprocess/sharedmemorybet… * Iostreams: http://www.boost.org/doc/libs/release/libs/iostreams/doc/classes/mapped_fil… why do we want a new one? Even if the two mentioned solutions were adequate, the problem domain would still merit a separate, dedicated library merely considering its complexity (which will become apparent in later points). (I suspect Ion would agree here considering he actually authored a related standardization proposal:) (2) Why a completely new library instead of a repackaging of existing functionality? I'm not satisfied with (a) the API semantics/design, (b) the API 'power'/library capabilities (c) and the implementation efficiency/overhead. a) Insistence on POSIX semantics: that shared memory objects have to be persistent (kernel lifetime) and resizable while not everyone wants or needs this (https://svn.boost.org/trac/boost/ticket/4827) This has implications both: - in the interface (requiring manual cleanup guards, additional platform specific shm types like windows_shared_memory) - and the overhead of the library (emulating shm with mapped files on major platforms that do not offer full POSIX compliance: Windows, OSX, iOS and Android) MMAP solves this with one class template 'named_memory' and policies: https://github.com/psiha/mmap/blob/master/include/boost/mmap/mappable_objec… so the user can choose: named_memory<scoped, resizable>, named_memory<persistent, fixed> or any other combination and the library chooses the best implementation. On POSIX, scoped semantics are achieved with a SEM_UNDO-enabled SysV semaphore acting as a kernel/system-global reference counter (which is then also used for automatic cleanup of shm zombies left by killed/crashed processes). On Windows the user can choose the Win32 backend (file emulation) or the NativeNT (not yet finished/commited) backend (with native persistence and resizability). b) - lack of a meta layer (e.g. so one can ask is_mappable<FILE *> or is_mappable<boost::filesystem::path>, is_mappable<HANDLE> etc...) - lack of related utility functions, for example: -- map_read_only_file( path ) which will open the file for reading, query its size, create a read only file mapping and map/return a read only view of the file -- guarded_operation( view, operation, error_handler ) - execute operation wrapped in SEH(Windows)/scoped signal handler(POSIX) guards that will catch access violations (e.g. when mmaping network files) and gracefully execute error_handler (with the faulting address as the parameter) https://github.com/psiha/mmap/blob/master/include/boost/mmap/mapped_view/gu… - in MMAP the mapped_view object (which should probably be renamed to just 'view' considering the enclosing mmap namespace) is just a RAII wrapper around an iterator_range therby providing the standard begin/end(), front/back(), operator[], etc. interface (as opposed to a get_data(), get_size() like interface) - general (not specific to mapping) virtual memory functionality (to be discussed in a separate point, MMAP also completely lacks this currently) - MMAP offers a comprehensive 'flags' system (e.g. https://github.com/psiha/mmap/blob/master/include/boost/mmap/flags/flags.hpp) for everything from object-level and system-level access privileges, over object parent-child inheritance to system life-time and access-pattern optimisation hints. Quite some time was invested in this area to produce a normalized interface that works for all objects (files, mappings...) while producing (near)zero adjustment codegen. Flags are 'packed'/grouped in structs (e.g. struct access_privileges with object_access, child_access and systen_access members) with public members so that, after flags are created with a factory function (a portable API) the flags can be further tweaked for a specific platform (e.g. adding some FreeBSD specific mmap hint which isn't covered by the portable/documented MMAP API) c) It is my view (if not a "self evident truth";D) that libraries that merely wrap existing low level functionality (such as OS or CRT APIs) should allow you to write code that is safe, portable and looks reasonably nice while at the same time incurs (near)zero overhead (i.e. with a reasonably intelligent compiler, produces codegen that looks nearly the same as it would had one used the underlying API directly) - and the existing solutions fail that. In the two related tickets I went into more detail on this so I'll avoid spaming this post by repeating those objections and analysis. Rather I'll present a trivial example that demonstrates what wannabeboost::mmap currently produces with a decent compiler, https://gist.github.com/psiha/c0823fefc01fa3b39662: #define BOOST_MMAP_HEADER_ONLY #include <boost/mmap/mapped_view/mapped_view.hpp> #include <boost/mmap/mappable_objects/file/utility.hpp> int main( int /*argc*/, char * /*argv*/[] ) noexcept { auto maybe_foo_view( boost::mmap::map_read_only_file( "foo" )() ); if ( !maybe_foo_view ) return static_cast<int>( maybe_foo_view.error() ); if ( maybe_foo_view->empty() ) return -1; return (*maybe_foo_view)[ 0 ]; } with Xcode 7.2.1 Clang -O3 build for x64 produces https://gist.github.com/psiha/f92a7b8a93c5ce1736ae (notice how the error handling is also correctly detected as such and placed at the end of the function, after the main return...) Besides not using shared_ptr pimpls or saving paths in std::strings as a 'nice to have' (YAGNI!:), part of the way this codegen is achieved is through the use of (also wannabe) Boost.Err (https://github.com/psiha/err) which makes it possible to avoid EH (in such simple/'localised' examples). It is also the reason for the somewhat awkward (optional<>-like) syntax: - map_read_only_file() returns a mmap::fallible_result<mmap::mapped_view> (an alias for err::fallible_result<mmap::mapped_view, mmap::error>, an "rvalue-only" type) - which is converted/'saved'/'pinned' into a result_or_error (the maybe_foo_view variable) with the additional operator() call - the !maybe_foo_view checks whether the call succeeded or the returned object contains an error - if error return the error (errno) code - else check if the view/file is empty (optional<>-like syntax for accessing the contained object through the -> and * operators) - else return the value of the first character in the file. Boost.Err was recently discussed on this list so I'll skip most of that now, let me just say that it also supports classic EH coding style (it auto adapts, no need for reconfiguration, macros or anything like that), i.e. the above code can be rewritten as: int main( int /*argc*/, char * /*argv*/[] ) noexcept { using namespace boost::mmap; try { read_only_mapped_view const foo_view( map_read_only_file( "foo" ) ); if ( foo_view.empty() ) return -1; return foo_view[ 0 ]; } catch ( std::runtime_error const & ) { return error::get(); } } ...now let me reverse the Q&A direction ;) 3. Library scope: currently the library covers the topic of memory mapping (of filesystem objects and virtual memory), however I think that 'the final' library should cover all resonably portable aspects of virtual memory (and be called something like vm with mmap as a nested namespace), tackling thingies such as: - process working set - portable low memory event handling, madvise, memfd... - prefetching, locking/unlocking virtual memory to/from physical memory (e.g. for realtime sensitive data) - allocators capable of contiguous resizing (for implementing realloc or vector.resize() that does no copying or moving, simply maps new pages at the end of the current allocation) - https://fgiesen.wordpress.com/2012/07/21/the-magic-ring-buffer ... does anyone have an objection/different approach to this? 4. Windows offers/has/uses the concept of an intermediate "mapping" object (i.e. you don't create a mapped view of a file, rather you create a 'mapping' of a file and then a view of the mapping). This of course complicates things but also gives more power, e.g. you can have a r/w file open and create a mapping (or several mappings) of it that only covers a part of its size and has stricter (e.g read only at object/process level) or wider access privileges (e.g. on the system level, only the parent process/user can access the file but the mapping is accesible by everyone). Boost.MMAP retains this distinction in its API (mapping vs mapped_view classes)...comments/thoughts on this please? 5. The above (Windows specific) 'mapping' concept makes it possible to create "named file mappings" (so that the object gets a system global name, like a shared memory object) which then another process can open by its name, erasing the difference between file mappings and vm mappings for client processes (kind of like the interface vs hidden implementation distinction). MMAP uses this on Windows for file-backed/'emulated' shared memory (e.g. that which needs persistence and/or resizabilty) - it is created named so that client processes can open and access it as 'normal'/native Windows shared memory. It might actually be possible to make this at least partially portable to POSIX systems that use virtual filesystems for implementing shared memory (e.g. Linux which uses /dev/shm) where we could symlink the file to the shm filesystem directory...(unfortunately I have no way of testing this as I have no Linux machine setup, I develop only for Windows, OSX, iOS and Android)...does this make any sense/would it be worth the hassle (i.e. ease any real world problems)? 6. The security part of the 'flags system' models the POSIX API: for named (system level) created objects you specify the permissions for the 'user', 'group' and 'world'. 'Behind the scenes', on Windows, 'user' maps to the user that created the process, 'group' maps to all groups that the 'user' belongs to and 'world' maps to the Everyone group..? When not using the predefined privilege/permission levels [e.g. process_default, unrestricted, nix_default (644)] things are currently pretty verbose here: namespace flags = boost::mmap::flags; using ap = flags::access_privileges; auto const default_privileges ( ap::system::user ( ap::all ) | ap::system::group( ap::read ) | ap::system::world( ap::read ) ); I have a prototype implementation that shortens this with user defined literals, so that one can write something like "rwxr-xr--"_perm...All in all, this thing looks like it merits a separate library in its own right... 7. Windows has another quirk up its sleeve: global vs local session objects - if you want to create a shared memory object visible across terminal sessions (this includes a server process running as a service, thereby in session 0, and client process created by a logged on user, or/also using the NativeNT backend/API to create a native persistent shared memory object which requires that it be created in the global session '0') you have to prefix its name with "Global\" (and have admin privileges)... I'm still pondering how to model this in the API or whether it should be automatically handled at all, e.g. whether to deduce if the Global\ prefix should be automatically added (based on the process privileges, type and access privileges of shm object being created etc) or leave it up to the user to know "if I'm running on Windows and want to do this and this I have to use the Global\ prefix"... There's more but the openning post is already too long so I'l stop...for now ;) -- "What Huxley teaches is that in the age of advanced technology, spiritual devastation is more likely to come from an enemy with a smiling face than from one whose countenance exudes suspicion and hate." Neil Postman --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

4 5

code naming conventions
by Michael Marcin 06 Mar '16

06 Mar '16

I've written a lot of code in the boost/standard library style. I've become increasingly annoyed at naming my variables when coding in this style. Looking to the standard library implementations for guidance isn't much help as they often use conventions like local variables are named with a leading double underscore and member variables are named with a leading underscore and capital letter. I.E. things I'm not allowed to do as I'm not a standard library implementer. Good names are generally taken by types leading to distress when trying to name objects and functions. Here's a concrete example: // type takes the most natural name enum class format { rgba, rgb, float // enum value wants reserved name }; class image { public: // getter wants the same name format format() const noexcept { return this->format; } // setter wants the same name void format( format format ) noexcept // parameter wants the same name { this->format = format; } private: // member variable wants the same name format format; }; format bits_to_format( int bits ) { // local variable wants the same name format format = format::rgba; if ( bits == 24 ) { format = format::rgb; } return format; } // unrestricted template parameter does *not* want the same name template< typename Format > std::ostream& print_format( std::ostream&, Format format ); // Concept template parameter *does* want the same name template< Format Format > std::ostream& print_format( std::ostream&, Format format ); What I end up doing right now is something like: // type takes the most natural name enum class format { rgba, rgb, float_ // add trailing underscore to reserved name }; class image { public: // prefix getter with get_ format get_format() const noexcept { return _format; } // prefix setter with get_ void set_format( format format_ ) noexcept // trailing underscore on parameter { _format = format_; } private: // leading underscore on member format _format; }; format bits_to_format( int bits ) { // cutesy abbreviation for local variable format fmt = format::rgba; if ( bits == 24 ) { fmt = format::rgb; } return fmt; } template< typename Format > std::ostream& print_format( std::ostream&, Format format_ ); // cutesy abbreviation for constrained template type template< Format Fmt > std::ostream& print_format( std::ostream&, Fmt format_ ); Having to come up with cutesy abbreviations for every local variable that are still meaningful is especially distracting. Surely enough code has been written that this has been solved. I looked through several boost library implementations but didn't see anything that stuck out as a clear convention. Adobe's ASL library seems to append _t postfix to type names and _m postfix to member variables. They also use very terse names for template parameter type names as well as parameter names and local variables. Like in: template <typename I, // I models ForwardIterator typename N, // N models IntegralType typename T, // T == result_type(P) typename C, // C models StrictWeakOrdering(T, T) typename P> // P models UnaryFunction(value_type(I)) -> T I lower_bound_n_(I f, N n, const T& x, C c, P p) { while (n != 0) { N h = n >> 1; I m = boost::next(f, h); if (c(p(*m), x)) { f = boost::next(m); n -= h + N(1); } else { n = h; } } return f; } What's your preferred convention? If possible please answer by modifying the initial concrete example and providing annotations.

3 2

[MSM] Surprising Entry Point behaviour
by Michael Caisse 06 Mar '16

06 Mar '16

Hi Christophe - I'm seeing some surprising behaviour when I have a sub-machine that can only be entered via an entry point. I have attached a diagram for quick reference. Code is below to demonstrate the "issue". Moving into the Sub state should only generate transitions into A with a 'none' event. The only way to get to B is via a transition from A with the 'event' event. MSM is trying to generate code into B for a transition with a 'none' event. This could be valid if the transition from Top::X wasn't via the entry point and just directly to Sub. I don't think there is a path to B with a 'none' event. Thoughts? Take care - michael ---------------- #include <boost/msm/front/state_machine_def.hpp> #include <boost/msm/front/functor_row.hpp> #include <boost/msm/back/state_machine.hpp> using boost::msm::front::none; using boost::msm::front::Row; namespace msm = boost::msm; struct event { int foo; }; struct Sub_ : public msm::front::state_machine_def<Sub_> { struct Enter : public msm::front::entry_pseudo_state<0> {}; struct A : msm::front::state<> {}; struct B : msm::front::state<> { template<class FSM> void on_entry(event const & evt, FSM &) {} }; using initial_state = A; struct transition_table : boost::mpl::vector< // Start Event Next Action Guard // +----------+---------+--------+-----------+-------- Row < Enter , none , A , none , none >, Row < A , event , B , none , none >, Row // +----------+---------+--------+-----------+-------- >{}; }; using Sub = msm::back::state_machine<Sub_>; struct Top_ : public msm::front::state_machine_def<Top_> { struct X : msm::front::state<> {}; using initial_state = X; struct transition_table : boost::mpl::vector< // S Event Next Action Guard // +----+-------+-----------------------------+-------+------- Row < X , none , Sub::entry_pt<Sub_::Enter> , none , none > // +----+-------+-----------------------------+-------+------- >{}; }; using Top = boost::msm::back::state_machine<Top_>; int main() { Top top; top.start(); } ------------------------- -- Michael Caisse Ciere Consulting ciere.com

2 1

Re: [boost] [Boost-users] [Fit] formal review - should we propose some parts to Boost.Config/Boost.Core
by Glen Fernandes 06 Mar '16

06 Mar '16

On Sat, Mar 5, 2016 at 9:21 PM, Vicente J. Botet Escriba wrote: > Others could be considered also as function.hpp, lambda.hpp and lift.hpp, as > the macros are there to workaround some missing language features, but those > are much more specialized (Boost.Core?) > Boost.Core is where we move code from existing Boost libraries that enables breaking cyclic dependencies between different Boost libraries. I'm not so sure new libraries will need to (or want to) put code there. Glen

2 1

[Fit] review
by Vicente J. Botet Escriba 06 Mar '16

06 Mar '16

Paul, could you send me a private mail, I don't reach to send you any private mail. I'm always getting Hallovicente.botet(a)wanadoo.fr, Sie erhalten diese E-Mail, weil die Gruppe, die Sie kontaktieren möchten (boost-devel-archive), möglicherweise nicht vorhanden ist bzw. Sie nicht die erforderlichen Berechtigungen haben, um der Gruppe Nachrichten zu posten. Nachstehend einige Detailinformationen zu den möglichen Gründen, warum Sie keine Nachricht posten konnten: ... :( Vicente

1 0

[Fit] review - github issuess
by Vicente J. Botet Escriba 06 Mar '16

06 Mar '16

Hi, we have started to create some issues in https://github.com/pfultz2/Fit/issues, and sometimes there are some interesting discussion. I will try to add post on the MLs the issues that are conflicting so that other are aware of the discussion. Anyway, if you are curious you can always take a look at and participate also. If you want to receive the updates I believe that you just need to click on watch (top right). Best, Vicente

1 0

[asio] Feature request: console IO
by Tatsuyuki Ishi 06 Mar '16

06 Mar '16

Hello everyone, here is a greeting for joining the list. I want to request console support in asio. Some reasons: 1. non-block stdin is useful for some applications. 2. Linux can do non-block IO on ttys. Implementation concept: 1. Linux: if using epoll, first check if target is a regular file. If not, fall back to threaded non-blocking IO. select(), poll() can be use on any valid fds. 2. Windows: this garbage doesn't support overlapped console IO. Create a separate thread for std{in,out,err}, then communicate with the thread. 3. Other *nix: I don't know. It could already be used through POSIX stream descriptor, but it is too limited and platform specific. A library can cover these gaps is great. I hope you like this idea.

3 2

[Block Pointer][Container] Works - Take 2
by Phil Bouchard 06 Mar '16

06 Mar '16

Sorry for all the confusion but I was very confused myself. Now the block_ptr<> works in all cases with Linux x86: - I removed the usage of an allocator. Now there is no need for any allocator anymore. - I removed the usage of the strange pointer proxy optimization. Now the memory manager might take more memory but the class is clean and correctly abstracted. - I removed the usage of weak references. This is just too error-prone. But I need to tell whether an address is on the stack or on the heap. There is no portable way to do this except from marking the heap boundaries by overloading an allocator or write assembly code for each architecture / OS. I prefer the latter and I think this should eventually be part of the standards. Once again the working examples are here: https://github.com/philippeb8/block_ptr/blob/master/example/benchmark.cpp https://github.com/philippeb8/block_ptr/blob/master/example/block_ptr_test1… https://github.com/philippeb8/block_ptr/blob/master/example/block_ptr_test2… Regards, -Phil

3 6

merge to master?
by Robert Ramey 05 Mar '16

05 Mar '16

I've (finally!) got the latest version of the serialization library to pass all the tests on develop. I would like to merge develop to master. May I do this? Robert Ramey

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[Block.Pointer][Container] Works!
by Phil Bouchard 05 Mar '16

05 Mar '16

Ok now everything works!! https://github.com/philippeb8/block_ptr/blob/master/example/block_ptr_test2… So now block_ptr<> is Boost.Container compliant! I still need to fix an issue but it's moving forward! Thanks, -Phil

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[test] Boost.Test fails to build with gcc-4.6
by John Maddock 05 Mar '16

05 Mar '16

See http://www.boost.org/development/tests/develop/developer/output/igaztanaga-…

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[Fit] pipable order of the arguments
by Vicente J. Botet Escriba 05 Mar '16

05 Mar '16

Hi, I would like to know what other think about the order of the pipe (See this issue https://github.com/pfultz2/Fit/issues/5) What would be the expected meaning of auto r1 =1 | pipable(f)(2); f(1,2) or f(2,1)? What would be the expected meaning of auto f2 = partial(f)(2); auto r1 =1 | pipable(f2); f(1,2) or f(2,1)? As the operator| has left-to-right associativity, we can not do auto x = 1 | 2 | pipable(f); We would need a way to pack the parameters auto x = forward_as_tuple(1, 2) | pipable(f); but this wouldn't compile as f has two parameters. or use parenthesis auto x = 1 | (2 | pipable(f)); and the result will be f(2, 1). Any ideas? Best, Vicente Vicente

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[fusion] getting type of attribute_proxy for BOOST_FUSION_ADAPT_ADT
by Jens Weller 05 Mar '16

05 Mar '16

Hello, Code below, first what I'm trying to do is... assign a value to a adapted struct (BOOST_FUSION_ADAPT_ADT), which works fine if both are of the same type or convertible: template<int I, class Seq, class V> typename std::enable_if< std::is_convertible< typename fusion::result_of::at_c<Seq, I>::type, V>::value ,void>::type assign(Seq& s, V& v) { fusion::get(s) = v; } Some of my input is string, and the struct member is bool, unsigned int etc. In this case I'd need to know the type to convert from string. boost::fusion::get returns the attribute_proxy for the adapted struct, so does at_c<>::type. template<int I, class Seq, class V> typename std::enable_if< !std::is_convertible< typename fusion::result_of::at_c<Seq, I>::type, V>::value /*&& !std::is_same<typename std::decay<V>::type,std::string>::value*/ ,void>::type assign(Seq& s, V& v) { std::stringstream ss; ss << v; ss >> fusion::get(s); } Obviously this does not compile. Is there any trick to get to the type of the proxy? One idea I have is decltype(fusion::get(s).get()), but not sure if I can get this to work in an enable_if... thanks, Jens Weller

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[operators] permission to merge develop to master
by Daniel Frey 05 Mar '16

05 Mar '16

May I merge the ADL protection from develop to master for utility/operators?

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[optional] Why was optional<T>::reset() deprecated?
by Nevin Liber 04 Mar '16

04 Mar '16

Does anyone know? We are considering adding it to std::optional this week. Thanks, -- Nevin ":-)" Liber <mailto:nevin@cplusplusguy.com <nevin(a)eviloverlord.com>> +1-847-691-1404

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[type_traits] is_base_of<B, D> should work when B is incomplete
by Andrzej Krzemienski 04 Mar '16

04 Mar '16

Hi, I have filed the following ticket: https://svn.boost.org/trac/boost/ticket/12027 The Standard ([meta.rel]) requires that in std::is_base_of<B, D> D must be a complete type, but it does not require the same of B. This makes sense, because if we compare a complete type D and an incomplete type B, the former is surely not derived from the latter. In contrast, boost::is_base_of imposes an additional constraint that B must also be complete. Could this restriction be lifted? Regards, &rzej

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[range] merge to master?
by Jürgen Hunold 04 Mar '16

04 Mar '16

Hi Neil, could you please merge Boost.Range to master? There are some merged PRs fixing bugs in develop which I'd like to see in 1.61.0 Yours, Jürgen -- * Dipl.-Math. Jürgen Hunold ! * voice: ++49 4257 300 ! Fährstraße 1 * fax : ++49 4257 300 ! 31609 Balge/Sebbenhausen * jhunold(a)gmx.eu ! Germany

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Re: [boost] [Fit] upcoming formal review for Boost.Fit
by Bjorn Reese 03 Mar '16

03 Mar '16

On 02/27/2016 05:16 PM, Vicente J. Botet Escriba wrote: > Documentation:http://pfultz2.github.io/Fit/doc/html/ In More Examples / Projections there is this example: std::sort(std::begin(people), std::end(people), by(&Person::year_of_birth, _ < _)); That strikes me as a very terse syntax, where the reader could easily miss the fact that two values are being compared. Have you considered the use of placeholders like _1 and _2 instead?

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[Block.Pointer][Container] List node allocator
by Phil Bouchard 02 Mar '16

02 Mar '16

I've refactored most of the internal algorithms of block_ptr<> and now it is much more robust. The following example works pretty well: https://github.com/philippeb8/block_ptr/blob/master/example/block_ptr_test1… The next step is to support Boost.Containers: https://github.com/philippeb8/block_ptr/blob/master/example/block_ptr_test2… But after debugging the code it looks like the allocator is not used to instantiate the nodes and I do not see how it is used by looking at the code: template <class T, class VoidPointer> struct list_node : public list_hook<VoidPointer>::type { private: //list_node(); public: typedef T value_type; typedef typename list_hook<VoidPointer>::type hook_type; T m_data; T &get_data() { return this->m_data; } const T &get_data() const { return this->m_data; } }; Am I missing something? Thanks a lot for your help, -Phil

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[gsoc16] Boost rejected as GSoC 2016 org
by Niall Douglas 02 Mar '16

02 Mar '16

Dear Boost, It is with a heavy heart I write to say that Boost was rejected as an org for Google Summer of Code 2016 by Google. We had our application submitted in time, it was reviewed by three members of the Boost leadership, our ideas list had six solid ideas with an especially solid seventh on the way, we were in very good standing with Google and there was no reason to expect rejection. We have asked for clarification as to why we were rejected, and we shall try to improve our application next year to improve our chances. We recognise that many students and mentors will be extremely disappointed by this news. We share in that disappointment, and all we can say is please try again next year. For those students and mentors who are continuing a previous GSoC on an existing Boost library, there may be a possibility that Boost may be able to fund those continuations this year. Each case will be approached by the steering committee on a case by case basis, and be aware that the standard required for funding by Boost is considerably above that of Google's with an accompanying high and detailed standard of funding application to the steering committee. Contact us privately if you want to know more. On other news we had been expecting to announce today that Bryce Adelstein Lelbach has generously agreed to take over as secondary GSoC admin from Boris Schäling who has served Boost GSoC for something like four years now, so he has definitely earned himself a rest! Our thanks to Boris for his service, and welcome Bryce to the team! Finally, I'd like to thank Jon Kalb who moved heaven and earth as he always does to get the GSoC application submitted in time. Yours, Niall Douglas -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/

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Re: [boost] [gsoc16] An update on GSoC 2016 contingency plans
by Bjorn Reese 02 Mar '16

02 Mar '16

On 03/02/2016 05:17 PM, Niall Douglas wrote: > * Boost.Http, mentored by Bjorn Reese. > https://boostgsoc14.github.io/boost.http/ > > Student: Vinícius dos Santos Oliveira > > Status: One peer review held I have been preparing a proposal for GSoC 2016 which got delayed due to the usual excuses (work-load.) This is a draft of the proposal: Title: HTTP parser combinator. This proposal explores a more flexible HTTP parser framework based on ideas from parser combinators and pull parsers. The framework differentiates itself from the existing HTTP parser libraries for C/C++ on several accounts. With the help of parser combinators it offers the possibility of parsing an entire HTTP message or just a piece of it. The framework should consist of mini-parsers for the individual BNF rules in the HTTP grammar [1]. This is useful when integrating with existing HTTP transport libraries, such as libcurl, which may deliver one HTTP header at the time through a calllback mechanism. Pull parsers gives us the opportunity to replace the parser during the parsing process. This is useful for HTTP Upgrade requests, where the grammar may change "in-flight." For example, WebSockets starts off using the normal HTTP grammar, but then changes to its own binary protocol. Other examples are the differently formatted data that occurs in HTTP messages, such as x-www-form-urlencoded [2] or JSON [3]. Pull parsers also allows for smaller memory footprint. [1] https://tools.ietf.org/html/rfc7230 [2] https://www.w3.org/TR/html401/interact/forms.html#h-17.13.4.1 [3] https://tools.ietf.org/html/rfc7159

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[gsoc16] An update on GSoC 2016 contingency plans
by Niall Douglas 02 Mar '16

02 Mar '16

Dear Boost, We've been collecting a list of veteran Summer of Code students where "veteran" means students whom have previously done a Google Summer of Code for Boost. It /may/ be possible for us to acquire enough funding from a number of contributors to tide over ongoing GSoC projects this summer during our year off from Google funding for veteran students only. The stipend to the student would be the same as with Google, $5,500. The mentor stipend would likely need to be waived under any substitute programme. We would therefore appreciate an update from student and/or mentor as to whether they were intending to submit a continuing GSoC this summer and would be willing to continue work on their Boost library under any funding we find. If we have forgotten any students or projects, please get in touch. Extant ongoing summer of code projects known to us are (please send corrections of any mistakes): * Boost Document, mentored by Antony Polukhin. https://anuragxel.github.io/boost-document/ Student: Anurag Ghosh Status: Not peer reviewed * Boost.Compute, mentored by Kyle Lutz. https://boostorg.github.io/compute/ Student: Jakub Szuppe Status: Official Boost library * Boost.Hana, mentored by Joel Falcou. https://boostorg.github.io/hana/ Student: Louis Dionne Status: Official Boost library * Boost.Http, mentored by Bjorn Reese. https://boostgsoc14.github.io/boost.http/ Student: Vinícius dos Santos Oliveira Status: One peer review held * Boost.Fixed-Point, mentored by Paul Bristow. https://github.com/BoostGSoC15/fixed_point Student: Nikhar Agrawal Status: Not peer reviewed We are aware of the following Boost libraries who have strong but new-to-Boost potential student candidates in the pipeline for summer of code 2016: * Boost.odeint, mentored by Karsten Ahnert and Mario Mulansky There is even less chance we can find funding for these, but if any of the veteran students or mentors has to suddenly pull out before the summer, we would substitute one of these projects instead. Therefore, if mentors had a really excellent student lined up for 2016, please let us know. None of the above should be read that summer of code 2016 is going ahead. We just need some hard numbers with which to lobby for funding. We will get back to the community as soon as we know more. We need all this information requested above back BEFORE this weekend as we will be making use of the Jacksonville ISO WG21 meeting currently happening to grab the right people to ask them for donations from their corporate bodies. If YOUR corporate org would be willing to help sponsor a summer of code student, either partially or in full, PLEASE get in touch. Donations to Boost are tax deductible for US taxpayers. Thank you all very much in advance! Niall --- Boost C++ Libraries Google Summer of Code 2016 admin https://svn.boost.org/trac/boost/wiki/SoC2016

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[serialization] Back Versioning issue
by Janusz Zradomia 02 Mar '16

02 Mar '16

We want to use boost::serialization with boost::asio in one of our software, but we have a critical issue which prevents our further work. It refers to the "Back Versioning" known problem in TODO section: "It has been suggested that a useful feature of the library would be the ability to create "older versions" of archives. Currently, the library permits one to make programs that are guaranteed the ability to load archives with classes of a previous version. But there is no way to save classes in accordance with a previous version. At first I dismissed this as a huge project with small demand. A cursory examination of the code revealed that this would not be very difficult. It would require some small changes in code and some additional tests. Also it would require special treatment in the documentation - perhaps a case study. " *We want to ask what is status of this issue and can we expect to fix this in near future.* This is a networking project, our program compiled with e.g. boost 1.62 or some future version must create archives that can be (sent over the network and then) read on the program compiled with older version like 1.57 for example (as now available by default of Windows/cygwin). We would hope that we can do something like; Archive ar; ar.set_compatibility_boost_version(1, 55); ar << ... We would also need to backport the patch to older version of boost archive, so they also can write archives readable by (even older) versions. In the end we expect to run machines with: boost 1.55 (plus patch to set compatibility) boost 1.57 (plus patch to set compatibility) boost 1.58 (plus patch to set compatibility) boost 1.62 (perhaps by default with the set compatibility option) and each of this computers needs to write archive readable by all other versions (set they would all set compatibility to lowest common version). Without this functionality we can not use boost archive in this project. We would like to help you test/backport this fix and perhaps even try to code it, although we do not yet have any experience in writing code for boost library itself. Can we expect this functionality to be written in e.g. this year? Best regards

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[doc] Liven up Boost Documentation with Java Script?
by Krzysztof Jusiak 01 Mar '16

01 Mar '16

Dear Boosters, I'm writing to ask about your opinion regarding more interactive documentation for Boost. I know already that some of you would like to see online documentation without Java Script and that's absolutely fine and I agree that documentation should be available for anyone and any configuration. Nevertheless, I would like to know what the Boost community thinks about having following features in the documentation... * Run the code online (allows to check library with one click) * Comments (allows commenting on the documentation) * Chats (allows discussing issues and solutions) Personally, I have found above features extremely useful when checking out other languages/libraries and therefore I have implemented solutions for C++ too. Please, check it out (JS is required)... http://boost-experimental.github.io/msm-lite http://boost-experimental.github.io/di If there is an interest I can provide generic solution to allow developers to write documentation using markdown (mkdocs) and simply integrate it with their libraries. Currently, theme is just slightly modified version of readthedocs, however Paul Fultz II has prepared a boost theme for Fit library ( https://github.com/pfultz2/mkdocs-boost) already and it might be easily integration with the JS facilities provided. Cheers, Kris

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[ublas]Contribute about Toeplitz Matrix
by Shangtong Zhang 01 Mar '16

01 Mar '16

Hi David Bellot, It’s disappointed that boost was rejected by gsoc 2016. I was interested in ublas project, and have implemented parts of toeplitz matrix. Anyway I don’t want to abandon my implementation half way, so I’d like to continue on toeplitz matrix. Would you like to guide me to succeed in integrating toeplitz matrix into ublas? Thanks, Shangtong Zhang, Senior Student, School of Computer Science, Fudan University, PRC.

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