May 2016 - Boost - lists.boost.org

doctest - the lightest feature rich C++ single header testing framework - if it can enter boost and if it/boost will benefit from that
by Viktor Kirilov 24 May '16

24 May '16

Hello! I just released doctest - https://github.com/onqtam/doctest All the info about it can be found on github. So do you think it can enter the boost project? How much work will it take to get it into boost except for adding boost in the title? Will it or boost benefit from that addition? Also I've sort-of followed the Best Practice Handbook (I consider it very valuable) as much as possible - https://svn.boost.org/trac/boost/wiki/BestPracticeHandbook Any feedback will be greatly appreciated. Thanks!

10 19

Rebooting Boost: Call for Lightning Talks @ CppCon
by Niall Douglas 23 May '16

23 May '16

At C++ Now a number of informal meetings showed there to be frustrations with the current ecosystem around the Boost C++ Libraries (to paraphrase a founder of Boost, "Boost is supposed to serve *the entire C++ community; it isn't Boost's goal to serve Boost's community*". Recent and recurrent boost-dev discussions have raised the lack of cmake based tooling; lack of ABI management and the consequent ODR violation when mixing Boost versions in the same process; the anti-social behaviour of Boost towards library end users, new ideas, new blood and the wider C++ community; and the chronic lack of maintenance of up to half the Boost libraries. One question which needs to be answered is whether a clean reboot of Boost from the first principles of proving high quality C++ libraries well suited for use with the latest C++ standard is viable. This new collection of C++ libraries would be started completely from scratch (even if some existing libraries were ported into the new organisation), so ANYTHING is possible. All we need is a critical mass of library developers willing to collaborate on developing a shared infrastructure mutually beneficial to all participants, whether library developer or library end user. To that end of discovering if this critical mass is there, five minute lightning talk topics are requested for CppCon this September on this topic: "What design pattern, practice or idiom should a standards aspiring collection of C++ 14/17 libraries share?" Please keep each talk topic focused on a single design pattern, practice or idiom (see suggested talk format below). Each speaker may submit up to THREE talk topics (not all may be accepted if there are a lack of slots, so please rank them in order of preference). Please send your talk topics to me privately by email, only if sufficient numbers present to fill a session will your name and your talk topic be shared with the CppCon Programme Committee. We'll try to arrange a short panel session at the end so attendees can ask questions of the speakers. After the lightning talk we'll arrange a restaurant so all the speakers and any interested attendees can dine together, followed by a night in a Bellevue bar. If after the dust has settled it is felt there is a critical mass sufficient to reboot a brand shiny new edition of Boost, we'll start development! I should *stress* that it is up to the CppCon Programme Committee whether these lightning talks are approved or not. I'll just copy and paste your proposed talk to the CppCon PC as-is. If insufficient lightning talk topics are received by me to fill a 60 minute session, I'll withdraw this talk proposal from CppCon. Suggested talk format ================ Five minutes is not much time, so here is a suggested lightning talk outline: 1. A current widely practiced library design pattern (show example). 2. The problems it generates for library users or maintainers. 3. Your proposed alternative design pattern (show example). 4. The problems the alternative design pattern fixes. 5. Any mockup, prototype or even live demo (!) of the alternative design pattern in action. Suggested talk themes might be documentation, packaging, distribution, testing, tooling, quality assessment, barriers to entry, governance, strategy, important gaps in the standard libraries, automation and deprecation/removal policies. Here is an example of such a lightning talk: 1. Current design pattern: Library v1.00: namespace boost { namespace lib { void foo(size_t, char); } } User code: boost::lib::foo(100, 'n'); 2. Problem: Library v1.01: namespace boost { namespace lib { void foo(char, size_t); } } User code: boost::lib::foo(100, 'n'); // oh oh! 3. Alternative: Library v1.00: namespace boost { namespace lib { inline namespace v100 { void foo(size_t, char); } } } #define BOOST_LIB_NAMESPACE_V100 boost::lib::v100 Library v1.01: namespace boost { namespace lib { inline namespace v101 { void foo(char, size_t); } } } #define BOOST_LIB_NAMESPACE_V101 boost::lib::v101 User code: // Mount v100 of Boost.Lib into "lib" namespace lib=BOOST_LIB_NAMESPACE_V100; lib::foo(100, 'n'); // ABI stable! No ODR violation possible! 4. Problems fixed: a) Mixing incompatible versions of individual Boost libraries in the same process (or even translation unit) is now safe. b) Libraries can now depend on other libraries without worrying about breaking code which depends on them which uses a different version of the same dependency. This greatly helps reduce change ripple effects. c) Forward compatibility or alternative implementation shims are now very easy to implement e.g. library users can externally configure either Boost.Filesystem or std::experimental::filesystem for your library to use, your code simply refers to _some_ Filesystem TS implementation e.g. namespace filesystem = FILESYSTEM_TS_IMPLEMENTATION; filesystem::path mypath; -- ned Productions Limited Consulting http://www.nedproductions.biz/ http://ie.linkedin.com/in/nialldouglas/

8 10

@boost-admins: permission to git-repo removed?!
by Oliver Kowalke 23 May '16

23 May '16

Hi, I can't push commits to git-repo boost.coroutine2: remote: Invalid username or password. fatal: Authentication failed for 'https://github.com/boostorg/coroutine2/' Could you please re-add user 'olk', please. thx, Oliver

3 3

What C++14/1z standard or TS libraries would you like to have available on a C++11 compiler?
by Vicente J. Botet Escriba 23 May '16

23 May '16

Hi, I would like to have your feedback on C++ standard library features you would like to have available for a C++11 compiler. The idea would be to present a Boost.StdExtensions library that would provide some of these features for review with some of these features. Please , let me know if you are interested in participating in this project and working on some specific parts. This library should avoid as much Boost dependencies as possible. How the library could be structured? I believe that it should follow the C++ standard files. Which folder should be used? boost/stdext? boost/stdext11? Which namespace? boost::stdext? I have prefixed with a * the lines that interest myself and with VBE* those that I could work on. The features that need compiler help or that need C++14/17 language features are excluded and prefixed by N/A. Please be free to add a * if you are interested and your name as well if you want to participate. Best, Vicente P.S. The project could be as well extended to C++98 compilers with C++11 standard libraries (But I would not have time to invest in). P.S.S. I would also be interested in extend the project to extended to C++14 compilers. C++14 standard libraries ================ VBE* N3658 - Compile-time integer sequences * N3654 - Quoted Strings N3656 - make_unique VBE* N3462 - std::result_of and SFINAE * N3668 std::exchange() N3469 Constexpr Library Additions: chrono N3470 Constexpr Library Additions: containers N3471 Constexpr Library Additions: utilities N3302 Constexpr Library Additions: complex VBE* N3545 An Incremental Improvement to integral_constant N3644 Null Forward Iterators N3670 Addressing Tuples by Type N3671 Making non-modifying sequence operations more robust N3642 User-defined Literals VBE* N3655 TransformationTraits Redux (excluding part 4) N3657 Adding heterogeneous comparison lookup to associative containers N3669 Fixing constexpr member functions without const N3659 Shared Locking in C++ N3779 User-defined Literals for std::complex N3789 Constexpr Library Additions: functional N3887 Consistent Metafunction Aliases N3891 A proposal to rename shared_mutex to shared_timed_mutex C++1z standard libraries ================ VBE* N3911 TransformationTrait Alias void_t N4089 Safe conversions in unique_ptr<T[]> VBE* N4169 A proposal to add invoke function template N4258 Cleaning-up noexcept in the Library. N4277 TriviallyCopyable reference_wrapper. N4279 Improved insertion interface for unique-key maps. VBE* N4280 Non-member size() and more N4284 Contiguous Iterators. N4387 improving pair and tuple VBE* N4389 bool_constant N4508 shared_mutex for C++17 N4366 LWG 2228 missing SFINAE rule N4510 Minimal incomplete type support for standard containers N/A* P0006R0 Adopt Type Traits Variable Templates for C++17. VBE* P0092R1 Polishing <chrono> VBE* P0007R1 Constant View: A proposal for a std::as_const helper function template. VBE* P0156R0 Variadic lock_guard(rev 3). P0074R0 Making std::owner_less more flexible VBE* P0013R1 Logical type traits rev 2 P0024R2 The Parallelism TS Should be Standardized P0226R1 Mathematical Special Functions for C++17 VBE* P0220R1 Adopt Library Fundamentals V1 TS Components for C++17 P0218R1 Adopt the File System TS for C++17 P0033R1 Re-enabling shared_from_this VBE* P0005R4 Adopt not_fn from Library Fundamentals 2 for C++17 P0152R1 constexpr atomic::is_always_lock_free N/A* P0185R1 Adding [nothrow-]swappable traits P0253R1 Fixing a design mistake in the searchers interface P0025R0 An algorithm to "clamp" a value between a pair of boundary values P0154R1 constexpr std::hardware_{constructive,destructive}_interference_size P0030R1 Proposal to Introduce a 3-Argument Overload to std::hypot P0031R0 A Proposal to Add Constexpr Modifiers to reverse_iterator, move_iterator, array and Range Access P0272R1 Give std::string a non-const .data() member function VBE* P0077R2 is_callable, the missing INVOKE related trait Fundamental V1 TS ============ Uses-allocator construction Changes to std::shared_ptr and weak_ptr Additions to std::function Additions to std::promise Additions to std::packaged_task Class erased_type VBE* Calling a function with a tuple of arguments N/A Type traits (_v) Other type transformations Compile-time Rational Arithmetic Time Utilities System Error Support Class memory_resource Class template polymorphic_allocator Template alias resource_adaptor Global memory resources Pool resource classes Class monotonic_buffer_resource Alias templates using polymorphic memory resource Searchers * Optional Objects Initial implementation * class any * string_view memory Algorithms library

6 8

Boost 1.61.0 has been released
by Rene Rivera 22 May '16

22 May '16

Release 1.61.0 of the Boost C++ Libraries is now available. These open-source libraries work well with the C++ Standard Library, and are usable across a broad spectrum of applications. The Boost license encourages both commercial and non-commercial use. This release contains four new libraries and numerous enhancements and bug fixes for existing libraries. New Libraries * Compute: Parallel/GPU-computing library, from Kyle Lutz. * DLL: Library for comfortable work with DLL and DSO, from Renato Tegon Forti and Antony Polukhin * Hana: A modern C++ metaprogramming library, from Louis Dionne. * Metaparse: A library for generating compile time parsers parsing embedded DSL code as part of the C++ compilation process, from Abel Sinkovics. For details, including download links, see http://www.boost.org/users/news/version_1.61.0 You can also download directly from SourceForge: http://sourceforge.net/projects/boost/files/boost/1.61.0/ Tom Kent has made pre-built windows binaries, and they are available at: https://sourceforge.net/projects/boost/files/boost-binaries/1.61.0/ To install this release on your system, see http://www.boost.org/doc/libs/release/more/getting_started/index.html Thanks, --The Boost release team Vladimir Prus Rene Rivera Marshall Clow Eric Niebler Daniel James Beman Dawes

11 18

Boost Evolution
by Robert Ramey 21 May '16

21 May '16

What I would like to see is more encouragement for the idea of boost evolution. But I have well defined ideas about how that should occur. I articulated these ideas is quite a bit of detail at C++Now in 2015 to a packed house. It wasn't recorded so you'll have to take my word for it. All is not lost though. For those who might be interested I kept my practice recordings for the narrative on the slides and attached them to each slide. So you can get a good feeling for the presentation by checking out http://www.blincubator.com/C++Now2015/index.html If you do this don't forget to checkout the last two slides (including the audio)! in real life it was much better!!! When I articulated my particular suggestions at the conference there was a lot of push back and I sort of lost control of things. On the other hand, there was a lot of enthusiasm for my "call to action". I didn't expect any drastic changes. But as I look back a year I do see some real progress. I see: a) more and better reviews b) more interest, discussion and criticism of documentation c) 30 libraries in the incubator. Some have already been added to boost. d) Now movement on opening up the build/test system to evolution. e) A program in place to make more resources available for maintaining existing libraries. The complains of unmaintained libraries have diminished by quite a bit - I don't know for a fact that this is related to this program - maybe it's just a happy coincidence. A couple of things have made much progress. a) modular deployment and dependency management. No surprise here as this is a job of major, major difficulty. b) policy for library deprecation - not really hard but really very low priority. c) improvements in incubator - no real progress - but it's probably as good as it needs to be. d) boost website improvement - no discernible progress. There is one big lesson from all this: a) Boost is not a company - we don't take direction from the top. b) Boost is not a government - we actually do something. c) Boost is a religion - want something changed, start preaching. Get other people on board. Convince people people to start doing something. Take a look at the CMake history. There was a huge effort undertaken from the top to switch to CMake for build / test. It was a failure because it tried to do it from the top down. I'm thinking that the promoters of this idea concluded that the problem wasn't ambitious enough and added deployment to the task and built rypll. This had as key collaborators our most capable and hard core developers - including David Abrahams and Eric Neibler. Huge amount of expended effort but not much came out of it. I think if you want to help boost evolve - remember Boost is a religion. We are the jesuits of C++. Bjarn's marines - the tip of the spear. We ambush the world with a new idea which builds or replaces something else. We do it in an insidious manner. The opening up to CMake has proceeded steadily over years until it's a the cusp of victory. No one saw it coming and here it is. The world doesn't change from great initiatives, it changes when the old order collapses while espending it's existence to deny change. I've been told on this is a right wing world view - and so it is - oh well. So I encourage those who want to contribute to Boost and by extension C++ to consider using this approach. I think you'll be more successful. Robert Ramey

19 47

A comment on cmake and subprojects
by Biddiscombe, John A. 20 May '16

20 May '16

In our task of the HBP (Human Brain Project), we have a lot of libraries with interdependencies and have standardised on a reasonably simple system that works well enough – it can/could be improved significantly, but in case it’s of interest to boost, here’s a brief description (which I’m writing from memory and all the actual names of commands etc are wrong, but I only aim to describe the process) A top level cmakelists file would contain something like project(my_big_project) add_subproject(subprojectX ${CMAKE_CURRENT_SOURCE_DIR}/x) add_subproject(subprojectY ${CMAKE_CURRENT_SOURCE_DIR}/y) etc subprojects X,Y,….. Are defined by either including the source for those projects in the relevant subdirs, or by providing an additional command along the lines of git_external_project(name URL branchname/SHA/etc) Or by supplying a .gitprojects file in the root of the master subproject (subproject can if they wish do this recursively) which may contain a list of desirable projects + urls that we know will be needed if enabled When the user runs cmake on the top-level source project (my_big_project) it provides OPTIONS of the form SUBPROJECT X ON/OFF SUBPROJECT Y ON/OFF Which the user can enable via the GUI or by cmake –DSUBPROJECT_X=ON …. The macros defined will decide that if project X is not present to do a git clone (--shallow, --branch, --anything you want to add in the config) of project X,Y,… from the git URL supplied and checkout the repo into the correct location, add_subproject then enters the subproject and cmake progresses as usual. Inside the subproject, another macro can defined DEPENDENCIES of the project via more instantiations of the same kind which will also be cloned as git subprojects if they are not already present (currently if X depends on A branch1 and Y depends on A branch2 we throw an error, but it would be possible to support this tight control of include_directories). Seeing the ongoing discussion of cmake in boost (I am one of the many it seems who cmakeified the parts of boost I needed years ago and then gave up around the time rypll came into being – hoping that the job would be done properly). So the top level boost cmakelists would simple contain a list of all the libraries and their git locations and release branches, each sub project (library) can say dependencies(atomic, filesystem, threads, context) and let the cmake scripts do the rest. A user checking out the “top” level boost would get only a single cmakelists file with a bunch of helper scripts containing the macros needed for install, versions, git cloning etc etc and would then run cmake –DSUBPROJECT_ATOMIC=ON –DSUBPROJECT_THREADS=ON –DSUBPROJECT_CONTEXT=ON ~/path/to/top/level/boost-cmakelists (you could change the SUBPROJECT to BOOSTMODULE or something like that if you preferred) If one of the libs the user ‘wants’ uses another library, it gets enabled by the dependencies declared in the lib and everything just builds and works. A make install will install all the libs that got built including those dependencies that were pulled in (some public/private options could no doubt be added to make that better if necessary). To give you an idea of what I’m referring to, https://github.com/Eyescale/CMake/blob/master/GitExternal.cmake<https://github.com/Eyescale/CMake/blob/master/SubProject.cmake> https://github.com/Eyescale/CMake/blob/master/SubProject.cmake Are a couple of scripts that do some of the work. The process has helped us to simplify somewhat our build and dependency process and it might be a useful mechanism for boost to use cmake. It isn’t perfect, isn’t pretty in some places and has been heavily tweaked beyond its original purpose so the scripts would not be considered usable in their current state – but with some cleaning up … One very nice feature is the one can create a simple script project(mystuff) #set some options we might beed set(boost_optionX,y,x…) add_subproject(boost) # and some more set(hpx_optionX,y,z…) add_subproject(hpx) set(my_optionX,y,z…) add_subproject(stuff_that_needs_them) And the user does not need to worry about cloning the projects as the gitproject refs will do it for them and take what’s needed on a per repo basis. (I use this for HPX extensively - the individual libs/projects must be careful with relative path names and using per project prefixes for options, tests etc etc) I would be happy to volunteer as a helper should you wish for help cmakeifying boost regardless of the method by which you proceed. JB -- John Biddiscombe, email:biddisco @.at.@ cscs.ch http://www.cscs.ch/ CSCS, Swiss National Supercomputing Centre | Tel: +41 (91) 610.82.07 Via Trevano 131, 6900 Lugano, Switzerland | Fax: +41 (91) 610.82.82

1 0

Files in individual libraries
by Edward Diener 20 May '16

20 May '16

As long as library authors follow the normal Boost guidelines for placing the necessary files for using, building ( for non-header only libraries ), testing, and documenting their library I really don't see why an author cannot add to their library whatever other files they want in whatever place in their library structure they want to put it. Can it really be such a big issue that this should not be allowed ? And, if so, why ? If the real issue being objected to is that the placement of additional files gives the end-user an impression that Boost libraries generally support additional things which an individual library supports with the additional files, wouldn't it just be better to encourage and/or require that an individual library developer document the additional files as personal extensions to what Boost requires.

2 2

Re: [boost] [Boost-users] Boost 1.61.0 has been released
by Daniel James 20 May '16

20 May '16

On 18 May 2016 at 08:05, Vladimir Prus <vladimir.prus(a)gmail.com> wrote: > > Tom has pointed a typo in file names in the file. Correct one is now > attached, and instructions > for validating are the same: I added the to the website, it's currently linked from the release notes, and if it's okay, I'll add a link to the download page at some point. Although it can't be underestimated just how little I care or understand about any of this stuff, so I'm sure I've done it all wrong. If line endings make a difference then it might not work since git converted the file to unix style automatically, so let me know. I also don't really want to add all the instructions to the release notes, so if someone wants to write generic instructions for another page, I could put that up and link to it.

1 0

DMARC and mailman
by James Sharpe 19 May '16

19 May '16

In June 2016 gmail is going to be changing its DMARC policy to reject any unaligned mail. This means that we will be seeing any mailing list responses from a gmail.com address to be considered spam by any mail server that enforces DMARC. For a while now yahoo.com has had this policy turned on which has meant that yahoo.com addresses have been considered spam. Mailman has released a workaround in version 2.1.18: https://www.mail-archive.com/mailman-users@python.org/msg64098.html The boost mailing list is currently on mailman 2.1.15. I'd strongly suggest that this should be updated as a matter of urgency else we'll find a lot of the conversations on this list will end up in the spam folder... Regards, James

1 0