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Boost.Build check to see if cxxflags flag is supported?
by James E. King III 07 Nov '18

07 Nov '18

I'm looking for an example for how I could check to see if "-fPIC" is supported for the compiler as part of project requirements. In some recent PRs that include building a static library which then gets included in a shared library, code needs to be built with "-fPIC" on supported platforms/toolsets. There is some code in gcc.jam to do this if the overall link mode is shared (note: this code is not in clang.jam!), but in this case the overall link mode is static, and a Jamfile wraps the result in a shared library, so the directives in gcc.jam are not applied. So at the top level Jamfile, I want to add a project requirement that basically says, "if the compiler supports <cxxflags>-fPIC then use it". Thanks, Jim

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Deadline for 1.69.0 beta extended
by Marshall Clow 07 Nov '18

07 Nov '18

The deadline for closing the master branch for the 1.69.0 beta has been extended until Friday, November 9th. The final release date has not been changed. -- Marshall (who is at a WG21 meeting all week)

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[release][predef] Permission to merge to master..
by Rene Rivera 07 Nov '18

07 Nov '18

I have a change that adds some missing version information for Cygwin OS detection < https://github.com/boostorg/predef/commit/62a50d3892789076272b771f560a419b9…>. Can I merge that to master? -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net

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"peer reviewed" - Rights and responsibilities of maintainers
by Alexander Grund 07 Nov '18

07 Nov '18

I'm having trouble with a maintainer of a boost library over a PR and am seeking for clarification. Background (may be skipped): A bug was introduced into the library which I noticed in one of "my" (company) projects leading to a reproducible crash. However the scenario is not that common (although others have the same problem) so it wasn't noticed earlier. I analyzed the problem and created a minimum working example to reproduce this and then opened a PR with a fix. The maintainer did not comment on this for multiple months so given it IS complicated, I factored out additional PRs with tests I created to show the problem, so each PR is fairly small. In the result there were PRs with tests that failed on travis and the fix-PR which included the test-PRs and the fix and succeeded on travis (and all other CIs) and users reported success using this PR. Still no response from the maintainer on any PR. He then added an own test claiming to be enough, while I (as the author of the original tests) knew it wasn't as e.g. it didn't fail. (so what's it worth then?) Furthermore he added a commit changing unrelated stuff and ADDITIONALLY changing code I touched in the fix claiming that it would be the essence of my patch and fix the problems. Again I (as the author of the original patch) know that this is not true especially as the test-PRs still fail with his patch applied. So my point/problem is: Is the maintainer allowed to simply do changes as he wishes without any review at all? My expected procedure is: - Someone creates a PR - Maintainer (and optionally the community) reviews (and comments on) it - It eventually gets merged or rejected with comments why OR: - Someones else (including the maintainer) creates a contra-PR fixing the same problem - That author explains, how and why this fixes the same problem and why it is superior to the original PR - This gets reviewed and either PR gets merged Arguments were made, that this doesn't apply to accepted boost libraries as e.g. "it's [the maintainers] heads that got chopped off if something gets broken". I would challenge this by the simple example at hand: This boost library IS broken and it crashes MY application (and others). But I see no heads rolling. Furthermore: If the maintainer is allowed to patch and change as he wants without ANY review, how can Boost still be called "peer reviewed"? My trust in Boost stems from the extensive review a library has to undergo before it is included in Boost. If afterwards no review is happening or reviews are actively avoided (as in the current example), then the older a Boost library gets, the less trust I would have in it as more and more unreviewed changes get included. So again: What is the Boost course on reviews of existing libraries and the statement on the rights and responsibilities of maintainers? Thanks, Alexander Grund

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[parameter] Go C++11 and above only, or keep C++03 support?
by Cromwell Enage 06 Nov '18

06 Nov '18

Hi, everyone. The end of section 3.2.1 of the current Boost.Parameter home page tutorial notes "that because of the forwarding problem, parameter::parameters::operator() can't accept non-const rvalues". I've submitted a PR to the develop branch on GitHub that would grant Boost.Parameter the ability to support perfect forwarding and eliminate this issue. However, the PR uses rvalue references (in parameter::keyword, parameter::parameters, and the code generation macros) and variadic templates (in parameter::parameters and the code generation macros). With the exception of BOOST_PARAMETER_TEMPLATE_KEYWORD, the PR would make Boost.Parameter a C++11 library. As a result--based on < http://pdimov.github.io/boostdep-report/develop/parameter.html#reverse-depe…>--the following Boost libraries known to use Boost.Parameter would also become C++11: Boost.Accumulators Boost.Convert Boost.Graph Boost.Heap Boost.Log Boost.MetaStateMachine or Boost.MSM Boost.Parameter_Python Boost.Signals2 I'd like to hear from everyone else, especially the maintainers and users of these libraries, if it's okay for Boost.Parameter to go C++11 and above only or if C++03 support is still necessary. Cromwell D. Enage

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[testing] Lots of spurious test runners
by John Maddock 05 Nov '18

05 Nov '18

There are rather a lot of test runners that fail all tests due to setup errors: sandia-gcc-5.4.0-c++11 cc1plus: error: unrecognized command line option "-std=c++11" sandia-gcc-5.4.0-c++14 cc1plus: error: unrecognized command line option "-std=c++14" sandia-gcc-6.4.0-c++11 cc1plus: error: unrecognized command line option "-std=c++11" sandia-gcc-6.4.0-c++14 cc1plus: error: unrecognized command line option "-std=c++14" sandia-intel-16.0-c++11 /bin/sh: line 1: icpc: command not found sandia-intel-16.0-c++14 /bin/sh: line 1: icpc: command not found sandia-intel-16.0 /bin/sh: line 1: icpc: command not found sandia-intel-17.0-c++11 /bin/sh: line 1: icpc: command not found sandia-intel-17.0-c++14 /bin/sh: line 1: icpc: command not found sandia-intel-17.0 /bin/sh: line 1: icpc: command not found teeks99-02-dc3.1-11-Docker-64on64 /usr/bin/../lib/gcc/x86_64-linux-gnu/4.8/../../../../include/c++/4.8/functional:2194:2: error: no type named 'type' in 'std::enable_if<false, void>' (and more errors from <functional> - the compiler appears to be unable to handle the std lib headers so I'm not sure what the point of testing it is?) igaztanaga-develop-gcc-3.4c++03 cc1plus.exe: error: unrecognized command line option "-fvisibility-inlines-hidden" cc1plus.exe: error: unrecognized command line option "-fvisibility=hidden" Best, John. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

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interest in a flag library
by Masse Nicolas 05 Nov '18

05 Nov '18

Hi all, This is the first time I post on this mailing list :). I'm posting because i'd like to know if people would be interested in a library to treat enum types as flags. I find that's something which is lacking in the language since the introduction of strongly typed enums, and I've since written some code in order to do this. So far I've seen some discussion on this mailing list about that, but it doesn't seems that any library have been written yet. So do you think it is worth the effort of porting and documenting my code so that it can integrated into boost, or not? Regards, Masse Nicolas. PS: For those interested, the code consists of a flag class, and overloads operators like '|' or &. It can be used like this: enum struct option : uint { none = 0, first = 1, second = 2, third = 4, forth = 8 }; static constexpr flags<option> var1 = option::first; static constexpr flags<option> var2 = option::second | option::third; static constexpr auto var3 = var1 | var2; /* type will be resolved into flags<option> */ static constexpr auto var4 = option::first | option::second | option::third; /* works too */ int main() { std::cout << var1 << std::endl; std::cout << static_cast<uint>(var2) << std::endl; /* note that static_cast<int> won't compile since the underlying type is uint */ std::cout << (var3 & option::forth) << std::endl; std::cout << (var3 == var4) << std::endl; return 0; }

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Boost.CI for Boost Repository Build Quality
by James E. King III 05 Nov '18

05 Nov '18

Continuous Integration is a modern cornerstone of delivering quality results in software engineering. When I started getting involved in boost as a maintainer (instead of a long-time consumer) it became a goal to get CI into as many repositories as possible. CI allows submitters to self-check their code changes without bothering the maintainer(s) of each repository. It eases the burden for maintainers as they can focus more on code review, and less on manual machinations to validate changes (by running code locally in their own environments). The wide coverage of builds in Boost.CI has helped identify a number of issues and improved the quality of those repositories. Performing these tests and analyses before code is merged catches issues earlier (but is not as comprehensive as the test matrix in terms of platform support due to limitations in the CI providers). Given that the Travis CI and AppVeyor builds for almost all the CMT repositories (and a few others) are using Boost.CI, it's proper place is under the "boostorg/" GitHub organization. Right now it's under my GitHub account, but I would like to move it to a more official location. https://github.com/jeking3/boost-ci Thanks, Jim

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Draft copy - Call for Submissions - CMake for Boost
by Robert Ramey 05 Nov '18

05 Nov '18

The following is a draft of the document of I have planned to post on behalf of Boost on or around 1 November 2018 as the first step in our next attempt to accommodate CMake in Boost. Robert Ramey Call for Submissions - CMake for Boost ====================================== For some time, there has been interest on many users and developers of Boost Libraries to make Boost easier to use with CMake. Discussions in the past have not resulted in an implementation which has been widely accepted. Never the less, hope springs eternal, and we intend to attempt this once again. It seems that often there are difficulties before such projects even start in that there are wide discrepancies as to what should be the goals and expectations of Boost support of CMake. The aim of this document is to try to build a consensus on this question before encouraging CMake developers and experts to submit proposals for Boost support of CMake. Requirements and Scope ====================== Requirements ------------ Submissions will fulfill the applicable requirements of any boost submission. This will include: a) any necessary code. b) specifications/requirements for things like directory structure and contents. b) A useful document. Document should provide information, examples and templates so that a typical C++ and CMake user should be able to do any of the following in a short time - say 10 minutes. Document at a minimum should be viewable as html and/or PDF file. 1) A library user should be able to incorporate a Boost Library into the CMake script. 2) A library user should be able to determine which additional Boost Libraries he needs. 3) A library developer should find it simple to create the requisite CMake files for his library. Thus the documentation should contain explanation and perhaps other means such as examples and/or "templates" for required CMake files. c) test of CMake facilities supported by the CMake implementation. This will include code, test of any features, capabilities that the submission provides. Users expect that if they follow the instructions in the documentation, they will get the promised results. A manner of proving this must be provided. A likely response to this requirement would be a "test project" which can be used to demonstrate that the submission actually works. This will be useful in the future for maintenance of the CMake Boost implementation. It will permit the maintainer of the Boost.CMake facility to work on and test their fixes and improvements without disrupting other developers and users. d) a Boost License Facilities and features ----------------------- CMake as it stands has lots of capabilities. But it has a fair amount of complexity as well. Lots of things can be accomplished in multiple different ways - each with subtly different results and effects. CMake for Boost will likely consist of documentation, examples, CMake code, and other stuff to use CMake to permit new features and facilities for users and developers of Boost libraries. What follows is a list of facilities that Boost users and developers would like to acquire with CMake for Boost. Those marked with * should be considered hard requirements. That is, submissions which don't include this feature can't be considered. Other items are interesting and would be considered if included in a submission. *a) incorporating selected Boost Libraries into a user's application *b) incorporating selected Boost Libraries into a user's library c) building a boost library d) building a boost tool such as Boost.bcp, Boost.boostdep, etc. e) testing a boost library - if testing of Boost libraries is to be supported, the following features should be considered. Those marked * should be considered essential. *1) execution tests - must pass/ must fail *2) compile only tests - must pass/ must fail *3) link only tests - must pass/ must fail 4) should be available to both users and developers 5) should not depend upon tools other than C++. 6) test should have the option of posting the results to some public "dashboard" 7) option for recursive testing and/or building of libraries might be nice. That is if library A uses library B and I test library A, this would automatically test library B beforehand. *f) In CMake, dependent libraries are specified as part of the library CMakeLists.txt files. There several ways to do this and the subject is pretty confusing to get right. Any submission documentation has to explain to library developers how do this. g) Some have suggested a highly automated process including downloading/updating, finding other components on other machines, etc. This shouldn't be considered h) packaging - preparation of distributable, installable files for various operating systems. That is support for the CPack facility. i) There has been a lot interest and work in automatically determining dependencies It's a much deeper subject than most people realize. Solving this problem is not a requirement of the submission. However, submitters are free to address this if they desire. *j) support of library modularity. This would mean: *1) independence of things outside the library directory structure. To wit - no presumption about any "super project". *2) building out of tree *3) no need for installing libraries not used by the build target k) ... Submission Rules and Procedures ------------------------------- a) This document constitutes a "Request for Submissions". It will be announced on the boost announcements list, boost developer's list, slack/boost, isocpp website and twitter account, reddit at r/cpp. Submissions will be open to anyone. b) Submissions will be accepted at an email address to be specified. Received submissions will receive a "prescreening" to determine that they meet the requirements specified for such submissions at the top of this document. Those that don't will be returned to the author. c) The name of the author of a submission will not be included in the submission. Authors will be expected to take reasonable efforts to maintain his anonymity via a github repo without a real name assigned, anonymous, email address etc. We understand that the nature of the submission and debate during subsequent review of the proposals. Never the less we believe that anonymity can be mostly maintained. The the true identity of the author of the selected proposal will not be revealed until the selection is made. The motivation for this anonymity is to attract submitters who find the boost review process distressing, annoying and/or unpleasant. It should also address the concerns of those who beleive that by not being a "boost insider" they won't get fair consideration. Boost is first and foremost a meritocracy. We seek the very best in everything regardless of other considerations. d) Submissions will be closed on or about 1 February 2019. Boost formal review will commence shortly there after. Depending on the number of submissions received, the process may last as long as month. e) As per the boost formal review rules and customs, some time after the review period terminates, the review manager will announce the review results. This will likely contain some conditions regarding alterations required in the submissions implementations. I the author find these too onerous, and declines the opportunity to integrate his submission as an official part of boost, the review manager may select an alternate submission. It's also possible that the review manager may decide to accept none of the submissions. f) when the submission is integrated into boost and is shown fulfill the requirements stipulated by the review manager. The author will receive a "prize" of $5000 and a large but cheap medal on a ribbon hopefully to be awarded at the next C++Now (Boost Con). As this is written, this prize is subject to finding a funding source. It's understood that this stipend is in no way compensation, for all the work and aggravation of this task. But we hope that it will serve as a tangible token of our gratitude for solving one of Boosts most pressing and difficult problems. Useful Resources =============== “Effective CMake" - https://www.youtube.com/watch?v=bsXLMQ6WgIk https://gist.github.com/mbinna/c61dbb39bca0e4fb7d1f73b0d66a4fd1 https://github.com/purpleKarrot/Boost.CMake https://steveire.wordpress.com/2016/08/21/boost-dependencies-and-bcp/

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Has anyone thought about adding a general case subset class?
by jrmarsha 04 Nov '18

04 Nov '18

I've got a lot working with my madlib version of graph, but I've been thinking over the elegant ways to add the subgraph feature in BGL. It occurred to me that this can be phrased as a more general problem as container subsets. And while we're at that, then we can add objects or operators for set operations like inner join, left join, and outer join. Can I get some thoughts?

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