November 2018 - Boost - lists.preview.boost.org

CMake Announcement from Boost Steering Committee
by Jon Kalb 13 Aug '24

13 Aug '24

The libraries produced by the Boost community have had a greater impact on the way that the C++ community writes code than any other library implementation. The focus of the Boost community will always be on the libraries, but it is undeniable that we are dependent on and often limited by the infrastructure of our trade. Years ago, the move to Git was contentious; yet, it was required to improve development. In a similar vein our build system has become an impediment for many developers and users, existing and prospective. Therefore, we, the Steering Committee, announce to the Boost community our desire and intent to move Boost’s build system to CMake for users and developers alike. We are soliciting comments and proposals from the community to guide the process and the goals. Our desire is that the community can come to consensus by the end of the calendar year with a vision of supporting users and developers. We understand that the actual process of achieving the end goal will be long, time consuming, and not without its share of conflict. We also recognize that the Boost community is comprised of bright and passionate individuals that are eager to get involved and help get work done. The members of the Steering Committee have been encouraged by the discussions and activity surrounding CMake on the mailing lists over the years and know that many people have voiced visions. We hope that each of you rejoins the discussion to support this initiative and contributes to the common goal of improving Boost’s integration into the broader C++ ecosystem. For the Boost Steering Committee, Jon Kalb, Chair jonkalb(a)boost.org

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[asio][coroutine] forbid_suspend blocks
by Vinícius dos Santos Oliveira 07 Aug '19

07 Aug '19

I've implemented a dumb linter using Python + clang API that allows you to mark certain blocks as “atomic in respect to coroutines” using C++11 attributes. Usage example follows: void f() { int yield; g(yield); [[bt::forbid_suspend]] { // Comment this call to make linter accept the code g(yield); t(); } } You can change bt::forbid_suspend to another identifier by tuning settings on the beginning of the script. The prefix forbid was inspired by Rust's linters[1] as you cannot disallow the linter from inside the forbid_suspend block. Some limitations follow: - A suspend point is identified by looking references to any id equals to yield in the last argument passed to function calls. It means that yield[ignored_ec] and alike will be correctly identified, but it needs to be named yield and it needs to be the last argument to the function call. - I haven't found a way to extract attributes related to COMPOUND_STMT nodes with clang API, so I manually look for token gaps and do a simple regex. It means you cannot use macros to [[bt::forbid_suspend]] as the macro won't be expanded. - You better call the script with '-x c++' and also ' -I/usr/lib/clang/5.0.1/include'. Like I've said in the beginning of the email, it's a *dumb* linter, which means it doesn't try to handle all cases. Therefore, I don't hope to do many changes to it or maintain it to work against newer releases of clang and I'm only uploading it to gist (not fullblow Github): < https://gist.github.com/vinipsmaker2/d930fbe5b7597432b021effe618da171>. It should also be easy to hack as it is very small. I'm releasing the linter under public domain. Enjoy. I have been using fibers in a daily basis on the last months of my job to solve networking problems on a gateway project. Some of the technologies I use are: - Boost.Asio and its spawn function. - A few custom synchronization primitives for the fibers (e.g. mutex, semaphore). - Eventually I'll have to write a custom spawn function that returns a joinable handle so I can kill the usage of a fiber::barrier in a few places. I've been using the linter for about a week already and looks fine. My use case are: - To prevent iterator invalidation in regions accessing shared variables. - To guarantee events order in algorithms that handle races (cannot yield while task YYY hasn't finished). The project I use it in is not an open source project, so I cannot talk much more about it. Also, I don't claim my solution is original. I wouldn't be surprised if the very same solution exists in the wild (please let me know if you know of a similar approach). This is not a new problem. It is know for some time. For instance, in P0171, Gor Nishanov noted this same problem: “In coroutines the suspend point is clearly marked with await, which tells the reader that something unusual happens in this function and allows the reader, for example, to confirm whether the lifetimes of the objects of interest align with the lifetime of the coroutine or not, whether some locks need to be acquired to protect some concurrently accessed data, and whether some locks need to be released before the execution reaches the suspend point.” — <http://open-std.org/jtc1/sc22/wg21/docs/papers/2015/p0171r0.html>, 2015 However, the solution he presented was to manually examine whole blocks of code without help from the compiler. I argue that the solution he presented is as error-prone as manually looking for exit paths that don't free acquired resources in languages lacking RAII. And I've been spoiled too much by RAII. Furthermore, I take this comment of his with highly suspicious look: “Since we are on the subject of maintenance nightmares, we would like to offer a conjecture that the absence of the await in P0114 is a likely source of many maintenance nightmares. Without a syntactic marker to signal to the person reading the code that something funny is going on, it is impossible to tell whether the following code is correct or not” — http://open-std.org/jtc1/sc22/wg21/docs/papers/2015/p0171r0.html If I had to give a vote to the proposal he was defending or Chris' proposal, I'd probably have chosen Chris'. [1] https://doc.rust-lang.org/reference/attributes.html# lint-check-attributes -- Vinícius dos Santos Oliveira https://vinipsmaker.github.io/

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Non-ASCII Path Names in Repo
by Tom Kent 25 May '19

25 May '19

In the last few days we've had a non-ASCII path name added to the repo: tools/boostdep/test/utf8-test-ßµ™∃ Which came with commit 8893d1c57951a [1] I noticed this because a python 2 script (calling shutil.copytree) I had running on windows that copied the repo around started to fail. I've long needed to update that script to python 3, and am working on this. However, I wanted to point this out to the list so we could discuss if there are any other ramifications of having a non-ascii path. I vaguely remember some discussion about something like this in the past, but couldn't find it via search. If this is already a settled topic, that's great. Tom [1] https://github.com/boostorg/boostdep/commit/8893d1c57951a4a83705ed203005576…

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Re: [boost] [ Interest? ] [ out_ptr ] Tiny C++ Abstraction for C-Style Output Pointers
by Bjorn Reese 12 May '19

12 May '19

On 06/28/18 21:03, ThePhD via Boost wrote: > out_ptr is a small abstraction for making types such as > std::unique_ptr, std::shared_ptr, boost::shared_ptr, and the upcoming > std::retain_ptr > <http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2016/p0468r0.html> work > work C-Style output functions as a parameter, addressing the need of > wanting to be able to do "my_c_api_init( foo, bar, &my_smart_ptr );". It's Does out_ptr have other use-cases than C interoperability?

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[thread] compiler error gcc 7.3 on cygwin
by James E. King III 06 May '19

06 May '19

Getting an internal compiler error with gcc 7.3 but only on cygwin 64-bit. Jim@pulsar /cygdrive/c/boost/libs/thread $ ../../b2 --abbreviate-paths toolset=gcc cxxstd=11 define=_POSIX_C_SOURCE=200112L define=__USE_ISOC99 threadapi=pthread address-model=64 variant=release -q ... gcc.compile.c++ ../../bin.v2/libs/thread/test/test_10963_c.test/gcc-7.3.0/rls/cxstd-11-iso/thrd-mlt/vsblt-hdn/test_10963_c.o In file included from ../../boost/thread/detail/invoker.hpp:30:0, from ../../boost/thread/future.hpp:31, from ../../libs/thread/test/test_10963.cpp:13: ../../boost/thread/detail/invoke.hpp: In function ‘decltype (*(forward<A0>)(boost::detail::invoke::a0).*boost::detail::invoke::f) boost::detail::invoke(Fp&&, A0&&) [with Fp = void (boost::executors::basic_thread_pool::*)(); A0 = boost::executors::basic_thread_pool*]’: ../../boost/thread/detail/invoke.hpp:102:43: internal compiler error: in gimplify_expr, at gimplify.c:12006 return (*boost::forward<A0>(a0)).*f; ^ Please submit a full bug report, with preprocessed source if appropriate. See <https://gcc.gnu.org/bugs/> for instructions. "g++" -std=c++11 -fvisibility-inlines-hidden -m64 -mthreads -O3 -finline-functions -Wno-inline -Wall -pedantic -fvisibility=hidden -Wextra -Wno-long-long -Wno-unused-parameter -Wunused-function -pedantic -DBOOST_ALL_NO_LIB=1 -DBOOST_THREAD_THROW_IF_PRECONDITION_NOT_SATISFIED -DNDEBUG -D_POSIX_C_SOURCE=200112L -D__USE_ISOC99 -I"../.." -c -o "../../bin.v2/libs/thread/test/test_10963_c.test/gcc-7.3.0/rls/cxstd-11-iso/thrd-mlt/vsblt-hdn/test_10963_c.o" "../../libs/thread/test/test_10963.cpp" ...failed gcc.compile.c++ ../../bin.v2/libs/thread/test/test_10963_c.test/gcc-7.3.0/rls/cxstd-11-iso/thrd-mlt/vsblt-hdn/test_10963_c.o... If I change the C++ language level to 03 the problem goes away. I also cannot reproduce it on linux with the same version of compiler (but it probably isn't the exact same compiler code). Should I go ahead and file that gcc bug? - Jim

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[test] unit test command-line handling
by Stefan Seefeld 22 Mar '19

22 Mar '19

Hello, this is a question concerning the Boost.Test framework. I'd like to pass command-line arguments to my tests, and I'm unsure of how to proceed. I have found https://www.boost.org/doc/libs/1_68_0/libs/test/doc/html/boost_test/adv_sce…, which shows how to access the command-line programmatically, but that's declared obsolete, and it's also lacking some important info, such as how I should handle the argv vector. Are there any examples that demonstrate this use case ? Specifically: * What (non-deprecated) API can I use to access command-line arguments during test initialization ? * How does my own handling of command-line arguments interact with Boost.Test's own command-line argument handling ? Thanks, Stefan -- ...ich hab' noch einen Koffer in Berlin...

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[Website] Revised $Date$
by Olaf van der Spek 11 Dec '18

11 Dec '18

Hi, I don't think this is what it's supposed to be. > Revised $Date$ https://www.boost.org/development/index.html -- Olaf

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Reminder: 1.69 closes for major changes Wednesday
by Marshall Clow 10 Dec '18

10 Dec '18

Upcoming dates: * 31-Oct: Boost 1.69.0 closed for major code changes * 7-Nov: Boost 1.69.0 closed for beta * 14-Nov: Boost 1.69.0 beta 1 * 5-Dec: Boost 1.69.0 closed for release * 12-Dec: Boost 1.69.0 release -- The Boost Release Team

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[histogram] should some_axis::size() return unsigned or int?
by Hans Dembinski 04 Dec '18

04 Dec '18

Dear community (especially the reviewers of boost.histogram), I am still working on finishing the library based on the excellent reviews I got in September. I cannot make up my mind about a specific detail of the library interface and would like to ask for your input. Every axis type is required to have a size() method, which returns the number of bins along that axis (without counting extra bins for under- and overflow). Should this method return `unsigned` or `int`? = The case for `unsigned` = The size of an axis is non-negative, so the return type should reflect this. All the STL containers return their size as an unsigned integer. Naturally, boost.histogram should be as consistent as possible with the STL, so you don't have think about exceptions from the general rule. Whether `size()` returns a signed or unsigned type matters even in times of `auto`, since compilers like to warn about comparisons between signed and unsigned integers. These warnings and the STL have slowly thought people to write indexed loops with unsigned integers, like so: ``` auto h = make_histogram(…); // 1D histogram for (unsigned i = 0; i < axis.size(); ++i) { auto x = h[i]; // do something with bin } ``` We don't want to break this painfully learned habit by letting `size()` return a signed integer, because it would generate a warning in this naive loop. = The case for `int` = The type of the bin index returned by an axis is `int`, because it can be negative. An axis is required to return -1 when the axis represents an ordered range and the value fall below the low edge of the first bin. So the index must be signed. The size of an axis is highest index + 1. It would be natural to use the same type for `size()` and for the returned index. Internally in the library, there are many less-than comparisons between the index and the size of the axis. If the type of the latter is unsigned, the size must be cast to `int` in all these comparisons to avoid compiler warnings, which is adding code clutter in the implementation. The library provides a range adaptor, called `indexed`, which allows one to iterate over the bins of a histogram with a special proxy, that can return the current bin index and the accumulated value for that bin. The following naive code to ignore under/overflow bins while iterating will generate a warning when `size()` returns `unsigned` ``` auto h = make_histogram(…); // 1D histogram // iterate over indexed bin range, ignore indices < 0 and indices > size (= underflow/overflow bins) for (auto x : indexed(h)) { if (x[0] < 0 || x[0] >= h.axis().size()) // without warning only when x[0] and h.axis().size() both return `int` continue; // do something with bin } ``` People are supposed to use the indexed range to iterate over the bins and not a combination of simple loops like in the first listing, because it scales nicely to multi-dimensional histograms. In multiple dimensions, it is also potentially more efficient. The `indexed` range adaptor automatically moves sequentially in memory, which this is not guaranteed if the index is created by looping manually over several indices, like so ``` for (unsigned i = 0; i < h.axis(0).size(); ++i) for (unsigned j = 0; j < h.axis(1).size(); ++j) { auto x = h.at(i, j); // this may jump around in memory, causing cache misses } ``` How the linear index is generated from the multi-dimensional index is an implementation detail (although the implementation should probably anticipate these naive loops…) So, if `indexed` is anyway the default recommended way of iterating over a histogram, then size() should return `int` to be compatible with the index type, which is also `int`, because it makes naive code work better. Sorry for the long email, I would really appreciate your input. Best regards, Hans

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Re: [boost] [histogram] should some_axis::size() return unsigned or int?
by Hans Dembinski 01 Dec '18

01 Dec '18

Dear Jim, > On 29. Nov 2018, at 13:31, Jim Pivarski <jpivarski(a)gmail.com> wrote: > > It seems to me that if other C++ containers use unsigned integers for size(), you should too, for minimal surprise. The issue you raise about the "which bin?" function returning -1 would be solved in a very-strongly typed language like Haskell as an optional<int>. I know that C++ has optional types now, but I don't know how widely they're used or if there's a significant performance penalty. If this wouldn't look too weird in a C++ program and wouldn't slow it down (or needlessly complicate the code), an optional type would describe your intent more fully than -1. there is boost::optional, which has the semantics of a pointer and can be used to represent a type that stores a value or not. ``` boost::optional o = some_fickle_function(); if (o) { // optional has a value? auto value = *o; // "dereference" to get the value } else { // handle case where value is missing } ``` This is not a good match here, because -1 here does not have the meaning of "value is missing", but it really is the logical index for the virtual bin that spans from -infinity to the lower edge of the first bin in the axis. Value arrow: -inf ——————— | ——————— | —————— | —————— |—————————> +inf bin -1 bin 0 bin 1 bin 2 bin 3 I think representing the underflow bin with -1 and the overflow bin with the value returned by size() is very intuitive and elegant. Best regards, Hans

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C++ project suggestion for Google summer of code (summer, 2019 )
by Ahmed Hussein 30 Nov '18

30 Nov '18

Dear boost , My name is Ahmed Mohamed Ahmed. I ‘m an Egyptian second year electrical engineering student (this is my third year but in Egypt we count 0,1,2,3,4). This my first time ever getting involved in open source. Nevertheless, I am eager to contribute to the vast open source community . I would love to create a C++ library under your supervision and guiding in the next Google summer of code (summer,2019). The attached document is an overview of the library, it is not a proposal with a time line but it answers questions regarding: How is this library going to benefit the open source community? What facilities will be provided by that library? What kind of libraries can be built by fellow programmers using this library? How can this library be extended in the future, whether by me or others? Thank you for your time . Sincerely Advanced mathematics for engineering applications <https://docs.google.com/document/d/1hxKHm0vv5nvia-d_OcGd3SG07gCf2ZtMQvDn_LF…>

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Current Guidance on Compiler Warnings?
by Brian Kuhl 29 Nov '18

29 Nov '18

I'd like to confirm the guidance on Warnings I find here https://svn.boost.org/trac10/wiki/Guidelines/WarningsGuidelines is still considered current? context ... At Wind River we are in the process of working with Boost 1.68 and VxWorks 7 (with Dinkum 7.00 with and Clang 6.0 for ARM and IA boards and GCC 8.1 for PowerPC ) with the hope of bundling Boost with our product. Many of our customers make certified systems ( Planes, Trains, Medical Equipment, Factory Automation, etc. ) and the trend in theses industries is to be pedantic about eliminating all compiler warnings. While we have not traditionally required zero warnings in open source code shipped with our product, there is pressure on us to move in that direction, and as result we will probably be contributing pull requests specifically to fix or suppress compiler warnings over the coming years. I'd like to establish clear guidelines for my team as to what is an appropriate "coding standard" for Boost in regards to compiler warnings. While it is simple to say, everything displayed by -Wall, in practice there are many edge cases, e.g. is an unused parameter acceptable in test code? So I'd like to get the maintainers guidance. Many thanks Brian Kuhl

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[graph] Tree data structure
by Jeremy Murphy 28 Nov '18

28 Nov '18

Dear Boost community, long ago, back in 2002 and 2009, Kasper Peeters proposed adding his tree data structure to Boost. http://tree.phi-sci.com/ There was a lot of discussion but nothing eventuated (so far as I am aware). There are links to the historical discussions on his website. ...2018.... Recently, a Boost.Graph user suggested adding a tree class to it, and I was like, "No, no, a tree is just a graph that satisfies certain constraints: a tree class won't yield better performance." But I also happen to be re-reading for nth time, Element of Programming, which touches ever so briefly but intensely on binary trees, and I realized "Oh, hold on, there is a world of conceptual difference between an arbitrary tree, and a k-ary tree." That discussion is here: https://github.com/boostorg/graph/issues/123 It seems very awkward to even try to represent a k-ary tree in existing Boost.Graph data structures, let alone a mutable k-ary tree. So I made a proof-of-concept, a mutable k-ary tree data structure with specialized implementations of depth-first search and isomorphism. Unless I've made a terrible mistake (which is possible), the performance gains are huge, and the ease of use in an existing library is also huge. OK, so huge things aside, this is really early days, exploratory work. And I'm no Boost.Graph expert. I'm interested in what people think, particularly whether they think it is an idea worth pursuing. I do. But I basically need help from people smarter and more experienced. I have made a PR for the sake of discussion, not for actually merging: https://github.com/boostorg/graph/pull/139 Cheers. Jeremy

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[threads] Launch deferred for async
by Stephan Menzel 28 Nov '18

28 Nov '18

Hello all, I am using boost::async() to create futures from tasks in order to wrap some behavior that may or may not be sync. This behavior is implemented behind an interface and can be small and fast operations or longer running and blocking things. All return a future as a result type, so I can hide the ugly truth. For the smaller stuff I'd like to use launch::deferred to avoid threading altogether and just execute the task when the user get()s the future. boost::future<bool> ret = boost::async(boost::launch::deferred, [this] () -> bool { // do some small cpu only impl return result; }); But when i get the result: const bool result = ret.get(); ...the application crashes. Debugging this I came to this in boost/thread/future.hpp:9373 } else if (underlying_cast<int>(policy) & int(launch::deferred)) { std::terminate(); //BOOST_THREAD_FUTURE<R> ret; //return ::boost::move(ret); // return boost::detail::make_future_deferred_shared_state<Rp>( // BF( // thread_detail::decay_copy(boost::forward<F>(f)) // ) // ); } else { To me this sounds like the application will always std::terminate() when launch::deferred is chosen. Why is that? When I use launch::any it seems to work but why is there a parameter that always yields unwanted results. What is the reason behind it? Can I get launch::deferred as it is described (not threading, just executing the task sync when get() is called) somehow? Platform is x64 Windows 10, MSVC14.1. Cheers, Stephan

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[release] 1.69.0 post-beta merges
by Marshall Clow 26 Nov '18

26 Nov '18

The master branch is is now open for post-beta merges, but only as described in the Post-Beta Merge Policy. See < https://github.com/boostorg/boost/wiki/Release-Beta-Merge-Policy> The master branch will close for the 1.69.0 release on 5-December. The release calendar is at https://www.boost.org/development/index.html -- The Boost release team.

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[release] 1.69.0 post-beta merges
by Oliver Kowalke 26 Nov '18

26 Nov '18

Hi, boost.context needs a post-beta merge in order to fix some issue on ELF asm. Do I get permission to merge to master? best, Oliver

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Guidence on #pragma once
by Robert Ramey 25 Nov '18

25 Nov '18

In the safe numerics library my *.hpp files start with the following boiler plate: #ifndef BOOST_NUMERIC_AUTOMATIC_HPP #define BOOST_NUMERIC_AUTOMATIC_HPP // MS compatible compilers support #pragma once #if defined(_MSC_VER) && (_MSC_VER >= 1020) # pragma once #endif ... I would like to replace all this in every file with just #pragma once according to https://en.wikipedia.org/wiki/Pragma_once#cite_note-9 this should be possible while supporting almost all which claim to be C++ 14 conformant. The exception noted is C++ for Cray. I realize that strictly speaking I shouldn't do this. But it would instantaneously remove some cruft from my code as long as the occasional error from repeating the same include guard text in multiple files. It might have some performance benefits and some other repercussions related to pre-compiled headers. Who knows what else. It would be interesting to know what others might have to say about this. Robert Ramey

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[Boost][DoubleEnded] Status?
by degski 25 Nov '18

25 Nov '18

We had the review of this library proposal/addition quite a while back and ever since I've been [eagerly] waiting for its official entry into Boost. https://github.com/erenon/double_ended does not show any activity and there is nothing in the Boost.Container going on either. What is the status? degski -- *“If something cannot go on forever, it will stop" - Herbert Stein*

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Geometry path length breaking windows regression runs
by Tom Kent 23 Nov '18

23 Nov '18

There has been a change to the geometry library, sometime around Nov 14, that is causing the windows regression runners I manage to crash. The issue is that it is creating *very* long filesystem paths, even with the regression --abbreviate-paths option set. There are a bunch of files such as: D:\teeks99-08\run\results\boost\bin.v2\libs\geometry\test\self_contained_headers\self-contained-algorithms-detail-buffer-buffered_piece_collection~hpp.test\msvc-14.1\dbg\adrs-mdl-64\async-excpt-on\thrd-mlt\self-contained-algorithms-detail-buffer-buffered_piece_collection~hpp.obj.rsp That seem to be created alright, but when I try to cleanup the run afterwards, windows doesn't allow me to delete the files. Tom

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Help - my disk is full! (of bin.v2 stuff)
by Paul A. Bristow 21 Nov '18

21 Nov '18

I note with surprise (and alarm) that my Boost-stuff disk partition is nearly full! Closer inspection reveals that I have a bin.v2 folder of over 50 GB. Obviously, I need to delete something. What are the implications of deleting things? What is the best option? Should I simply delete the whole folder bin.v2 (I have, in desperation, gone nuclear some time ago) or just bin/v2/libs or ? Expert advice welcome. Thanks Paul --- Paul A. Bristow Prizet Farmhouse Kendal UK LA8 8AB +44 (0) 1539 561830

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Rotating on-call review managers
by Zach Laine 19 Nov '18

19 Nov '18

Boost was originally created to incubate libraries that target eventual standardization. When new libraries are proposed, many of the Boost community members that participate in C++ Standard Committee (WG21) meetings ask "How many users does this have, and did you consider Boost first?" Often the answer is that they considered Boost but could not figure out what they were supposed to do to make that happen, or that they had difficulty finding a review manager. There are other things that can be done to make getting a library Boost-review-ready, but most of them require a bit of work up front. The review manager requirement is relatively easier to satisfy. This volunteer effort is to better facilitate Boost's value in the ISO C++ standardization process and so the reviewers would need to recognize intent to standardize the proposed libraries. Submissions that are supported with a paper in a mailing or a draft will make it easier to source a review manager from this queue, but authors without either are encouraged to get in contact with reviewers on this list to find out what that entails. This is the list of volunteers: Zach Laine Micheal Caisse Matt Calabrese Louis Dionne Vinnie Falco Glen Fernandes Jeff Garland David Sankel The list will rotate; the first person on the list will be "on-call". If you'd like to help, let me know and I'll add your name to the list. Also, I've made a PR that adds this list and a note like the description above to https://www.boost.org/development/submissions.html (#6 Seek a Review Manager): https://github.com/boostorg/website/pull/387 Zach

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[release] Boost 1.69.0 Beta 1 Release Candidate 1
by Marshall Clow 19 Nov '18

19 Nov '18

The release candidates for the first 1.69.0 beta release are now available at: <https://dl.bintray.com/boostorg/beta/1.69.0.beta.1.rc1/source/> The release notes are not yet available. The updated documentation is not yet available. [ They will be available in a day or two. ] The SHA256 checksums are as follows: db6b346389714647490d6503db881e4178dd8cd498f850999bebf72cacd4c4ed boost_1_69_0_b1_rc1.7z d128c82351becbd37a02b9b4818994d3f66ff8bdbc0a18838206f4c070db97af boost_1_69_0_b1_rc1.tar.bz2 4df6262db53cfd0d0f934cb126f7e48e94872fe4441cbac6bf72a43bfb136a45 boost_1_69_0_b1_rc1.tar.gz e2908e33cc15f92cda06ddde6a3da43b18967a83105355571fc3cf6e75820c7f boost_1_69_0_b1_rc1.zip 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 Boost Release Managers

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[release] Boost 1.69.0 Beta 1
by Marshall Clow 19 Nov '18

19 Nov '18

Boost release 1.69.0 beta 1 is now available at: <https://dl.bintray.com/boostorg/beta/1.69.0.beta1/source/> The SHA256 checksums are as follows: ee0ecd7d31f58474c1e0210089c9e66bd878d4d1e7436ac511e359aa4a9d3e86 ./boost_1_69_0_b1.7z 3e25c46f2171799caabbeb419ba7859fffb62208f3a1c80798713377ab07af0e ./boost_1_69_0_b1.tar.bz2 71f4b57175058af1b8c320971cf29226e5a652931a679f7e1c086655147ecafb ./boost_1_69_0_b1.tar.gz ec9ef7d2c9f0d41f560769e67bc7ff207cc999243a7dd6c3f6bcfbdbf0827a7b ./boost_1_69_0_b1.zip For details of what's in the release, see < https://www.boost.org/users/history/version_1_69_0.html>. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

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`b2 toolset=clang-win` now works on Appveyor
by Peter Dimov 18 Nov '18

18 Nov '18

With the current develop branch (since Boost.Build hasn't been merged to master yet), b2 toolset=clang-win now works on Appveyor without additional configuration. You can see it in action at https://ci.appveyor.com/project/pdimov/assert/builds/20331077/job/0hux9a6ml…

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[release] Boost 1.69.0 Beta 1 Release Candidate 2
by Marshall Clow 18 Nov '18

18 Nov '18

The release candidates for the second 1.69.0 beta release are now available at: <https://dl.bintray.com/boostorg/beta/1.69.0.beta1.rc2/source/> The release notes are not yet final. The SHA256 checksums are as follows: 77827b25121159a4e65cfbdf19713e2d589fce267fd6f08615a453d24753c9d3 ./boost_1_69_0_b1_rc2.7z ea05c6e01c856369afdab1f6c075e06fb0f965ab1c247f753ed5c951a9db4e71 ./boost_1_69_0_b1_rc2.tar.bz2 b393a73cf084be716c40ef346cfacb1c95e7b14637e8385eeeb50774dd0b99ed ./boost_1_69_0_b1_rc2.tar.gz 74c0c0a19a700fee2b4f434bb7df50840642e3c35924e85864b278bd519af062 ./boost_1_69_0_b1_rc2.zip 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 Boost Release Managers

9 29

Re: [boost] [bjam] [build] Documentation for 1.69
by Rene Rivera 17 Nov '18

17 Nov '18

On Fri, Nov 16, 2018 at 1:54 PM Edward Diener <eldiener(a)tropicsoft.com> wrote: > On 11/16/2018 2:40 PM, Rene Rivera wrote: > > On Fri, Nov 16, 2018 at 1:27 PM Edward Diener via Boost < > boost(a)lists.boost.org> wrote: > >> >> It is not really a website/webpage issue but a distribution issue. The >> distribution has an index.html, which gives the doc for the >> distribution, and the link in the doc for the Tool Boost.Build never >> actually exists. >> > > This index.html? <https://github.com/boostorg/boost/blob/master/index.html> > Or some other one? > > In our distribution the top-level index.html brings up the doc. In the doc > there is a link to tools/build/index.html but this html file never exists > in a Boost distribution. Check out any of the past distributions, such as > Boost 1.68, and you will see this. > This <https://github.com/boostorg/boost/pull/218> should fix it. But We'll have to wait until the master branch is open again before it makes it to the release. -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net

1 0

[release] Boost 1.69.0 Beta 1 Release Candidate 3
by Marshall Clow 17 Nov '18

17 Nov '18

[ Ok, I've rebuilt the RC - and it contains only the changes to function and MPL ] The release candidates for the third 1.69.0 beta release are now available at: <https://dl.bintray.com/boostorg/beta/1.69.0.beta1.rc3/source/> The release notes are not yet final. The SHA256 checksums are as follows: ee0ecd7d31f58474c1e0210089c9e66bd878d4d1e7436ac511e359aa4a9d3e86 ./boost_1_69_0_b1_rc3.7z 3e25c46f2171799caabbeb419ba7859fffb62208f3a1c80798713377ab07af0e ./boost_1_69_0_b1_rc3.tar.bz2 71f4b57175058af1b8c320971cf29226e5a652931a679f7e1c086655147ecafb ./boost_1_69_0_b1_rc3.tar.gz ec9ef7d2c9f0d41f560769e67bc7ff207cc999243a7dd6c3f6bcfbdbf0827a7b ./boost_1_69_0_b1_rc3.zip 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 Boost Release Managers

1 1

[spirit] Request to update the master branch with minor doc changes
by Nikita Kniazev 16 Nov '18

16 Nov '18

Do I have a chance to cherry-pick minor doc changes into the upcoming release? I forgot to update version numbers in docs https://github.com/boostorg/spirit/commit/b4f5833cc69f510d3842ba226d8878bb4…

2 1

[build] targeting different versions of libstdc++
by James E. King III 16 Nov '18

16 Nov '18

If I make a system with libstdc++6-dev, libstdc++7-dev, and libstdc++8-dev on it, is there a way to tell clang to use one over the other? By default it will use the latest one. I know that for linking one can use the clang flag "--gcc-toolchain=/usr/lib/gcc/x86_64-linux-gnu/7" to get the link to point at it, but I'm not sure if this also handles the header paths or not. If this option works for both header inclusion and for linking, would I need to specify it as <cxxflags> and also as <linkflags>? Thanks, Jim

2 1

[bjam] [build] Documentation for 1.69
by Cromwell Enage 16 Nov '18

16 Nov '18

Hi, everyone! Will the documentation for Boost.BJam and Boost.Build be included in the release of Boost 1.69? Cromwell D. Enage

5 7

Announcing LEAF, a new error handling library suitable for low latency applications
by Emil Dotchevski 15 Nov '18

15 Nov '18

LEAF (Low-latency Error Augmentation Framework) is a new error handling library which could possibly become the successor of Boost Exception, though LEAF can be used without exceptions too. Official documentation: https://zajo.github.io/leaf/ Features: - No dynamic memory allocations. - Associate objects of arbitrary types with any failure -- when it is initially reported or at a later time. - Compatible with std::error_code, errno and any other error handling API. - Use with or without exception handling. - Support for multi-thread programming. Emil

4 9

Re: [boost] [Boost-users] [release] Boost 1.69.0 Beta 1 Release Candidate 1
by Marshall Clow 14 Nov '18

14 Nov '18

On Mon, Nov 12, 2018 at 4:30 PM Tom Kent via Boost-users < boost-users(a)lists.boost.org> wrote: > > On Mon, Nov 12, 2018 at 9:36 AM Marshall Clow via Boost-users < > boost-users(a)lists.boost.org> wrote: > >> The release candidates for the first 1.69.0 beta release are now >> available at: >> >> <https://dl.bintray.com/boostorg/beta/1.69.0.beta.1.rc1/source/> >> > 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. >> > > toolset arch compile Link Execute > msvc-8.0 32 FAIL X X > msvc-8.0 64 FAIL X X > msvc-9.0 32 X X X > msvc-9.0 64 X X X > msvc-10.0 32 X X X > msvc-10.0 64 X X X > msvc-11.0 32 X X X > msvc-11.0 64 X X X > msvc-12.0 32 X X X > msvc-12.0 64 X X X > msvc-14.0 32 FAIL X X > msvc-14.0 64 FAIL X X > msvc-14.1 32 X X X > msvc-14.1 64 X X X > > Compile means that the b2 command completed without errors > Link means that visual studio was able to link a sample executable to a > library (libboost_thread-vcXXX-mt[-gd]-1_XX.lib) > generated > Execute means that the linked program executed without errors. > > Full build logs can be found here: > https://gist.github.com/teeks99/526cf2598d1697557e45e590ce9517be > > Lots of errors with msvc-8.0: > > compile-c-c++ > bin.v2\libs\log\build\msvc-8.0\release\link-static\threadapi-win32\threading-multi\trivial.obj > trivial.cpp > .\boost/parameter/aux_/arg_list.hpp(227) : error C2064: term does not > evaluate to a function taking 1 arguments > .\boost/parameter/aux_/arg_list.hpp(390) : see reference to class > template instantiation 'boost::parameter::aux::arg_list<TaggedArg,Next>' > being compiled > > If there is an easy way to fix arg_list.hpp that would be nice, but if > this is the time to stop build 8.0, that's fine too. > > Also numerous errors for many (all dlls?) of the libraries with msvc-14.0. > They all look something like this: > > > msvc.link.dll > bin.v2\libs\atomic\build\msvc-14.0\release\threading-multi\boost_atomic-vc140-mt-x32-1_69.dll > Creating library > bin.v2\libs\atomic\build\msvc-14.0\release\threading-multi\boost_atomic-vc140-mt-x32-1_69.lib > and object > bin.v2\libs\atomic\build\msvc-14.0\release\threading-multi\boost_atomic-vc140-mt-x32-1_69.exp > msvc.link.dll > bin.v2\libs\system\build\msvc-14.0\release\threading-multi\boost_system-vc140-mt-x32-1_69.dll > Creating library > bin.v2\libs\system\build\msvc-14.0\release\threading-multi\boost_system-vc140-mt-x32-1_69.lib > and object > bin.v2\libs\system\build\msvc-14.0\release\threading-multi\boost_system-vc140-mt-x32-1_69.exp > msvc.link.dll > bin.v2\libs\container\build\msvc-14.0\release\threading-multi\boost_container-vc140-mt-x32-1_69.dll > Creating library > bin.v2\libs\container\build\msvc-14.0\release\threading-multi\boost_container-vc140-mt-x32-1_69.lib > and object > bin.v2\libs\container\build\msvc-14.0\release\threading-multi\boost_container-vc140-mt-x32-1_69.exp > msvc.manifest.dll > bin.v2\libs\atomic\build\msvc-14.0\release\threading-multi\boost_atomic-vc140-mt-x32-1_69.dll > 'mt' is not recognized as an internal or external command, > operable program or batch file. > > if exist > "bin.v2\libs\atomic\build\msvc-14.0\release\threading-multi\boost_atomic-vc140-mt-x32-1_69.dll.manifest" > ( > call "bin.v2\standalone\msvc\msvc-14.0\msvc-setup.bat" x86 >nul > mt -nologo -manifest > "bin.v2\libs\atomic\build\msvc-14.0\release\threading-multi\boost_atomic-vc140-mt-x32-1_69.dll.manifest" > "-outputresource:bin.v2\libs\atomic\build\msvc-14.0\release\threading-multi\boost_atomic-vc140-mt-x32-1_69.dll;2" > ) > > ...failed msvc.manifest.dll > bin.v2\libs\atomic\build\msvc-14.0\release\threading-multi\boost_atomic-vc140-mt-x32-1_69.dll > bin.v2\libs\atomic\build\msvc-14.0\release\threading-multi\boost_atomic-vc140-mt-x32-1_69.lib... > ...removing > bin.v2\libs\atomic\build\msvc-14.0\release\threading-multi\boost_atomic-vc140-mt-x32-1_69.dll > ...removing > bin.v2\libs\atomic\build\msvc-14.0\release\threading-multi\boost_atomic-vc140-mt-x32-1_69.lib > > I'm on the fence if we should continue supporting 8.0, so if that doesn't > get fixed then no big deal. However the issue with (the build tool?) for > 14.0 seems like a showstopper for this RC. > > Do we have any idea why MSVC 14 is failing? -- Marshall (who has been distracted by WG21 stuff)

4 4

What part of "The master branch is closed except by explicit permission" is confusing?
by Marshall Clow 14 Nov '18

14 Nov '18

That means "DO NOT COMMIT TO THE MASTER BRANCH" FULL STOP. I just turned on the auto-updating for the release, expecting two changes: * one from MPL * one from Function. Instead, I got updated from: * Update mpl from master * Update function from master * Update atomic from master * Update log from master * Update convert from master * Update iostreams from master You're making the release process harder. -- Marshall

3 2

Re: [boost] [Boost-users] [release] Boost 1.69.0 Beta 1 Release Candidate 1
by Marshall Clow 14 Nov '18

14 Nov '18

On Wed, Nov 14, 2018 at 9:02 AM Edward Diener via Boost-users < boost-users(a)lists.boost.org> wrote: > On 11/14/2018 11:06 AM, Marshall Clow via Boost-users wrote: > > On Mon, Nov 12, 2018 at 4:30 PM Tom Kent via Boost-users > > <boost-users(a)lists.boost.org <mailto:boost-users@lists.boost.org>> > wrote: > > > > > > On Mon, Nov 12, 2018 at 9:36 AM Marshall Clow via Boost-users > > <boost-users(a)lists.boost.org <mailto:boost-users@lists.boost.org>> > > wrote: > > > > The release candidates for the first 1.69.0 beta release are now > > available at: > > > > <https://dl.bintray.com/boostorg/beta/1.69.0.beta.1.rc1/source/> > > > > 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. > > > > > > toolset arch compile Link Execute > > msvc-8.0 32 FAIL X X > > msvc-8.0 64 FAIL X X > > msvc-9.0 32 X X X > > msvc-9.0 64 X X X > > msvc-10.0 32 X X X > > msvc-10.0 64 X X X > > msvc-11.0 32 X X X > > msvc-11.0 64 X X X > > msvc-12.0 32 X X X > > msvc-12.0 64 X X X > > msvc-14.0 32 FAIL X X > > msvc-14.0 64 FAIL X X > > msvc-14.1 32 X X X > > msvc-14.1 64 X X X > > > > Compile means that the b2 command completed without errors > > Link means that visual studio was able to link a sample executable > > to a library (libboost_thread-vcXXX-mt[-gd]-1_XX.lib) > > generated > > Execute means that the linked program executed without errors. > > > > Full build logs can be found here: > > https://gist.github.com/teeks99/526cf2598d1697557e45e590ce9517be > > > > Lots of errors with msvc-8.0: > > > > compile-c-c++ > > > bin.v2\libs\log\build\msvc-8.0\release\link-static\threadapi-win32\threading-multi\trivial.obj > > trivial.cpp > > .\boost/parameter/aux_/arg_list.hpp(227) : error C2064: term does > > not evaluate to a function taking 1 arguments > > .\boost/parameter/aux_/arg_list.hpp(390) : see reference to > > class template instantiation > > 'boost::parameter::aux::arg_list<TaggedArg,Next>' being compiled > > > > If there is an easy way to fix arg_list.hpp that would be nice, > > but if this is the time to stop build 8.0, that's fine too. > > I have essentially backed out a fix on 'develop' for VC++8.0 which > intended to fix another problem with a multiple definitions linking > error, https://github.com/boostorg/mpl/pull/36. > > I would like to push this change to 'master'. It should fix your problem > above with VC++8.0. I will subsequently take another look at the > original fix and see if it can not be corrected. > If you're confident that this will fix the problem, then please do so. -- Marshall

1 0

Re: [boost] [Boost-users] [release] Boost 1.69.0 Beta 1 Release Candidate 1
by Marshall Clow 14 Nov '18

14 Nov '18

On Wed, Nov 14, 2018 at 8:35 AM Edward Diener via Boost-users < boost-users(a)lists.boost.org> wrote: > On 11/14/2018 11:06 AM, Marshall Clow via Boost-users wrote: > > On Mon, Nov 12, 2018 at 4:30 PM Tom Kent via Boost-users > > <boost-users(a)lists.boost.org <mailto:boost-users@lists.boost.org>> > wrote: > > > > toolset arch compile Link Execute > > msvc-8.0 32 FAIL X X > > msvc-8.0 64 FAIL X X > > msvc-9.0 32 X X X > > msvc-9.0 64 X X X > > msvc-10.0 32 X X X > > msvc-10.0 64 X X X > > msvc-11.0 32 X X X > > msvc-11.0 64 X X X > > msvc-12.0 32 X X X > > msvc-12.0 64 X X X > > msvc-14.0 32 FAIL X X > > msvc-14.0 64 FAIL X X > > msvc-14.1 32 X X X > > msvc-14.1 64 X X X > [snip] > Lots of errors with msvc-8.0: > [snip] > This is a result of a change in MPL for VC++8. I will back out this change. > Appreciated. Please test locally, and we'll watch the bots. (Looks like we have two MSVC-8 bots) -- Marshall

1 0

What is status of Boost.Sync?
by Mateusz Loskot 13 Nov '18

13 Nov '18

Hi, The library docs docs say it's been in Boost since 1.55. Boost master has no submodule for it. Boost develop has submodule for it If Sync was removed, why it is still in develop? If Sync was added, hence it is in develop, why the docs mention 1.55 and why it is not in master? What is the status of this thing? Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

2 2

Boost Test Matrix - no clang release builds?
by James E. King III 12 Nov '18

12 Nov '18

I was putting together some additional testing for a library and my CI jobs were failing in release mode. I was able to reproduce the issue locally. On examination of the boost test matrix however I was unable to see the same failures. When I dug into it a little bit more, it looks like the clang linux build jobs only build the default variant (debug), and therefore will not catch release-mode optimization issues when running the unit tests. Here's one of the job details: https://www.boost.org/development/tests/develop/teeks99-02-dc6-17-Docker-64… Given this matrix is the last line of defense before code is merged from develop to master, I'd suggest that the build jobs should all be targeting variant=release instead of variant=debug. The former directly impacts a release, and the latter does not. - Jim

4 3

[hash] Missing boost::hash_value for std::forward_list
by Alexander Zaitsev 11 Nov '18

11 Nov '18

Hello. Recently I found that boost::hash_value has no overload for std::forward_list. Who can tell me - why? Is there any reason and/or limitation? Thank you. -- Best regards, Alexander Zaitsev

1 0

[config] std::uncaught_exceptions
by Lorenzo Caminiti 11 Nov '18

11 Nov '18

Hello all, std::uncaught_exception (singular) is deprecated in C++17 and will be removed in C++20. std::std::uncaught_exceptions (plural) should be used instead. Will Boost.Config have a macro to detect if std::uncaught_exceptions is supported or not by the current compiler? (For example, Boost.Contract implementation uses std::uncaught_exception and it will need to use std::uncaught_exceptions on C++20 compilers instead.) Thanks. --Lorenzo

2 3

[release] 1.69.0 closed for Beta
by Marshall Clow 10 Nov '18

10 Nov '18

The master branch is now closed for all changes except by permission for the Beta release. Also, remember to add your libraries' changes to the release notes at: < https://github.com/boostorg/website/blob/master/feed/history/boost_1_69_0.q… > You can preview the release notes at: <http://www.boost.org/users/history/in_progress.html> Thanks, -- The Boost Release Team

1 0

[release] many release notes pending
by Joaquin M López Muñoz 09 Nov '18

09 Nov '18

Just a heads up about the existence of many umerged lib-specific release notes at: https://github.com/boostorg/website/pulls I seem to remember this same issue happened in 1.68. Maybe some other protocol is needed for handling release notes. Best Joaquín M López Muñoz

6 10

Suggestions for TMP/function introspection problem?
by Hans Dembinski 09 Nov '18

09 Nov '18

Hi all, I am trying to figure out how to solve an introspection problem since a few days, and I am not making progress. I could use some help, it is for boost.histogram. Maybe what I want is not possible... Here is my problem. I have some classes A, B, ... which have some overloaded methods, let's call them `foo`. struct A { void foo(int, char); void foo(bool, int, char); }; struct B { void foo(double); void foo(bool, double); }; I need a way to detect how many arguments the shorter methods has. If the shorter method is foo(Ts...), the longer method is always (bool, Ts...). This is guaranteed. I do not know what Ts... is, it can be anything. I cannot use boost::callable_traits, because an overloaded member function cannot be fetched by name using t = boost::callable_traits::args_t<decltype(&A::foo)>; // fails, overload is ambiguous Can't I match the member function with a template of the form something(bool, Ts...) somehow? Any ideas? Best regards, Hans

2 4

Re: [boost] Boost.Build check to see if cxxflags flag is supported?
by Peter Dimov 09 Nov '18

09 Nov '18

> Note 4: > > This should probably be a feature, like <position-independent>on, which > toolsets translate to -fPIC as appropriate. ... which will fix the case where a shared library uses a static library, but -fPIC is not applied to the static library.

3 3

clang-win, (Thin)LTO this time
by degski 08 Nov '18

08 Nov '18

Starting new thread. Substantial progress has been made towards the goal of compiling Boost with Clang/LLVM (clang-cl.exe, targeting MSVC). The latest PR in this respect by Peter has achieved this. The next step is to be also able to use lld (lld-link in case of clang-cl.exe targeting MSVC) to generate the Boost-libs (static/dynamic). The main interest, IMO, is to be able to use LTO (Thin or Full), which is not possible without the use of LLD. A secondary benefit appears to be faster link times (info from the lld manual). In order to build static ThinLTO-enabled libs, it suffices to pass <compileflags>-flto=thin in the project jam file. The archiving, though, needs to be done with lld-link.exe, passing /lib as the first option (this way it will act as lib.exe, while being able to handle the llvm-byte-code [lib.exe finds the so generated .obj-files to be corrupt]). At consumption time of the libs, lld-link needs to be used for linking. Hacking clang-win.jam:156 to: toolset.flags clang-win.archive .LD $(cond) : "\"C:\\Program Files\\LLVM\\bin\\lld-link.exe\"" /lib ; achieves this goal. I would like to ask (probably Peter) to have a look into whether this can be achieved "the proper way", i.e. to programmatically set that particular line to the required value for this use-case. degski -- *“If something cannot go on forever, it will stop" - Herbert Stein*

4 13

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

3 2

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)

1 0

[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

2 1

"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

15 52

[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

14 37

[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

4 3

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; }

8 9

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

3 4

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/

10 28

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?

1 0

Fwd: Errors in test matrix
by Stefan Seefeld 03 Nov '18

03 Nov '18

[I haven't received a reply on the boost-testing list, so I'm resending to the general list in the hopes that someone can help.] -------- Forwarded Message -------- Subject: Errors in test matrix Date: Wed, 31 Oct 2018 09:41:05 -0400 From: Stefan Seefeld <stefan(a)seefeld.name> To: Running Boost regression tests <boost-testing(a)lists.boost.org> Hello, [I'm not entirely sure this is the right place for the report. Please let me know if it isn't, and where to post instead.] On https://www.boost.org/development/tests/develop/developer/numeric-ublas.html, I'm looking at failures in the "Sandia" columns. Following one link takes me to https://www.boost.org/development/tests/develop/developer/output/Sandia-gcc…, which demonstrates a couple of issues: * What compiler version is this using ? The URL contains both "5.4.0" as well as "4.4.7". * The actual error reads "unrecognized command line option -std=c++11". Given that Boost.uBLAS itself doesn't specify this flag, I assume it's part of the test runner's configurations. However, it seems to be used with a compiler version that doesn't support it (though again, it isn't clear which compiler version we are actually talking about). Unfortunately there are quite a large number of columns with similarly generic errors, i.e. errors more likely to be caused by invalid set ups, rather than genuine errors in the library (libraries, as I'm seeing similar errors in other libraries). What can I do about this ? Ignore the errors ? It would be good if the metainfo that is displayed with the test runners included a point of contact (mail address ?) to report such errors. Thanks, Stefan -- ...ich hab' noch einen Koffer in Berlin...

2 1

Re: [boost] [parameter] Go C++11 and above only, or keep C++03 support?
by Nikita Kniazev 03 Nov '18

03 Nov '18

The major problem is that Boost does not see its users; most of them do not read mail lists and changelogs, even documentation is read only during active development and by developers who actually touches boost namespace. To library maintainers they usually appear only when something is completely broken and we cannot blame anyone about it, but it makes nearly impossible to gather any statistics. The other point is that Boost is free and users may decide not to raise their voice because it can look like they try to dictate investment priorities of others spare time. If Boost really wants to survey C++03 users it can be most effectively done in the code by showing them a message with a conditional pragma #error “Boost wants to hear your voice. It is time to revise the minimal requirements. Please give us feedback about your preferences at <url> or mail list. To continue #define BOOST_I_ACKNOWLEDGE_EMERGING_CXX03_DEATH” in some libraries or globally in Boost.Config headers. It is not too late to make this for 1.69.

2 1

[release] 1.69.0 closed for major changes
by Marshall Clow 01 Nov '18

01 Nov '18

The master branch is now closed for new libraries and breaking changes, and will be closing for the beta in one week. Also, if you're ready, you can also add your libraries' changes to the release notes at: < https://github.com/boostorg/website/blob/master/feed/history/boost_1_69_0.q… > After editing the release notes, you should get a form to create a pull request, remember to submit it, otherwise I won't see your change. Thanks, -- The Boost Release Team

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