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boost::streambuf default size/capacity still set to 128 in spite of size provided in constructor.
by Aniket Pugaonkar 05 Dec '22

05 Dec '22

Hello, I was checking the implementation of boost streambuf and noticed that buffer_delta value is defaulted to 128, which results in the capacity of the container to 128 bytes by default, and based on that, there is no way to change it even if we provide max size as some custom number (say 1500 for receiving a packet on socket). The initial allocation (buffer_.resize is done with 128. But when we call *buf.prepare(1500)*, it again results in resize(n) operation (through reserve(n) function call. Is there any other way to change this other than modifying the constructor in our codebase to provide a user defined value of buffer_delta Not sure if this needs to be enhanced. the maximum_size argument seems to be of no use in this case... Kindly advise. Regards Aniket. /// Construct a basic_streambuf object. /** * Constructs a streambuf with the specified maximum size. The initial size * of the streambuf's input sequence is 0. */ explicit basic_streambuf( std::size_t maximum_size = (std::numeric_limits<std::size_t>::max)(), const Allocator& allocator = Allocator()) : max_size_(maximum_size), buffer_(allocator) { *std::size_t pend = (std::min<std::size_t>)(max_size_, buffer_delta);* *buffer_.resize((std::max<std::size_t>)(pend, 1));* setg(&buffer_[0], &buffer_[0], &buffer_[0]); setp(&buffer_[0], &buffer_[0] + pend); } -- Thanks and regards, Aniket Pugaonkar

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Reminder: Release notes
by Marshall Clow 29 Nov '22

29 Nov '22

If you’ve been meaning to write release notes for your library for the 1.81.0 release, now is the time to do it. ;-) — Marshall

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[release] Boost 1.81.0 beta 1 released
by Marshall Clow 24 Nov '22

24 Nov '22

Boost release 1.81.0 beta 1 is now available at: https://boostorg.jfrog.io/artifactory/main/beta/1.81.0.beta1/source/ The SHA256 checksums are: 135f03965b50d05baae45f49e4b7f2f3c545ff956b4500342f8fb328b8207a90 boost_1_81_0_b1.tar.gz 736b041748d04c573d145613161cf2e54beb210c5511b67e6fac5510b82b6646 boost_1_81_0_b1.7z 941c568e7ac79aa448ac28c98a5ec391fd1317170953c487bcf977c6ee6061ce boost_1_81_0_b1.tar.bz2 c58d50acf58a98d4f5a7d891257d154efa50ca90312ca446586c7b4f9b7d3f14 boost_1_81_0_b1.zip Release notes (still need updates): https://www.boost.org/users/history/version_1_81_0.html Please try the beta and report any problems you encounter. Thanks to everyone who contributed to the release. -- Boost Release Team

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GSoC 2023
by David Bellot 21 Nov '22

21 Nov '22

Dear Boost developers, organization applications for the Google Summer of Code 2023 will start next year in January, that is in about 2 months from now. In order to prepare the application for Boost C++, I would like to have a list of interested mentors and the topics they would like to propose to their students. The Google Summer of Code is a good opportunity for Boost to try ideas or improve existing libraries. Contact me now if you have any questions and are interested in mentoring next summer. Cheers, David

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minor incident report, boost.org
by Sam Darwin 16 Nov '22

16 Nov '22

Hi, This morning around 7am PST the boost.org website appeared to be unavailable. Upon investigation the cause of the problem was traced to DNS. boost.org resolved in DNS. However boost.org redirects to www.boost.org and that failed to resolve at the upstream DNS provider. # nslookup > server dns1.easydns.com > www.boost.org Server: dns1.easydns.com Address: 2400:cb00:2049:1::a29f:1835#53 ** server can't find www.boost.org: REFUSED A "dig" command also showed "..Request blocked by policy". After an hour or so, the situation cleared up. Most likely something at easydns.com. A similar event occurred earlier this year. The C++ Alliance has set up web proxies to alternative domains boostcpp.org and boostlibraries.org in case boost.org is unavailable. Those were online and may be used as a backup. Best Regards, Sam Darwin sam(a)cppalliance.org

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Boost tarball release that works with CMake
by Mojca Miklavec 16 Nov '22

16 Nov '22

Dear developers, For a CMake-based project we need to fetch Boost sources as part of the build process (unless boost is already installed, in which case that version can be used). We are using CMake's FetchContent that recursively clones the repository from GitHub, but that process is extremely slow. On the Windows runner in GitHub actions it takes roughly 3 extra minutes to "git clone" boost alone (or 11 minutes for something like "choco install boost-msvc-14.3"). I tried to fetch the .7z file instead, but that one doesn't work because the CMake support gets stripped from the distributed sources when generating the tarballs. A single file would result in a much faster and more reliable workflow. The file can be cached on GitHub Actions, on a local computer one doesn't need to repeatedly clone the repository (which also slows down other parts of CMake) etc. I started the discussion here: https://github.com/boostorg/release-tools/pull/35 where it has been explained to me that: - either the CMake support needs to be heavily refactored (unlikely to happen soon) - or the project could generate one tarball using the layout that's consistent with git repository The second option might eventually be fulfilled automatically by GitHub, but that is probably not likely to happen any time soon either. I can imagine that creating one extra '.tar.xz' with a slightly different layout to support CMake builds might be straightforward to make. Is there any chance to fulfill my dream to be able to build a boost tarball with CMake out-of-the-box? Thank you very much, Mojca

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The C++ Alliance
by Louis Tatta 15 Nov '22

15 Nov '22

Hello, my name is Louis Tatta and I am the CEO of The C++ Alliance, a non-profit founded by Vinnie Falco to support and bolster the C++ ecosystem through open source and education. This serves as a formal introduction and description of our recent activities to support Boost. As you all know, Travis CI (continuous integration) became unusable for Boost needs over a year ago. To ensure the availability of CI services, our CTO and chief of devops Samuel Darwin (“Sam”) has deployed Drone CI, an open source continuous integration framework, onto scalable Amazon Web Services instances rented by us. Over the last year there has been some turnover in terms of key individuals who administer the Boost website and support the Boost release process. We have made Sam’s time and expertise available to the Boost organization to support the release managers and core developers as needed to resolve IT issues. Vinnie has outlined a vision for revitalizing Boost by developing a new, modern website to stimulate technical discussion and publication of educational resources and ideas. To this end we have retained a design firm and the leading Python development house to build a new interactive website for Boost. The designs have been completed, and the coding for the website has been underway now for almost a year. Given the current trajectory we estimate that this project will be ready for internal viewing, testing, and feedback by authors and maintainers at the end of Q1 2023. Our current engineer staffing and projects are as follows: Klemens Morgenstern, a full-time Staff Engineer, is maintaining the Boost.Beast library and developing a new high client library built on Beast and Asio. Alan de Freitas, a full-time Staff Engineer, has been working on Boost.URL (now accepted) for the last year and has also taken over maintenance of Boost.StaticString. Dmitry Arkhipov, a part-time Staff Engineer is maintaining Boost.JSON, adding new features with guidance from Peter Dimov. Christian Mazakas, a full-time Staff Engineer and Joaquín M López Muñoz, a part-time Staff Engineer, have been working on the Boost.Unordered improvement project which is overseen by Peter Dimov. If anyone has questions about any of this please feel free to ask, or reach out to me by email.

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[release] Boost 1.81.0 Beta 1 Release Candidate 2 is available
by Marshall Clow 15 Nov '22

15 Nov '22

Unfortunately, people found a few problems in the RC1 (Thanks to everyone who tried it, and especially to those who reported problems) We now have a RC2, available at: <https://boostorg.jfrog.io/artifactory/main/beta/1.81.0.beta1/source/> The SHA256 checksums are as follows: bff5cf561ab65be658c030f6b348a4907cce039611e96112dc8f6e27b6a9f44b boost_1_81_0_b1_rc2.7z 7f300d48189b9f25bf3b214168912043681819f0ace332b0e9de503f7e23e72c boost_1_81_0_b1_rc2.tar.bz2 1619545e2f180caf6615eb83220ebcc1342c20704307b59871d987b95adb1326 boost_1_81_0_b1_rc2.tar.gz 3f9ebb8b23cab1617a7ae9a38b251e4803c917832b0c4c96b907cf122dec428f boost_1_81_0_b1_rc2.zip The changes are: 1) Fixed a compile error in Boost.ASIO 2) Fixed several compilation errors on Mac OS with libstdc++. (Boost.Config) 3) Fixed Boost.JSON compilation error with X11 4) Fixed a crashing but on shared_ptr on PPC (Boost.Sharedptr, Boost.Align) 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 Release Managers

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[Release] Boost 1.81.0 closed for beta
by Marshall Clow 14 Nov '22

14 Nov '22

Master is closed for all changes. See the release schedule at: https://www.boost.org/development/index.html <https://www.boost.org/development/index.html> -- Release managers

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[release] Boost 1.81.0 Beta 1 Release Candidate 1 is available
by Marshall Clow 13 Nov '22

13 Nov '22

Available at: <https://boostorg.jfrog.io/artifactory/main/beta/1.81.0.beta1/source/> The SHA256 checksums are as follows: 6b6b95fde0ec9c6c0e1584f35c6c2dc4eb6c8629c9635e844b8e6a9ad9594da1 boost_1_81_0_b1_rc1.tar.gz 9f2ce5d1cefb8f6b7e8cfcabc73632f348958e7cba2604dcb3688fecf6463d67 boost_1_81_0_b1_rc1.tar.bz2 e7547a789339499c6fc582a96ffb8989d97074f107520ddebc1ed5f30a0d6964 boost_1_81_0_b1_rc1.zip 758af4ae4f4224b6f2bd8f05fe0109d1f248c0377ee2dce03ccbeb30d82fb8b4 boost_1_81_0_b1_rc1.7z As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. -- The Release Managers

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ccmath::abs() gives wrong result
by Gero Peterhoff 11 Nov '22

11 Nov '22

Hi Matt, ccmath::abs() gives wrong result for FP-values std::numeric_limits<FP-Type>::min() in constexpr context. test case: using type = float; constexpr type a = std::numeric_limits<type>::min(), b = boost::math::ccmath::abs(a); std::cout << a << std::endl << b << std::endl; 1.17549e-38 nan The Problem is: template <typename T> inline constexpr T abs_impl(T x) noexcept { return boost::math::ccmath::isnan(x) ? std::numeric_limits<T>::quiet_NaN() : boost::math::ccmath::isinf(x) ? std::numeric_limits<T>::infinity() : x == -0 ? T(0) : x == (std::numeric_limits<T>::min)() ? std::numeric_limits<T>::quiet_NaN() : x > 0 ? x : -x; } In the case of FP-types, only the sign-bit has to be deleted, since one cannot assume that quiet_NaN() and/or signaling_NaN() are always unsigned. thx Gero

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Boost 1.81.0 closed for major changes
by Glen Fernandes 09 Nov '22

09 Nov '22

Release has closed for major changes. Next week, 2022/11/09, master closes for all changes, in preparation for the beta. - Release team

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Build Issue - URL - msvc-14.0
by Tom Kent 05 Nov '22

05 Nov '22

In preparation for the upcoming lockdown and release, I just grabbed the latest snapshot from here: https://boostorg.jfrog.io/artifactory/main/master/boost_1_81_0-snapshot.tar… I ran it through the build process and got some issues with boost::url running on msvc-14.0. Some examples of them are: D:\RB\boost_1_81_0\boost/url/param.hpp(886): error C2134: 'boost::urls::grammar::string_view_base::string_view_base': call does not result in a constant expression D:\RB\boost_1_81_0\boost/url/param.hpp(886): note: failure was caused by call of undefined function or one not declared 'constexpr' The full output log is here: https://gist.github.com/teeks99/8d14da5b50cffda13f9ad5e23a8d80aa Tom

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Does ASIO really still uses reactor instead of proactor on some OSes or is documentation just outdated?
by Ivan Matek 29 Oct '22

29 Oct '22

If you go to https://www.boost.org/doc/libs/1_80_0/doc/html/boost_asio/overview/core/asy… you will see that it says: * On many platforms, Boost.Asio implements the Proactor design pattern in terms of a Reactor, such as select, epoll or kqueue. This implementation approach corresponds to the Proactor design pattern as follows: * *[...]* * On Windows NT, 2000 and XP, Boost.Asio takes advantage of overlapped I/O to provide an efficient implementation of the Proactor design pattern. This implementation approach corresponds to the Proactor design pattern as follows: * I am unfortunately not a pattern or OS expert, but I would expect that on every modern OS proactor can be implemented without using reactor, e.g. see *https://stackoverflow.com/a/57451551/700825 <https://stackoverflow.com/a/57451551/700825>* The fact that mentioned Windows are NT, XP and 2000 also furthers my suspicion that docs are outdated.

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Boost.StaticString
by Vinnie Falco 29 Oct '22

29 Oct '22

Alan de Freitas has generously stepped up to maintain Boost.StaticString in the absence of Krystian. -- Regards, Vinnie Follow me on GitHub: https://github.com/vinniefalco

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1.81.0 closed for new libraries and breaking changes
by Glen Fernandes 28 Oct '22

28 Oct '22

Next deadline: On 2022-11-02 Boost 1.81.0 closes for major code changes. Still open for serious problem fixes and docs changes without release manager review. - Boost release team

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Wants to start contributing to boost libraries
by Shivam Rajput 28 Oct '22

28 Oct '22

Hey, I'm really interested to start contributing to boost, it would be really great if any of you could suggest which libraries that i can start with? Maybe any of the gsoc projects that need maintenance and more work? Currently I'm more interested in c++23 features and trying to implement some of them into libcxx. Thanks and regards Shivam

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Reminder: Oct 26, 1.81.0 closed for new libraries and breaking changes
by Glen Fernandes 18 Oct '22

18 Oct '22

1.81.0 closes for new libraries and breaking changes next Wednesday (2022-10-26). We have two new accepted libraries: MySQL and URL, but only URL has been imported into the organization and has a submodule right now. Glen

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New Library Proposal: xvec/simd
by Towner, Daniel 17 Oct '22

17 Oct '22

I would like to propose a SIMD/data-parallel header-only library for inclusion in boost. The library is an example implementation already developed by Intel of a C++ TS proposal called std::experimental::parallelism_v2::simd [1]. The library is styled as a data-parallel library where the programmer specifies the data parallelism available in the source program, and the compiler will generate the appropriate simd instruction sequences. The library is agnostic of simd element type and length, and within reason, should be able to target any processor with simd capabilities. Intel has added further generic extensions to the proposal, such as permutation operations and support for complex numbers [2]. Motivation: The concept of simd needs little introduction as the technique is widely used in high performance software and there are many libraries providing varying level of abstraction and portability. In [1], Matthias Kretz made a proposal to provide a standard C++ library which implements many data-parallel concepts in a portable, vendor-neutral style, and with tight integration with C++ (e.g., operator overloading, overloads for all appropriate standard library functions). That proposal and the feedback on it have been discussed in WG21 and Intel supports the proposal. There was an attempt to add a boost.simd library in the past but that was abandoned after its authors decided to commercialise it. Despite the availability of other simd or data-parallel libraries in the wider community there is still a gap for a data-parallel, width-agnostic, vendor neutral library with close integration into C++. The std::simd library proposal and its example implementation from Intel seem to fill this gap. The existence of an example implementation in boost will also make it easier to get users to adopt the TS and provide feedback to improve its API and feature set for real-world code. History: There are two strands of history that come together in this proposal: Intel's own vector libraries, and the C++ std::simd proposal. Intel has a long history of developing simd-capable processors and has its own libraries for accessing simd features [3]. A recent Intel project to refresh those libraries resulted in a new library called `xvec' which incorporates many modern C++ features and is deliberately vendor and target neutral, with the target being selected at compile-time. In 2013 the proposal was started, and then a C++ TS was published in 2018 [1] and discussed in WG21. Due to the similarities of the two libraries and their common goals, myself and Matthias Kretz are now working together on merging the simd specification from the Parallelism TS 2 into the IS for C++26. Status and Implementation: The `xvec' example library implemented by Intel supports most of the features of the std::simd proposal [1], along with a number of extensions to add some capabilities (e.g., generic permutation, complex number support) [2]. The library works in Linux and Windows, and can be compiled with GCC 12, LLVM 14 and Intel's oneAPI 2022. It is currently tested using googletest. Most of the library is implemented on top of the LLVM and GCC vector extensions [4], which makes it compilable on any target supported by those extensions. In a limited number of places intrinsics are used to access specific Intel instructions, but efficient generic fall-backs are also provided for simd targets which don't have those instructions (and this can included unsupported Intel processors too). Request: I would welcome any comments, questions or ideas on how to proceed with this proposal. [1] ISO/IEC TS 19570:2018, Programming Languages - Technical Specification for C++ Extensions for Parallelism, by Matthias Kretz. http://open-std.org/JTC1/SC22/WG21/docs/papers/2019/n4808.pdf [2] P2638R0: Intel's response to P1915R0 for std::simd parallelism in TS 2. https://wg21.link/p2638r0 [3] https://www.intel.com/content/www/us/en/develop/documentation/cpp-compiler-… [4] https://clang.llvm.org/docs/LanguageExtensions.html#vectors-and-extended-ve…

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Github Actions slow
by Sam Darwin 12 Oct '22

12 Oct '22

On https://github.com/boostorg/json we have noticed very slow Github Actions times such as "Total duration: 6h 8m 47s" This is very likely caused by Github throttling jobs. https://docs.github.com/en/actions/learn-github-actions/usage-limits-billin… mentions limits of between 20 and 180 which would apply to the entire boostorg account. A reminder to any boost developers who are seeing slow processing time that they may use Drone CI, instructions at https://github.com/boostorg/boost-ci

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Boost.URL examples
by Alan de Freitas 10 Oct '22

10 Oct '22

Hi, Would anyone like to suggest examples you'd like to see in Boost.URL? Best, -- Alan Freitas https://alandefreitas.github.io/alandefreitas/ <https://github.com/alandefreitas>

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[checking interest] boost.tcl
by Klemens Morgenstern 01 Oct '22

01 Oct '22

Is there any interest in C++ Tcl bindings? I wanted to find out how far I can push boost.describe so I create C++ tcl binding based on it, PoC is here https://github.com/klemens-morgenstern/boost.tcl It's currently a rough PoC so it'd be a lot of work to make this a proper boost library, hence the question if there's some actual interest, otherwise it's a nice toy project. All you need to do is to use boost.describe for your enum or class and then you can use them in tcl: // C++ enum test_enum {foo = 1}; BOOST_DESCRIBE_ENUM(test_enum, foo); struct my_class { double foo; void bar(int); }; BOOST_DESCRIBE_STRUCT(my_class, (), (foo, bar)); BOOST_TCL_PACKAGE(Test_module, "1.0", mod) { auto & cmd = boost::tcl::create_command(mod, "test"); auto & enm = cmd.add_subcommand("enum"); enm.add_enum<test_enum>(); auto & fun = cmd.add_subcommand("add").add_function(+[](int i, int j) {return i + j;); auto & cl = cmd.add_subcommand("add") .add_class<my_class>() // adds all the members based on boost.describe .add_constructor<my_class(int, std::string)>(); } # TCL # create `test_enum` from it's int valid set e1 [test enum 1] # create test_enum from it's name set e2 [test enum foo] # call the function - overloading is supported [test add 1 2] # create an instance of my_class set mc [my_class new 1 test-string] # get a data-member puts [ *$mc .get foo ] # call a method *$mc bar 42

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Re: [boost] [Boost-users] [signals2][variant] inline warning with MSVC 2022
by Frank Mori Hess 23 Sep '22

23 Sep '22

On Wed, Sep 21, 2022 at 12:21 PM Frank Mori Hess <fmh6jj(a)gmail.com> wrote: > > On Mon, Sep 19, 2022 at 3:16 AM Gavin Lambert via Boost-users > <boost-users(a)lists.boost.org> wrote: > > > > >,struct boost::mpl::l_iter<struct boost::mpl::l_end> > *)' marked > > as __forceinline not inlined > > > > I'm not sure whether the Real Bug™ is in signals2 or in variant, but I > > don't think it's in any of my code since it doesn't name any of my types > > above that I can see. > > The problem is not in signals2, as it makes no direct use of > __forceinline. variant does make use of BOOST_FORCEINLINE so it > probably needs to have the pragma suppression added somewhere. > Actually, maybe the easiest thing would be to just put the pragma suppression in the header that defines BOOST_FORCEINLINE (config/detail/suffix.hpp). -- Frank

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[codecov] blowing up like the Hindenburg
by Vinnie Falco 20 Sep '22

20 Sep '22

All: Over the last 15 months, codecov.io has been undergoing a refactoring/rewriting of its user interface and in my opinion it is not for the better. There is a significant loss of functionality and the interface designs which have replaced the old designs are less usable. There's been an open issue for receiving feedback: <https://github.com/codecov/Codecov-user-feedback/issues/1> As you can see a lot of people are having problems. I have scheduled a call with the CEO. My purpose for this thread is to identify other Boost authors, maintainers, and users who have a stake in seeing codecov preserve its functionality and not get worse. And to show where you can go and complain if you are so inclined. Sam is investigating coveralls as an alternative solution. Its UI isn't quite as good as the old codecov. But it is better than the new codecov. Happy to hear anyone's thoughts on this matter. -- Regards, Vinnie Follow me on GitHub: https://github.com/vinniefalco

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[range] Concept check failing with custom C++20 range support
by Jared McIntyre 19 Sep '22

19 Sep '22

I've been toying around with a pull request that was entered against boost::range to support integration of boost range_v2 and C++20 ranges to see how flexible it would be: https://github.com/boostorg/range/pull/123 I have a need to continue to use boost::any_range in some of our interfaces, but it would be nice to switch to using C++20 ranges under the covers. A lot of it seems to work well with the type definitions from the pull request, but I'm running into an issue with concept check on line 228 or any_iterator_wrapper.hpp specifically when using the transform adaptor. I don't have the same issue with boost::adaptors::transformed. What has me confused is that I think that the result views::transform should be forward traversal, but I'm not really clear on exactly why it is failing. I created a test if anyone wants to play around with it in a compiler and help me understand what is going on: https://godbolt.org/z/1hMsofbrv Switching between the two commented out base_range declarations will get you different results. Here is the code for anyone that just wants to look at it here: #include <boost/range.hpp> #include <boost/range/adaptors.hpp> #include <boost/range/any_range.hpp> #include <ranges> #if 1 namespace boost::range_detail { template< std::ranges::common_range C > struct range_mutable_iterator< C > { typedef std::ranges::iterator_t< C > type; }; template< std::ranges::common_range C > struct range_const_iterator_helper< C > { typedef std::ranges::iterator_t< C const > type; }; } #endif int main() { std::vector<int> vec(5, 0); auto mul2 = [](int i) { return i * 2; }; auto base_range = vec | std::views::transform(mul2); //auto base_range = vec | boost::adaptors::transformed(mul2); boost::any_range<int, boost::forward_traversal_tag> new_range = base_range; }

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