December 2022 - Boost - lists.preview.boost.org

Library proposal - indexed_array
by Julien Blanc 12 Oct '23

12 Oct '23

Hi, I've written and released a (rather small) library which allows defining arrays with arbitrary index mechanisms (hence the name, indexed_array). This especially allows indexing with scoped enums, use non zero-starting indexes, or use sparse indexes. This is not a view, but an array in the sense that it owns the data, and provides the same guarantees and functionalities as std::array, such as triviality propagation, being able to reside in read-only program sections, etc. It also supports multidimensional indexing, and provides an indexed_span template class to access lower dimension content (which can be used outside indexed_array). Finally, it provides an opt-in safer way to initialize the array content, which is especially useful when using complex and/or changing indexing schemes (like based on externally generated files). The library is available here: https://github.com/Julien-Blanc-tgcm/indexed_array And the doc is here: https://julien-blanc-tgcm.github.io/indexed_array/ It requires C++17 and mp11, and has first-class support for describe-d enums. If there is some interest, i'd like to propose it for inclusion in boost. So i'm looking for people who would endorse it. Thanks and best regards, Julien

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Decommissioning Trac (svn.boost.org)
by Glen Fernandes 31 Jan '23

31 Jan '23

We have Trac in read-only mode after we migrated to Git, but we're still paying for the server. Do people still want to preserve any part of the content in some way? The wiki aside, there are old issues, with comments, and some of them have patches attached. Peter had the idea of generating static HTML content from Trac and hosting that on an archive section on boost.org. (I don't know how difficult this is to do). Thoughts? Suggestions? Glen

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Regression Results Not Updating
by Tom Kent 15 Jan '23

15 Jan '23

The results from the pages at: https://www.boost.org/development/tests/develop/developer/summary.html https://www.boost.org/development/tests/master/developer/summary.html Have not updated in almost a month. Can someone check on the process that manages this? Thanks, Tom

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Paul Bristow
by John Maddock 30 Dec '22

30 Dec '22

I've just heard that Paul Bristow who helped so much with the development of Boost.Math and indeed many other libraries, passed away peacefully last week. RIP Paul. Much missed. John.

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New Boost library proposal, Mustache
by Peter Dimov 30 Dec '22

30 Dec '22

I'm looking for endorsements and a review manager volunteer for a new library, Boost.Mustache. It's an implementation of Mustache templates (http://mustache.github.io/) in C++11 and at the moment supports the mandatory portions of the Mustache spec (https://github.com/mustache/spec) The repository is https://github.com/pdimov/mustache. Mustache is a simple templating language in which tags of the form {{something}} are replaced with the value of the entity `something`, which typically means with the member "something" of the JSON object passed when rendering the template. Boost.Mustache can take a Boost.JSON object as the context against which data references are resolved, but it can also take arbitrary values that can be converted to boost::json::value by using boost::json::value_from. This allows, for instance, described classes (structs and classes annotated with Boost.Describe) to be passed as the data context, such that references to e.g. {{title}} in the template are resolved to the corresponding `title` member of the class. A simple usage example demonstrating the above is: ``` #include <boost/mustache.hpp> #include <boost/describe.hpp> #include <iostream> struct item { std::string title; std::string author; std::string link; }; BOOST_DESCRIBE_STRUCT(item, (), (title, author, link)) struct reference { std::string heading; std::vector<item> items; }; BOOST_DESCRIBE_STRUCT(reference, (), (heading, items)) int main() { reference ref = { "Reference", { { "Better Bit Mixing - Improving on MurmurHash3's 64-bit Finalizer", "David Stafford", "https://zimbry.blogspot.com/2011/09/better-bit-mixing-improving-on.html" }, { "Stronger, better, morer, Moremur; a better Murmur3-type mixer", "Pelle Evensen", "https://mostlymangling.blogspot.com/2019/12/stronger-better-morer-moremur-b…" }, { "Improved mx3 and the RRC test", "Jon Maiga", "http://jonkagstrom.com/mx3/mx3_rev2.html" } } }; std::string tmpl = R"(<html> <body> <h1>{{heading}}</h1> <ul> {{#items}} <li> {{title}} {{author}} <a href="{{link}}">{{link}}</a> {{/items}} </ul> </body> </html>)"; boost::mustache::render( tmpl, std::cout, ref, {} ); } ``` The resulting output is <html> <body> <h1>Reference</h1> <ul> <li> Better Bit Mixing - Improving on MurmurHash3's 64-bit Finalizer David Stafford <a href="https://zimbry.blogspot.com/2011/09/better-bit-mixing-improving-on.html">https://zimbry.blogspot.com/2011/09/better-bit-mixing-improving-on.html</a> <li> Stronger, better, morer, Moremur; a better Murmur3-type mixer Pelle Evensen <a href="https://mostlymangling.blogspot.com/2019/12/stronger-better-morer-moremur-b…">https://mostlymangling.blogspot.com/2019/12/stronger-better-morer-moremur-b…</a> <li> Improved mx3 and the RRC test Jon Maiga <a href="http://jonkagstrom.com/mx3/mx3_rev2.html">http://jonkagstrom.com/mx3/mx3_rev2.html</a> </ul> </body> </html>

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Tribute to John Kalb
by Robert Ramey 27 Dec '22

27 Dec '22

It's the end of 2022. I wanted to take a moment to recognize the contributions to Boost over the last dozen years or so by Jon Kalb. I first met Jon at a Microsoft Meeting named "Going Native" which was promoting a "resurgence" of C++ over Languages like Java and C#. It seems that this was related to the C++ committee incorporating large parts of Boost into the standard library and Microsofts renewed commitment to C++. This is my take, I'm sure someone else could provide more details on this. My view that was that there wasn't much more for Boost to do. Dave Abrahams was moving on to bigger things which reinforced this impression. Jon was enthusiastic about taking the lead on Boost. It was clear that he and I had a different visions. I sort of cringed - it looked to me like he got suckered. He asked me if I planned to attend C++Now - I weaseled out of actually answering. Of course he turned out to be right and I was wrong. The C++ committee hasn't really been able to replace Boost. It's too slow and cumbersome. Working as a design committee isolated from actual implementation doesn't seem to conducive to designing good, clean, elegant software. And it takes forever. It's odd to me that the committee adopted a large part of Boost software, but failed to learn anything from Boost about how to make this kind of stuff. So in this environment Jon led Boost. He worked from top to bottom on all the stuff that needs to be done - finances, legal, C++Now planning, recruitment of collaborators, etcetra . Very successful and, like many successful people, made it look easy. Hence he has not been appreciated to the extent he should be. Now he as moved on from Boost - he will be missed. Apparently this was in the works for some time but was pushed along by complaint about his handling about an alleged code of conduct violation which in my view was blown way out of proportion. I think the Boost BOD has treated Jon shabbily regarding this incident. My aim here is to correct that. Boost has had a large role in saving C++ from decline into obscurity. David Abrahams and Beman Dawes were the primary promoters at Boost at it's start. I don't think it's too much to say that these two persons saved C++. To this list, I'd like to add the name of Jon Kalb, without whom Boost would likely have wound down with C++11. -- Robert Ramey www.rrsd.com (805)569-3793

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Why do Predef and Config exist?
by Hans Dembinski 27 Dec '22

27 Dec '22

Hi all, since there were concerns that the email list is so quiet, here is some noise. Is someone willing to explain to me why we have Predef and Config? It looks like these two libraries have a strong overlap in scope. Shouldn’t they be merged? Best regards, Hans

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Proposing a Redis client library for inclusion in Boost
by Marcelo Zimbres Silva 22 Dec '22

22 Dec '22

Hi, I would like to propose my Redis client library for inclusion in Boost Github: https://github.com/mzimbres/aedis Homepage: https://mzimbres.github.io/aedis Redis: https://redis.io Aedis implements asynchronous communication with a Redis server using the RESP3 protocol [1] and is built on top of Boost.Asio, which makes it similar to Boost.Beast and Boost.MySql. For more information, please, refer to the project homepage. I am looking for someone who would like to endorse the library and also for a review manager. Thanks, Marcelo [1] https://github.com/redis/redis-specifications/blob/master/protocol/RESP3.md

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[Test] How to make test framework create Core dump in case of any unhandled exceptions?
by Sergey P 21 Dec '22

21 Dec '22

Dear developers, Is it possible to force Boost.Test framework to create Core dump in case of catching any kind of unhandled exception from code that is being tested? We tried to use parameter: *--catch_system_error=no* but it creates core dump for system signals only, while we need core dump for any exceptions, even custom ones. We would appreciate any suggestions or hints. Thank you very much! Best regards, Sergey Podolyan

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[release] Boost 1.81.0
by Marshall Clow 17 Dec '22

17 Dec '22

Release 1.81.0 of the Boost C++ Libraries is now available. These open-source libraries work well with the C++ Standard Library, and are usable across a broad spectrum of applications. The Boost license encourages both commercial and non-commercial use. This release contains one new library and numerous enhancements and bug fixes for existing libraries. * URL: A library for parsing, modifying, and printing URLs using only C++11, from Vinnie Falco and Alan de Freitas. For details, including download links, see <http://www.boost.org/users/news/version_1.81.0> You can also download directly from: <https://boostorg.jfrog.io/artifactory/main/release/1.81.0/> To install this release on your system, see <http://www.boost.org/doc/libs/release/more/getting_started/index.html> Thanks to everyone who participated in this release. -- The Boost Release Team Marshall Clow, Glen Fernandes, Michael Caisse

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Master is open for merges
by Glen Fernandes 15 Dec '22

15 Dec '22

Master is open again, with no restrictions. Boost version numbers bumped (boost, config, more), and new release notes stubbed (website). Glen

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[release] Boost 1.81.0 Release Candidate 1 is available
by Marshall Clow 14 Dec '22

14 Dec '22

The first release candidates for the 1.81.0 release are now available at: <https://boostorg.jfrog.io/artifactory/main/release/1.81.0/source/> The SHA256 checksums are as follows: 205666dea9f6a7cfed87c7a6dfbeb52a2c1b9de55712c9c1a87735d7181452b6 boost_1_81_0_rc1.tar.gz 6e689b266b27d4db57f648b1e5c905c8acd6716b46716a12f6fc73fc80af842e boost_1_81_0_rc1.zip d7bc4e2a2aee374a8c24832cacfed1265680c1e824d09fab3e00f87508155353 boost_1_81_0_rc1.7z 71feeed900fbccca04a3b4f2f84a7c217186f28a940ed8b7ed4725986baf99fa boost_1_81_0_rc1.tar.bz2 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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Revitalization
by David Sankel 09 Dec '22

09 Dec '22

Hi all, At C++Now this year I gave a talk on the status of Boost and presented this graph which illustrated the trend of Boost mailing list participation. https://docs.google.com/presentation/d/1ocX8Dh4B98gxfXJTWOriaEU1tmJN61M4Rfj… I'm interested to hear your opinions as to what happened over that time period to cause such a trend. There's truth to the claim that this question is being asked of the wrong people; those who left, stopped participating, or would otherwise start probably have good insight. Nevertheless, I think it would be interesting for us to brainstorm on this. Thanks in advance for your thoughts. -- David

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[ASIO] boos::asio::basic_streambuf does not accept user defined size during construction. Still defaults to 128
by Aniket Pugaonkar 09 Dec '22

09 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 9000 for receiving an encapsulated packet on socket). The initial allocation (buffer_.resize is done with 128. But when we call *buf.prepare(9000)*, 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 for the same. For time being, I modified the library code to the following to ensure it does not break the default argument, but accepts user defined value. Alternatively, I can change buffer delta to be of larger value, but don't want to end up with a large buffer for no reason. if (max_size_ == std::numeric_limits<std::size_t>::max()) pend = (std::min<std::size_t>)(max_size_, buffer_delta); else pend = std::max<std::size_t>(max_size_, buffer_delta); Regards Aniket. -------------------- original code ---------------- enum { buffer_delta = 128 }; /// 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); }

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Biuld boost with MSVC
by Mauro Ziliani 09 Dec '22

09 Dec '22

Hi all. My name's Mauro. I need to build boost 1.80.0 against v141_xp MSVC toolset. Which is the correct syntax for bootstrap ot b2? Best regards, MZ -- https://www.linkedin.com/in/mauroziliani

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[release] Master Branch is closed for all changes
by Marshall Clow 08 Dec '22

08 Dec '22

The master branch is closed for all changes. Release expected on 14-Dec-2022 - Release Managers

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missing patch
by Gero Peterhoff 07 Dec '22

07 Dec '22

Hi Matt, i'm missing patch #871/#872 (https://github.com/boostorg/math/issues/871) in 1.81rc2. thx Gero

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Master branch is now open for bug fixes
by Marshall Clow 07 Dec '22

07 Dec '22

The master branch is now open for bug fixes and documentation changes. Other changes by release manager permission, as described in https://github.com/boostorg/wiki/wiki/Releases%3A-Beta-Merge-Policy The next deadline: On December 7th, master closes for all changes. As always, the calendar is at https://www.boost.org/development/ <https://www.boost.org/development/> — Marshall

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Boost.Text is looking for a (mini-)review manager
by Zach Laine 07 Dec '22

07 Dec '22

I've made all the recommended changes to Boost.Text that came up in the review. Glen, the previous review manager, recommended a mini review of Boost.Text once I'd made those changes. If you'd like to manage the mini-review, please let me know. For everyone, including potential reviewers and review managers, here are the major changes: * All the specific review feedback issues have been addressed. * The string layer is now gone. * The text layer got a major re-work. It is now a set of template-based adaptors (basic_text<>, vs. a text typedef. etc.), which lets everyone get what they want. You can change the underlying storage type (including whatever allocator you prefer), select UTF-8 or UTF-16, and change the normalization form. Glen recommended I drop this layer, but the library is way less useful without this stuff, and these changes address all the concerns raised about the text layer in the review. The updated docs can be found here: https://tzlaine.github.io/text/doc/html/index.html Oh yeah, and I added concept constraints to the whole library when you build in C++20 mode. Zach

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Re: [boost] Revitalization
by William Linkmeyer 07 Dec '22

07 Dec '22

For bringing up new talent, I agree with Niall. For Boost’s usage, I maintain that new libraries in the hardware space are useful — audio, visual, libraries. No great ones exist. For C++ as a whole, I’m not sure I would recommend this language to newcomers until we break ABI and more of the cppfront syntax & safety is introduced. Our hashing and regex performance is embarrassing. Our syntax is cluttered. We can and should solve those problems. WL > On Dec 6, 2022, at 6:44 PM, Gavin Lambert via Boost <boost(a)lists.boost.org> wrote: > > On 7/12/2022 10:42, Robert Ramey wrote: >> c) use the boost tool (I forget the name) to scan my code and list the required source modules >> d) include those source files in my b2 or CMake file. > > These steps are atypical. Most users will run b2 to build binaries (static or dynamic) and then link with these, or will use the prebuilt bintray or whatever binaries, or the prebuilt Linux distro binaries. > > While it's possible to import individual .cpp files, that's never the encouraged method to depend on any C++ libraries, Boost or otherwise. > > > _______________________________________________ > Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost

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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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