May 2024 - Boost - lists.boost.org

Two mqtt libraries
by Robert Ramey 03 Oct '24

03 Oct '24

I've been contacted by my friend and sometime collaborator Takatoshi Kondo regarding his submission of a boost library: https://github.com/redboltz/async_mqtt. It has received two endorsements. He has asked me to be review manager and I'm inclined to accept this request as he was very helpful to me during the refinement of the boost serialization library. There is also mqtt client library that is proposed to the Boost. https://github.com/mireo/async-mqtt5 It also has endorsements and a review manager. A cursory examination of the git hub pages suggest considerable overlap between the two submissions. In general, boost has discouraged the acceptance of multiple libraries with this much overlap - and for good reason. An accepted library often becomes the canonical implementation in large parts of the C++ world. Having two high quality libraries that do almost the same thing is not where we would like to be. I would like to propose that we review both libraries simultaneously in order to try to reach a consensus as to which, if either we want to accept. I know this is a difficult task, but I think it is important that we do this. It's going to be tough to reject a well written library because a better one has been accepted. But it would be worse to reject a well written library merely because another one was submitted first. Normally I don't participate as a review manager as I'm pretty bogged down in Boost stuff as it is. But I'm willing to make an exception in this case due to the importance of this case and my strong personal ties to Takatoshi. BTW - who is the review wizard these days? I presume that he will be the one making the decision about this. Robert Ramey

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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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Boost Governance?
by René Ferdinand Rivera Morell 10 Aug '24

10 Aug '24

A disclaimer: I write this solely as a Boost Library author. And not in any other capacity or representing any other interest. It's now been at least a year since Boost switched from the Software Freedom Conservancy to the Boost Foundation for its governance organization. But have people noticed any difference? Did you know that switch happened? Did you know that they held an election for the Board of Directors and for the Officers? Do you know when that election happened? Do you know who got elected? Do you know how they were selected? Do you know what their responsibilities are? Do you know what their bylaws are? Do you know their financials? More importantly: Did you answer "no" to any of those questions? As a library author, I can say I definitely answered no to many of those questions. This is a problem. As authors, without asking, we should know those answers from the organization that governs our work. We should have input into how that organization governs. In other words, we deserve open and transparent governance; not the closed and opaque status quo. -- -- René Ferdinand Rivera Morell -- Don't Assume Anything -- No Supone Nada -- Robot Dreams - http://robot-dreams.net

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Paul Bristow
by John Maddock 09 Aug '24

09 Aug '24

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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boost::any_cast gives build errors with VS2022, boost v1.82 and C++17
by Bhuyan, Jyotideep 01 Jul '24

01 Jul '24

Hi, I was using VS2019, boost v1.78, and C++14 version and the below code was working well. Same code gives build error with VS2022, boost v1.82, and C++17 due to "o << *boost::any_cast<T>(&a); " Instruction. I wanted to know why it behaves differently. Code : class any_out { struct streamer { virtual void print(std::ostream& o, const boost::any& a) = 0; virtual streamer* clone() = 0; virtual ~streamer() {} }; public: any_out() : m_streamer(nullptr) { } ~any_out() { delete m_streamer; } template <typename T> any_out(const T& value) : m_streamer(new streamer_imp<T>), m_object(value) { } any_out(const any_out& a) : m_streamer(a.m_streamer ? a.m_streamer->clone() : nullptr), m_object(a.m_object) { } template <typename T> any_out& operator=(const T& r) { any_out(r).swap(*this); return *this; } any_out& operator=(const any_out& r) { any_out(r).swap(*this); return *this; } any_out& swap(any_out& r) noexcept { std::swap(m_streamer, r.m_streamer); std::swap(m_object, r.m_object); return *this; } friend std::ostream& operator<<(std::ostream& o, const any_out& a) { if(a.m_streamer) { a.m_streamer->print(o, a.m_object); } return o; } boost::any& get() { return m_object; } const boost::any get()const { return m_object; } bool empty() const { return m_object.empty(); } private: template <typename T> struct streamer_imp : public streamer { virtual void print(std::ostream& o, const boost::any& a) { try { if (a.empty()) { o << "<empty>"; } else { o << *boost::any_cast<T>(&a); } } } virtual streamer* clone() { return new streamer_imp<T>(); } }; // Members streamer* m_streamer; boost::any m_object; }; I have migrated to VS2022, boost v1.82, and C++17, and due to a build error, I have changed the code below. virtual void print(std::ostream& o, const boost::any& a) { try { if (a.empty()) { o << "<empty>"; } else { o << boost::any_cast<T*>(a); } } } any_out anyTest; anyTest = 100; std::string actualStr; actualStr = make_string() << anyTest; actualStr prints nullptr (0000000) instated of value 100 for VS2022, boost v1.82 and C++17 Best Regards, Jyotideep (JD) Please be advised that this email may contain confidential information. If you are not the intended recipient, please notify us by email by replying to the sender and delete this message. The sender disclaims that the content of this email constitutes an offer to enter into, or the acceptance of, any agreement; provided that the foregoing does not invalidate the binding effect of any digital or other electronic reproduction of a manual signature that is included in any attachment. Confidential - Company Proprietary

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[boost.QVM] can you explain quaternions in the docs?
by Andrzej Krzemienski 19 Jun '24

19 Jun '24

Hi Everyone, I landed on this library docs when trying to learn what quarterions are for. Although the library has a vast documentation it doesn't explain what quaternions are and why they are used. When I was taught algebra for the purpose of computer graphics, vectors and matrices were on the table, but no quaternions. The examples show that I need to create a quaternion only to turn it into a rotation matrix. I am pretty sure there has to be more to it. Could I request an introduction section in the docs that would explain what quaternions are and why one would want to use them? The corresponding GitHub issue: https://github.com/boostorg/qvm/issues/51 Regards, &rzej;

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[container] Draft development plan for Boost.Container
by Ion Gaztañaga 11 Jun '24

11 Jun '24

Hi to all, Boost.Container was accepted in 2011 when container classes were spun off from Boost.Interprocess to form a new library. At that time it offered new features like emulated move semantics for "classic" STL-like containers and some new classes like flat_map and stable_vector. During these years more containers/main features were added: - The scoped allocator Model was added in Boost 1.50 (2012) - static_vector was added in Boost 1.54 (2013) - small_vector was added in Boost 1.58 (2015) - Polymorphic Memory Resources were added in Boost 1.60 (2015) - devector was added in Boost 1.75 (2020) Lately I've been collecting some ideas about how to improve the library and keep it interesting/useful both for other Boost libraries and Boost users. I've somewhat formalized a bit some of those ideas and I'd like to share them here in order to obtain feedback from the developers. Here's the document: https://docs.google.com/document/d/1VdMTheFUczC946dP3VKPseOoUq3sVKjU73oMvK8… Note that this document does not outline a schedule for all those ideas, it's an initial description of possible developments that should be evaluated/prioritized, as developing a substantial subset of the proposals would be a huge task. Thanks in advance for your attention and comments. Best, Ion

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Boost Downloads
by Sam Darwin 07 Jun '24

07 Jun '24

Summary: Boost downloads will be hosted at a new location, with the URL format https://archives.boost.io/release/1.85.0/source/boost_1_85_0.tar.gz Details: During the last couple of years the Boost downloads have been hosted on JFrog Artifactory, and before that on Bintray. JFrog has been very generous in providing the bandwidth and hosting services. Recently, bandwidth increased into the 150TB/month range. JFrog requested the download be moved behind a CDN, or migrated to another service entirely. At the C++ Alliance, we have set up load balanced AWS EC2 instances, and configured a Fastly CDN, on the domain archives.boost.io. Fastly offered a discounted bulk rate based on the large amount of traffic. The boost.org website now shows links to the new CDN. If you are using any automated scripts that point to jfrog.io, the existing JFrog links will continue to function until December 2024. - Sam Darwin

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Docs in release tarballs
by Ruben Perez 07 Jun '24

07 Jun '24

Hi all, For someone that hasn't been that long involved in Boost, it feels strange to distribute the documentation in the same release tarball as the code, specially considering the usual complains about "Boost size". I'm sure there are reasons behind it, and I'd like to learn about them. This is a candid question, out of being a newbie here. Thanks, Ruben

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Decimal Floating Point Library Beta
by Matt Borland 31 May '24

31 May '24

Hello, For the past year Chris Kormanyos and I have been working on a new library to implement IEEE 754 decimal floating point types. We are pleased to announce the library is now in beta, and can be found at: https://github.com/cppalliance/decimal, and the documentation is at: https://cppalliance.org/decimal/decimal.html First, what are Decimal Floating Point Numbers? They are floating point numbers where the significand is stored in base-10 (decimal) instead of base-2 (binary). This means that numbers can be represented exactly avoiding cases such as the famous 0.1 + 0.2 != 0.3: https://0.30000000000000004.com. The library provides types decimal32, decimal64, and decimal128 as specified in IEEE 754 and STL-like functionality. The library is header-only, has no dependencies, and only requires C++14. It provides most of the STL functionality that you are familiar with such as <cmath>, <cstdlib>, <charconv>, etc. We are proceeding as a beta right now rather than pursuing complete boost review as we are missing STL features such as C++17 special math, and believe we can continue to increase performance. We do intend to go through the review process at a later time. Please give the library a go, and let us know how we can make it better. We look forward to any and all feedback. If you use the Cpplang slack channel I am active (from the Central European Time zone) on both #boost and #boost-decimal. On a personal note as of today I have also moved from being employed half-time to full-time with the C++ Alliance. This affords me a greater opportunity to develop and maintain new and existing Boost libraries. Matt Borland —- C++ Alliance Staff Engineer

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