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Call for Submissions: International Conference on Information Society (i-Society 2019)
by International Conference on Information Society 18 Mar '19

18 Mar '19

If you are not able to see this mail, click http://r.confinfosoc.org/mk/mr/hHTtReTMggQeh5kiYnT0MxUABiXYJEhpmmVH7xlJw4VK… for Submissions: International Conference on Information Society (i-Society 2019) ********************************************************************************** International Conference on Information Society (i-Society 2019) 22-24 October, 2019 Venue: Royal Marine Hotel Dún Laoghaire, Co. Dublin, Ireland www.i-society.eu ********************************************************************************* The i-Society is a global knowledge-enriched collaborative effort that has its roots from both academia and industry. The conference covers a wide spectrum of topics that relate to information society, which includes technical and non-technical research areas. The mission of i-Society 2019 conference is to provide opportunities for collaboration of professionals and researchers to share existing and generate new knowledge in the field of information society. The conference encapsulates the concept of interdisciplinary science that studies the societal and technological dimensions of knowledge evolution in digital society. The i-Society bridges the gap between academia and industry with regards to research collaboration and awareness of current development in secure information management in the digital society. The topics in i-Society 2019 include but are not confined to the following areas: *New enabling technologies - Internet technologies - Internet of Things (IoT) - Wireless applications - Mobile Applications - Cloud and iCloud - Multimedia Applications - Protocols and Standards - Ubiquitous Computing - Virtual Reality - Human Computer Interaction - Geographic information systems - e-Manufacturing - Electronic Discovery (eDiscovery) - Software Applications - Disruptive Technology *Intelligent data management - Intelligent Agents - Intelligent Systems - Intelligent Organisations - Content Development - Data Mining - Data Management Software - e-Publishing and Digital Libraries - Information Search and Retrieval - Knowledge Management - e-Intelligence - Compliance and Recovery from Data Loss - Knowledge networks - Risk Mitigation - Cost Efficiency - Quality Assurance - Information Management - Support Litigation - Complex Investigations *Secure Technologies - Internet security - Web services and performance - Secure transactions - Cryptography - Payment systems - Secure Protocols - e-Privacy - e-Trust - e-Risk - Cyber Security Investigations and Defence - Cyber law - Forensics - Information assurance - Mobile social networks - Peer-to-peer social networks - Sensor networks and social sensing - Information Security Compliance *e-Learning - Collaborative Learning - Curriculum Content Design and Development - Delivery Systems and Environments - Educational Systems Design - e-Learning Organisational Issues - Evaluation and Assessment - Virtual Learning Environments and Issues - Web-based Learning Communities - e-Learning Tools - e-Education *e-Society - Global Trends - Social Inclusion - Intellectual Property Rights - Social Infonomics - Computer-Mediated Communication - Social and Organisational Aspects - Globalisation and developmental IT - Social Software - Smart City *e-Health - Data Security Issues - e-Health Policy and Practice - e-Healthcare Strategies and Provision - Medical Research Ethics - Patient Privacy and Confidentiality - e-Medicine *e-Governance - Democracy and the Citizen - e-Administration - Policy Issues - Virtual Communities *e-Business - Digital Economies - Knowledge economy - eProcurement - National and International Economies - e-Business Ontologies and Models - Digital Goods and Services - e-Commerce Application Fields - e-Commerce Economics - e-Commerce Services - Electronic Service Delivery - e-Marketing - Gig Economy - Online Auctions and Technologies - Virtual Organisations - Teleworking - Applied e-Business - Electronic Data Interchange (EDI) - Innovative Strategies - Business Intelligence - Information Intelligence - Forensic Accounting *e-Art - Legal Issues - Patents - Enabling technologies and tools *e-Science - Natural sciences in digital society - Biometrics - Bioinformatics - Collaborative research *Industrial developments - Trends in learning - Applied research - Cutting-edge technologies - Industrial Control Systems - Communications Compliance * Research in progress - Ongoing research from undergraduates, graduates/postgraduates and professionals SUBMISSION INSTRUCTIONS: * You can submit your extended abstract or paper online at http://www.i-society.eu/paper-submission/ or email it to papers(a)i-society.eu * You can submit your poster via email at posters(a)i-society.eu * You can submit your workshop or tutorial proposal at workshop(a)i-society.eu or tutorial(a)i-society.eu * You can submit your speaker's proposal at speakers(a)i-society.eu IMPORTANT DATES: *Abstract or Extended Abstract Submission Date: April 25, 2019 *Notification of Abstract or Extended Abstract Acceptance / Rejection: April 30, 2019 *Research Paper Submission Date: May 01, 2019 *Notification of Research Paper Acceptance / Rejection: May 15, 2019 *Camera Ready Paper Due: July 15, 2019 *Proposal for Workshops / Tutorials: May 01, 2019 *Notification of Workshop/Tutorials Acceptance / Rejection: May 05, 2019 *Poster / Demo Proposal Submission: May 01, 2019 *Notification of Poster / Demo Acceptance: May 05, 2019 *Early Bird Registration Deadline: June 01, 2019 *Late Bird Registration Deadline: July 01, 2019 *Conference Dates: October 22-24, 2019 For more details, please visit www.i-society.euIf you wish to unsubscribe from our newsletter, click http://r.confinfosoc.org/mk/un/cJt0lk_6hTiWU2mR1gcBlsWcuOzQ_Zs4QdpVvm0OQwTN…

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question about GSoC 2019
by Aziz Mousa 18 Mar '19

18 Mar '19

hello there, I want to participate in boost project in the GSoC but I am confused a little bit and there is some points that I don't understand and I need some help here please * First : to be involve in this event if I don't have my own idea should I choose one project form the list like boost.GIL or boost.uBLAS as all or should choose a specific project inside one of them like project 1, or project 2 * second: if I choose project in boost.uBLAS should I be professional in machine learning? because I am still in the start of road in this field but I am work on it and will make progress as soon as possible * third : is there any thing should I do or submit before the student registration opens in GSoC website ? thanks in advance.

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Networking TS + Beast, NEW Tutorials, Read this to learn std::net !!!
by Vinnie Falco 17 Mar '19

17 Mar '19

Fellow C++, Boost, and WG21 Enthusiasts, lend me your ear! I write to inform you about exciting developments in C++ networking. First, a bit of background. Networking comes in three flavors: * Networking TS <https://cplusplus.github.io/networking-ts/draft.pdf> * Boost.Asio <https://www.boost.org/doc/libs/1_69_0/doc/html/boost_asio.html> * Standalone Asio <https://github.com/chriskohlhoff/asio> These three are for the most part identical, except that Asio flavors have additional features like ssl::stream and signal_set which are not in the TS, but will very likely appear in a future update or version. We've had Asio for over a decade now, but there is a shortage of experts. Some people believe this shortage is because Asio in particular (and thus, Networking TS since they have identical interfaces) is "difficult to use." I believe it is wrong to blame Asio for this. Concurrent programs in general are hard to write. This is applicable: "Unfortunately, today's reality is that only thoughtful experts can write explicitly concurrent programs that are correct and efficient. This is because today's programming models for concurrency are subtle, intricate, and fraught with pitfalls that easily (and frequently) result in unforeseen races (i.e., program corruption) deadlocks (i.e., program lockup) and performance cliffs (e.g., priority inversion, convoying, and sometimes complete loss of parallelism and/or even worse performance than a single-threaded program). And even when a correct and efficient concurrent program is written, it takes great care to maintain — it's usually brittle and difficult to maintain correctly because current programming models set a very high bar of expertise required to reason reliably about the operation of concurrent programs, so that apparently innocuous changes to a working concurrent program can (and commonly do, in practice) render it entirely or intermittently nonworking in unintended and unexpected ways. Because getting it right and keeping it right is so difficult, at many major software companies there is a veritable priesthood of gurus who write and maintain the core concurrent code." - Herb Sutter, "The Trouble with Locks", <http://www.drdobbs.com/cpp/the-trouble-with-locks/184401930> Although this was written in 2005 it is still relevant today. It is understandable that Asio will be the first target of anger and frustration when writing concurrent programs, since it is on the "front line" so to speak. There has also been a distinct shortage of *good* tutorials and examples for Asio. Articles or blog posts which teach you step by step, explaining everything, and giving example code which demonstrates best practices. Boost.Beast is my low-level HTTP/WebSocket library which builds on Boost.Asio: <https://github.com/boostorg/beast> In the original release of Beast, the documentation stated "prior understanding of Boost.Asio is required." However, field experience has shown that users ignore that requirement and attempt to write complex, concurrent programs as their first-time introduction to both Beast and Asio. Based on feedback from committee members, and to serve users better, the scope of Beast has been enlarged to include first-time users of networking. The upcoming Boost 1.70 release reflects this new scope and I am excited to announce some very nice things which you can access today. First of all, Beast documentation and examples no longer use the "boost::asio" namespace, they the namespace alias "net::". While this is cosmetic, it reinforces the notion when inspecting code that it is equally applicable to Boost.Asio, Asio, and Networking TS (identifiers which are not in the TS, such as signal_set, are still qualified with boost::asio). A new documentation page explains the three flavors of networking: <https://www.boost.org/doc/libs/master/libs/beast/doc/html/beast/using_io.ht…> This is also explained in my 2018 CppCon presentation: <https://youtu.be/7FQwAjELMek?t=444> I have added a "Networking Refresher", a complete overview of networking from soup to nuts. No prior knowledge or understanding of networking is required, everything is explained in detail so if you want to learn this is the place to start. I also kept it short, but it is loaded with hyperlinks for further learning: <https://www.boost.org/doc/libs/master/libs/beast/doc/html/beast/using_io/as…> There was a recent paper in Kona, P1269R0 ("Three Years with the Networking TS") about difficulty of implementing timeouts. To address this, Beast now has a stream class which implements configurable timeouts for you, and callers no longer have to fiddle with timers manually anymore. Everything "Just Works." It achieves the P1269R0 author's goal of having timeouts "built-in to asynchronous operations", but in a way that fits in with the design of the TS: <https://www.boost.org/doc/libs/master/libs/beast/doc/html/beast/using_io/ti…> I feel that this `beast::basic_stream` serves as an existence proof that the current design of Networking TS is sound - the TS offers a flexible toolbox which lets you build your own framework the way that you want it, without making odd choices for you. We are still discovering ways of leveraging it to maximum use. The beast::websocket::stream also has built-in timeouts, but they are enhanced to support "idle pings" (keeping client connections alive) and everything is fully configurable: <https://www.boost.org/doc/libs/master/libs/beast/doc/html/beast/using_webso…> All you need to do to get sensible, suggested websocket timeouts is add one line of code after creating your stream: ws.set_option(websocket::stream_base::timeout::suggested( beast::role_type::server)); To address the cumbersome boilerplate of writing composed operations (specifically the need to propagate the associated allocator and associated executor, and to avoid invoking the completion handler from within the initiating function when the operation would complete immediately) Beast adds two new utility base classes, with plentiful documentation and examples throughout: <https://www.boost.org/doc/libs/master/libs/beast/doc/html/beast/using_io/wr…> There are two well-rounded examples which show you step by step how to write these things in a safe way: <https://www.boost.org/doc/libs/master/libs/beast/doc/html/beast/using_io/wr…> <https://www.boost.org/doc/libs/master/libs/beast/doc/html/beast/using_io/wr…> I have a big, new open source project which implements a server, that uses the `system_context`, taking full advantage of native Windows and Mac OS system-level execution context features. To support this use case and industry feedback, the examples in Beast now default to being always thread-safe. All examples use a "strand", and leverage P1322R0 ("Networking TS enhancement to enable custom I/O executors"). Yes, this paper which was approved in Kona, is now implemented in both Boost.Beast, and Boost.Asio, including all of the Beast examples, so if you pick up Boost 1.70 (or the master branches from github) you can start playing with this as soon as you're done reading this message!! <http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p1322r0.html> We have an active #beast channel in the C++ Slack (https://slack.cpp.al) where experienced users can help, no question is too small! I hope you will join me and the rest of the Beast and Asio community in exploring what the very powerful Networking TS and Asio libraries have to offer, and build something great together! Regards P.S. Don't forget to star the repository! <https://github.com/boostorg/beast>

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I am interested to participate in BOOST GSOC2019 project
by raghuchandra kanakamedala 17 Mar '19

17 Mar '19

I am raghuchandra studying 3rd year B.Tech at IIIT Hyderabad.It would be great to contribute to Boost.GIL: generic image library.I have ideas for both the projects.I had this course Digital Image Processing also done a project "Road detection from satellite images" based the paper attached.my implementation link on git https://github.com/savera2020/dip_project/.I have good skills in C++ programming. so can you provide the mail id of mentor so that we can go more deeper about the project.please consider my request to contribute to project.without a doubt i will give my best. Thanking You.

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How should I teach a C++ college class?
by Joshua Marshall 17 Mar '19

17 Mar '19

I need some general input here. I'd like to pitch and run a semester long C++ course to students who have at least 1 year of programming experience. I'd like to have this open to open ended input. The biggest technical restrictions are that the University systems are running RHEL 7.4 (7.5?) with software collections devtoolset-8.

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Re: [boost] [Boost-users] Networking TS + Beast, NEW Tutorials, Read this to learn std::net !!!
by Vinnie Falco 15 Mar '19

15 Mar '19

On Fri, Mar 15, 2019 at 7:38 AM Stian Zeljko Vrba <vrba(a)quine.no> wrote: > I have an idea of how to accomplish the same in C++, and > it's not pleasant -- worker thread, promise/future, blocking > queue and CancelSynchronousIO. Cannot even use > std::async because CancelSynchronousIO needs a > target thread ID. Yes, yes! I see now...your ideas on how to implement it in C++ convince me more than anything that the documentation is the problem. There's no need for any of that stuff, the code you provided could be implemented in C++ using asio without too much fuss, and there are actually several ways to do it all of which are succinct and will work wonderfully.

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Re: [boost] [Boost-users] Networking TS + Beast, NEW Tutorials, Read this to learn std::net !!!
by Vinnie Falco 15 Mar '19

15 Mar '19

On Fri, Mar 15, 2019 at 7:19 AM Stian Zeljko Vrba <vrba(a)quine.no> wrote: > > I believe it is wrong to blame Asio for this. > > I disagree. Recently, I've been coding parallel, including networked & > asynchronous, programs in C# and Java, and the experience has been a JOY. You > get threads, executors, synchronization primitives, tasks, cancellation, > monadic futures and concurrent (blocking and non-blocking) data structures > out of the box with the platform, plus a myriad of extensions as libraries. > As for executors, you don't need to be bothered with them unless you really > want to for some reason. > If you were to compare POSIX or BSD sockets to C# and Java, you would say exactly the same things. Asio (like Beast) is a low-level, portable abstraction of I/O. You can BUILD "threads", "executors", "synchronization primitives", "tasks", "cancellation", "monadic futures", and "concurrent data structures" with it. Does this mean OS-level sockets are the wrong abstraction? Of course not. The reason C# seems "ahead" of C++ is two-fold: 1. WG21 goofed up by delaying networking 2. C# is not developed through the International Standards Process These mistakes are being fixed though, and you will see library support in C++ catch up by leaps and bounds. And when we finally get these things (built on top of Asio/Networking TS, which has proven over and over to be the correct low-level abstraction) it will be better than C#, Java, or Rust. Compare the documentation for Vertx (vertx.io) or netty (both Java toolkits > for writing asynchronous reactive programs) with that of asio. > Yes I agree, there is a lack of documentation and especially tutorials for beginners (which I am trying to fix). This has nothing to do with whether Asio is the right portable, low-level abstraction (it is) but the lack of guidance from the author could lead you to believe incorrect things about the lib. Once I attempted to write an asio service, tried to understand the simple > example from the documentation, and I gave up. I used a thread, blocking > call and CancelSynchronousIO (and I consider myself fortunate to develop > for Windows only that has it). > The documentation on services is particularly scant. There is no explanation of what they are for, how to use them, best practices, or even "Frequently Asked Questions." I was able to figure it out though, but I am able to focus all of my time on it. > Asio _is_ a relatively nice wrapper around socket and serial port APIs, > but that's about it > Yes now you're getting close to an accurate description. More correct would be to say that Asio provides robust abstractions of buffers, dynamic buffers, synchronous I/O, and asynchronous I/O. Networking is a subset of that (but not the only part, see signals and serial ports, and soon file I/O). > IMO. On the other hand, I could have written the same wrappers around > native APIs in two days and not haul along what I consider the baggage of > technical debt that is asio in the codebase. > There is no API technical debt. That is to say, that the interfaces are modern and up-to-date. You could argue that particular implementations such as Boost.Asio have extra code to provide C++03 compatibility, but this has nothing to do with the soundness of the design. As these interfaces are part of a TS, there will be implementations in gcc and clang appearing shortly (if not already so). These will be written from scratch so there will be no support for older C++. > Conclusion, if any: many people just want/need thread per client and > synchronous IO for simplicity, but until asio/networking TS provide for > timeouts and cancellation of synchronous requests, it's a wrong tool for > those people, me included. > If you define struct sync_socket { net::io_context ioc_; net::ip::tcp::socket_; net::steady_timer timer_; ... template<class Buffers> std::size_t write_some (Buffers const& b); }; You can easily implement timeouts in `write_some` thusly: template<class Buffers> std::size_t sync_socket:: write_some (Buffers const& b, error_code& ec) { std::size_t n; timer_.expires_after(seconds(30)); timer_.async_wait( [&](error_code ec) { socket_.cancel(ec): }); socket_.async_write_some(b, [&](error_code ec_, std::size_t n_) { ec = ec_; n = n_; }); ioc_.run(); return n; } Now, you can use `sync_socket` with all the usual sync write operations like `net::write`, and get timeouts. Thanks

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Re: [boost] [Boost-users] Networking TS + Beast, NEW Tutorials, Read this to learn std::net !!!
by Vinnie Falco 15 Mar '19

15 Mar '19

On Fri, Mar 15, 2019 at 2:45 AM Cristian Morales Vega <cristian(a)samknows.com> wrote: > I have not used the synchronous API at all. But section 3.1 of P1269R0 > seems to make a good point about the lack of timeouts in synchronous > calls, doesn't it? > beast::basic_stream makes using timeouts in the async API way simpler, > but is the sync API really basically unusable because of the lack of > timeouts thing? Synchronous APIs are perfectly fine. Asio defines SyncReadStream and SyncWriteStream named requirements, allowing for generic algorithms to be implemented. Not everything is a socket (for example, a serial port). A synchronous stream represents the reliable, in-order delivery of bytes using functions that block, nothing more and nothing less. For example, serial file I/O can be represented using a synchronous stream. If the synchronous stream requirements mandated timeouts, it would eliminate a broad set of implementations (including sockets on some platforms).

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Status of Disjoint Sets ?
by Brian Kuhl 15 Mar '19

15 Mar '19

Disjoint Sets is in the last few releases, has it's own test suite and github archive, but isn't mentioned on the documentation page? An oversight, or intentional? https://www.boost.org/doc/libs/1_69_0/ I see a defect that says it should move into Graph, is that part of the puzzle? https://github.com/boostorg/disjoint_sets/issues Brian

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Networking TS + Beast, NEW Tutorials, Read this to learn std::net !!!
by Mike 15 Mar '19

15 Mar '19

> All in all nice intro, unfortunately it requires users to understand > templates quite well, but honestly not sure if it is avoidable, with a > gazillion customization points in ASIO. Anyone aware of a wrapper library around ASIO that doesn't offer all those customization points and maybe not the full functionality/ efficiency but is easier to use? Am 15.03.19, 01:09, Ivan Matek via Boost <boost(a)lists.boost.org> schrieb: Here are comments from somebody who "knows C++" but does not know a lot about NW and has read only the 1st <[1]https://www.boost.org/doc/libs/master/libs/beast/doc/html/beast/ using_io/asio_refresher.html> page. // get iterators representing the range of characters in the buffer auto begin = range::begin(buffer.data()); auto end = range::end(buffer.data()); Quite a weird pattern, where buffer does not have member begin, end. Maybe a sentence or two describing the rationale and complexity would be nice. I know it is O(1), but it is weird that begin/end are called on pointer. std::size_t read_lineI am tired, but is this function O(n^2)? cb += bytes_transferred; // adjust the pointer and sizeI would maybe switch to write instead of write_some to keep the code shorter, and mention write_some as another option in text. [](error_code ec, std::size_t bytes_transferred) For learning purposes I would capture something in lambda by value and note that reference capture would be buggy. using type = std::allocator<void>; Personal preference: not a fan of typedefs for relatively short types used once. All in all nice intro, unfortunately it requires users to understand templates quite well, but honestly not sure if it is avoidable, with a gazillion customization points in ASIO. _______________________________________________ Unsubscribe & other changes: [2]http://lists.boost.org/mailman/listinfo.cgi/boost References 1. https://www.boost.org/doc/libs/master/libs/beast/doc/html/beast/using_io/as… 2. http://lists.boost.org/mailman/listinfo.cgi/boost

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Coordinating Boost Releases with compiler releases
by Marshall Clow 14 Mar '19

14 Mar '19

In the thread "MSVC 2019 and 1.70 beta", there has been a discussion about what to do about support for MSVC 2019, which is due to be released right about the same time that Boost 1.70. One person suggested that we delay the boost release until after the MSVC release (I think the suggestion was "May"). This general question has been discussed before (several times), since tools get released fairly often - and so does Boost. In general, I am not in favor of delaying boost releases in order to add support for 'about to be released' development tools. There are two main reasons for this: * There's always another compiler / tool about to be released. Clang 8 is imminent - currently at RC5. GCC 9.1 is scheduled to be released in early May. * Boost releases happen every four months. August is not really that far off. People who want support for tool XXXX can use "the trunk", getting it either from git or from bintray. [ Everyone knows about the tarballs at bintray, right? https://dl.bintray.com/boostorg/master/ ] Also, if we were to delay the boost release until May, then what would happen to the August release? The release process for 1.71.0 is scheduled to start at the end of June. -- Marshall

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[filesystems]
by Florian Lindner 14 Mar '19

14 Mar '19

Hello, I have this innocent piece of code: namespace fs = boost::filesystem; auto path = getFilename(); // returns a string fs::create_directories(fs::path(path).parent_path()); std::ofstream ofs(path + "~"); ofs << info; ofs.close(); fs::rename(path + "~", path); which causes the exception: boost::filesystem::rename: No such file or directory: "../9f/061b4f7a5e529c964659226eedd4e5~", "../9f/061b4f7a5e529c964659226eedd4e5" However, I have no idea how that could happen. I use the rename, so that a reading process never sees an empty file, but only no file or filed with info. Is there any race involved between ofs.close() and fs:rename()? The code was executed on a distributed network filesystem (lustre). Any ideas anyone? Thanks, Florian

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Re: [boost] [Boost-users] Networking TS + Beast, NEW Tutorials, Read this to learn std::net !!!
by Vinnie Falco 14 Mar '19

14 Mar '19

On Thu, Mar 14, 2019 at 10:50 AM james <dirtydroog(a)gmail.com> wrote: > This is excellent news. Timeouts are ASIO's biggest downfall. I'll definitely check it out. > If it's low level, and performant enough, then it paves the way for ASIO-ed connectors for things like Redis and ZeroMQ. Thanks! And we are very happy to answer questions, feel free to open an issue or come to the #beast Slack channel. Regards

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Cannot serialize pointer through base without void_cast_register and register_type.
by Nicolas Guillot 14 Mar '19

14 Mar '19

Hello. *** CONTEXT *** I use your serialization library since several years on linux (gcc). Now, I'm moving to windows (_MSC_VER == 1600) (boost 1.55, but same issues on boost 1.69). For my example, I use a class A in a DLL, another class B inheriting from A in its DLL and an exe, linked to those DLLs, which serializes a B object, through its A base. _______ | A | ------- /_\ | | _______ | B | ------- I make a class serializable like that (I summurize on purpose (no #include, ...)). For A it's the same thing, but it has no base class. ----> B.h ---------------------------------------- #ifdef B_EXPORTS #define B_DLL __declspec(dllexport) #else #define B_DLL __declspec(dllimport) #endif class B_DLL B: public A { public: B(); virtual ~B(); private: friend class boost::serialization::access; template <class Archive> void serialize(Archive & ar, const unsigned int version); int i; }; BOOST_CLASS_EXPORT_KEY(B) ----> B.cpp ---------------------------------------- B::B() : i(123) {} B::~B() {} template <class Archive> void B::serialize(Archive & ar, const unsigned int) { ar & SERIALIZE_BASE(ClassA); ar & SERIALIZE(i); } #define FULL_SCOPED_SERIALIZABLE_CLASS B #include "Common/InstanciateSerializationTemplate.h" ----> InstanciateSerializationTemplate.h ---------------------------------------- This file purpose is to instanciate the template B::serialize methods for each archive type, and to register the class. Here is its contents (once again, no namesapce nor include to make it easier to read): // explicit instantiate code for all archive types expected to be use: // MUST COME BEFORE BOOST_CLASS_EXPORT_IMPLEMENT // binary: template __declspec(dllexport) void FULL_SCOPED_SERIALIZABLE_CLASS::serialize<binary_iarchive>(binary_iarchive & ar, const unsigned int version); template __declspec(dllexport) void FULL_SCOPED_SERIALIZABLE_CLASS::serialize<binary_oarchive>(binary_oarchive & ar, const unsigned int version); // XML: template __declspec(dllexport) void FULL_SCOPED_SERIALIZABLE_CLASS::serialize<xml_iarchive>(xml_iarchive & ar, const unsigned int version); template __declspec(dllexport) void FULL_SCOPED_SERIALIZABLE_CLASS::serialize<xml_oarchive>(xml_oarchive & ar, const unsigned int version); // TXT: template __declspec(dllexport) void FULL_SCOPED_SERIALIZABLE_CLASS::serialize<text_iarchive>(text_iarchive & ar, const unsigned int version); template __declspec(dllexport) void FULL_SCOPED_SERIALIZABLE_CLASS::serialize<text_oarchive>(text_oarchive & ar, const unsigned int version); BOOST_CLASS_EXPORT_IMPLEMENT(FULL_SCOPED_SERIALIZABLE_CLASS) *** MY ISSUE *** All that stuff works in linux, gcc, but not in Windows. If I write in my exe this serialization code: std::ofstream ofs; ofs.open("D:\\TestSerial.xml"); boost::archive::xml_oarchive ar(ofs); shared_ptr<B> b = shared_ptr<B>(new B()); shared_ptr<A> a = b; try { ar << SERIALIZE(a); } catch (boost::archive::archive_exception& ex) { std::cout << "Serialization to stream error, what: " << ex.what() << std::endl; } catch (...) { std::cout << "Catch ... Serialization to stream error" << std::endl; } ofs.close(); With this code, I have an archive_exception: "unregistered class - derived class not registered or exported". I have to write the serialization like that: ar.register_type(static_cast<B*>(0)); boost::serialization::void_cast_register(static_cast<B*>(0), static_cast<A*>(0)); ar << SERIALIZE(a); *** QUESTION *** At least, my question: I cannot do like that: what I would like to achieve: when a new class is made serializable like above, I expect the class to be registered automatically (probabley with BOOST_CLASS_EXPORT_IMPLEMENT in InstanciateSerializationTemplate.h). It's too painfull to write the register_type and void_cast_register each time I want to serialize. What am I missing? Thank you very much for any help or recommandations. Nico

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Re: [boost] MSVC 2019 and 1.70 beta
by Peter Dimov 14 Mar '19

14 Mar '19

> Tom Kent wrote: > > > Build support for VS 2019 RC (msvc-14.2) is on develop in boost build. > > Do we want to merge that to master for the release? > > I think we do. 1.70 and 2019 will release at about the same time. In fact looking at the calendar, 2019 will release (Apr 2) just before 1.70 is closed for release (Apr 3.)

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boost-install-ing zlib (Was: Re: [Release] Boost 1.70.0 Beta 1 Release Candidate 2)
by Peter Dimov 13 Mar '19

13 Mar '19

> I'll need to try and see what happens with <source> in user-config. > Probably nothing good, because one would expect neither <build-name> nor > <tag> to be specified in such a case. If I remove the check for ZLIB_SOURCE, and just do alias boost_zlib : /zlib//zlib ; libraries-to-install += boost_zlib ; unconditionally in libs/iostreams/build/Jamfile, this is what happens: - when `using zlib : : <source>C:/Projects/zlib-1.2.11 ;` is in user-config, the default `b2 install` fails because `address-model=32,64 variant=debug,release` conflict as all try to build `libz.lib`. When address-model=32 variant=debug is given, `libz.lib` is installed in C:\Boost\lib, and the CMake configuration for boost_zlib correctly points to it. - when using a prebuilt `using zlib : : <include>C:/Projects/include <search>C:/Projects/lib <name>zlib-8 ;`, the CMake configuration file for boost_zlib points to "${_BOOST_LIBDIR}/zlib-8", which is not correct.

2 2

(no subject)
by Marshall Clow 13 Mar '19

13 Mar '19

Boost release 1.70.0 beta 1 is now available at: <https://dl.bintray.com/boostorg/beta/1.70.0.beta1/source/> The SHA256 checksums are as follows: dbf89645e509acb2e53eac3c633834f1dec80bd8622e6e652a9741dcf0807f17 ./boost_1_70_0_b1.7z 957b984b58656a3ec00661ecad7ef82e3a094bad36e37b9e6624843237854679 ./boost_1_70_0_b1.tar.bz2 76d149c1fb9e8a5ceb3bc1e5587edc40fa79a43e8b990d877c2210f0382b9421 ./boost_1_70_0_b1.tar.gz 71e990b2c26880521fd98459b184ee172ce1c46dcf554b6eaab7776b8b6369a6 ./boost_1_70_0_b1.zip For details of what's in the release, see < https://www.boost.org/users/history/version_1_70_0.html>. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

2 3

[rational] permission to merge cmake change?
by James E. King III 13 Mar '19

13 Mar '19

Before 1.70.0 beta started, some cmake changes from Mike Dev were merged into rational. There was a typo in one of the cmake options (BOOST_RATIONA_INCLUDE_TESTS). This does not affect code nor the boost build system. Would it be okay to merge this now or should I wait? https://github.com/boostorg/rational/pull/35 Thanks. - Jim

1 1

[release] Boost 1.70.0 Beta 1 Release Candidate 3
by Marshall Clow 12 Mar '19

12 Mar '19

A new release candidates for the first 1.70.0 beta release are now available at: https://dl.bintray.com/boostorg/beta/1.70.0.beta1.rc3/source/ Changes since RC2: * Relative paths for --prefix, --libdir, etc. are now bound relative to the current working directory, instead of being relative to the Jamfile. Thanks to Tom Kent for the report, and Steven and Peter for the fixes. Changes since RC1: * The Jamfile for Boost.Predef has been updated to allow running the tests from /status. Thanks to mike.dev(a)gmx.de for the report, and to Rene for the fix. The release notes are not yet available. The SHA256 checksums are as follows: dbf89645e509acb2e53eac3c633834f1dec80bd8622e6e652a9741dcf0807f17 ./boost_1_70_0_b1_rc3.7z 957b984b58656a3ec00661ecad7ef82e3a094bad36e37b9e6624843237854679 ./boost_1_70_0_b1_rc3.tar.bz2 76d149c1fb9e8a5ceb3bc1e5587edc40fa79a43e8b990d877c2210f0382b9421 ./boost_1_70_0_b1_rc3.tar.gz 71e990b2c26880521fd98459b184ee172ce1c46dcf554b6eaab7776b8b6369a6 ./boost_1_70_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

5 8

[Release] Boost 1.70.0 Beta 1 Release Candidate 2
by Marshall Clow 12 Mar '19

12 Mar '19

A new release candidates for the first 1.70.0 beta release are now available at: https://dl.bintray.com/boostorg/beta/1.70.0.beta1.rc2/source/ Changes since the last RC: * The Jamfile for Boost.Predef has been updated to allow running the tests from /status. Thanks to mike.dev(a)gmx.de for the report, and to Rene for the fix. The release notes are not yet available. The SHA256 checksums are as follows: 26dba8156ad08041c6da52c84a2654aefda292180afe3546a9a74dda0dfb3781 ./boost_1_70_0_b1_rc2.7z ee794d98429bc2bfae054f2fab6fde53ea95f7c5967d8b267e57c894a4d46e57 ./boost_1_70_0_b1_rc2.tar.bz2 bca5f189d87b26ab903838dee2fd4c54e9043bd35d27b8923cdef42651ae7261 ./boost_1_70_0_b1_rc2.tar.gz 6c8f3af4e64d3a04a3d3a5e98499d2f6bb460ad82c1f33ff7da800b5ab182b0b ./boost_1_70_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

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Re: [boost] [Boost-users] [release] Boost 1.70.0 Beta 1 Release Candidate 1
by Tom Kent 11 Mar '19

11 Mar '19

On Fri, Mar 8, 2019 at 9:44 PM Tom Kent <lists(a)teeks99.com> wrote: > > > On Fri, Mar 8, 2019 at 8:57 PM Tom Kent <lists(a)teeks99.com> wrote: > >> >> >> On Fri, Mar 8, 2019 at 6:42 PM Marshall Clow via Boost-users < >> boost-users(a)lists.boost.org> wrote: >> >>> On Fri, Mar 8, 2019 at 10:21 AM Marshall Clow <mclow.lists(a)gmail.com> >>> wrote: >>> >>>> The release candidates for the first 1.70.0 beta release are now >>>> available at: >>>> >>>> https://dl.bintray.com/boostorg/beta/1.70.0.beta.1.rc1/source/ >>>> >>>> The release notes are not yet available. >>>> >>>> The SHA256 checksums are as follows: >>>> >>>> a7c570d6307d05dc8d45a3b4c69a0afdcba2b22eac0c4da4d496559f53db7b89 >>>> ./boost_1_70_0_b1_rc1.7z >>>> 4b91b9a203cf12f6001cf39de83c7cc005fbc5390e2b4b2fc29ce7b19c0537a7 >>>> ./boost_1_70_0_b1_rc1.tar.bz2 >>>> 460dd6499bba9df04c6bfa219b26097bad803b8758304ba45f2fc291aa42c96e >>>> ./boost_1_70_0_b1_rc1.tar.gz >>>> f209c9a086ed2c7882a0bc8755792f436eb141eaeb8c823ed57295ca9ce25b93 >>>> ./boost_1_70_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. >>>> >>> >>> >> I'm having a problem with B2 in this release. >> >> For many releases now, I have run a command such as: >> b2 -j16 --build-type=complete toolset=msvc-10.0 address-model=64 >> architecture=x86 --prefix="./" --libdir=lib32-msvc-10.0 >> --includedir=temp_inc install >> >> to get the windows builds of each toolset. For the install, I set the >> prefix as the current directory, so that I'll get a lib{arch}-msvc-{ver} >> directory for each toolset in there. However, with this 1.70 release, it >> seems to ignore my prefix and put the headers in >> libs/headers/build/temp_inc/boost-1_70/boost, instead of >> temp_inc/boost-1_70/boost. For the libraries, it scattered them throughout >> the build in directories such as libs/coroutine/build/lib32-msvc-10.0/. >> >> Any thoughts on what might be causing this? Am I using the --prefix >> --libdir and --inlcudedir correctly? Or at least not badly enough to >> warrant this? >> > > Also, even though I have BZIP2_SOURCE and ZLIB_SOURCE set, I'm not seeing > the appropriate bzip2 and zlib libraries being generated. > > After updating my scripts to us "staging" instead of "install" to avoid the above issue, I was able to get everything else to build successfully for Visual Studio (msvc-10.0 through msvc-14.1, note this is the first release I haven't built against msvc-8.0 and 9.0). The only exception being the lack of bzip2 and zlib support mentioned above. toolset arch compile Link Execute 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 X X X msvc-14.0 64 X 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 at https://gist.github.com/teeks99/0aeed77c9251ba02090d9ab7372e2c73 Tom

4 4

Regarding GSoc 2019
by karmanya grover 11 Mar '19

11 Mar '19

Sir/Madam, I am a Google Summer of Code 2019 aspirant. This email is regarding inquiry of possible projects that I am interested in. Please provide the specifics for following questions. In Boost.uBLAS library, I want to know if there's some work done for python integration previously or not. I also want to inquire about Boost Astronomy library. Looking into git repository, I found that this library is fairly new. What are the aspects hoped to be achieved for this library as a full efficient and mathematical friendly. I have always been interested in Astrophysics and applying those concepts in problem solving. Apart from that, What were the previous works done in Boost.Real library by past GSoc'ers. with regards, Yours sincerely, Karmanya Grover (B.E). NSUT

3 2

[release] 1.70 Windows binaries
by Sean Farrow 10 Mar '19

10 Mar '19

Hi, I know there is a discussion regarding building 1.70 with zlib in another thread, but wondered whether there are any binaries available for msvc without zlib for the 1.70 beta rc1/2? Kind regards Sean.

1 0

[variant2] documentation request
by Andrzej Krzemienski 10 Mar '19

10 Mar '19

Hi Peter, Given that the never-empty guarantee appears to be at the heart of the motivation for boost::variant2, I would suggest to: 1. put in the documentation some motivation behind pursuing the never-empty guarantee. 2. Make it clear that never-empty guarantee is not a strong exception-safety guarantee. 3. Describe the algorithm for achieving the guarantee. The current description does not seem to cover all interesting cases, and I found the behavior quite surprising. For instance, the variant's move assignment will sometimes use T's move assignment rather than move constructor when changing the variant's type, as in the following example: https://wandbox.org/permlink/GDRyS54bpdLP7GVa Regards, Andrzej

10 32

[gsoc19] Seeking Guidance along with mentor for Boost.GIL Project
by Keshav Gupta 10 Mar '19

10 Mar '19

Respected Sir, I am Keshav Gupta currently doing my B.E. in Computer Engineering from Thapar University, Patiala, Punjab, India. Actually I want to participate in GSOC19 and want to work with you during that period. Actually I am interested in implementing various Image Processing algorithms using BOOST.GIL. and I think that I can perfectly work upon this as I am also currently doing my research in the area of Fingerprint Matching and you absolutely know that this definitely includes the usage of image processing algorithms and that why I am interested for this as I know I have the proper knowledge of C++ along with image processing algorithms. Kindly guide me how to proceed further so as to increase my chances of getting being selected in GSOC19. Also please tell me any other way how to contact the mentor of this project as I have mailed him certain number of times but didn't get any response. Waiting for your reply Regards Keshav Gupta

2 1

Re: [boost] [Release] Boost 1.70.0 Beta 1 Release Candidate 2
by Peter Dimov 09 Mar '19

09 Mar '19

> Tom Kent wrote: > > > * Can't create libraries for bzip2 and zlib (showstopper? anyone else > > seeing this?) > > I haven't seen your initial report of this issue (on the users list?) but > it's probably caused by this change: > > https://github.com/boostorg/build/commit/5ad92cd76ff393792f30aa50688c95eff2… Or maybe not. This is in 1.69.0, so it can't be the cause.

1 0

[release] Boost 1.70.0 Beta 1 Release Candidate 1
by Marshall Clow 09 Mar '19

09 Mar '19

The release candidates for the first 1.70.0 beta release are now available at: https://dl.bintray.com/boostorg/beta/1.70.0.beta.1.rc1/source/ The release notes are not yet available. The SHA256 checksums are as follows: a7c570d6307d05dc8d45a3b4c69a0afdcba2b22eac0c4da4d496559f53db7b89 ./boost_1_70_0_b1_rc1.7z 4b91b9a203cf12f6001cf39de83c7cc005fbc5390e2b4b2fc29ce7b19c0537a7 ./boost_1_70_0_b1_rc1.tar.bz2 460dd6499bba9df04c6bfa219b26097bad803b8758304ba45f2fc291aa42c96e ./boost_1_70_0_b1_rc1.tar.gz f209c9a086ed2c7882a0bc8755792f436eb141eaeb8c823ed57295ca9ce25b93 ./boost_1_70_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

4 9

Interest in GSoC Project
by Kanav Gupta 09 Mar '19

09 Mar '19

Hello, I am third-year undergrad research student at International Institute of Information Technology, Hyderabad. I would like to contribute to Boost.GIL as a part of GSoC '19. I am currently working on a research project involving image processing and have also worked on various projects involving C++ so I guess I am competent for the project. Can you please guide me on how should I proceed? Thanks and Regards, Kanav Gupta

1 0

[release] 1.70.0 closed for major changes
by Marshall Clow 07 Mar '19

07 Mar '19

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. As always, the calendar for the release cycle is available at: https://www.boost.org/development/ Thanks, -- The Boost Release Team

7 9

[Release 1.70] Master branch is now closed for the beta
by Marshall Clow 07 Mar '19

07 Mar '19

Except with explicit permission by a release manager. Do whatever you want on develop, just don't change master. We'll re-open master after the beta. As always, check the calendar at https://www.boost.org/development 6-Mar: Boost 1.70.0 closed for all changes 13-Mar: Boost 1.70.0 beta; master branch re-opened 2-Aug: Release closed for all changes, except by permission of a release manager. 3-Apr: Boost 1.70.0 closed for all changes 10-Apr: Boost 1.70.0 release -- The release managers

2 1

[build] Boost.Build/develop broken with msvc?
by John Maddock 07 Mar '19

07 Mar '19

Currently I see: D:/data/boost/boost/tools/build/src/tools\msvc.jam:1388: in configure-really *** argument error * rule generate-setup-cmd ( version : command : parent : options * : cpu : global-setup ? : default-global-setup-options : default-setup ) * called with: ( 14.16.27023 14.11.25503 : D:/compilers/visual studio/2017/VC/Tools/MSVC/14.11.25503/bin/HostX64/x64 : D:\compilers\visual studio\2017\VC\Tools\MSVC\14.11.25503\bin\HostX64 : <command>D:\compilers\visual studio\2017\VC\Tools\MSVC\14.16.27023\bin\Hostx64\arm\cl.exe <command>D:/compilers/visual studio/2017/VC/Tools/MSVC/14.11.25503/bin/HostX64/x64/cl.exe : i386 : : x86 : vcvars32.bat ) * extra argument 14.11.25503 D:/data/boost/boost/tools/build/src/tools\msvc.jam:1003:see definition of rule 'generate-setup-cmd' being called D:/data/boost/boost/tools/build/src/tools\msvc.jam:393: in configure D:/data/boost/boost/tools/build/src/tools\msvc.jam:345: in msvc.init D:/data/boost/boost/tools/build/src/build\toolset.jam:44: in toolset.using D:/data/boost/boost/tools/build/src/build\project.jam:1104: in using C:\cygwin64\home\John Maddock\user-config.jam:46: in modules.load D:/data/boost/boost/tools/build/src\build-system.jam:255: in load-config D:/data/boost/boost/tools/build/src\build-system.jam:453: in load-configuration-files D:/data/boost/boost/tools/build/src\build-system.jam:607: in load D:\data\boost\boost\tools\build\src/kernel\modules.jam:295: in import D:\data\boost\boost\tools\build\src/kernel/bootstrap.jam:139: in boost-build D:\data\boost\boost\boost-build.jam:17: in module scope Master is fine BTW. Best, John. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

2 3

[interprocess] support for a new synchronisation mechanism
by Dudi Likvornik 06 Mar '19

06 Mar '19

Hi, My name is David, I would like to suggest a new synchronisation mechanism based on linux futex. as far as I saw, its not being supported as of now with in the interprocess communication library. One suggestion is to support a mutex, here is an example, possible partial implementation, based upon the following paper: http://dept-info.labri.fr/~denis/Enseignement/2008-IR/Articles/01-futex.pdf Mutex::Mutex(): m_word(UNLOCK) {} void Mutex::lock() { int lockState = UNLOCK; if(std::atomic_compare_exchange_strong(&m_word, &lockState, static_cast<int>(LOCK_SINGLE)) == false) { if(lockState != LOCK_MANY) lockState = std::atomic_exchange(&m_word, static_cast<int>(LOCK_MANY)); while(lockState != UNLOCK) { #if defined(__linux) syscall(SYS_futex, &m_word, FUTEX_WAIT, LOCK_MANY, nullptr, nullptr, 0); #else throw Exception(__CORE_SOURCE, "wait is not being supported by current platform"); #endif lockState = std::atomic_exchange(&m_word, static_cast<int>(LOCK_MANY)); } } } void Mutex::unlock() { if(std::atomic_fetch_sub(&m_word, 1) == LOCK_SINGLE) return; m_word = UNLOCK; #if defined(__linux) syscall(SYS_futex, &m_word, FUTEX_WAKE, 1, nullptr, nullptr, 0); #else throw Exception(__CORE_SOURCE, "wake is not being supported by current platform"); #endif } bool Mutex::try_lock() { int lockState = UNLOCK; return std::atomic_compare_exchange_strong(&m_word, &lockState, static_cast<int>(LOCK_SINGLE)); } ————————————————————————————————————————————————————————— And a conditional variable: Condition::Condition(): m_command(SLEEP), m_waitersCount(0){} void Condition::signal(Command command) { m_wakeLock.lock(); if(m_waitersCount == 0) { m_wakeLock.unlock(); return; } m_command.store(command, std::memory_order_relaxed); #if defined(__linux) syscall(SYS_futex, &m_command, FUTEX_WAKE, command == NOTIFY_ONE ? 1 : std::numeric_limits<int>::max(), nullptr, nullptr, 0); #else throw Exception(__CORE_SOURCE, "wake is not being supported by current platform"); #endif while(m_command.load(std::memory_order_relaxed) != SLEEP && m_waitersCount.load(std::memory_order_relaxed) != 0){} m_wakeLock.unlock(); } void Condition::wait(std::unique_lock<core::Mutex> &lock) { m_waitersCount++; lock.unlock(); while(true) { while(m_command.load(std::memory_order_relaxed) == SLEEP) #if defined(__linux) syscall(SYS_futex, &m_command, FUTEX_WAIT, SLEEP, nullptr, nullptr, 0); #else throw Exception(__CORE_SOURCE, "wait is not being supported by current platform"); #endif int fromCommand_one = NOTIFY_ONE; if(m_command.compare_exchange_strong(fromCommand_one, static_cast<int>(SLEEP), std::memory_order_relaxed)) { m_waitersCount--; lock.lock(); return; } else if(m_command.load(std::memory_order_relaxed) == NOTIFY_ALL) { if(m_waitersCount.fetch_sub(1, std::memory_order_relaxed) == 1) m_command.store(SLEEP, std::memory_order_relaxed); lock.lock(); return; } } } ConditionVariable::ConditionVariable() {} void ConditionVariable::wait(std::unique_lock<core::Mutex> &lock) { m_condition.wait(lock); } void ConditionVariable::notify_one() { m_condition.signal(Condition::NOTIFY_ONE); } void ConditionVariable::notify_all() { m_condition.signal(Condition::NOTIFY_ALL); } class ConditionVariable { public: ConditionVariable(); ConditionVariable(const ConditionVariable&) = delete; ConditionVariable& operator=(const ConditionVariable&) = delete; void wait(std::unique_lock<Mutex>& lock); template<typename Predict> void wait(std::unique_lock<Mutex>& lock, const Predict& predict) { while(predict() == false) m_condition.wait(lock); } void notify_one(); void notify_all(); private: Condition m_condition; }; Your thoughts of the idea, if any. p.s. Please be soft, its my first post ever :).

1 0

Boost.uBLAS [gsoc19]
by Sarthakag 06 Mar '19

06 Mar '19

Hello, I am Sarthak Agarwal, 3rd-year undergraduate student from Birla Institute of Technology and Science, Pilani - Goa, India currently pursuing a double major MSc. Mathematics and B.E. Computer Science and Engineering. I am an active Competitive Programmer on various online judges for the last 4 years. I am comfortable in C/C++(STL) and Python(Django). I wish to contribute to Boost.uBLAS, specifically to Project 4 on implementing non-negative matrix factorization(NMF). I would also like to know if there are any upcoming ideas to implement in Boost.intrusive. I have completed the Boost Competency test and learned a lot while doing it. How can I share it for valuable feedback? I look forward to your guidance. Sarthak Agarwal -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Dev-f2600599.html

1 0

Regarding GSOC'19
by Keshav Gupta 05 Mar '19

05 Mar '19

Hi I am Keshav Gupta from India and wanted to work with Boost during GSOC 2019 on the major topic of Boost GIL. So can you tell me how to proceed with? Regards Keshav Gupta

1 0

[variant2] Need rationale for never-empty guarantee
by Andrzej Krzemienski 04 Mar '19

04 Mar '19

Hi Peter, Thank you for writing and sharing this implementation of variant. I am sorry if I am bringing back an issue that has been already discussed and solved before, but I do not understand the rationale behind doing compromises in order to provide the never-empty guarantee. The short rationale provided in Boost.Variant library: https://www.boost.org/doc/libs/1_69_0/doc/html/variant/design.html#variant.… was provided before we got C++11 the moved-from state in the language. Today, it should come as no surprise to programmers that a type might be in a "moved from" state where only a limited interface of an object can be used. The guarantee provided by variant's assignment is not a strong exception safety guarantee: it is possible that my variant has value A, I want to assign value B, and (due to an exception) I end up with value C. If this happens, the only thing I can reasonably do is to either abandon whatever I was doing or reset the variant to the state that I need. So the guarantee that it is not left empty does not seem to be of much use. But the cost to be paid is noticeable. I think that this question should be addressed in the documentation. Regards, Andrzej

13 51

[gsoc19][astronomy] Code for review
by Avinal Kumar 04 Mar '19

04 Mar '19

where should I submit my code for programming competency test ??

2 1

Mentors invitations
by David Bellot 04 Mar '19

04 Mar '19

Dear Boost C++ mentors, it seems we only have 5 mentors this year. It's not a lot. Usually, we have one student per mentor, but we also have 6 to 8 students as well. We need at least one or two mentors more. I've just sent the invite from the GSOC website to become a mentor. If you didn't receive it yet, it's surely because I forgot your name. Can you please send me a reminder now with your correct email address? If you didn't propose to become a mentor but want to now, please let me know as well. Cheers, David

1 0

GSoC 2019 Introduction|Boost.Python-C++-Python Integration Project
by Roopkatha Samanta 04 Mar '19

04 Mar '19

Hi, I am Roopkatha Samanta, studying in 2nd year CSE (undergrad) at Jadavpur University, Kolkata, India. I am very well versed with programming languages like C, C++, Python and Java. I am very much into mathematics too and also interested in machine learning and deep learning. Presenly I am working on two projects in domain of Image Processing as my undergrad project and also trying to develop games on my own. I would like to contribute toBoost.Python-C++-Python Integration Project as my GSoC 2019 Project. Kindly guide me through the process on how to start. Regards, Roopkatha Samanta

2 1

[gsoc19] Logo
by Cem Bassoy 04 Mar '19

04 Mar '19

Hi, is there a chance to change the current logo on the organization list https://summerofcode.withgoogle.com/organizations/?sp-page=5 with https://de.wikipedia.org/wiki/Boost_(C%2B%2B-Bibliothek)#/media/File:Boost.… The current image on the google summer of code page does not look too good and all other organization have smooth ones. Best Cem

5 6

GSoC 2019
by Shourya IIT B 04 Mar '19

04 Mar '19

Respected Sir, I am Parashuram Shourya from India. Currently, I am doing my Master’s in Geoinformatics from Centre of Studies in Resources Engineering(CSRE), Indian Institute of Technology Bombay(IITB). I have a Bachelor's degree in Computer Science and Engineering. Currently, I am learning Machine Learning and High-Performance Computing. I have vast programming experience in C, C++, Python I would love to contribute to The Qt Project in the upcoming Google Summer of Code 2019. I would be very grateful to get any directions to start with so that I can pursue and participate in GSoC 2019 with your organization.

2 1

GSoC 2019: we're in again!
by David Bellot 04 Mar '19

04 Mar '19

Dear Boost community, this year again, Boost C++ has been accepted as a mentor organization for the Google Summer of Code 2019. We are very happy to be part of this program every year because it brings talented students and a substantial amount of money to our organization to support our work toward the best libraries in C++. If you want to be a mentor, please propose your project now here: https://github.com/boostorg/boost/wiki/Google-Summer-of-Code:-2019 It's very important to write your proposal as soon as possible to attract the best students. If you have any questions, please contact me immediately. If you happen to be in Sydney, come and have a chat with me directly. Happy coding, David

3 3

Regarding project idea for GSOC 2019
by Syed Souban 04 Mar '19

04 Mar '19

Hi guys! I am a machine learning enthusiast looking forward to work in implementing some machine learning algorithms in c++ as a gsoc 2019 project. I know that a similar project has been done last year. So in a way I want to extend to that idea. I needed some suggestions and or pointers on which algorithms are feasible to implement. Regards, Souban

2 1

(no subject)
by Roopkatha Samanta 04 Mar '19

04 Mar '19

I want to contribute to boost C++-Python integration project for my GSoC 2019 project.

1 0

[Boost.Intrusive]
by PREET THAKKAR 03 Mar '19

03 Mar '19

I am a 2nd year computer science student. I want to contribute to Boost.Intrusive as part of GSoC '19. I have some ideas to enhance Boost.Intrusive and also add more features to previous year's project in Intrusive. I am new to Boost. Any help regarding getting started with the library would be appreciated. Regards, Preet Thakkar

2 1

Re: [boost] Review request for variant2, review manager wanted
by Peter Dimov 03 Mar '19

03 Mar '19

> If anyone would like to step forward to manage the review, please do. Michael Caisse was the first to graciously offer his services (via Slack) and I'll be glad to have him manage the review. Thanks to Niall who also volunteered. :-) With respect to Niall's request for compile time and run time measurements, I've added a benchmark https://github.com/pdimov/variant2/blob/develop/benchmark/benchmark1.cpp and the results from compiling and running it on my machine are at https://github.com/pdimov/variant2/blob/develop/benchmark/benchmark1.md This is not a cherry-picked example that makes variant2 look good, so it loses to std::variant here and there. :-)

7 13

Runtime code generation
by VIKRAM LODHI 03 Mar '19

03 Mar '19

I am trying to write a grammar based code but can't seems to find starting point. Is there anything I should go through first. Grammar based . All the functions are written in string formats by user and parsed into binary at runtime and are able to use that function.

1 0

[release][multi_index] Permission to merge to master
by Joaquin M López Muñoz 03 Mar '19

03 Mar '19

I'm asking permission to merge the following fairly trivial changes to master: https://github.com/boostorg/multi_index/compare/bbb915bd344463ba767aebe7988… Travis and AppVeyor tests are passing. BTW, the conditions for allowed commits at this release stage ("closed for major changes") are not clear to me. Do I really need to ask for permission if the change (as is this case) is deemed minor? Joaquín M López Muñoz

2 4

Re: [boost] [Boost-testing] Running regression tests for msvc-14.2 (preview)
by Tom Kent 02 Mar '19

02 Mar '19

On Tue, Feb 26, 2019 at 7:13 AM Mateusz Loskot via Boost-Testing < boost-testing(a)lists.boost.org> wrote: > On Tue, 26 Feb 2019 at 14:02, Tom Kent via Boost-Testing > <boost-testing(a)lists.boost.org> wrote: > > I was hoping to start running regression tests for the upcoming Visual > Studio 2019 (toolset 14.2) and got stumped by an issue. > > I've set a user-config.jam: > > using msvc : 14.2 ; > > Is this toolset even supported? > > As I explained in > https://lists.boost.org/Archives/boost/2019/02/245143.php, > I had to 'fake' it as 14.1 in project-config.jam: > > using msvc : 14.1 : "C:\\Program Files (x86)\\Microsoft Visual > > Studio\\2019\\Preview\\VC\\Tools\\MSVC\\14.20.27323\\bin\\HostX64\\x64\\cl.exe" > I was able to get the regression tests to run using this workaround in user-config.jam. Here's what the config_info is: https://www.boost.org/development/tests/develop/developer/output/teeks99-te… I'm disappointed that we can't have general support for future versions of msvc. We don't seem to have this problem with pre-release versions of GCC/Clang. https://www.boost.org/development/tests/develop/developer/output/teeks99-02… Tom

3 5

Gsoc 2019 Boost.GIL project
by fady faragallah 02 Mar '19

02 Mar '19

Hi,I am fady faragallah 4th year student at faculty of computer engineering. I am interested in Boost.GIL and would like to contribute to the project. I have good experience in C++ programming and image processing algorithms and I am currently working on image processing and deep learning projects using convolutional neural networks. I need to know where I can deliver the competency test and how to contact the mentors. Thanks

1 0

Interested in working on Boost.GIL
by AvZ NaV 01 Mar '19

01 Mar '19

Hello, I am Arnav Tiwari, a sophomore year undergraduate student of IIT Kharagpur. I am interested in working on Boost.GIL. I have prior experience in image processing and C++ so I feel I will be able to pick up the project and get to work quickly. I would really appreciate it if someone can point me in the right direction to get started. I hope I'm not spamming the mailing list, apologies if that is the case. -- Regards, Arnav Tiwari

2 1

Re: [boost] [variant2] Need rationale for never-empty guarantee
by Nikita Kniazev 01 Mar '19

01 Mar '19

> This reply actually addresses my question: visitation on boost::variant2 is > faster than on std::variant because it does not have to account for the > valueless state. I would not expect perfomance differences on CPUs with branch predictor or if visitation translated into jump table (variant uses switch for this?). > For example, resizing a std::vector implements the strong guarantee that > state will be restored to before the resize if an exception is thrown in > the middle of the resize. Probably one should use different container type if a data types move/copy can throw. There even a vector implementation that will not copy/move on resize https://www.youtube.com/watch?v=Ke1mJiGO-pU (for CPU with virtual memory).

1 0

[appveyor] basic question
by Raffi Enficiaud 01 Mar '19

01 Mar '19

Hi Boost, Can somebody explain me like I am 5 what I need to do in order to activate Appveyor builds for boost.test? I am not admin of the repository. Thanks! Raffi

3 3

Review request for variant2, review manager wanted
by Peter Dimov 28 Feb '19

28 Feb '19

I'd like to request a formal Boost review for the Variant2 library, https://github.com/pdimov/variant2. Variant2 contains an implementation of a variant<T...> type that is an almost conforming std::variant, except it doesn't require C++17 and supports C++11 and above. It's also never valueless and has a few other extensions. The same library also contains an expected<T, E...> type, which is like the proposed std::expected<T, E>, but supports more than one error type. expected<> is not yet production-ready and has no test suite, but I will finish it if the library is accepted. The documentation for the variant<T...> class is at https://pdimov.github.io/variant2/index.html. If anyone would like to step forward to manage the review, please do.

10 15

Contributing to Boost.Algorithm
by Juho Lauri 28 Feb '19

28 Feb '19

Hello all, I'd be interested in contributing towards Boost.Algorithm - what's the appropriate way forward? Or perhaps this question has already been asked somewhere and I'd appreciate if you could point me to the right place. Thanks

1 0

A Unicode library?
by Can Topal 28 Feb '19

28 Feb '19

Hello everyone, Since I regularly work with Unicode text, I have started to design a Unicode library for handling UTF 8,16 and 32. The current support in C++ is still limited. Mainly I'm trying to implement a STL like support for file reading/writing, I/O operations and memory storage. So a user could read/write and process Unicode text like an ASCII string without knowing how the text is encoded. I thought people might have use for it. Even though libraries like ICU exist, they aren't beginner friendly and I couldn't find one with decent support for I/O. Is there demand for this? And if so do you guys have any suggestions? Thank you. - Onur

4 3

[GSOC19] [GIL]Image processing algorithms
by Shardul Parab 27 Feb '19

27 Feb '19

Hi! I am Shardul Parab, a computer science student from the Birla Institute of Technology and Science, Pilani. I am highly interested in contributing to Boost via GSoC 2019 and would love to contribute to the GIL library(as per the project idea listed). I believe that I have good practical experience of image processing techniques and if given the opportunity would be a great learning opportunity too. I have a decent experience with the library and would like to ask as to whether there is any particular task that I could begin with for the project and begin contributing from now itself under the guidance of a mentor. Thanking you, Regards. Shardul Parab

2 1

[GSOC2019][uBLAS] Linear and Multilinear Algebra with Matrix and Tensor Computations
by Ashar 27 Feb '19

27 Feb '19

Hi, I am Ashar Khan, a Second Year Computer Science Student from India. I would like to work with boost for Summer of Code 2019 and improve on the existing *boost.uBLAS *library. I have completed the Programming Competency test of uBLAS and find myself perfect for the task. I am looking forward to a mentor who can help me in the later parts of the project. I request any Potential mentor of uBLAS (David Bellot, Stefan Seefeld, and Sem Bassoy) to help me start my work. You can check my programming test on the following link here <https://github.com/coder3101/gsoc19-boost-test> Any Suggestions and opinions on the test are welcomed. Sorry if I did wrong by open-sourcing my test. I did not find any specific instructions as to how to submit the test. Looking forward to hearing from you soon. Thanks and Regards Ashar

2 1

Help regarding GSoC '19
by VIVEK MODI 27 Feb '19

27 Feb '19

Hey, I hope I am in the right mailing list. I am Vivek here. I am interested in working in the project Boost generic image library (project 1) listed by mentor Stefan Seefeld. If anyone can guide how to proceed further regarding the programming competency test and contributing to the project it would be of great help. -- Regards - Vivek Modi BTech(Information Technology) NIT Durgapur INDIA

2 1

[gsoc2019][astronomy] Program competency test
by rittik verma 27 Feb '19

27 Feb '19

Hello, I was reading through the competency test for boost astronomy and was struck by a question, should each coordinate has its own unit, for example, x - length, y - time, z-force? or just one unit for all coordinates? Thank you

2 1

clang-win clang-cl.exe on Windows 10 - is it time to add clang-win to the Boost test matrix?
by Paul A. Bristow 27 Feb '19

27 Feb '19

Confirming the work of others (pdimov and degski et al), I am now getting good results using clang-win (Clang 8.0.0 rc using GCC provided by Mingw64) on Windows 10. (Clang 8.0.0 should be finally released very soon now). Working the develop branch (fully up-to-date), I can run the Boost.Math examples and tests, and build the a set of most libraries (4 versions of most, for example) 27-Feb-19 14:32 15,872 boost_atomic-clangw8-mt-d-x64-1_70.dll 27-Feb-19 14:32 2,442 boost_atomic-clangw8-mt-d-x64-1_70.lib 27-Feb-19 14:32 9,728 boost_atomic-clangw8-mt-x64-1_70.dll 27-Feb-19 14:32 2,420 boost_atomic-clangw8-mt-x64-1_70.lib (but there are some failures to compile or to link). Examples in Addendum below: My user-config.jam contains using clang-win : # Clang Version. 8.0.0 : # Location of Clang compiler .exe file(s). Must use clang-cl driver, not clang++.exe # Copied path is "C:\LLVM\clang-700\LLVM\bin\clang-cl.exe" "C:/LLVM/clang-800/LLVM/bin/clang-cl.exe" -fuse-ld=lld # Use lld linker https://lld.llvm.org/, not clang++. # : # Options. <cxxflags>-v # Verbose output for testing only. ? --verbose does not work for clang? # <define>BOOST_CONFIG_SUPPRESS_OUTDATED_MESSAGE # <compileflags>-m64 Use address-model=64 on command line. <compatibility>vc14 # MS version compatibility. <cxxflags>-fmsc-version=1915 <cxxflags>-fms-compatibility <cxxflags>-fno-delayed-template-parsing #https://clang.llvm.org/docs/CommandGuide/clang.html#cmdoption-s # options are -flto, -flto=full, -flto=thin, -emit-llvm # Generate output files in LLVM formats, suitable for link time optimization. # The default for -flto is "full", in which the LLVM bitcode is suitable for monolithic Link Time Optimization (LTO), # where the linker merges all such modules into a single combined module for optimization. # With "thin", ThinLTO compilation is invoked instead. <cxxflags>-flto=thin # MS clang-cl compatibility settings: <cxxflags>"/std:c++17" # Must be c++17, not earlier. <cxxflags>"/Zc:forScope" <cxxflags>"/Zc:wchar_t" <cxxflags>"/EHsc" # exception handling # https://docs.microsoft.com/en-us/cpp/build/reference/eh-exception-handling-… # (/EHsc), catches C++ exceptions only and tells the compiler to assume that # functions declared as extern "C" never throw a C++ exception. <cxxflags>"/Zc:inline" <cxxflags>"/Gd" <cxxflags>"/diagnostics:classic" # Clang flags: # https://clang.llvm.org/docs/ClangCommandLineReference.html#compilation-flags # <cxxflags>-std=c++17 - already declared as a MS option. <cxxflags>-Wno-deprecated <cxxflags>-Wno-delete-non-virtual-dtor # <cxxflags>-fmacro-backtrace-limit=0 # <cxxflags>-Wno-invalid-token-paste <cxxflags>-Wno-language-extension-token <cxxflags>-Wno-microsoft-enum-value <cxxflags>-Wno-literal-range <cxxflags>-Wno-unknown-pragmas <cxxflags>-Wno-unused-variable <cxxflags>-Wno-microsoft-enum-value # <cxxflags>-Wno-invalid-constexpr # Need to stop reporting an error in Boost.System? <cxxflags>-Wno-unknown-argument <cxxflags>-Wno-unknown-pragmas <cxxflags>-Wno-macro-redefined <cxxflags>-Wno-unused-variable <cxxflags>-Wno-mismatched-tags <cxxflags>-Wno-deprecated-declarations <define>_CRT_SECURE_NO_DEPRECATE <define>_CRT_SECURE_NO_WARNINGS # Not all these may be needed to get a mostly warning-free build. ... My build command is \modular-boost>b2 -j4 toolset=clang-win-8.0.0 address-model=64 architecture=x86 --libdir=I:/modular-boost/lib --build-type=complete --without=mpi --without=python install 1>../boost_clang-win-8.0.0_64_config_27-Feb-19_1507.log I wonder if this means that it is time to add clang-win-8 configuration to the Boost Test summary at https://www.boost.org/development/tests/develop/developer/summary.html ? Paul PS What I have failed to get working is __float128 which works using GCC, but even after a patch enabling Clang in multiprecision's config and ensuring that quadmath.h is visible to the Clang compiler. It reports "not supported" :-( I have enquired if any progress can be made on making this work. Addendum - problem examples: ======================== LLVM ERROR: Associative COMDAT symbol '??_7codecvt_error_cat@?A0x15DB13AB@@6B@' does not exist. lld-link: error: undefined symbol: __imp_CryptGenRandom >>> referenced by I:\modular-boost\libs\random\src\random_device.cpp:121 >>> lto.tmp:("public: unsigned int __cdecl boost::random::random_device::impl::next(void)" (?next@impl@random_device@random@boost@@QEAAIXZ)) clang-cl: error: linker command failed with exit code 1 (use -v to see invocation) "C:/LLVM/clang-800/LLVM/bin/clang-cl.exe" "-fuse-ld=lld" -m64 /link /incremental:no /DLL /DEBUG /subsystem:console /out:"bin.v2\libs\random\build\clang-win-8.0.0\debug\address-model-64\threading-multi\boost_random-clangw8-mt-d-x64-1_70.dll" /IMPLIB:"bin.v2\libs\random\build\clang-win-8.0.0\debug\address-model-64\threading-multi\boost_random-clangw8-mt-d-x64-1_70.lib" @"bin.v2\libs\random\build\clang-win-8.0.0\debug\address-model-64\threading-multi\boost_random-clangw8-mt-d-x64-1_70.dll.rsp" if %ERRORLEVEL% NEQ 0 EXIT %ERRORLEVEL% and most annoyingly, since Boost.Test is a key library, "I:\modular-boost\lib\boost_unit_test_framework-clangw8-mt-d-x64-1_70.dll" "I:\modular-boost\lib\boost_unit_test_framework-clangw8-mt-d-x64-1_70.lib" but no release variants :-( clang-win.link.dll bin.v2\libs\test\build\clang-win-8.0.0\release\address-model-64\threading-multi\boost_unit_test_framework-clangw8-mt-x64-1_70.dll LLVM ERROR: Associative COMDAT symbol '??_7results_reporter_impl@?A0x22C2280D@results_reporter@unit_test@boost@@6B@' does not exist. clang-cl: error: linker command failed with exit code 1 (use -v to see invocation) "C:/LLVM/clang-800/LLVM/bin/clang-cl.exe" "-fuse-ld=lld" -m64 /link /incremental:no /DLL /subsystem:console /out:"bin.v2\libs\test\build\clang-win-8.0.0\release\address-model-64\threading-multi\boost_unit_test_framework-clangw8-mt-x64-1_70. dll" /IMPLIB:"bin.v2\libs\test\build\clang-win-8.0.0\release\address-model-64\threading-multi\boost_unit_test_framework-clangw8-mt-x64-1_ 70.lib" @"bin.v2\libs\test\build\clang-win-8.0.0\release\address-model-64\threading-multi\boost_unit_test_framework-clangw8-mt-x64-1_70.dll. rsp" if %ERRORLEVEL% NEQ 0 EXIT %ERRORLEVEL% ...failed clang-win.link.dll bin.v2\libs\test\build\clang-win-8.0.0\release\address-model-64\threading-multi\boost_unit_test_framework-clangw8-mt-x64-1_70.dll bin.v2\libs\test\build\clang-win-8.0.0\release\address-model-64\threading-multi\boost_unit_test_framework-clangw8-mt-x64-1_70.lib... --- Paul A. Bristow Prizet Farmhouse Kendal UK LA8 8AB +44 (0) 1539 561830

1 0

Running regression tests for msvc-14.2 (preview)
by Tom Kent 27 Feb '19

27 Feb '19

I was hoping to start running regression tests for the upcoming Visual Studio 2019 (toolset 14.2) and got stumped by an issue. I've set a user-config.jam: using msvc : 14.2 ; using python : 2.7 # version : C:\\Python27-32\\python.exe # Interperter/path to dir : C:\\Python27-32\\include # includes : C:\\Python27-32\\libs # libs : <address-model>32 <address-model> # conditions ; using python : 2.7 # version : C:\\Python27-64\\python.exe # Interperter/path to dir : C:\\Python27-64\\include # includes : C:\\Python27-64\\libs # libs : <address-model>64 # conditions ; Then I ran the command, from a vs2019 developer command prompt: D:\tmp>C:\Python27-64\python.exe run.py --runner=teeks99-test02 --toolsets=msvc-14.2 --tag=develop The full build output (minus some repetitive git and mklink commands) can be found here: https://gist.github.com/teeks99/2d72382bf13569855dbdcd2e0850c1cf A couple notable parts... Bootstrap says it is using the vc7 toolset, which isn't installed D:\tmp\boost_bb\src\engine>build.bat could not find "vswhere" ### ### Using 'vc7' toolset. ### but succeeds anyway, probably because cl.exe is available in the path in the vs2019 command prompt. B2.exe is successfully created and seems to work. During... notice: [python-cfg] Configuring python... [snip] ImportError: No module named numpy but that is normal. Finally, at the end...the real issue: ...skipped <p..\..\bin\testing\build\msvc-14.2\release\threading-multi>process_jam_log.obj for lack of <p..\..\bin\standalone\msvc\msvc-14.2>msvc-setup.nup... ...skipped <p..\..\bin\common\build\msvc-14.2\release\threading-multi>process_jam_log.obj for lack of <p..\..\bin\standalone\msvc\msvc-14.2>msvc-setup.nup... common.mkdir D:\tmp\boost_root\bin.v2 if not exist "D:\tmp\boost_root\bin.v2\\" mkdir "D:\tmp\boost_root\bin.v2" common.mkdir D:\tmp\boost_root\bin.v2\libs if not exist "D:\tmp\boost_root\bin.v2\libs\\" mkdir "D:\tmp\boost_root\bin.v2\libs" common.mkdir D:\tmp\boost_root\bin.v2\libs\filesystem if not exist "D:\tmp\boost_root\bin.v2\libs\filesystem\\" mkdir "D:\tmp\boost_root\bin.v2\libs\filesystem" common.mkdir D:\tmp\boost_root\bin.v2\libs\filesystem\build if not exist "D:\tmp\boost_root\bin.v2\libs\filesystem\build\\" mkdir "D:\tmp\boost_root\bin.v2\libs\filesystem\build" common.mkdir D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2 if not exist "D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\\" mkdir "D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2" common.mkdir D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release if not exist "D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\\" mkdir "D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release" common.mkdir D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static if not exist "D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\\" mkdir "D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static" common.mkdir D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi if not exist "D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi\\" mkdir "D:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi" ...skipped <pD:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi>codecvt_error_category.obj for lack of <p..\..\bin\standalone\msvc\msvc-14.2>msvc-setup.nup... ...skipped <pD:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi>operations.obj for lack of <p..\..\bin\standalone\msvc\msvc-14.2>msvc-setup.nup... ...skipped <pD:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi>path.obj for lack of <p..\..\bin\standalone\msvc\msvc-14.2>msvc-setup.nup... ...skipped <pD:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi>path_traits.obj for lack of <p..\..\bin\standalone\msvc\msvc-14.2>msvc-setup.nup... ...skipped <pD:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi>portability.obj for lack of <p..\..\bin\standalone\msvc\msvc-14.2>msvc-setup.nup... ...skipped <pD:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi>unique_path.obj for lack of <p..\..\bin\standalone\msvc\msvc-14.2>msvc-setup.nup... ...skipped <pD:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi>utf8_codecvt_facet.obj for lack of <p..\..\bin\standalone\msvc\msvc-14.2>msvc-setup.nup... ...skipped <pD:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi>windows_file_codecvt.obj for lack of <p..\..\bin\standalone\msvc\msvc-14.2>msvc-setup.nup... ...skipped <pD:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi>libboost_filesystem-vc142-mt-1_70.lib for lack of <pD:\tmp\boost_root\bin.v2\libs\filesystem\build\msvc-14.2\release\link-static\threading-multi>codecvt_error_category.obj... ...skipped <p..\..\bin\testing\build\msvc-14.2\release\threading-multi>process_jam_log.exe for lack of <p..\..\bin\testing\build\msvc-14.2\release\threading-multi>process_jam_log.obj... ...skipped <pD:\tmp\boost_regression\stage\bin>process_jam_log.exe for lack of <p..\..\bin\testing\build\msvc-14.2\release\threading-multi>process_jam_log.exe... ...skipped 14 targets... ...updated 599 targets... # Searching for "process_jam_log.exe" in "D:\tmp\boost_regression\stage\bin"... Traceback (most recent call last): File "run.py", line 71, in <module> runner(root) File "D:\tmp\boost_regression_src\regression.py", line 286, in __init__ self.main() File "D:\tmp\boost_regression_src\regression.py", line 623, in main getattr(self,action_m)() File "D:\tmp\boost_regression_src\regression.py", line 580, in command_regression self.command_setup() File "D:\tmp\boost_regression_src\regression.py", line 351, in command_setup self.build_if_needed(self.process_jam_log,self.pjl_toolset) File "D:\tmp\boost_regression_src\regression.py", line 714, in build_if_needed tool[ 'build_path' ] = self.tool_path( tool ) File "D:\tmp\boost_regression_src\regression.py", line 739, in tool_path , '\n'.join( [ name_or_spec[ 'path' ], build_dir ] ) Exception: Cannot find "process_jam_log.exe" in any of the following locations: D:\tmp\boost_regression\stage\bin\process_jam_log.exe D:\tmp\boost_regression\stage\bin What is the msvc-setup.nup and where does it come from? Thanks, Tom

3 4

Building the Release Notes locally
by Vinnie Falco 27 Feb '19

27 Feb '19

Does anyone know how to build the release notes locally? I would like to know if they render correctly without going through an 8-hour Travis turnaround. The rumor mill says @Daniel James knows how to do it... Anyone?? Thanks

2 2

[Boost.astronomy]
by Viraj Sonaje 24 Feb '19

24 Feb '19

This is for the respective authority I am a 4th year engineering student. I want to contribute to Boost.astronomy library for GSOC 2019. I am familiar with the co-ordinate systems but I am new to boost.

2 1

Graph Algorithms
by Siddhartha Sen 24 Feb '19

24 Feb '19

Is there any interest in a library containing graph algorithms? Also, I am unable to find the list of maintainers of the respective libraries. Any information on that would be appreciated.

7 7

add serialization to circular_buffer
by Yuval Lifshitz 24 Feb '19

24 Feb '19

Dear Community,I have a PR [1] for supporting serialization of the circular_buffer. Main drive for this change, is my effort for adding serialization to boost accumulators [2] (some accumulators hold data internally in a circular buffer).The maintainers list [3] is not up to date regarding circular buffer, so, I'm not sure who the maintainer is (or if there is one). Would appreciate your help, so I can drive that to completion. Yuval Lifshitz [1] https://github.com/boostorg/circular_buffer/pull/25[2] https://github.com/boostorg/accumulators/pull/18 [3] https://github.com/boostorg/boost/blob/master/libs/maintainers.txt

1 0

BGL
by Siddhartha Sen 22 Feb '19

22 Feb '19

I looked up https://github.com/boostorg/boost/wiki/Google-Summer-of-Code:-2019 . No project ideas have been added for BGL as of yet, it seems. I hope there is something in BGL in this years GSOC, as I am really passionate about graphs and graph algorithms. Also, will you be mentoring this year? If not, do you have any information on the potential mentors for this BGL project? Thanks.

2 1

Re: [boost] Graph Algorithms
by Siddhartha Sen 22 Feb '19

22 Feb '19

Thanks for the feedback! But what if I focus on C++14 then? Is that a good idea? On Fri, 22 Feb, 2019, 6:14 PM Vinnie Falco, <vinnie.falco(a)gmail.com> wrote: > On Fri, Feb 22, 2019 at 12:49 AM Siddhartha Sen > <siddhartha99.sen(a)gmail.com> wrote: > > From what I've read in the mailing lists, I think the demand has > shifted > > from C++11 to more modern versions, like C++14 and C++17. Anyways, > > thanks for the tip. Will you be mentoring this year? > > I will not be mentoring directly although I do offer advice on the mailing > list. > > People say they want C++14 and C++17 but I don't think its a good idea > to require those language versions in a library, because most people > are still on C++11. Have a look at the latest developer survey: > > <https://www.jetbrains.com/research/devecosystem-2018/cpp/> > > If a library requires C++17 then most C++ users will not be able to > use it. And this is bad for the library, because fewer users means > less testing, less feedback, less popularity, and in general this > makes the library not as good. > > In terms of the API (interface) of a library, C++17 does not offer > much more than C++11 except for things like, avalability of > string_view, variant. But Boost has these things already (e.g. > boost::string_view, boost::variant) and they work in C++11. So there > is really no benefit to C++17 other than some improvements in the way > you can write the implementation. But that doesn't affect users > directly. > > In summary, by requiring C++17 most users will be unable to use the > code, and there will be very little benefit to C++17 users. > > Regards >

3 7

BGL
by Siddhartha Sen 22 Feb '19

22 Feb '19

I apologise. Actually, there was a suggestion in the boost mailing lists that there is a demand for this. Anyways, I am familiar with C++14 and a C++17 as well(a bit). Will you be mentoring this year? I have already read the documentation of LEMON and started using it as well. Please let me know what should I do next, or if there are any particular issues you would like me to work on. Thanks. Regards. Siddhartha.

2 1

BGL: Graph11
by Siddhartha Sen 22 Feb '19

22 Feb '19

Hi, I am SIddhartha Sen, a second year student in Information Science and Engineering. I hope to contribute to the BGL. I have heard that there is some interest in themodernization of BGL using modern C++11 concepts for improved performance. Being a GSOC 2019 aspirant, I was looking for a potential mentor in this domain to pair up with and get started on this project. Any help would be greatly appreciated. Thank You.

2 1

PR not merged
by Sreejith S 21 Feb '19

21 Feb '19

I have sent a PR[1]. Can I know why the PR is still not merged ? [1]:https://github.com/boostorg/graph/pull/158 -- Regards, Sreejith.S Amrita Vishwa Vidyapeetham FOSS@Amrita <http://amfoss.in> | Github <https://github.com/sreejithsankar55> | Blog <http://sreejithsankar.wordpress.com>

1 0

Re: [boost] [build] PROBLEM specifying libc++!!!!
by Nikita Kniazev 21 Feb '19

21 Feb '19

> Anyone know how to do this and have the will to make life easier for > poor overworked library maintainers? I have `b2 <stdlib>libc++` on CI for Spirit with https://github.com/boostorg/spirit/blob/develop/.travis.yml#L119-L121 When I tried to make a PR I stuck at the thing that I do not know how (or it is not possible) to format (free-)future value into some flags, i.e: > toolset.flags clang-linux.compile OPTIONS <stdlib> : -stdlib=[ value-of-feature <stdlib> ] ; > toolset.flags clang-linux.link OPTIONS <stdlib> : -stdlib=[ value-of-feature <stdlib> ] ; But since in the wild there are two possible options it might be ok to just hardcode them for now.

1 0

[GIL] Contribution to the library.
by Gaurav Hoskote 21 Feb '19

21 Feb '19

This is to inform the concerned authority that I am willing to participate in GSOC 2019 and wish to contribute to the GIL library. I am a final year student and have good understanding of operations like Thresholding, Morphology and various filters. I have an idea of how the library works and I wish to contribute to it under the guidance of a mentor.

2 1

Image Processing for [GIL] Boost.
by Gaurav Hoskote 21 Feb '19

21 Feb '19

The Boost GIL library lacks image processing header files for operations like thresholding, morphology etc. I intend to contribute to this library by proposing some header files that can be placed in this library. I have worked on image processing algorithms before and am familiar with all the concepts.I wish to work under the mentorship of Stefan Seefeld who posted this project on github for GSOC 2019. I have attached a proposal pdf file (gilpro.pdf) to this email which gives details about my work and how the project will be implemented along with goals and milestones to be achieved. Also, for competency test I have attached a sample header file (threshold.h) which gives a basic idea of what I wish to implement for my project. Feedback would be appreciated. Regards, Gaurav Hoskote.

1 0

[build] PROBLEM specifying libc++!!!!
by Vinnie Falco 21 Feb '19

21 Feb '19

This is hard to teach, hard to remember, and error prone: script: b2 -j3 libs/beast/test toolset=clang cxxstd=11 cxxflags=-stdlib=libc++ linkflags=-stdlib=libc++ There's an issue to address it in a straightforward fashion: <https://github.com/boostorg/build/issues/287> Anyone know how to do this and have the will to make life easier for poor overworked library maintainers? Regards

1 0

[GSoC 2019] cpp_int Improvement
by Fenil Mehta 20 Feb '19

20 Feb '19

Hi, Integers with the capability to store large numbers has always been a requirement in C++ which has successfully been implemented by boost/multiprecision/cpp_int. Other languages such as Python and Java also supports such integer datatypes. I performed a speed test for C++ and python integers. While comparing speed of cpp_int and python int, I noticed that even though C++ source program was compiled with -O2 and -O3 flags, cpp_int was slow as compared for python int for multiplication and left-shift operations. The time taken for multiplication was: 1) cpp_int = 17.06 seconds 2) python int = 8.39 seconds I used the attached files to perform the testing on Linux. The execution time was measured using the time command. I would like to optimize this library. Being a GSoC aspirant, I was looking to pair up with a potential mentor in this domain who could guide me. Any feedback would be appreciated. Regards, Fenil Mehta

2 1

[asio] windows compilation error
by Vinnie Falco 19 Feb '19

19 Feb '19

This program fails to compile under msvc.latest: #include <boost/asio.hpp> int main { return 0; } This program does compile: #define BOOST_ASIO_DISABLE_WINDOWS_RANDOM_ACCESS_HANDLE 1 #define BOOST_ASIO_DISABLE_WINDOWS_STREAM_HANDLE 1 #include <boost/asio.hpp> int main { return 0; } Thanks

1 0

Integer sorting
by Fenil Mehta 19 Feb '19

19 Feb '19

I have written a sorting algorithm which is way faster than std::sort for all array size. The link is as follows: https://github.com/fenilgmehta/Fastest-Integer-Sort Some guidance would be appreciated on how to improve the project structure and the steps to get it included in boost. Regards, Fenil Mehta

11 24

Regression tests broken
by Tom Kent 19 Feb '19

19 Feb '19

All- Sometime around 7pm yesterday (2-17) a commit went in (master and develop?, regression scripts?) that broke all my regression runners (linux and windows). I haven't had a ton of time to dig in, but the end of the results look like this: notice: using boost library auto_config <layout>system ../libs/contract/test/Jamfile.v2:417: Unescaped special character in argument <define>BOOST_CONTRACT_ON_MISSING_CHECK_DECL="{ throw err(); }" notice: [libjpeg] Using pre-installed library notice: [libjpeg] Condition notice: [zlib] zlib is already configured notice: [libpng] Using pre-installed library notice: [libpng] Condition notice: [libtiff] Using pre-installed library notice: [libtiff] Condition /var/boost/run/boost_bb/src/build/feature.jam:447: in extend-feature from module feature error: coverage is already associated with the "<variant>" feature /var/boost/run/boost_bb/src/build/feature.jam:624: in feature.extend from module feature /var/boost/run/boost_bb/src/tools/features/variant-feature.jam:79: in variant from module variant-feature ../libs/histogram/Jamfile:15: in modules.load from module Jamfile</var/boost/run/boost_root/libs/histogram> /var/boost/run/boost_bb/src/build/project.jam:372: in load-jamfile from module project /var/boost/run/boost_bb/src/build/project.jam:64: in load from module project /var/boost/run/boost_bb/src/build/project.jam:109: in load-parent from module project /var/boost/run/boost_bb/src/build/project.jam:513: in initialize from module project /var/boost/run/boost_bb/src/build/project.jam:348: in load-jamfile from module project /var/boost/run/boost_bb/src/build/project.jam:64: in load from module project /var/boost/run/boost_bb/src/build/project.jam:142: in project.find from module project Jamfile.v2:122: in run-tests from module Jamfile</var/boost/run/boost_root/status> Jamfile.v2:196: in modules.load from module Jamfile</var/boost/run/boost_root/status> /var/boost/run/boost_bb/src/build/project.jam:372: in load-jamfile from module project /var/boost/run/boost_bb/src/build/project.jam:64: in load from module project /var/boost/run/boost_bb/src/build/project.jam:142: in project.find from module project /var/boost/run/boost_bb/src/build-system.jam:618: in load from module build-system /var/boost/run/boost_bb/src/kernel/modules.jam:295: in import from module modules /var/boost/run/boost_bb/src/kernel/bootstrap.jam:139: in boost-build from module /var/boost/run/boost_root/boost-build.jam:17: in module scope from module Any thoughts? Tom

6 6

[Asio][ssl] develop broken
by Damian Jarek 18 Feb '19

18 Feb '19

After the changes today (introduced in https://github.com/boostorg/asio/commit/0568d3bf0b492887c6c48d05f5492a782da… ) an overload of async_handshake( https://github.com/boostorg/asio/blob/develop/include/boost/asio/ssl/stream…) fails to compile because of the signature mismatch in async_result. This is a show-stopper, because it breaks quite a bit of code in Beast.

2 1

Searching and Sorting algorithms
by Siddhartha Sen 18 Feb '19

18 Feb '19

Sorry for the typo. I meant "generic", not genetic. Anyways, I went through the non-mutating algorithms section and can't think of anything to possibly add. I had three questions though: 1. Is there any interest in libraries aimed at solving any small but particular problem, for example, say tower of hanoi in minimum possible time? 2. For any existing algorithm, if we add some features would it be useful? For example, as far as I know, binary search returns true if an element is found and false, if not. What if we add the elements position if found? Does not change complexity, but makes it better to use,doesn't it? 3. I want to contribute to the sorting algorithms library as well, any idea where to start? Is there any scope for improvement of any existing algorithms? Also, if we want to add any entirely new algorithms of our own, any suggestions where to start? I am working on an algorithm currently and was hoping to propose it to the boost libraries. Sorry if my post got too lengthy. Any help would be appreciated. Thank You.

2 1

[Asio] develop broken on Windows
by Vinnie Falco 18 Feb '19

18 Feb '19

This program fails to compile on Windows: #include <boost/asio.hpp> int main() { return 0; } Regards

1 0

Searching Algorithm
by Siddhartha Sen 17 Feb '19

17 Feb '19

Looking to contribute to the sorting library under algorithms. Any mentors available? Also, is their any interest in searching algorithms? I looked up the boost libraries but couldn't find any. Are there any mentors available? I want to make a searching library which will be genetic in nature and applicable for all data types. Any guidance would be appreciated. Thanks. Siddhartha

2 1

building, debugging and contributing to an individual boost library
by Sean Farrow 17 Feb '19

17 Feb '19

Hi, Once I have forked an individual boost library, what is the best way of building the library with b2? How are dependencies on other libraries handled? Secondly, how can I build, run and debug tests using visual studio? Any help appreciated. Kind regards Sean.

6 7

New user need guidance.
by SHREYANS JAIN 17 Feb '19

17 Feb '19

Hi I am Shreyans Jain. I am new to opensource programming, can anyone guide me how to start contributing here. Thank You

1 0

Re: [boost] Mail list is poorly indexed by Google
by Nikita Kniazev 15 Feb '19

15 Feb '19

> > Indeed! Google stopped indexing January 2017. Strange, I linked mid-December thread, if crawlers stopped indexing in January there was more than two weeks to index it, is not it?

3 3

String Algorithms
by Siddhartha Sen 14 Feb '19

14 Feb '19

Hi, I would like to contribute to the string algorithms library for GSOC 2019. Are there any potential mentors to pair up with? I am also interested in algorithms in general, especially sorting and searching libraries. Is there any scope for contribution there as well? Any answers would be appreciated

1 0

Mail list is poorly indexed by Google
by Nikita Kniazev 13 Feb '19

13 Feb '19

I was going to find the https://lists.boost.org/Archives/boost/2018/12/244648.php thread, but it did not worked with Google (looked all the pages <https://www.google.com/search?q=dropping+support+for+msvc+9+site%3Alists.bo…>), while DuckDuckGo shows it as the first link <https://ddg.gg/?q=dropping+support+for+msvc+9+site%3Alists.boost.org>. Can webmasters look into this with the Google's Search Console <https://search.google.com/search-console/about>? Or it is a policy to supplant the all-embracing Google? :-)

2 1

Regarding Boost.Real
by Sreejith S 13 Feb '19

13 Feb '19

Hi all I am Sreejith, a sophomore at Amrita University. I had gone through GSoC projects and I found Bringing Boost.Real to review-ready state interesting. As a beginner, I tried to understand the blog post of previous year's GSoC-18 project of the same. It seemed too difficult for me. Is it ok to work on it without any experience? -- Regards, Sreejith.S Amrita Vishwa Vidyapeetham FOSS@Amrita <http://amfoss.in> | Github <https://github.com/sreejithsankar55> | Blog <http://sreejithsankar.wordpress.com>

1 0

[gsoc2019][astronomy]
by rittik verma 12 Feb '19

12 Feb '19

Hello everyone, I am Rittik Verma, a third year Computer Science student. I am looking forward to contributing to the Astronomy library for GSoC 2019. I have studied the repository and would like to add the expected features to the library. I was wondering if the potential mentor has already paired up with a student or the position is still available? My projects: https://github.com/codectile Thank you

4 3

GSoC 2019
by Shourya IIT B 12 Feb '19

12 Feb '19

Respected Sir, I am Parashuram Shourya from India. Currently, I am doing my Master’s in Geoinformatics from Centre of Studies in Resources Engineering(CSRE), Indian Institute of Technology Bombay(IITB). I have a Bachelor's degree in Computer Science and Engineering. Currently, I am learning Machine Learning and High-Performance Computing. I have vast programming experience in C, C++, Python I would love to contribute to Boost C++ Libraries in the upcoming Google Summer of Code 2019. I would be very grateful to get any directions to start with so that I can pursue and participate in GSoC 2019 with your organization.

1 0

[GSOC 19] Programming competency test for ublas
by Amit Singh 10 Feb '19

10 Feb '19

Hi, My name is Amit Singh and I’m interested in machine learning lib for ublas as already provided in my idea list in mailing list. I have completed my programming competency test for ublas and wanted to know where to submit it.

1 0

An interest in a neural net library?
by Sergei Marchenko 09 Feb '19

09 Feb '19

Hi everyone. I would like to get your opinion if there is any interest for a library that implements simple neural networks trained via backpropagation. The main idea is to define the configuration of a feed-forward multi-layer network via template parameters, and also provide implementations for a couple of well-known variations of networks (i.e. convolutional, sampling, network ensemble etc). // Define a network ensemble with two networks with the same input and output size, // but different number of neuron layers and different number of neurons in each layer. typedef neural_network<100, 50, 10> network_1; typedef neural_network<100, 70, 20, 10> network_2; auto network = ensemble(network_1(), network_2()); // Train the network from a training set. // item.input is a 100-element input vector. // item.target is the 10-element desired output vector. for (auto item : training_set) network.train(item.input, item.target, learning_rate); // Feed some input data into the network to get the result. auto result = network.process(input); This code on github that my nephew and myself wrote a couple of years ago can be used as a more detailed illustration for the idea: https://github.com/nsokolnikov/mathlib/blob/master/src/neuralnet.h Also, this github repo has two sample projects that illustrate usage of the library. First sample trains a simple network with a simulated activity pattern and then uses the network to classify more simulated load as low, medium, or high: https://github.com/nsokolnikov/mathlib/tree/master/samples/NeuralNetwork Second sample trains a network on a part of MNIST data set of hand-written digits, and then uses the network to recognize the remaining part of the MNIST data set: https://github.com/nsokolnikov/mathlib/tree/master/samples/TextRecognition Thank you, Serguei Martchenko

1 0

Sorting and Searching Algorithms Library
by Siddhartha Sen 09 Feb '19

09 Feb '19

Actually, I am interested equally in both searching and sorting algorithms. In sorting algorithms, I am actually trying recursive implementations of all the known algorithms myself, to see if somehow I can find any variations or maybe even an whole new algorithm which can give a better time complexity. As far as searching algorithm goes, my knowledge is unfortunately limited to only binary search and linear search and DFS and BFS if graphs are counted . However I am working on patterns in numbers to try and create a generic searching algorithm for integer arrays and strings. Apart from this, I am afraid I don't have a lot of idea and hence I am seeking guidance. Thanks On Sat, 9 Feb, 2019, 5:30 PM , <boost-request(a)lists.boost.org> wrote: > Send Boost mailing list submissions to > boost(a)lists.boost.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.boost.org/mailman/listinfo.cgi/boost > or, via email, send a message with subject or body 'help' to > boost-request(a)lists.boost.org > > You can reach the person managing the list at > boost-owner(a)lists.boost.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Boost digest..." > > > The boost archives may be found at: http://lists.boost.org/Archives/boost/ > > > Today's Topics: > > 1. building boost libraries with pdb files under windows > (Sean Farrow) > 2. Re: Boost Digest, Vol 5998, Issue 1 (Siddhartha Sen) > 3. Re: building boost libraries with pdb files under windows > (Daniela Engert) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Fri, 8 Feb 2019 12:05:58 +0000 > From: Sean Farrow <sean.farrow(a)seanfarrow.co.uk> > To: "boost(a)lists.boost.org" <boost(a)lists.boost.org> > Subject: [boost] building boost libraries with pdb files under windows > Message-ID: > < > DB6PR0501MB27593FBAC29B49059A752178C6690(a)DB6PR0501MB2759.eurprd05.prod.outlook.com > > > > Content-Type: text/plain; charset="us-ascii" > > Hi, > > Is there a way to build boost libraries with PDB files under visual C++ > 2017? > > Any help appreciated. > > Kind regards > Sean. > > > ------------------------------ > > Message: 2 > Date: Fri, 8 Feb 2019 22:32:18 +0530 > From: Siddhartha Sen <siddhartha99.sen(a)gmail.com> > To: boost(a)lists.boost.org, phdcluster(a)gmail.com > Subject: Re: [boost] Boost Digest, Vol 5998, Issue 1 > Message-ID: > < > CA+iicpFdnd67wpP25MVjXtBxW5TFEkGb78XL-SK5RPosw_nMHQ(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > Actually, I am interested equally in both searching and sorting algorithms. > In sorting algorithms, I am actually trying recursive implementations of > all the known algorithms myself, to see if somehow I can find any > variations or maybe even an whole new algorithm which can give a better > time complexity. As far as searching algorithm goes, my knowledge is > unfortunately limited to only binary search and linear search and DFS and > BFS if graphs are counted . However I am working on patterns in numbers to > try and create a generic searching algorithm for integer arrays and > strings. Apart from this, I am afraid I don't have a lot of idea and hence > I am seeking guidance. > Thanks > > On Fri, 8 Feb, 2019, 5:30 PM , <boost-request(a)lists.boost.org> wrote: > > > Send Boost mailing list submissions to > > boost(a)lists.boost.org > > > > To subscribe or unsubscribe via the World Wide Web, visit > > https://lists.boost.org/mailman/listinfo.cgi/boost > > or, via email, send a message with subject or body 'help' to > > boost-request(a)lists.boost.org > > > > You can reach the person managing the list at > > boost-owner(a)lists.boost.org > > > > When replying, please edit your Subject line so it is more specific > > than "Re: Contents of Boost digest..." > > > > > > The boost archives may be found at: > http://lists.boost.org/Archives/boost/ > > > > > > Today's Topics: > > > > 1. qxcalc(GSoC2019) (Ggh) > > 2. qxcalc(GSoC2019)-2 (Ggh) > > 3. Sorting Algorithms Library (Siddhartha Sen) > > 4. Re: Sorting Algorithms Library (phdcluster) > > 5. Re: Feedback desired for reflective enum library (David Sankel) > > > > > > ---------------------------------------------------------------------- > > > > Message: 1 > > Date: Thu, 07 Feb 2019 10:07:10 +0200 > > From: Ggh <ggh(a)multi.fi> > > To: boost(a)lists.boost.org > > Subject: [boost] qxcalc(GSoC2019) > > Message-ID: > > <20190207100710.Horde.VkEf1bfe3uAO1wELKmHKrul(a)webmail.multi.fi> > > Content-Type: text/plain; charset=utf-8; format=flowed; DelSp=Yes > > > > > > Hi all, > > Not sure if there is interest, but some years ago I coded a > > parser/lexer with flex and yacc to do math. > > > > The project is online here > > "http://qxcalc.sourceforge.net/" > > > > Greg > > > > > > > > ------------------------------ > > > > Message: 2 > > Date: Thu, 07 Feb 2019 11:01:16 +0200 > > From: Ggh <ggh(a)multi.fi> > > To: boost(a)lists.boost.org > > Subject: [boost] qxcalc(GSoC2019)-2 > > Message-ID: > > <20190207110116.Horde.VeAEqWouVIYk0-9NMfOsi9P(a)webmail.multi.fi> > > Content-Type: text/plain; charset=utf-8; format=flowed; DelSp=Yes > > > > Some links on my page(these pages are not always online): > > > > http://www.multi.fi/~ghaga/qxcalcdocs/html/index.html > > http://www.multi.fi/~ghaga/qxcalc/ > > http://www.multi.fi/~ghaga/qxcalc/download.php > > > > Ty, > > Greg > > > > > > > > > > ------------------------------ > > > > Message: 3 > > Date: Fri, 8 Feb 2019 01:43:42 +0530 > > From: Siddhartha Sen <siddhartha99.sen(a)gmail.com> > > To: boost(a)lists.boost.org > > Subject: [boost] Sorting Algorithms Library > > Message-ID: > > <CA+iicpGMx+zroF= > > RhE7AtAqJiN4Rw6Fz3hvPnvKmKP6+htKQJg(a)mail.gmail.com> > > Content-Type: text/plain; charset="UTF-8" > > > > Hi, > > This is Siddhartha Sen, a student of Information Science and > > Engineering. I am proficient in C++ and am particularly interested in > > sorting algorithms. Being a GSOC aspirant, I was looking to pair up with > a > > potential mentor in this domain, who could give me some much needed > > guidance. > > Thank You > > > > > > ------------------------------ > > > > Message: 4 > > Date: Thu, 7 Feb 2019 17:30:36 -0500 > > From: phdcluster <phdcluster(a)gmail.com> > > To: boost(a)lists.boost.org > > Cc: Siddhartha Sen <siddhartha99.sen(a)gmail.com> > > Subject: Re: [boost] Sorting Algorithms Library > > Message-ID: > > < > > CAKYCxYFSbMoxJf4ycjgMxLQSQq9ddkuZUa1BF7bMfBOhntWO1Q(a)mail.gmail.com> > > Content-Type: text/plain; charset="UTF-8" > > > > What particular sorting algorithm you are interested in? Or what > algorithms > > you have in mind? > > > > Thanks, > > > > Wen > > > > On Thu, Feb 7, 2019 at 3:50 PM Siddhartha Sen via Boost < > > boost(a)lists.boost.org> wrote: > > > > > Hi, > > > This is Siddhartha Sen, a student of Information Science and > > > Engineering. I am proficient in C++ and am particularly interested in > > > sorting algorithms. Being a GSOC aspirant, I was looking to pair up > with > > a > > > potential mentor in this domain, who could give me some much needed > > > guidance. > > > Thank You > > > > > > _______________________________________________ > > > Unsubscribe & other changes: > > > <http://lists.boost.org/mailman/listinfo.cgi/boost> > > > http://lists.boost.org/mailman/listinfo.cgi/boost > > > > > > > > > ------------------------------ > > > > Message: 5 > > Date: Thu, 7 Feb 2019 19:39:11 -0500 > > From: David Sankel <camior(a)gmail.com> > > To: Nir Friedman <quicknir(a)gmail.com> > > Cc: Boost <boost(a)lists.boost.org> > > Subject: Re: [boost] Feedback desired for reflective enum library > > Message-ID: > > < > > CAFYdOOLxMqup9-0Vub+UNJGgpvaqTGL0mWr1d1txuq4mstMJGg(a)mail.gmail.com> > > Content-Type: text/plain; charset="UTF-8" > > > > On Tue, Feb 5, 2019, 2:00 PM Nir Friedman <quicknir(a)gmail.com> wrote: > > > > > Sure, I'm open to such a thing. Although, I feel like there may be > > caveats > > > to that (i.e. whether the reflection TS interface is easy to use, > whether > > > it's easy to emulate library-only, how likely it is to continue > changing, > > > etc). Do you have a link to a paper that shows what the latest in the > > > reflection TS for enums looks like? > > > > > > > http://cplusplus.github.io/reflection-ts/draft.pdf > > > > > > > > > > > ------------------------------ > > > > Subject: Digest Footer > > > > _______________________________________________ > > Unsubscribe & other changes: > > http://lists.boost.org/mailman/listinfo.cgi/boost > > > > > > ------------------------------ > > > > End of Boost Digest, Vol 5998, Issue 1 > > ************************************** > > > > > ------------------------------ > > Message: 3 > Date: Fri, 8 Feb 2019 19:16:44 +0100 > From: Daniela Engert <dani(a)ngrt.de> > To: boost(a)lists.boost.org > Subject: Re: [boost] building boost libraries with pdb files under > windows > Message-ID: <9a268d74-c868-f79b-2f2e-52f693482356(a)ngrt.de> > Content-Type: text/plain; charset=iso-8859-15 > > Hi Sean! > > Am 08.02.2019 um 13:05 schrieb Sean Farrow via Boost: > > > Is there a way to build boost libraries with PDB files under visual C++ > 2017? > > Well, I am generating PDBs for a couple of years now using a slightly > modified msvc.jam (see > https://github.com/DanielaE/boost.build/commits/vc) Unfortunatly, this > is just a hack that happens to work well enough for my use-case and > requires an additional step to collect the PDBs from the build tree to > the stage directory using some script. Putting more effort into this > isn't economical for at most three distribution build per year. > > Ciao, > Dani > > > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Unsubscribe & other changes: > http://lists.boost.org/mailman/listinfo.cgi/boost > > > ------------------------------ > > End of Boost Digest, Vol 5999, Issue 1 > ************************************** >

1 0

building boost libraries with pdb files under windows
by Sean Farrow 08 Feb '19

08 Feb '19

Hi, Is there a way to build boost libraries with PDB files under visual C++ 2017? Any help appreciated. Kind regards Sean.

2 1

Re: [boost] Boost Digest, Vol 5998, Issue 1
by Siddhartha Sen 08 Feb '19

08 Feb '19

Actually, I am interested equally in both searching and sorting algorithms. In sorting algorithms, I am actually trying recursive implementations of all the known algorithms myself, to see if somehow I can find any variations or maybe even an whole new algorithm which can give a better time complexity. As far as searching algorithm goes, my knowledge is unfortunately limited to only binary search and linear search and DFS and BFS if graphs are counted . However I am working on patterns in numbers to try and create a generic searching algorithm for integer arrays and strings. Apart from this, I am afraid I don't have a lot of idea and hence I am seeking guidance. Thanks On Fri, 8 Feb, 2019, 5:30 PM , <boost-request(a)lists.boost.org> wrote: > Send Boost mailing list submissions to > boost(a)lists.boost.org > > To subscribe or unsubscribe via the World Wide Web, visit > https://lists.boost.org/mailman/listinfo.cgi/boost > or, via email, send a message with subject or body 'help' to > boost-request(a)lists.boost.org > > You can reach the person managing the list at > boost-owner(a)lists.boost.org > > When replying, please edit your Subject line so it is more specific > than "Re: Contents of Boost digest..." > > > The boost archives may be found at: http://lists.boost.org/Archives/boost/ > > > Today's Topics: > > 1. qxcalc(GSoC2019) (Ggh) > 2. qxcalc(GSoC2019)-2 (Ggh) > 3. Sorting Algorithms Library (Siddhartha Sen) > 4. Re: Sorting Algorithms Library (phdcluster) > 5. Re: Feedback desired for reflective enum library (David Sankel) > > > ---------------------------------------------------------------------- > > Message: 1 > Date: Thu, 07 Feb 2019 10:07:10 +0200 > From: Ggh <ggh(a)multi.fi> > To: boost(a)lists.boost.org > Subject: [boost] qxcalc(GSoC2019) > Message-ID: > <20190207100710.Horde.VkEf1bfe3uAO1wELKmHKrul(a)webmail.multi.fi> > Content-Type: text/plain; charset=utf-8; format=flowed; DelSp=Yes > > > Hi all, > Not sure if there is interest, but some years ago I coded a > parser/lexer with flex and yacc to do math. > > The project is online here > "http://qxcalc.sourceforge.net/" > > Greg > > > > ------------------------------ > > Message: 2 > Date: Thu, 07 Feb 2019 11:01:16 +0200 > From: Ggh <ggh(a)multi.fi> > To: boost(a)lists.boost.org > Subject: [boost] qxcalc(GSoC2019)-2 > Message-ID: > <20190207110116.Horde.VeAEqWouVIYk0-9NMfOsi9P(a)webmail.multi.fi> > Content-Type: text/plain; charset=utf-8; format=flowed; DelSp=Yes > > Some links on my page(these pages are not always online): > > http://www.multi.fi/~ghaga/qxcalcdocs/html/index.html > http://www.multi.fi/~ghaga/qxcalc/ > http://www.multi.fi/~ghaga/qxcalc/download.php > > Ty, > Greg > > > > > ------------------------------ > > Message: 3 > Date: Fri, 8 Feb 2019 01:43:42 +0530 > From: Siddhartha Sen <siddhartha99.sen(a)gmail.com> > To: boost(a)lists.boost.org > Subject: [boost] Sorting Algorithms Library > Message-ID: > <CA+iicpGMx+zroF= > RhE7AtAqJiN4Rw6Fz3hvPnvKmKP6+htKQJg(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > Hi, > This is Siddhartha Sen, a student of Information Science and > Engineering. I am proficient in C++ and am particularly interested in > sorting algorithms. Being a GSOC aspirant, I was looking to pair up with a > potential mentor in this domain, who could give me some much needed > guidance. > Thank You > > > ------------------------------ > > Message: 4 > Date: Thu, 7 Feb 2019 17:30:36 -0500 > From: phdcluster <phdcluster(a)gmail.com> > To: boost(a)lists.boost.org > Cc: Siddhartha Sen <siddhartha99.sen(a)gmail.com> > Subject: Re: [boost] Sorting Algorithms Library > Message-ID: > < > CAKYCxYFSbMoxJf4ycjgMxLQSQq9ddkuZUa1BF7bMfBOhntWO1Q(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > What particular sorting algorithm you are interested in? Or what algorithms > you have in mind? > > Thanks, > > Wen > > On Thu, Feb 7, 2019 at 3:50 PM Siddhartha Sen via Boost < > boost(a)lists.boost.org> wrote: > > > Hi, > > This is Siddhartha Sen, a student of Information Science and > > Engineering. I am proficient in C++ and am particularly interested in > > sorting algorithms. Being a GSOC aspirant, I was looking to pair up with > a > > potential mentor in this domain, who could give me some much needed > > guidance. > > Thank You > > > > _______________________________________________ > > Unsubscribe & other changes: > > <http://lists.boost.org/mailman/listinfo.cgi/boost> > > http://lists.boost.org/mailman/listinfo.cgi/boost > > > > > ------------------------------ > > Message: 5 > Date: Thu, 7 Feb 2019 19:39:11 -0500 > From: David Sankel <camior(a)gmail.com> > To: Nir Friedman <quicknir(a)gmail.com> > Cc: Boost <boost(a)lists.boost.org> > Subject: Re: [boost] Feedback desired for reflective enum library > Message-ID: > < > CAFYdOOLxMqup9-0Vub+UNJGgpvaqTGL0mWr1d1txuq4mstMJGg(a)mail.gmail.com> > Content-Type: text/plain; charset="UTF-8" > > On Tue, Feb 5, 2019, 2:00 PM Nir Friedman <quicknir(a)gmail.com> wrote: > > > Sure, I'm open to such a thing. Although, I feel like there may be > caveats > > to that (i.e. whether the reflection TS interface is easy to use, whether > > it's easy to emulate library-only, how likely it is to continue changing, > > etc). Do you have a link to a paper that shows what the latest in the > > reflection TS for enums looks like? > > > > http://cplusplus.github.io/reflection-ts/draft.pdf > > > > > > ------------------------------ > > Subject: Digest Footer > > _______________________________________________ > Unsubscribe & other changes: > http://lists.boost.org/mailman/listinfo.cgi/boost > > > ------------------------------ > > End of Boost Digest, Vol 5998, Issue 1 > ************************************** >

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Feedback desired for reflective enum library
by Nir Friedman 08 Feb '19

08 Feb '19

Hey, I have a reflective enum library available here: https://github.com/quicknir/wise_enum. I've been working on this on and off for a couple of months. I've added features, dealt with various issues, added docs, expanded support through 11-17 and as idiomatically as possible. Overall I think the library is in nice shape (lacks unit tests though, though I do already have a boost license for the code). I feel like a reflective enum is just a very standard requirement in pretty much every codebase I've ever worked on. Simply to be able to reasonably log enums already makes it mandatory. It's also invaluable in configuration, error message alerting, and many other places. There is nothing for this in boost and actually there isn't really much of a standard, standalone solution anyway. The closest is Better Enums ( http://aantron.github.io/better-enums/) but this has some major issues (it doesn't actually create enums but rather enum-like classes, it targets 03). So I think a library like this is needed and my implementation ticks off the major requirements. Feedback on the overall design, any issues, any key features it fails to meet, would be very useful. The library itself is very small and simple so its easy to review. Once it seems like there's some consensus on the core design I'm willing to do the work involved getting it into boost (naming conventions/requirements, directory structure, tests, boost-style docs, etc). Note I'm not on the boost mailing list so please respond directly to this email so I can see! Cheers, Nir

3 4

Sorting Algorithms Library
by Siddhartha Sen 07 Feb '19

07 Feb '19

Hi, This is Siddhartha Sen, a student of Information Science and Engineering. I am proficient in C++ and am particularly interested in sorting algorithms. Being a GSOC aspirant, I was looking to pair up with a potential mentor in this domain, who could give me some much needed guidance. Thank You

2 1

qxcalc(GSoC2019)-2
by Ggh 07 Feb '19

07 Feb '19

Some links on my page(these pages are not always online): http://www.multi.fi/~ghaga/qxcalcdocs/html/index.html http://www.multi.fi/~ghaga/qxcalc/ http://www.multi.fi/~ghaga/qxcalc/download.php Ty, Greg

1 0

qxcalc(GSoC2019)
by Ggh 07 Feb '19

07 Feb '19

Hi all, Not sure if there is interest, but some years ago I coded a parser/lexer with flex and yacc to do math. The project is online here "http://qxcalc.sourceforge.net/" Greg

1 0

GSoC 2019
by David Bellot 07 Feb '19

07 Feb '19

Hi Boost community, this year again we applied to the GSoC programm, Google Summer of Code. We hope to be as successfull as usual. I'm taking care of the admin work again this year. I completed an application for Boost on the Google website. It is somehow similar to our successfull applications from previous years. What we need from the community now is the following: 1) if you want to be a backup admin (I will need maybe one or two extra names at most), please let me know and I'll send you an invite. 2) if you wish to be a mentor, please let us know now and if possible on this mailing list so that students will be aware of it too. Don't forget to put the [gsoc2019] tag in the header of your email. You can write your proposals on this wiki: https://github.com/boostorg/boost/wiki/Google-Summer-of-Code:-2019 Ideally, we want to see many proposals before beginning of next week. 3) if you are a student and wants to participate, it's about time to speak loudly on the mailing list to pair with a potential mentor. The sooner the better. You can find ideas from previous years here: https://github.com/boostorg/boost/wiki/Google-Summer-of-Code%3A-Overview Happy coding. David

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find_package(Boost) support
by Peter Dimov 04 Feb '19

04 Feb '19

The current master and develop branches now install the necessary BoostConfig.cmake file (in $prefix/lib/cmake) such that f.ex. the CMake command find_package(Boost REQUIRED filesystem) will find Boost 1.70 using the config file, rather than via FindBoost.cmake (*) (if the Boost installation prefix is in CMake's prefix search path.) Interested parties are invited to test this support and share their experiences. Instead of a Git checkout, you can use the 1.70 release snapshots from https://dl.bintray.com/boostorg/master/ or https://dl.bintray.com/boostorg/develop/, as those better represent what the 1.70 release will contain. (*) Actually, the above command will invoke FindBoost.cmake, but FindBoost will look for a config file as a first step and use that, if found. To disable FindBoost completely, use find_package(Boost CONFIG REQUIRED filesystem) Or, on Windows, assuming the default C:\Boost installation, find_package(Boost REQUIRED filesystem PATHS C:/Boost)

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Coordinating Parameter 'master' merging for dependent libraries
by Edward Diener 03 Feb '19

03 Feb '19

I intend to merge Parameter 'develop' to 'master' for the next release of Boost. Cromwell Enage has done a great job of adding modern improvements to the Parameter library via PRs, while maintaining full backward compatibility with the Parameter public interface. I have reviewed and approved those changes and, where I have been lax, Peter Dimov has pointed out weaknesses in some of those changes, which Cromwell has corrected. The changes which Cromwell has made have also involved improvements in the Parameter private interface(s), which have entailed some updates to the 'develop' branch of some Boost libraries which unfortunately depended on some aspects of the Parameter private interface. These updates have already been made in those other library's 'develop' branch. At this point any further possible changes for Parameter for a while will very likely be in the Parameter documentation, which requires no syncing with other libraries, so this is an excellent time for merging. Since the merging for other libraries dependent on Parameter must be synced to the merging of Parameter from 'develop' to 'master' what is the best way to go about this ? Obviously I have first to merge Cromwell's changes from 'develop' to 'master', which is easily done. How should I inform other libraries that they need to merge their Parameter dependent 'develop' changes to 'master' ? Should I create PRs for doing this ? We do not normally create PRs for the 'master' branch of any Boost library. Should I create Issues for those other libraries and hope the maintainers of the other libraries will take the appropriate action ? Or should I inform the maintainers of the other libraries in this thread, and prompt them to review their changes here to get them to merge them from 'develop' to 'master' ? The other libraries involved are: Accumulators, Log, Convert, Lockfree, Signals2, and Graph. Cromwell knows more about the specific 'develop' changes in those libraries which need to be merged to 'master' than I do, since he was instrumental in creating the PRs that would allow these libraries to work with the updated Parameters' internals, so he may chime in here, but I would like to get this done so that Parameter and its dependent Boost libraries get properly updated for the next Boost release. Of course I will also plan with Cromwell update notes for Parameter to be part of the next release.

3 2

[GSoC19] run-time Ratios
by Fenil Mehta 03 Feb '19

03 Feb '19

Hi everyone, It has been noticed that C++ provides a class to store ratios/fractions at compile-time. They provide very limited functionalities and are not modifiable during run-time. My *idea* is to have a *Ratio class* which provides all the necessary functionalities at run-time as well. I have already implemented this partially and I am willing to make it 100% ready for inclusion in Boost. Some guidance would be appreciated on how to proceed with this idea for GSoC19. Would anybody be interested in mentoring this idea for GSoC19 ? Regards, Fenil Mehta

2 1

[interprocess] 32-bit offset_ptr
by Phil Endecott 03 Feb '19

03 Feb '19

Dear Experts, I have some old code that uses 32-bit offset_ptrs, i.e. typedef boost::interprocess::offset_ptr<void, int32_t, int32_t> ptr_t; This has stopped working on 64-bit systems at some point since 1.58. git blame suggests a commit on 14 Oct 2015. There is now a static assert that checks that OffsetType is at least as large as a raw pointer. In the current case, I'm using these pointers within memory-mapped files which will always be vastly smaller than the 32-bit limit. Using 32-bit offsets seemed like a worthwhile optimisation at the time, and now I am hoping to maintain binary compatibility with those files. In the past I've also used them to save memory on 64-bit systems with pointer-heavy data structures (using boost.intrusive) using an allocator that operates within a small memory region. Has something changed within the implementation that makes this restriction necessary? Was it never supposed to work as I was using it? There is also an assert that OffsetType is unsigned, which wasn't there before. Maybe I was doing that wrong. Thanks for any advice. Regards, Phil.

3 3

[GSOC 19] Boost.ublas project Idea
by Amit Singh 02 Feb '19

02 Feb '19

Hi, My name is Amit Singh and I’m a 2nd year student. 1. I have studied last years ublas stats project and before that ublas lacked any statistics features, I would like to take boost.ublas stats further with 1. Linear Regression 2. Logistic Regression 3. Rigid Regression 4. Kernels ( Exponential Kernel, Gaussian Kernel, etc) 5. Correlation (Pearson product-moment correlation, Linear correlation, etc) 2. In ublas there is no expression solver which can solve a expression and assign the value to variable for ex:- A. matrix<double> m = “A^2 * (B * A^-1) + (det(A) * I)”; B. matrix<double> m = “A + 3” ; =>[ m = A + 3*I ] 3. In ublas to modify matrix you have to iterate using for loop. I’m hoping to create a function similar to transform in c++ or map in javascript 1. This is my small machine learning library that I implemented in c++ https://github.com/amitsingh19975/ML Would anybody be interested in mentoring my project for gsoc 19? or help me to improve my project ideas.

1 0

[thread] Passing function with parameters to boost::barrier
by André Offringa 01 Feb '19

01 Feb '19

Hi Boost developers, I'm having a problem with passing a completion function to a boost::barrier, causing a segfault, and I suspect it is a bug in the barrier code. The following is a minimal example that shows the problem: #include <boost/thread/barrier.hpp> void func(int) { } int main() { boost::barrier b(1, std::bind(func, 42)); b.wait(); } Running inside gdb and doing a bt shows some infinite recursion happening, starting with: #0 0x000055555555e41a in boost::thread_detail::decay_copy<boost::detail::nullary_function<void ()>&>(boost::detail::nullary_function<void ()>&) ( t=<error reading variable: Cannot access memory at address 0x7fffff7feff0>) at /usr/include/boost/thread/detail/move.hpp:355 #1 0x000055555555d814 in boost::detail::nullary_function<void ()>::nullary_function<boost::detail::nullary_function<void ()>&>(boost::detail::nullary_function<void ()>&) ( this=0x7fffff7ff0c0, f=...) at /usr/include/boost/thread/detail/nullary_function.hpp:81 ... When I change "std::bind(func, 42)" to just "func" (and declare func without parameters), it does work and the program exits normally. Passing a lambda to barrier (e.g. barrier(1, [&]() { func(0); } ) ) causes the same segfault, and the same holds when I change std::bind to boost::bind. I'm using Boost 1.67 on Debian Linux, amd64, gcc 8.2.0. Is this a bug? Cheers, André

2 1

[asio]https significantly reduce performance
by lx 31 Jan '19

31 Jan '19

Hi Boost experts: I build a https server from asio example of server2, let it support ssl.we use the codes from: *https://www.boost.org/doc/libs/1_47_0/doc/html/boost_asio/example/http/server2/main.cpp <https://www.boost.org/doc/libs/1_47_0/doc/html/boost_asio/example/http/serv…>* *https://www.boost.org/doc/libs/1_39_0/doc/html/boost_asio/example/ssl/server.cpp <https://www.boost.org/doc/libs/1_39_0/doc/html/boost_asio/example/ssl/serve…>* I complie the codes with boost_1_64 and openssl-1.1.0j, the commed line of complie is: *g++ -g -Wall -o https_server2 *.cpp -I/usr/local/include/ -I/usr/local/openssl-1.1.0j/include -L/usr/local/openssl-1.1.0j/lib -I/usr/local/boost_1_64_0/include /usr/local/boost_1_64_0/lib/libboost_thread.a /usr/local/boost_1_64_0/lib/libboost_system.a -Wl,-Bstatic -lglog -lunwind -Wl,-Bdynamic -lpthread -lcrypto -lssl -ldl -lrt* I test the https_server2 by ngrinder, the TPS is just 400, If I test is just http request , the TPS is 36000. So https significantly reduce performance. The perf top result is: [image: 1.png] The top result is: [image: 2.png] When I test it by http request, the top result is: [image: 4.png] I have push the codes on github. https://github.com/lxlenovostar/Programming_language/tree/master/cpp/test/s… I test 2, 4, 8, 24, 32 threads,but this can't improve the TPS.I test the nginx with 32 worker process, The TPS is about 5000. So maybe lock in asio ? btw: cpu is 32 cores, and Intel(R) Xeon(R) CPU E5-2440 v2 @ 1.90GHz memory is 66GB. os is CentOS 6.5 kernel is 2.6.32 Thank you.

5 6

[gsoc19][astronomy]
by Pranam Lashkari 30 Jan '19

30 Jan '19

Hello everyone, Last year I worked on the new astronomy library[0] and successfully completed GSoC with the help of my mentor *Vinícius dos Santos Oliveira*. In last GSoC, I completed basic coordinate systems and FITS file reading. *Current State of the Library:* Currently, this library has 7 basic astronomical coordinate systems implemented (Alt-Az, CIRS, ICRS, Galactic, Geocentric, Heliocentric, Supergalactic) which as actually wrappers around Boost::Geometry. IO module provides support for FITS reading. Right now, It can read primary HDU and image extensions. Development during GSoC can be found on the master branch[1] To preserve all the development done during the period of GSoC a separate branch was created after completion of GSoC named "gsoc18"[2]. All the development done after the period of GSoC can be found on develop branch[3]. No changes were merged to master after GSoC 18. *Idea for Boost GSoC19:* After communicating with the Boost::geometry community, integration of Boost::geometry and Boost::units is not supported and without using units scientific calculations are not error proof. As a result current coordinate systems can not be used with large projects as there are high possibilities of error. So this year I would like to implement Boost::unit with Boost::astronomy::coordinate to provide a robust astronomical coordinate system. Apart form this I would also complete the remaining parser for the FITS to read complete file including all types of extensions. I am targeting to complete the first coordinate system and FITS reader at the end of this GSoC and making this library ready for its first release. [0]: https://summerofcode.withgoogle.com/projects/5503102778605568 [1]: https://github.com/BoostGSoC18/astronomy/tree/master [2]: https://github.com/BoostGSoC18/astronomy/tree/gsoc18 [3]: https://github.com/BoostGSoC18/astronomy/tree/develop Thank you, Pranam Lashkari

2 2

explicit-failures-markup.xml
by Niall Douglas 30 Jan '19

30 Jan '19

I'm trying to tell the Boost regression matrix that GCC 8 failures are to be expected using explicit-failures-markup.xml, but it seems to not be working: https://www.boost.org/development/tests/master/developer/outcome.html Here is my explicit-failures-markup.xml: <?xml version="1.0" encoding="utf-8"?> <explicit-failures-markup>  <library name="outcome"> <mark-unusable> <toolset name="clang-linux-3*"/> <toolset name="gcc-3*"/> <toolset name="gcc-4*"/> <toolset name="gcc-5*"/> <toolset name="gcc-mngw-3*"/> <toolset name="gcc-mngw-4*"/> <toolset name="gcc-mngw-5*"/> <toolset name="msvc-7*"/> <toolset name="msvc-8*"/> <toolset name="msvc-9*"/> <toolset name="msvc-10*"/> <toolset name="msvc-11*"/> <toolset name="msvc-12*"/> <toolset name="msvc-13*"/> <toolset name="msvc-14.0.*"/> <note author="Niall Douglas">Complete C++14 support is the minimum requirement.</note> </mark-unusable> <mark-expected-failures> <toolset name="gcc-8*"/> <note author="Niall Douglas">GCC 8 currently ICEs with Outcome's unit tests in C++ 17 or later.</note> </mark-expected-failures> </library> </explicit-failures-markup> What am I doing wrong? Thanks, Niall

2 2

[lexical_cast] Assumed internal double conversion of float?
by Brian Kuhl 30 Jan '19

30 Jan '19

Hi Boost experts, We are chasing down some test failures with floats on VxWorks using the Dinkum clib and c++lib. We are testing with clang on Intel and Arm targets and GCC on PowerPC targets. An example failure at the bottom of this email. We have determined that boost::detail::lcast_get_precision<float>() is returning 9, well in access of the defined FLT_DIG of 6, or the practical float limit of 6.92. Specifically this code here: bool shl_real_type(float val, char* begin) { using namespace std; const double val_as_double = val; finish = start + #if defined(_MSC_VER) && (_MSC_VER >= 1400) && !defined(__SGI_STL_PORT) && !defined(_STLPORT_VERSION) sprintf_s(begin, CharacterBufferSize, #else sprintf(begin, #endif "%.*g", static_cast<int>(boost::detail::lcast_get_precision<float>()), val_as_double); return finish > start; } Where does boost::detail::lcast_get_precision<float>() come from, and why is it 9 ? Is it perhaps assuming some intermediate double conversion internally? In Dinkum's C library, Plager conservatively does not promote to a double, when converting to a string. Many thanks, Brian Wind River ->cmd "LD_LIBRARY_PATH=/opt/TestTriggerLocalPath/Workspace/vx7-boost/2019-01-13/vsb/app/boost/fsl_imx6_llvm_up_32_vxWorks/usr/root/llvm/bin;/opt/TestTriggerLocalPath/Workspace/vx7-boost/2019-01-13/vsb/app/boost/fsl_imx6_llvm_up_32_vxWorks/usr/lib/common" [vxWorks *]# cd /opt/TestTriggerLocalPath/Workspace/vx7-boost/2019-01-13/vsb/app/boost/fsl_imx6_llvm_up_32_vxWorks/3pp/BOOST/boost_1_68_0/status [vxWorks *]# run -x -t 0x01000000 -u 100000 -- ../bin.v2/libs/lexical_cast/test/lexical_cast_float_types_test.test/clang-vxworks/debug/cross-compile-vxworks/static-only-on/lexical_cast_float_types_test.vxe Launching process '../bin.v2/libs/lexical_cast/test/lexical_cast_float_types_test.test/clang-vxworks/debug/cross-compile-vxworks/static-only-on/lexical_cast_float_types_test.vxe' ... Process '../bin.v2/libs/lexical_cast/test/lexical_cast_float_types_test.test/clang-vxworks/debug/cross-compile-vxworks/static-only-on/lexical_cast_float_types_test.vxe' (process Id = 0x20482f10) launched. Running 3 test cases... unknown location(0): [4;31;49mfatal error: in "lexical_cast float types unit test/test_conversion_from_to_double": boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::bad_lexical_cast> >: bad lexical cast: source type value could not be interpreted as target [0;39;49m ../libs/lexical_cast/test/lexical_cast_float_types_test.cpp(299): [1;36;49mlast checkpoint [0;39;49m unknown location(0): [4;31;49mfatal error: in "lexical_cast float types unit test/test_conversion_from_to_long_double": boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::bad_lexical_cast> >: bad lexical cast: source type value could not be interpreted as target [0;39;49m ../libs/lexical_cast/test/lexical_cast_float_types_test.cpp(299): [1;36;49mlast checkpoint [0;39;49m

4 3

GSoC 19
by Sandesh Ghanta 30 Jan '19

30 Jan '19

Hey All, I am Sandesh Ghanta, a junior majoring in Computer Science and Engineering. I am interested in contributing to boost and would also like to work with boost in GSoC 19. I am good with C, C++, data structures, algorithms and am currently trying to fix some issues in boost. As I am a beginner to boost I am currently confused as to what project to contribute to, I have been looking at the various issues available to see what I am interested in, but it would be really helpful if someone could guide me. Yours Sincerely, Sandesh Ghanta, FOSS@Amrita <http://amfoss.in> GitHub <https://github.com/sandeshghanta> | Codechef | <http://www.codechef.com/users/sandeshghanta>Codeforces <http://www.codeforces.com/profile/sandeshghanta>

1 0

[gsoc2019] Searching for student
by Damian Vicino 30 Jan '19

30 Jan '19

Hi, I would like to mentor again this year. Some projects I'm particularly interested are getting safefloat or real ready for a formal review (both projects are from previous years and near completion). I'm also open to other projects too. Just ping me with an idea of what you would like to do. Best regards, Damian

1 0

LEAF has been refactored, it now has a much simplified error handling interface
by Emil Dotchevski 29 Jan '19

29 Jan '19

LEAF is a C++11 error handling library for use in low-latency environments. I'm looking for a Boost Review Manager. Any one of you good people willing to volunteer? :) https://zajo.github.io/leaf/ Features: -Header-only, no dependencies. - No dynamic memory allocations. - Any error-related object of any movable type is efficiently delivered to the correct error handler. - Compatible with std::error_code, errno and any other error code type. - Support for multi-thread programming. - Can be used with or without exception handling.

4 10

Wanted to contribute in your projects
by Jibran Zia 29 Jan '19

29 Jan '19

Hello I am Jibran Zia studying in National University of Information and Technology. I wanted to contribute in your projects for 2019 Google summer of Code. Please give me general overview about how I start working and from where I get code of your projects and how I will contribute in it... Thank you so much

2 1

GSOC 19
by Amit Singh 29 Jan '19

29 Jan '19

Hi Sir/Ma'am, My name is Amit Singh and I'm 2nd year CS student. 1. Extending GSoC 18 boost stats idea with regression model and tools for statistics. 2. Expression solver 3.Some features of functional programming similar to transform in c++ which could help programmer to apply functions to whole matrix or vector or transform the data.

1 0

Re: [boost] [histogram] discussion of accessor interface design
by Bjorn Reese 28 Jan '19

28 Jan '19

On 1/15/19 12:35 PM, Hans Dembinski via Boost wrote: > Pros: > - really terse > - you can access methods on the pointee with x->method() as well! (useful when histogram counters are not PODs) > - you can iterate over x to get the indices, for (auto i : x) { … } works Doesn't range-for use operator* so you will get the values? > - since x acts like an array to the indices, you can pass it to functions which accept ranges or iterators (it has .begin() and .end()) > - x can be (and is) enhanced with other useful methods > * x.bin(N) returns the current bin interval for the N-th axis, allowing you to access the central value, width, edges > * x.density() returns the current density (bin value divided by product of current bin widths) > Cons: > - *x and x[0] do completely different things: *x gives you the bin value, x[0] gives you the first index An alternative is to rename x[i] to x.index(i).

2 1

UBSan question
by Raffi Enficiaud 25 Jan '19

25 Jan '19

Hi, I am trying to correct for the errors reported by UBSAN in boost.test. A lot of them were false positive, as ... in boost.test, we check the capacity of the framework to catch various errors in the program. I compile/run the tests with the following: ../../../b2 \ --toolset=clang \ cxxflags=-std=c++11 \ cxxflags=-fno-omit-frame-pointer \ cxxflags=-fsanitize=undefined \ cxxflags=-fno-sanitize-recover=undefined \ cxxflags=-fsanitize-recover=integer-divide-by-zero \ cxxflags=-fsanitize-recover=float-divide-by-zero \ linkflags=-fsanitize=undefined \ linkflags=-fno-sanitize-recover=undefined \ linkflags=-fsanitize-recover=integer-divide-by-zero \ linkflags=-fsanitize-recover=float-divide-by-zero \ linkflags=-fuse-ld=gold \ variant=debug I have an exception that is failing the tests on clang-6/ubuntu18.04 (UBSAN exiting the process), but not on gcc-8/ubuntu18.04 (full log below). UndefinedBehaviorSanitizer:DEADLYSIGNAL ==8303==ERROR: UndefinedBehaviorSanitizer: FPE on unknown address This FPE is happening for instance after reading from a null pointer. I've searched on how to silence/blacklist this, but none of the approaches worked so far, and I am not sure what is provoking this FPE. Is there any UBsan specialist? Does anyone have an idea? Thanks, Raffi clang-linux.compile.c++.without-pch ../../../bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/prg_exec_monitor-ts/system-exception-test.o clang-linux.link ../../../bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test testing.capture-output ../../../bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test.run ====== BEGIN OUTPUT ====== prg_exec_monitor-ts/system-exception-test.cpp:38:15: runtime error: division by zero #0 0x42d03f (/home/bambooagent/bamboo-agent-home/xml-data/build-dir/RS-BCB187-CLAN/library/bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test+0x42d03f) #1 0x42f344 (/home/bambooagent/bamboo-agent-home/xml-data/build-dir/RS-BCB187-CLAN/library/bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test+0x42f344) #2 0x42e8b1 (/home/bambooagent/bamboo-agent-home/xml-data/build-dir/RS-BCB187-CLAN/library/bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test+0x42e8b1) #3 0x43dafa (/home/bambooagent/bamboo-agent-home/xml-data/build-dir/RS-BCB187-CLAN/library/bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test+0x43dafa) #4 0x43a6f2 (/home/bambooagent/bamboo-agent-home/xml-data/build-dir/RS-BCB187-CLAN/library/bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test+0x43a6f2) #5 0x436d13 (/home/bambooagent/bamboo-agent-home/xml-data/build-dir/RS-BCB187-CLAN/library/bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test+0x436d13) #6 0x43726f (/home/bambooagent/bamboo-agent-home/xml-data/build-dir/RS-BCB187-CLAN/library/bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test+0x43726f) #7 0x42d148 (/home/bambooagent/bamboo-agent-home/xml-data/build-dir/RS-BCB187-CLAN/library/bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test+0x42d148) #8 0x42e216 (/home/bambooagent/bamboo-agent-home/xml-data/build-dir/RS-BCB187-CLAN/library/bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test+0x42e216) #9 0x7f648e20fb96 (/lib/x86_64-linux-gnu/libc.so.6+0x21b96) #10 0x405859 (/home/bambooagent/bamboo-agent-home/xml-data/build-dir/RS-BCB187-CLAN/library/bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test+0x405859) UndefinedBehaviorSanitizer:DEADLYSIGNAL ==8303==ERROR: UndefinedBehaviorSanitizer: FPE on unknown address 0x00000042d049 (pc 0x00000042d049 bp 0x7ffe501ec660 sp 0x7ffe501ec630 T8303) #0 0x42d048 (/home/bambooagent/bamboo-agent-home/xml-data/build-dir/RS-BCB187-CLAN/library/bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test+0x42d048) #1 0x42f344 (/home/bambooagent/bamboo-agent-home/xml-data/build-dir/RS-BCB187-CLAN/library/bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test+0x42f344) #2 0x42e8b1 (/home/bambooagent/bamboo-agent-home/xml-data/build-dir/RS-BCB187-CLAN/library/bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test+0x42e8b1) #3 0x43dafa (/home/bambooagent/bamboo-agent-home/xml-data/build-dir/RS-BCB187-CLAN/library/bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test+0x43dafa) #4 0x43a6f2 (/home/bambooagent/bamboo-agent-home/xml-data/build-dir/RS-BCB187-CLAN/library/bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test+0x43a6f2) #5 0x436d13 (/home/bambooagent/bamboo-agent-home/xml-data/build-dir/RS-BCB187-CLAN/library/bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test+0x436d13) #6 0x43726f (/home/bambooagent/bamboo-agent-home/xml-data/build-dir/RS-BCB187-CLAN/library/bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test+0x43726f) #7 0x42d148 (/home/bambooagent/bamboo-agent-home/xml-data/build-dir/RS-BCB187-CLAN/library/bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test+0x42d148) #8 0x42e216 (/home/bambooagent/bamboo-agent-home/xml-data/build-dir/RS-BCB187-CLAN/library/bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test+0x42e216) #9 0x7f648e20fb96 (/lib/x86_64-linux-gnu/libc.so.6+0x21b96) #10 0x405859 (/home/bambooagent/bamboo-agent-home/xml-data/build-dir/RS-BCB187-CLAN/library/bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test+0x405859) UndefinedBehaviorSanitizer can not provide additional info. ==8303==ABORTING EXIT STATUS: 1 ====== END OUTPUT ====== (failed-as-expected) ../../../bin.v2/libs/test/test/system-exception-test.test/clang-linux-6.0.0/debug/threading-multi/visibility-hidden/system-exception-test.run

3 7

Any interest in Compile Time Hash Containers library?
by Ivan Matek 25 Jan '19

25 Jan '19

Hi everybody, my first message, I hope I do not mess this up. I was contemplating writing a Compile Time Hash Containers library and I wrote a test implementation for sets and benchmarked it against mostly ska:: sets since they are the best. Document is here: https://docs.google.com/document/d/1IsUiWl3K0h2pgttYgMt67CxgJ3zeXBKZEA7hvAQ… It is quite long, but it aims to provide a introduction to the problem for people unfamiliar with details of hashing, and also it goes into a lot of discussions, if you care just about the numbers you can skip the "boring parts". My interpretation of benchmarks is that it performs very well in some cases, decently in others, but I am biased. :) Code is not available online since I do not want to dump a test project online without extensive documentation, but if somebody has a problem that may be benefited by this test implementation feel free to let me know, I would be happy to get some real world feedback on prototype. Limitations is that test implementation only works for sets, so no maps and if your objects are not integers you will probably not get much speedup. Also if your set has more than 100ish items GCC will run out of memory and VC++ does not compile code at all, so clang is the only way for most use cases today. One more disclaimer is that I do not want this library to be some beast like ranges that takes years to implement, so if after reading the document you consider implementation quite basic I won't be offended :) In other words I feel that library like this although relatively simple compared to regular Boost libraries can provide quite a lot of benefit for some usecases where people really really care about performance of hash containers where values are known during compile time. I know you can not predict the future of an unimplemented library, but I would be happy with some general feedback, and if you think this library would be nice boost proposal I would be interested in some pointers wrt how to proceed. If somebody wonders how user code looks at the moment: #include "cxhash_set.h" // also could be a result of constexpr function, no need for initializer list static constexpr std::array<int, 20> ints{0,1,2,3,5,8,21,34,64,128,256,512,1024,1701,1729,2048,4096,12345,123456,1234567}; int main() { cxhash_set<ints> ints_set; // contains could(should be?) static, but for now it is "normal" member fn std::cout << std::boolalpha << ints_set.contains(21) << std::endl; std::cout << std::boolalpha << ints_set.contains(22) << std::endl; } P.S. feel free to comment in the google doc, I actually find mailing lists quite limited when it comes to prolonged and or detailed discussions. Maybe we can ping Alexandrescu for an instance of dlang forums, so we get a better discussion tools, and he gets a way to convert us to D. :)

5 7

Status of Boost GSoC 2019?
by Mateusz Loskot 24 Jan '19

24 Jan '19

Hi, (I've asked this David Bellot by email some time ago. No response arrived, so asking here again.) One student asked about GSoC recently [1] but w/o answer. An empty repo for this year has been created. And, the timeline [3] says organizations need to apply by Feb 6. I wonder, what is the status of the preparation for GSoC 2019? [1] https://lists.boost.org/Archives/boost/2019/01/244849.php [2] https://github.com/BoostGSoC19 [3] https://summerofcode.withgoogle.com/how-it-works/ Best regards, -- Mateusz Loskot, http://mateusz.loskot.net <http://mateusz.loskot.net>

1 0

[stacktrace] libbacktrace callback for backtrace_pcinfo invalid return value
by Muazin Mugadr 24 Jan '19

24 Jan '19

Hello all See also: https://stackoverflow.com/questions/54333608/boost-stacktrace-not-demanglin… I am cross compiling boost on Unix for Windows with MINGW. I am using libbacktrace compiled using the same toolchain from here: https://github.com/ianlancetaylor/libbacktrace Digging through the code of libbacktrace I was able to deduce that in a success case the return value of backtrace_pcinfo will be the return value of the callback supplied to that function (for DWARF search). The callback boost is giving looks like this: inline int libbacktrace_full_callback(void *data, uintptr_t /*pc*/, const char *filename, int lineno, const char *function) { pc_data& d = *static_cast<pc_data*>(data); if (d.filename && filename) { *d.filename = filename; } if (d.function && function) { *d.function = function; } d.line = lineno; return 0; } As you can see it will always return 0. This causes an issue with the way the function is called: ::backtrace_pcinfo:( state, reinterpret_cast<uintptr_t>(addr), boost::stacktrace::detail::libbacktrace_full_callback, boost::stacktrace::detail::libbacktrace_error_callback, &data ) || ::backtrace_syminfo:( state, reinterpret_cast<uintptr_t>(addr), boost::stacktrace::detail::libbacktrace_syminfo_callback, boost::stacktrace::detail::libbacktrace_error_callback, &data ); If the symbol is found using backtrace_pcinfo the return value will be 0. If its not found it will be 0. It will always use the value provided by backtrace_syminfo. Is this intended? BR Cromon

1 0

Tests: Runtime type_mismatch after upgrade to 1.69
by Florian Lindner 24 Jan '19

24 Jan '19

Hello, after my distribution rolled out the upgrade to Boost 1.69 I am unable to compile my application anymore. I try to get the log_level set. Minimal compiling example: #define BOOST_TEST_DYN_LINK #include <boost/test/unit_test.hpp> #include <boost/test/unit_test_parameters.hpp> bool init_unit_test() { using namespace boost::unit_test; auto logLevel = runtime_config::get<log_level>(runtime_config::btrt_log_level); return true; } int main(int argc, char* argv[]) { int retCode = boost::unit_test::unit_test_main( &init_unit_test, argc, argv ); return retCode; } which compiles fine g++ -std=c++11 -lboost_unit_test_framework boosttesting.cpp but gives an runtime error: % ./a.out Test setup error: boost::runtime::arg_type_mismatch: Access with invalid type for argument corresponding to parameter log_level Thanks! Florian

1 0

C++Now 2019 Registration is Open
by Jon Kalb 24 Jan '19

24 Jan '19

Boosters, Registration for C++Nows 2019 (aka BoostCon) is now open: http://cppnow.org/announcements/2019/01/2019-registration-is-open/ Please help us to spread the word about this announcement. Thanks. Note that the Aspen Meadows Resort online registration link is also up on the lodging page. Because there will be another group in the hotel, we’ve been allocated fewer rooms this year. Please either reserve a room very soon or plan to stay at the Lamplighter or another hotel in town. See you in Aspen in May. Jon

1 0

[gsoc19][GIL] Project proposal
by Miral Shah 23 Jan '19

23 Jan '19

Hello everyone, I am Miral Shah a computer engineering student from India. I have been talking with Boost.GIL community on GIL's Gitter channel since last few weeks to come up with the new idea for GSoC19. After many suggestions and a long discussion on various ideas with the contributors, we have come up with the idea to expand the GIL by introducing new image processing algorithms into it. I would also like to thank Stefan Seefeld and Mateusz Loskot for their guidance and support. Proposal idea can be found here: https://github.com/boostorg/gil/wiki/GSoC-2019 Thank you, Miral Shah

1 0

Boost log issues and workarounds
by hh h 21 Jan '19

21 Jan '19

Hi, I like the boost log, but there are many small issues, appreciate your kind help: I followed the following link to use a good macro LOG: https://stackoverflow.com/questions/35895199/boost-log-and-severity-local-a… But calling LOG(error) caused much trouble for the name space collision, alternative is to use full namespace boost::log::trivial::error, but that is too cumbersome,I tried to use an uppercase ERROR to replace it in an enum ERROR = boost::log::trivial::error, obviously that could not be complied, although it is defined as enum severity_level in trivial.hpp, it does not look like the boost::log::trivial::error is an enum value. Any workarounds? Another issue from that link is it has to call LOGGABLE prior to call LOG(error) in each function, that makes more clumsy, software developers in my team are not happy about it. Any workaround to have a fixed argument in BOOST_LOG_STREAM_WITH_PARAMS, without need to claim boost::log::sources::severity_logger<boost::log::trivial::severity_level> slg; in each function? You guys are genius that must be a way to do it, appreciate your advice. Thank you

4 22

[lockfree] wait-free multi-queue?
by Shawn Yarbrough 18 Jan '19

18 Jan '19

Is it practical to have a wait-free, multi-producer/multi-consumer queue? I ask because Boost's Lockfree multi-queue is only advertised as being "lock-free". (Boost does offer a wait-free single-queue.) https://www.boost.org/doc/libs/1_69_0/doc/html/lockfree.html Shawn Y.

2 1

Re: [boost] [parameter] Helping user libraries adjust to recent changes in GitHub develop branch
by Cromwell Enage 17 Jan '19

17 Jan '19

Happy New Year, everyone! > I've been contributing upgrades to Boost.Parameter functionality > and documentation in the GitHub develop branch for the past > couple of months. These upgrades include the addition of code > generation macros for Boost.Parameter-enabled function call > operators and support for perfect forwarding, and more upgrades > are yet to come. It's been an enjoyable experience so far, > but understandably there are some growing pains. I've taken > pains to ensure that as long as user libraries access only the > public interface of Boost.Parameter, they won't be affected by > the changes. However, there are several notable libraries that > currently use non-public portions of Boost.Parameter, so > whenever possible I've submitted PRs to those libraries that > either change the usage to access only public portions > (preferred) or make quick fixes (temporary). Update: As of this writing, I have active PRs for the following libraries: Boost.Accumulators Boost.Convert Boost.Graph Boost.Log AFAIK, these are the libraries most directly affected by the changes. To reiterate: I'm willing to help the library maintainers resolve these issues as quickly as possible. I should be able to answer any questions you have about the changes to Boost.Parameter. Cromwell D. Enage

3 2

[histogram] discussion of accessor interface design
by Hans Dembinski 15 Jan '19

15 Jan '19

Dear all, work on boost.histogram is progressing fast. I am still implementing feedback from the review, simplifying the interface, adding requested features, such as axes that can grow. STL compatibility was further improved, you can now also write to histograms via iterators. The normal iterators make sense when you iterate over a 1D histogram. When you iterate over a multi-dimensional histogram, you also want to know the current multi-dimensional index. After considering many options, and I really thought about this a lot, I went for the following design, which is a bit unusual. Therefore I would appreciate feedback. I think it is great, once you overcome an initial feeling of awkwardness. The accessor class is "polymorphic", it behaves like a pointer to the histogram value, and like an array for the multi-dimensional index. In code, this is how you use it: auto h = make_histogram(…) // make 2D histogram for (auto && x : indexed(h)) { // indexed produces a range of accessors // x is a special accessor type, combining two non-overlapping concepts // - it acts like a pointer to the histogram value // - it acts like an array to the current index std::cout << "current value " << *x << std::endl; // "dereference" to get value std::cout << "current index " << x[0] << " " << x[1] << std::endl; // use subscript operator to get index } This syntax is beautifully terse, e.g. see https://github.com/HDembinski/histogram/blob/develop/examples/guide_access_… for a full example, especially line 66. Pros: - really terse - you can access methods on the pointee with x->method() as well! (useful when histogram counters are not PODs) - you can iterate over x to get the indices, for (auto i : x) { … } works - since x acts like an array to the indices, you can pass it to functions which accept ranges or iterators (it has .begin() and .end()) - x can be (and is) enhanced with other useful methods * x.bin(N) returns the current bin interval for the N-th axis, allowing you to access the central value, width, edges * x.density() returns the current density (bin value divided by product of current bin widths) Cons: - *x and x[0] do completely different things: *x gives you the bin value, x[0] gives you the first index The last point is, of course, where people have a problem. But if you take C++ concepts seriously then the accessor is a perfect model of a pointer and a perfect model of an array. These two roles are non-overlapping and they have non-overlapping sets of interfaces, which I exploit here. If you have the expectation that *x and x[0] should do the same thing, it is so because of C. C has no extensive type system like C++ and does not distinguish between arrays and pointers, although these are very different concepts. A pointer points to a value, and an array is a collection of values. "dereferencing" a collection of values makes no sense, we are just used to it because of our C heritage. C++ has a better type system, and better classes for pointers and arrays than raw pointers. The stdlib authors recognize that *x has no meaning when x is a sequence of values. *x fails when x is a std::vector, std::deque, std::list, or any kind of collection in the stdlib. Even for std::unique_ptr, they made sure that the interfaces for the pointer-to-object and pointer-to-array specializations behave differently: ``` #include <memory> int main() { std::unique_ptr<int> p(new int); // pointer version // p[0]; // fails *p; // OK std::unique_ptr<int[]> a(new int[3]); // array version // *a; // fails a[0]; // OK } ``` Once you accept that the two concepts of pointers and arrays have non-overlapping interfaces in C++, it becomes possible to make a combined object which has both interfaces, and uses these two sets to return different information. If you have read this far, I hope your initial reaction of "woah, this looks really inconsistent and confusing!" turned to "hmm, maybe it is not inconsistent after all". I am looking forward to hear your thoughts. Best regards, Hans PS: The alternative would be to return a std::pair<index_type, value_reference_type>, but this has disadvantages. Unpacking the pair is going be nice in C++17 with structured bindings, but not so much in C++14. Also, it prevents me from adding convenience methods, like the above-mentioned bin(N) and density() methods.

1 0

boost log to concatenate just one log file
by hh h 15 Jan '19

15 Jan '19

Hi, I added boost::log::keywords::open_mode = std::ios_base::app to the log configuration, but it did not stop log file proliferation, every time I started the program, it created a new log file mylog.log0000x, how can I stop creating new logs? Thank you.

2 2

Is it possiable to use a simple LOG(info) in boost log?
by hh h 15 Jan '19

15 Jan '19

Hi, After trying many days on boost log, still have many issues. Google log has a nice LOG(INFO) << "debug";, looks like that kind thing cannot do in boost log, the close online code in https://stackoverflow.com/questions/35895199/boost-log-and-severity-local-a… has to call LOGGABLE first then to use LOG(info) << "my log", it is really cumbersome, is it possible to call LOG(info) like glog? Thank you.

1 1

Boost.Build requirements to exclude GCC 5
by Niall Douglas 14 Jan '19

14 Jan '19

Outcome is now into Boost, and is being tested nightly: Docs in BoostDoc theme: https://www.boost.org/doc/libs/develop/libs/outcome/doc/html/index.html Regression matrix: https://www.boost.org/development/tests/develop/developer/outcome.html One problem is how to exclude from testing GCC 5 which Outcome cannot support due to GCC 5's incorrect parsing of variable templates in nested template classes [1], so I need some sort of Boost.Build project requirement which explicitly excludes GCC 5. Unfortunately, GCC 5 appears to Boost.Config as fully implementing C++ 14, so this is not straightforward. What might work is to specify a requirement for one of the library items at https://github.com/boostorg/config/blob/develop/checks/Jamfile.v2 which we know for a fact libstdc++ 5 does not implement, but libstdc++ 6 does. However, clang with libstdc++ 5 would then be excluded incorrectly, as clang does not have this parsing bug. I guess ideally speaking Boost.Config gains a new test testing for this specific compiler parsing bug. But it seems a bit much to ask for this just for Outcome. Guidance is sought! Niall [1]: https://www.boost.org/development/tests/develop/developer/output/teeks99-02…

4 5

C++Now 2019 Submission Deadline
by Jon Kalb 14 Jan '19

14 Jan '19

The deadline for submitting to C++Now 2019 is just a few days away. If you’ve been thinking of submitting, please do not delay: http://cppnow.org/announcements/2018/12/2019-call-for-submissions/ <http://cppnow.org/announcements/2018/12/2019-call-for-submissions/> Thanks. Jon

1 0

High number of integer_sequence/index_sequence implementations
by Nikita Kniazev 14 Jan '19

14 Jan '19

Bunch of Boost libraries have their own integer_sequence/index_sequence implementation. Wouldn’t it be better if there was boost::integer_sequence/boost::index_sequence? boost\beast\core\detail\integer_sequence.hpp boost\callable_traits\detail\polyfills\make_index_sequence.hpp boost\context\detail\index_sequence.hpp boost\fusion\support\detail\index_sequence.hpp boost\mp11\integer_sequence.hpp boost\phoenix\core\detail\index_sequence.hpp (alias of fusion one) boost\poly_collection\detail\functional.hpp (uses mp11 one) boost\test\data\index_sequence.hpp boost\variant\detail\multivisitors_cpp11_based.hpp

4 4

(no subject)
by Siddhartha Sen 14 Jan '19

14 Jan '19

Hey, This is Siddhartha. I have been interested in contributing to boost and hopefully work with boost in GSOC 2019. I apologise for the delay as my exams were going on and I hope it is not too late to start. I have looked in to the ideas list as well as last year's projects. Currently, I am proficient in c and c++,especially algorithms,data structures and maths. Any help regarding how to get started would be appreciated. I myself have some ideas about implementation of a few libraries which I would like to discuss as well. Thank You

1 0

Regression matrix stopped updating
by Nikita Kniazev 13 Jan '19

13 Jan '19

For past month or two regression matrix update frequency was fluctuating in a big range, sometimes not updating for two-three days. As for now master is not updated for 7 days and develop for 5 days. https://www.boost.org/development/tests/master/developer/summary.html Summary: Master Report Time: Tue, 11 Dec 2018 01:44:54 +0000 https://www.boost.org/development/tests/develop/developer/summary.html Summary: Develop Report Time: Thu, 13 Dec 2018 06:05:04 +0000 Is it down for maintenance or what is going on?

6 8

Safe numerics at Meeting C++
by Robert Ramey 12 Jan '19

12 Jan '19

News Flash for both of you interested in the Boost Safe Numerics Library. Checkout https://www.youtube.com/watch?time_continue=942&v=tcyb1lpEHm0 at 1 hour in. The whole rest of the talk is about a safe integer implementation written D. He uses it to illustrate his concept of "Introspective Programming". ALL the features and techniques he mentions (and more) are implemented in the safe numerics library. The Safe Numerics library is the Next Big thing! Robert Ramey

1 0

question/guidence regarding merge to master
by Robert Ramey 12 Jan '19

12 Jan '19

I'm looking to merge my develop branch into the master so that they will be in sync. I'm thinking that this the changed in develop should be squashed so that the master branch doesn't included all the the intermediate changes made during the develop phase. Is there any boost rule/practice/guidence regarding this?. Ideally, I'd like to see the master have only one set of consolidated changes for each release. But I'm not the person who decides these things or does the work. Any insight by other parties would be appreciated. Robert Ramey

10 29

Re: [boost] A class for embedded friendly callbacks.
by Bjorn Reese 12 Jan '19

12 Jan '19

On 1/4/19 1:30 PM, Mikael Rosbacke via Boost wrote: > I'm Mikael Rosbacke and new to this list. The last couple of months I've > been writing on a class for storing callbacks to different forms of > callables (member functions, functors, free functions). The main focus A while back, a somewhat similar library underwent a formal review. You may want to read the review report to see if any of the comments applies to your library: https://lists.boost.org/boost-announce/2016/12/0484.php

1 0

Re: [boost] Feedback desired for reflective enum library
by Nir Friedman 12 Jan '19

12 Jan '19

I had to fill in the subject for this manually, because of settings for the mailing list. I really hope it ends up on the right thread. Apologies if it doesn't. Hi Geert, There is an ADAPT macro, which is similar to your concept of CONVERT_TO_WISE_ENUM. However, it does require listing the enumerators; after all there's no way to find them out after the fact or else this library wouldn't exist in the first place. That said, I'm not quite sure what you mean by "changing your whole codebase". To take advantage of wise enums, all you'd need to do is change the original enum declaration to the wise enum macro. Everything else in your codebase will continue to work exactly as before. No typedef shenangians are necessary. Changing the original enum declaration is exactly the same amount of work as writing an adapt macro, but you don't have to maintain the list of enumerators twice. So I can't imagine a reason to write things the way you have (unless you want a conditional build dependency on WISE_ENUM but that seems unnecessary). The ADAPT macro is designed to be use wise_enum functionality generically with enumerators whose source you don't control, and therefore cannot change the declaration. Hope that clarifies things. Cheers, Nir

1 0

boost log to display source code name and lines
by hh h 11 Jan '19

11 Jan '19

Hi, I am looking for good log library to replace google log, my plan is to use boost log, but I am not sure if it is mature or it has been used seriously. It lacks some simple basic features such as display source code name and lines in log file, I've searched on line discussion, there are many suggestion to fix it in piece of code, but I could not get that work, difficult to use it may be overstated. Are there any good examples to display source program name and lines similar to asio socket examples on line? What is your opinion about boost log? Should I still pursue it? Thank you. - jhh

3 10

GSoC19
by Pranam Lashkari 10 Jan '19

10 Jan '19

Hello, Organization application date is going to start soon. I was trying to find our idea page for this year but couldn't find it. can anyone help!? Thank you, Pranam Lashkari

1 0

Requesting formal review for (Boost) LEAF
by Emil Dotchevski 10 Jan '19

10 Jan '19

LEAF is a small C++11 error handling library (the acronym stands for Low-latency Error Augmentation Framework). Features: - Header-only, NO dependencies. - 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. Official documentation: https://zajo.github.io/leaf. LEAF is designed for use in low-latency environments without exception handling, but it also works with exception handling; in that case it is a better, more optimal replacement for Boost Exception. This link can be helpful for refactoring existing Boost Exception code: https://zajo.github.io/leaf/#boost_exception.

5 9

async_read SEGFAULT
by hh h 09 Jan '19

09 Jan '19

I use one io_service in one process to run two servers A and B each has its own port, own context and SSL configuration to accept inbound connections. Although both A and B have boost::asio::deadline_timer, but I think there is only one thread is running: (gdb) info threads Id Target Id Frame * 1 Thread 0x7ffff7fe0bc0 (LWP 31204) "ssl_connection" 0x00007ffff4a690a3 in __epoll_wait_nocancel () at ../sysdeps/unix/syscall-template.S:84 The problem I got: - If I started only one server A, it worked just fine for both async_read and async_write. - If I started both servers A and B, even B was in idle, server A could sometime be crashed after receiving and responding just one message, then crashed at next async_read in the first second, it was more stable if it did not call async_write. SEGFAULT: Fault address=0x55b3700d00cf, #4 0x000055555557f98a in boost::asio::detail::task_io_service_operation::complete (this=0x55555584adc0, owner=..., ec=..., bytes_transferred=0) at /usr/include/boost/asio/detail/task_io_service_operation.hpp:38 #5 0x0000555555581f82 in boost::asio::detail::task_io_service::do_run_one ( this=0x555555814710, lock=..., this_thread=..., ec=...) at /usr/include/boost/asio/detail/impl/task_io_service.ipp:372 #6 0x0000555555581ab4 in boost::asio::detail::task_io_service::run ( this=0x555555814710, ec=...) at /usr/include/boost/asio/detail/impl/task_io_service.ipp:149 #7 0x000055555558221f in boost::asio::io_service::run (this=0x7fffffffe150) at /usr/include/boost/asio/impl/io_service.ipp:59 It seems that async_write and async_read messed up, but that problem was intermittent, especially when the server A passed first second, it could be running for hours for doing consequent many async_read and async_write simultaneously. It was only one thread, what could cause that problem? Thank you.

2 11

b2 --exec-prefix=...
by Peter Dimov 09 Jan '19

09 Jan '19

Our "b2 --help" documentation says --exec-prefix=<EPREFIX> Install architecture dependent files here. Default: <PREFIX> --libdir=<LIBDIR> Install library files here. Default: <EPREFIX>/lib and bootstrap.sh also supports --exec-prefix and when given, records it in project-config.jam. But it doesn't work and has never worked. Only --prefix is honored, --exec-prefix is simply ignored. I think that we should bring the documentation and the actual behavior in sync, either by making --exec-prefix work as documented, or removing it from the documentation. Which one should we do? Comments?

5 4

Boost wiki - revised Boost guidance for authors on Warnings - RFC
by Paul A. Bristow 08 Jan '19

08 Jan '19

As promised at the end of a long (hijacked!) thread on 'Warnings' http://boost.2283326.n4.nabble.com/Current-Guidance-on-Compiler-Warnings-td… starting from a query by Brian Kuhl of Wind River on Boost's policy on compiler warnings, I have spent some time revising the previous guidance document on Trac that I edited many years ago. This was a long and tedious task as Markdown, as most conveniently used on Github, is rather different from the mark-up language on Trac, leaving me slightly in fumble mode :-( I have made some updates en passant, but there is still much to do updating for the much improved granularity of warning suppression and perhaps more about other code improvement tools like Lint, UBSan. The overall structure leaves a lot to be desired, but I don't want to put any more work into this without some encouragement that it will prove useful. I have posted the result of my efforts on https://github.com/boostorg/boost/wiki/Guidelines:-Warnings and I am as promised I am starting this new thread on warning for your comments, corrections, condemnations etc. HTH Paul --- Paul A. Bristow Prizet Farmhouse Kendal UK LA8 8AB +44 (0) 1539 561830

3 2

[cmake] Pull request announcement - update
by mike.dev＠gmx.de 07 Jan '19

07 Jan '19

I think it is time for an update on this issue. #################################################### # TLDR: There are now ~25 boost libraries that can be directly used in a cmake project via the add_subdirectory & target_link_library - workflow. And I want to encourage library maintainers to comment/merge outstanding PRs or make similar additions to their libraries themselves. ################################################### # A summary what that thread was about: In September last year I was informing the mailing list that I was about to make a bunch of PRs adding a set of minimal CMake files to various boost libraries. Their sole purpose was to enable the following workflow from within a cmake project: add_subdirectory( <path-to-boost-libfoo-directory> ) target_link_library( my_app Boost::libfoo ) Without needing b2 or the boost super project for that matter (although support in the super project would be very welcomed) For that, the cmake file in libfoo has to - provide the target Boost::libfoo - attach the dependency information for Boost::libfoo - attach the proper include directory for Boost::libfoo - if necessary, build libfoo with whatever toolchain and compile flags the parent cmake project defines - if necessary, attach any necessary compile definitions to Boost::libfoo Although things like running the unit-tests or provide and install target can be added by any library maintainer (and some have done just that) it is not part of my PRs. ################################################### # What is the current state. For a quick overview, I uploaded a picture of the boost dependency graph (code based on boostdep) that shows which libraries Have a cmake file in their root and which don't [1]. So far, about 25 libraries have gained cmake files as part of this effort (not all from me). And of course there are a couple of libraries that Already used cmake before I started my efforts, but AFAIK, most of them can not be used in the above mentioned work-flow. Of course, there remains a lot to do, but at least progress is happening and we now have fitted almost all "foundational" libraries , so from here on out, the pace should increase. Currently, I have 7 outstanding PRs and I would ask the Respective maintainers to comment on them as soon as they can find some spare time, as further PRs are blocked on them. Even if the PRs get completely rejected, I at least know for which part of boost I should no longer pursue this quest and/or find a workaround. Finally a big thanks to all maintainers that added such cmake files on their own. Best Mike [1] https://gist.github.com/Mike-Devel/46d04409d6ae6053861706e3ad91e4dc Explanation for the linked picture: It shows the boost dependency graph (generating code based on boostdep). - Green libs already have a cmake file in their root directory - Yellow libraries don't have such a cmake file, but all their dependencies have one, so one could be added and most likely there is already a PR for that - Red libraries have at least one direct or indirect Dependency that lacks a cmake file, so I consider Them "blocked" for now.

4 3

A class for embedded friendly callbacks.
by Mikael Rosbacke 07 Jan '19

07 Jan '19

Greetings. I'm Mikael Rosbacke and new to this list. The last couple of months I've been writing on a class for storing callbacks to different forms of callables (member functions, functors, free functions). The main focus has been to make it suitable for embedded work with small footprint and dependable exception and heap behavior. The code can be found on github: https://github.com/rosbacke/delegate It has reached a stage where I'm getting sort of 'done'. I feel it could be useful to a wider audience so I would like to get some feedback about if this is suitable for that and if it is worth starting a new branch for possibly adapting it to boost for inclusion in some future version of boost. Any feedback is appreciated. Cheers, --- Mikael Rosbacke

2 2

Should pass boost::asio::io_service by raw pointer or smart pointer?
by hh h 07 Jan '19

07 Jan '19

Hi, In many examples and even implementations, programmers like to pass boost::asio::io_service by raw pointer: MyClass::MyClass(boost::asio::io_service &io_service) : myRawIoService(io_service) {} Will this cause issues to pass raw pointer for large size of classes, should it be replaced by passing smart pointer: MyClass::MyClass(const std::shared_ptr<boost::asio::io_service> &io_service) : myIoService(io_service) {} Thank you.

5 9

Is there interest in an "iofiber" library?
by Vinícius dos Santos Oliveira 06 Jan '19

06 Jan '19

I have written a completion token for Boost.Asio that is a little more advanced than plain ASIO's spawn featuring abstractions such as join(), detach() and even interrupt(). I'd like to know if there is interest in seeing this library merged as part of Boost. https://vinipsmaker.github.io/iofiber/ (there is also a mutex and a semaphore, but these are undocumented as of now and were poorly ported from the previous token supporting abstractions and need rework) Boost.Fiber integration with ASIO is problematic: https://github.com/boostorg/fiber/issues/102#issuecomment-263558882 Default Boost.Asio yield token will do as long as you don't need communication between fibers. When primitive communication is necessary, you can work around it by exploiting the completion token protocol. In fact, after having rolled my own solution, I eventually was made aware of Peter's solution (which he rolled on his own independently) which was incredibly similar to my solution: https://github.com/equalitie/ouinet/blob/a2afaf9932c8a23434d1f0a10be06fc407… If you need anything more advanced such as careful strand integration, join, or interruption API, you'll just have to roll your own token. That's what I end up doing after working around ASIO's token for many months. There was also a recent request by Vinnie to turn Boost.Coroutine 1 deprecation warning off. This separate library would be an alternative (although it is still a far from review-ready). -- Vinícius dos Santos Oliveira https://vinipsmaker.github.io/

3 4

Re: [boost] Skipping regression builds for unsupported toolsets
by Nikita Kniazev 05 Jan '19

05 Jan '19

> > How can I 'tell' regression builders to skip building GIL > where required C++ version is not supported? Add requirements to you tests Jamfile, something like: import config : requires ; project /boost/gil/test : requirements [ requires cxx11_constexpr cxx11_decltype cxx11_template_aliases cxx11_variadic_templates ] (those checks come from Config library which most likely you are pulling already in your CI builds). I noticed that some libraris specify "std" in libraries.json, for example: > - Any: "std": [ "c++17" ] > - Ratio: "std": [ "proposal" ] > What is the purpose of these? > Is this respected by regression builds? I doubt those do anything. IIUC `libraries.json` is used only for https://www.boost.org/doc/libs/ list generation.

2 1

Skipping regression builds for unsupported toolsets
by Mateusz Loskot 05 Jan '19

05 Jan '19

Hi, The regression builds report unreloved issues for number of libraries: https://www.boost.org/development/tests/develop/developer/issues.html In particular, for Geometry and GIL those issues happen on msvc-8.0. For GIL, specifically, this is due to the fact GIL now requires C++11. How can I 'tell' regression builders to skip building GIL where required C++ version is not supported? I noticed that some libraris specify "std" in libraries.json, for example: - Any: "std": [ "c++17" ] - Ratio: "std": [ "proposal" ] What is the purpose of these? Is this respected by regression builds? Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

1 0

iround() and itrunc() in Conceptual Requirements for Real Number Types
by Matt Pulver 04 Jan '19

04 Jan '19

Hello, Regarding the page Conceptual Requirements for Real Number Types https://www.boost.org/doc/libs/1_69_0/libs/math/doc/html/math_toolkit/real_… Is it still accurate to list these 2 rows under Standard Library Support Requirements? - iround(cr1) | int - itrunc(cr1) | int The motivation in asking this is two-fold: 1. I don't see either of these functions listed in the Standard Library. Perhaps this is just old documentation, or I am not looking in the right place. Instead, I do find lround() and truncl(). 2. One of the design goals of Boost.Autodiff (WIP) is to satisfy all of the requirements on this page, and these are the only two which I am unable to satisfy for the above reason. If someone were to update this page, or otherwise advise on how to reconcile, it would be appreciated so that the Boost.Autodiff <https://github.com/pulver/autodiff> library could accurately claim to satisfy 100% of Boost's Real Number Type requirements. Best regards, Matt

2 2

Could shared_ptr cause memory leak?
by hh h 04 Jan '19

04 Jan '19

Suppose I have a session object A, the shared_ptr<A> is created and stored in a global connection list after a connection is accepted by async_accept, when the connection is terminated, the reference in connection list is removed, but since A has a member B still holds A reference, that session object is never deleted, is it memory leak? class A : public boost::enable_shared_from_this<A> { public: A(); ~A(); void Start() {b = make_shared<B>(shared_from_this());} void Stop(); private: shared_ptr<B> b; };

3 6

Re: [boost] [multi_index] problem with Travis integration
by Nikita Kniazev 31 Dec '18

31 Dec '18

Aah, you repository has both Travis enabled. Formerly Travis had two separated sites, one (.org) served for open source project and other (.com) for private projects. A while ago they opened .com for open sources and announced that they will merge .org to .com, but actually nothing changed. https://docs.travis-ci.com/user/open-source-on-travis-ci-com/ > Looking closer, there is a duplication. In commit 1af32b3, the "Travis > CI - Branch" link redirects > (indirectly) to > > https://travis-ci.com/boostorg/multi_index/builds/95957238 > > while the "continuous-integration/travis-ci/push" points to > > https://travis-ci.org/boostorg/multi_index/builds/473601408 > > Note the most surprising fact that *the first link is **to travis-ci.com > and the second **to > travis-ci.org*. These two domains don't see each other (If i try to see > 473601408 in > travis-ci.com or 95957238 in travis-ci.org I get a "we couldn't find > that build" screen). > > Joaqu?n M L?pez Mu?oz

2 1

[multi_index] problem with Travis integration
by Joaquin M López Muñoz 30 Dec '18

30 Dec '18

Sorry to be such a noob when it comes to Travis integration, but for the life of me I just can't see how to fix the following: Travis was activated for boostorg/multi_index yesterday, and, in addition, I've been given admin privileges to boostorg/multi_index so I can, in theory, control how the Github/Travis communication happens. Evreything is working OK except that, when I push something to develop, *two* Travis tasks are created, named "Travis CI - Branch"and "continuous-integration/travis-ci/push": whereas in all the other boostorg libs I've examined, only "continuous-integration/travis-ci/push" appears (example with smart_ptr): I've walked all over the settings pages for both Travis and Github, looked up on the Internet and didn't come to any conclusion as to what this "Travis CI - Branch" thing is and how it can be turned off so that integration looks the same way as for any other Boost lib. Any clue much appreciated. Joaquín M López Muñoz

2 3

Re: [boost] [multi_index] problem with Travis integration
by Nikita Kniazev 30 Dec '18

30 Dec '18

This might be connected to GitHub Services deprecation https://developer.github.com/changes/2018-04-25-github-services-deprecation/ https://blog.travis-ci.com/2018-09-27-deprecating-github-commit-status-api-… Sorry to be such a noob when it comes to Travis integration, but for the > life of > me I just can't see how to fix the following: > Travis was activated for boostorg/multi_index yesterday, and, in > addition, I've been given > admin privileges to boostorg/multi_index so I can, in theory, control > how the Github/Travis > communication happens. Evreything is working OK except that, when I push > something to > develop, *two* Travis tasks are created, named "Travis CI - Branch"and > "continuous-integration/travis-ci/push": > whereas in all the other boostorg libs I've examined, only > "continuous-integration/travis-ci/push" appears (example with smart_ptr): > I've walked all over the settings pages for both Travis and Github, > looked up on > the Internet and didn't come to any conclusion as to what this "Travis > CI - Branch" > thing is and how it can be turned off so that integration looks the same > way > as for any other Boost lib. > Any clue much appreciated. > Joaqu?n M L?pez Mu?oz

2 1

[multi_index] Travis/AppVeyor activation request
by Joaquin M López Muñoz 29 Dec '18

29 Dec '18

Hi, Could some administrator with the required permissions activate Travis and AppVeyor integration for boostorg/multi_index? Thank you! Joaquín M López Muñoz

2 2

GSOC 2019
by Amit Singh 28 Dec '18

28 Dec '18

Hi Sir/Ma'am, My name is Amit Singh and I'm 2nd year CS student. I would like extend GSoC 18 boost stats idea with few ML models and tools

1 0

Does async_accept only access connection object raw pointer and wrapped it by shared pointer internally?
by hh h 27 Dec '18

27 Dec '18

I don't like to use raw pointer by new and delete, but the following code will be crashed by double delete, can't async_accept accept shared pointer? std::shared_ptr<session> new_session = std::make_shared<session>(io_service_, context_); acceptor_.async_accept(new_session->socket(), boost::bind(&server::handle_accept, this, new_session.get(), boost::asio::placeholders::error)); Thank you.

3 3

[GSoC-2019] Guidance about GSoC 2019
by Karthik Kothuri 24 Dec '18

24 Dec '18

Hi, I am Karthik Kothuri, a 2nd year Computer Science and Engineering student at National Institute of Technology, Warangal. I would like to contribute to this organization in view of GSoC 2019. Any mentor is requested to guide me regarding this and tell me where to get started. I am experienced with moderate C++ and have been using it extensively for over an year for my Data Structures and Algorithms course. I also have a basic knowledge of object oriented programming which I will improve over the course of the next few months as part my college curriculum. Thanks.

1 0

[uuid] constexpr uuid from string and ""_uuid literal
by Tobias Loew 24 Dec '18

24 Dec '18

Hi, while searching for constexpr GUID from string generators, I found https://gist.github.com/AlexBAV/b58e92d7632bae5d6f5947be455f796f . Since I still work with VS 2015, I wrote a C++11 constexpr version incl. boost-uuid generators. If there's interest adding this to boost uuid, please have a look at https://github.com/tobias-loew/constexpr-GUID-cpp-11 NB. This is not a finished version to be added to uuid. Comments and BOOST-Macros for constexpr needs to be added. Tobias -- Sent from: http://boost.2283326.n4.nabble.com/Boost-Dev-f2600599.html

1 0

ASIO TCP socket scalability for large scale connections
by hh h 24 Dec '18

24 Dec '18

Hi, In regard to ASIO TCP socket implementation, for each connections the server needs to open and to maintain a session, obviously there need be adequate RAM and CPU resources for supporting large connections, but does ASIO TCP socket itself has any limitation for connecting to large clients which could be over 10000 or more simultaneously? What will be the maximum connections a single ASIO TCP socket server can handle? Thank you.

3 5

Re: [boost] Should pass boost::asio::io_service by raw pointer or smart pointer?
by Vinnie Falco 24 Dec '18

24 Dec '18

On Thu, Dec 20, 2018 at 6:45 PM Richard Hodges <hodges.r(a)gmail.com> wrote: > ...even with Vinnie's easy to follow guide, it requires a hundred lines of > boilerplate to implement what amounts to one async method. Yes, that is kind of irritating. I've been working on some tools to make it easier. The function wrap_handler returns a new completion handler which wraps your function object (lambda) and inherits the allocator and executor of another completion handler: <https://github.com/vinniefalco/beast/blob/8afbc6090bded0cdfda46871d829ea778…> The class template base_handler<> is meant as a base class for composed operations, it holds the handler for you and it provides all the hooks. I notice that you didn't include an overload for asio_handler_invoke in your example, which will certainly cause undefined behavior in some cases: <https://github.com/vinniefalco/beast/blob/8afbc6090bded0cdfda46871d829ea778…> You can see both wrap_handler and handler_base used together to implement a composed operation, a flavor of async_read_some which has a built-in timeout: <https://github.com/vinniefalco/beast/blob/8afbc6090bded0cdfda46871d829ea778…> In particular, handler_base let me leave out all of the boilerplate which is nice. It is possible that with some adaptation these utilities can be used to achieve the result you desire. These experimental features will appear in Boost.Beast version 1.70.0. Regards

4 7

GitHub testing issues
by Cromwell Enage 22 Dec '18

22 Dec '18

Hi, everyone! Starting yesterday, I experienced failures on all my test builds. Their logs contain the following message: travis_time:end:1a83bdea:start=1545229245463720000,finish=1545229258317024000,duration=12853304000 [0Ktravis_fold:end:install.10 [0Ktravis_fold:start:install.11 [0Ktravis_time:start:04d79bf0 [0K$ ./b2 headers boost-install.jam: No such file or directory Jamroot:307: in boost-install ERROR: rule "boost-install.boost-install" unknown in module "Jamfile</Users/travis/build/CromwellEnage/boost-root>". libs/atomic/build/Jamfile.v2:38: in modules.load /Users/travis/build/CromwellEnage/boost-root/tools/build/src/build/project.jam:372: in load-jamfile /Users/travis/build/CromwellEnage/boost-root/tools/build/src/build/project.jam:64: in load /Users/travis/build/CromwellEnage/boost-root/tools/build/src/build/project.jam:89: in load-used-projects /Users/travis/build/CromwellEnage/boost-root/tools/build/src/build/project.jam:75: in load /Users/travis/build/CromwellEnage/boost-root/tools/build/src/build/project.jam:142: in project.find /Users/travis/build/CromwellEnage/boost-root/tools/build/src/build-system.jam:618: in load /Users/travis/build/CromwellEnage/boost-root/tools/build/src/kernel/modules.jam:295: in import /Users/travis/build/CromwellEnage/boost-root/tools/build/src/kernel/bootstrap.jam:139: in boost-build /Users/travis/build/CromwellEnage/boost-root/boost-build.jam:17: in module scope travis_time:end:04d79bf0:start=1545229258327432000,finish=1545229259660893000,duration=1333461000 [0K [31;1mThe command "./b2 headers" failed and exited with 1 during . [0m It's also happening on Appveyor, and just from looking at < https://github.com/boostorg/graph/pull/144>, I'm not the only one who is encountering these errors. Any help would be appreciated. Thanks! Cromwell D. Enage

7 11

New library proposal: Autodiff
by Matt Pulver 21 Dec '18

21 Dec '18

Hello, An automatic differentiation <https://en.wikipedia.org/wiki/Automatic_differentiation> C++ library - Autodiff - is released under the Boost License and is proposed for inclusion into Boost: - Github: https://github.com/pulver/autodiff - Boost Library Incubator: http://blincubator.com/bi_library/autodiff-2/?gform_post_id=1716 Features: - Instances of autodiff variables satisfy Boost's Conceptual Requirements for Real Number Types <https://www.boost.org/doc/libs/1_69_0/libs/math/doc/html/math_toolkit/real_…>. In fact the class and function template definitions are based upon the tables in this page. - No use of dynamic memory. The only member variable is a std::array<>. - Consistent with Boost's type promotion templates. When adding/multiplying/etc. variables of differing dimension number and sizes, the resulting data type is calculated at compile-time. - Single header-only file. - Intuitive and minimal API. Requirements: - C++17 compiler that supports constexpr if statements. There are a fair amount of calculations done at compile-time which would require messy SFINAE hacks to make this C++14-compatible. Todo: - A github build matrix that also includes clang and MSVC. - Additional documentation, including the mathematics. Feedback and endorsements for Boost Library inclusion are welcome and requested. Best regards, Matt

8 11

[parameter] Helping user libraries adjust to recent changes in GitHub develop branch
by Cromwell Enage 20 Dec '18

20 Dec '18

Hi, everyone! I've been contributing upgrades to Boost.Parameter functionality and documentation in the GitHub develop branch for the past couple of months. These upgrades include the addition of code generation macros for Boost.Parameter-enabled function call operators and support for perfect forwarding, and more upgrades are yet to come. It's been an enjoyable experience so far, but understandably there are some growing pains. I've taken pains to ensure that as long as user libraries access only the public interface of Boost.Parameter, they won't be affected by the changes. However, there are several notable libraries that currently use non-public portions of Boost.Parameter, so whenever possible I've submitted PRs to those libraries that either change the usage to access only public portions (preferred) or make quick fixes (temporary). I'm drawing off Peter Dimov's page < https://pdimov.github.io/boostdep-report/develop/parameter.html> as a guide to focus my efforts. As of this writing, I have active PRs for the following libraries: Boost.Convert Boost.Graph Boost.Lockfree I also have my eye on the following libraries, which I know have been broken by the latest changes: Boost.Accumulators Boost.Log I'm willing to help the library maintainers resolve these issues as quickly as possible. This post can serve as a discussion starting point, and I should be able to answer any questions you have about the changes to Boost.Parameter. Cromwell D. Enage

1 0

Feature/cmake-config merged to develop; yml files need to be updated
by Peter Dimov 19 Dec '18

19 Dec '18

I've just merged the superproject branch feature/cmake-config to develop. This updates `b2 install` to export CMake configuration files into the `cmake` subdirectory of the library directory. These configuration files enable a Boost installation to be used from CMake via `find_package(boost_filesystem)`, without relying on FindBoost. Unfortunately, this change adds two necessary submodules to the superproject, `tools/boost_install` and `libs/headers`. As a result, all .travis.yml and appveyor.yml files that rely on a partial checkout need to be updated to perform git submodule update --init tools/boost_install git submodule update --init libs/headers in addition to the usual git submodule update --init tools/build git submodule update --init libs/config I'm sorry for the inconvenience this will cause, or perhaps already has caused.

5 7

Ignoring unused type aliases in concepts
by Mateusz Loskot 18 Dec '18

18 Dec '18

Hi, In concepts, such unused type aliases are not uncommon. What is the best way to ignore compiler warnings about those? Options I'm aware of are: 1. Adjust compile options in build configuration (Jamfile) 2. Use #pragma in headers 3. Use boost::ignore_unused_variable_warning(alias{}) (or little brother boost::ignore_unused) 4. Ignore ignoring them. The options 1 and 2 are mentioned on https://svn.boost.org/trac10/wiki/Guidelines/WarningsGuidelines The option 3 is not and is there any particular reason why? Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

5 16

Error to convert to boost::asio::streambuf to raw buffer char *buffer
by hh h 18 Dec '18

18 Dec '18

boost::asio::streambuf sb; char *raw = sb; error: cannot convert ‘boost::asio::streambuf {aka boost::asio::basic_streambuf<>}’ to ‘char*’ in initialization I've checked the boost::asio::streambuf reference, but could not find anything to fix it, appreciate any clues.

3 3

[cmake] Has the latest effort stalled?
by Andrey Semashev 17 Dec '18

17 Dec '18

Hi everyone, hi Robert, I've been informed[1] that the latest effort to call for CMake submissions and then review them collectively in February has stalled or failed. Is this true? What is the status of this effort, and if it's still on track, what is the current schedule? I'm asking because there is an ongoing effort by Mike-Devel (sorry, don't know your full name) to add minimalistic support for CMake across a number of Boost libraries, including those I maintain, and I've been holding off his submissions until after the review according to Robert's plan. If that plan is no longer in force, I might as well accept Mike's PRs and we (Boost as a whole) might as well accept his solution as the only one we have close to implementation. [1] https://github.com/boostorg/winapi/pull/73#issuecomment-447760554

2 1

Mixing async/sync code thanks to boost::context
by Christophe Bailly 16 Dec '18

16 Dec '18

Hello, I am new in this mailing list, I hope this is the right list to post my issue. Context: I often have to deal with some code which is originally synchronous. When we introduce an asynchronous call, all the callers must be made asynchronous with async/await everywhere. Let's take a concrete example: Suppose we have an existing synchronous library which makes computation. Suppose we can give a custom function to this library to compute a part of the calculation. We decide that this function will call a server... We may wish the main compute function to become asynchronous... Now the big question: Why isn't it possible so far to do this without changing all the functions ?? I find this really ugly, this is really difficult to make a good design. With asymetric async calls, I doubt this is possible, so I tried boost::context. In my example, the "library" is represented by the function calculate which is synchronous. It calls a function call_server which simulates the call to a server, in fact it will just wait for 5 seconds but in a asynchronous way. The main function will do a computation in parallel while the server will be called. You will find the code at the end of the mail. This sounds too good to be true but in this case, where did I miss something ? I haven't implemented a socket with a select but this would work, right ? The library can still be used in an asynchronous or synchronous context (with no extra cost). To help the understanding of the code, we have 3 tasks, the continuation are stored in the tasks vector. task are identified thanks to their indice in the vector: - 0: main task (id_main) - 1: reactor(id_reactor) - 2; computation_task (id_computation) I implement a kind of future, whose value is retrieved at the end of the main function and which launches a task to compute the value. Remarks: 1/ This is not optimised, we could make fewer context switches. There is no need for a specific task for the reactor, it could be called directly. 2/ The call_server function could detect automatically the sync or async context, if the reactor is not active (no waiting tasks to be run), then it would run i a synchronous way. 3/ This solution is based on a singleton for the reactor, but this is what we want, 4/ This could be certainly better coded, I am not an expert, I use to code more in Python and wanted to use C++ to see if I could solve these designs problems. I am curious to read what you think about this, I certainly missed something so please clarify and tell me if a clean solution is possible. Thanks a lot for reading. Regards, Chris #include <boost/lambda/lambda.hpp> #include <iostream> #include <iterator> #include <boost/context/continuation.hpp> #include <iostream> #include <string> #include <vector> #include <tuple> #include <queue> #include <time.h> int a = 0; int result = 0; namespace ctx = boost::context; std::vector<ctx::continuation> tasks; std::queue<int> tasks_to_run; std::vector<int> end_tasks; // list of tasks which ended using clock_info = std::tuple<int, time_t, int>; // task, start_time, duration using wait_info = std::tuple<int, int>; // source, target: source wainting for target to end std::queue<clock_info> clocks; // timer to wake up tasks std::queue<wait_info> waits; const int id_main = 0; const int id_reactor = 1; const int id_computation = 2; void add_clock(int task, int duration) { time_t start; time(&start); clocks.push(std::make_tuple(task, start, duration)); } void wait_for(int source, int target) { waits.push(std::make_tuple(source, target)); } void end(int task) { end_tasks.push_back(task); } ctx::continuation reactor(ctx::continuation && main_continuation) { ctx::continuation task; std::cout << "start reactor" << std::endl; tasks.push_back(std::move(main_continuation)); // add main continuation to list of tasks tasks_to_run.push(id_main); unsigned int k; time_t end_time; for (;;) { if (tasks_to_run.size()) { int id_task = tasks_to_run.front(); tasks_to_run.pop(); tasks[id_task] = tasks[id_task].resume(); } time(&end_time); for (k = 0; k < clocks.size(); k++) { clock_info clock = clocks.front(); int elapsed = end_time - std::get<1>(clock); if (elapsed > std::get<2>(clock)) { tasks_to_run.push(std::get<0>(clock)); } else clocks.push(clock); clocks.pop(); } for (k = 0; k < waits.size(); k++) { wait_info wait = waits.front(); if (std::find(end_tasks.begin(), end_tasks.end(), std::get<1>(wait)) != end_tasks.end()) { tasks_to_run.push(std::get<0>(wait)); } else waits.push(wait); waits.pop(); } } return std::move(main_continuation); } struct int_future { std::function<int()> func; int future_result; int_future(std::function<int()> f) :func(f) {} auto make_task() { return [this](ctx::continuation && main_cont) { tasks[id_reactor] = main_cont.resume(); future_result = this->func(); end(id_computation); tasks[id_reactor] = tasks[id_reactor].resume(); return std::move(main_cont); }; } int get() { wait_for(id_main, id_computation); tasks[id_reactor] = tasks[id_reactor].resume(); return future_result; } }; int call_server() { std::cout << "waiting for server results" << std::endl; add_clock(id_computation, 5); tasks[id_reactor] = tasks[id_reactor].resume(); result = 5; std::cout << "server returned result " << result << std::endl; return result; } int calculate() { return 1 + call_server(); } int main() { ctx::continuation task; tasks.push_back(ctx::callcc(reactor)); std::cout << "launch computation task" << std::endl; int_future fut(calculate); tasks.push_back(ctx::callcc(fut.make_task())); tasks_to_run.push(id_computation); tasks_to_run.push(id_main); tasks[id_reactor] = tasks[id_reactor].resume(); std::cout << "main task running" << std::endl; for (int j = 0; j < 10; ++j) { std::cout << a << " "; } std::cout << std::endl; std::cout << "wait for future" << std::endl; std::cout << "future result:" << fut.get() << std::endl; }

4 6

[docs] Building docs for release?
by John Maddock 15 Dec '18

15 Dec '18

Is there now a way for quickbook docs that aren't integrated under /doc/ to be built automatically for each release? And if so, what's the magic incantation to test this? Many thanks! John. --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

2 1

Windows quarantines boost_1_68_0.7z
by Miguel Ojeda 15 Dec '18

15 Dec '18

Quick note: it seems that Windows currently quarantines boost_1_68_0.7z. Could someone from Boost please contact Microsoft to whitelist it? Thanks, Miguel

5 11

C++Now (BoostCon) 2019 Call for Submissions
by Jon Kalb 14 Dec '18

14 Dec '18

The C++Now (formerly BoostCon) 2019 Call for Submissions is now open. http://cppnow.org/announcements/2018/12/2019-call-for-submissions/ C++Now will be held in Aspen, Colorado on May 5th - 10th. Colorado has become trendy for C++ conferences, but BoostCon was here first. If you are interested in Boost Libraries and have never attended C++Now, you owe it to yourself to have the BoostCon experience. The best way to get your company to send you is to have an accepted submission. The deadline is early in the new year, so don’t delay. Jon Kalb Conference Chair C++Now

1 0

Let's discuss dropping support for msvc <= 9.0 (2008), gcc < 4.6, clang < 3.4
by James E. King III 13 Dec '18

13 Dec '18

During the Boost 1.69.0 release there was a regression on Visual Studio 2005 (msvc-8.0). Microsoft ended support for msvc-8.0 on December 4, 2016. I was going to argue we let it happen, but it wasn't the right time to discuss that sort of change. Boost has a very large compatibility matrix which increases the effort required, and sometimes limits solutions development, to get out a quality release. The boost project as a whole agreed in summer 2018 that if repository maintainers wanted to drop C++03 support per repository to make substantial improvements or simplifications, or to ease maintenance then they are able to do so. *Folks who need support for older language levels and older compilers can always download an older version of Boost.* The compilers I mentioned in the subject have trouble with C++11 and are no longer maintained. msvc-8.0 (Visual Studio 2005) ended support Dec 10 2016 msvc-9.0 (Visual Studio 2018) ended support April 10 2018 The last release of gcc 4.6 was April 12, 2013 The last release of gcc 4.5 was July 02, 2012 The last release of gcc 4.4 was March 13, 2012 The compilers by default in Ubuntu Trusty 14.04.5 LTS, supported through April 2019, is gcc-4.8, currently at gcc-4.8.2, and clang 3.4 (however clang-3.8 is available). My argument is that this is a huge project, and maintaining backwards compatibility is not always efficiently possible. We spend build matrix resources testing and analyzing those tests. We find and develop fixes and workarounds. In some cases we hobble potential solutions to cater to decade-old compilers. Given the summer 2018 discussions about language level, and the aging vendor support matrix, I'd like us to consider dropping support for msvc <= 9.0 (2008), gcc < 4.6, clang < 3.4. What does this mean exactly? 1. We no longer test these compilers in the post-commit build matrix. 2. We no longer test these compilers in continuous integration. 3. We no longer develop fixes for issues that affect these compilers. 4. We are allowed, over time, to remove workarounds for these compilers. 5. We no longer block releases due to incompatibility with these compilers. 6. We remove these compilers from the documented environments in the release notes. 7. We direct anyone looking for support of these compilers to download a previous release of Boost that given them that support. 8. We do not update older Boost releases to fix issues with older compiler support. What would we remove from the release notes as a result? primary: linux: clang: c++03: 3.0 c++0x: 3.0 c++11: 3.0, 3.1, 3.2, 3.3 gcc: c++03: 4.4.7, 4.5.3 c++0x: 4.4.7 windows: gcc: c++03: 3.4.5, 4.1.2, 4.2.4, 4.3.3, 4.4.0, 4.5.4 msvc: - msvc-7.0 (Visual C++ 7.1) - msvc-8.0 (Visual Studio 2005) - msvc-9.0 (Visual Studio 2008) additional: linux: clang: c++03: 3.0, 3.8.1, 3.9.1, 4.0.1 c++0x: 3.0 c++11: 3.0, 3.1, 3.2, 3.3 gcc: c++03: 4.4.7, 4.5.3 c++0x: 4.4.7 windows: gcc: c++03: 3.4.5, 4.1.2, 4.2.4, 4.3.3, 4.4.0, 4.5.4 msvc: - msvc-7.0 (Visual C++ 7.1) - msvc-8.0 (Visual Studio 2005) - msvc-9.0 (Visual Studio 2008) The release notes section on compiler compatibility should probably be updated to match the current state of the post-commit matrix and duplicates in the "additional" section that are present in the "primary" section should be removed, or simply merge them. Why do we have a distinction here? Thanks for your consideration, Jim

12 16

Is disabling boost log auto flush the only way to control the log flush? Or can you change log auto flush rate?
by hh h 13 Dec '18

13 Dec '18

Hi, I use boost log in an embedded system where flushing log message to flash storage need be controlled. I could not find how to change log auto flush rate, is it the only way to disable auto flush boost::log::keywords::auto_flush = false? I think there must be a way to change a desired log flush rate value without disabling auto flush, appreciate any tips. Thank you. JHH

2 2

[coroutine] Boost.Coroutine 1.0 Deprecation Warning
by Vinnie Falco 13 Dec '18

13 Dec '18

Can we please turn off this deprecation warning for now? At least when Boost.Coroutine is being included to work with Asio? I get neverending complaints from users about this warning in Beast: <https://travis-ci.org/vinniefalco/beast/jobs/466272022#L1091> I am of course defining BOOST_COROUTINES_NO_DEPRECATION_WARNING: <https://github.com/boostorg/beast/blob/010fb4b08c05ce82cf4a87d9985c5b4998d9…> But this warning happens when building the coroutine library not when compiling Beast's tests and examples. Regards

3 2

[release] 1.70.0 open for merging
by Marshall Clow 12 Dec '18

12 Dec '18

The master branch is open for merging all stable changes from develop, including bug fixes and major upgrades to existing libraries. Breaking changes should be coordinated via the mailing list with the developers of the other libraries affected. New libraries may be added, but require permission of a release manager. In other words, merging does not require permission from a release manager, except for new libraries. Boost Calendar with the release schedule: http://www.boost.org/development/index.html Release schedule explanation: https://github.com/boostorg/boost/wiki/Release-Schedule Release practices for developers: http://svn.boost.org/trac/boost/wiki/ImprovingPractices -- The Boost Release Team

2 1

GSOC-19 Ideas
by Arihant Samar 12 Dec '18

12 Dec '18

Dear Boosters, I am new to the community. I wanted to ask if there will be any new suggested GSOC ideas for 2019. I went through the suggested proposals of 2018 but projects have already been done on most of them so It will be helpful if you could give some starting points. Sent from Mail for Windows 10 --- This email has been checked for viruses by Avast antivirus software. https://www.avast.com/antivirus

2 2

[release] Boost 1.69.0
by Marshall Clow 12 Dec '18

12 Dec '18

Release 1.69.0 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 numerous enhancements and bug fixes for existing libraries. For details, including download links, see < http://www.boost.org/users/news/version_1.69.0> You can also download directly from: < https://dl.bintray.com/boostorg/release/1.69.0/> SHA-256 sums: af05616f71006f97833e130aad886c96136457511ace4b5496d6566e69cbe0ca boost_1_69_0.7z 8f32d4617390d1c2d16f26a27ab60d97807b35440d45891fa340fc2648b04406 boost_1_69_0.tar.bz2 9a2c2819310839ea373f42d69e733c339b4e9a19deab6bfec448281554aa4dbb boost_1_69_0.tar.gz d074bcbcc0501c4917b965fc890e303ee70d8b01ff5712bae4a6c54f2b6b4e52 boost_1_69_0.zip 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. Thanks, -- The Boost Release Team Vladimir Prus, Marshall Clow, Daniel James, Micheal Caisse

2 3

[release] 1.69.0 closed for release
by Marshall Clow 12 Dec '18

12 Dec '18

The master branch is now closed for all changes except by permission. The commit-bot isn't running on master, so the super project will need to be manually updated for any changes. If all goes well, the release candidate should be out later today. Thanks, -- The Boost Release Team

4 7

The Master branch is still closed; it will be opened tomorrow
by Marshall Clow 12 Dec '18

12 Dec '18

Thanks for your patience -- The boost release managers

1 0

Fwd: [run-clang-tidy] new replacement overlaps with an existing replacement
by Mateusz Loskot 11 Dec '18

11 Dec '18

(I'm forwarding here my clang-tidy problem I posted to cfe-user mailing list, since it touches Boost library, a highly templated library, and I'm hoping we have experienced clang-tidy users among Boost developers. Considering it a part of Boost library development, I hope it is not off-topic here.) ---------- Forwarded message --------- From: Mateusz Loskot <mateusz(a)loskot.net> Date: Mon, 10 Dec 2018 at 22:14 Subject: [run-clang-tidy] new replacement overlaps with an existing replacement To: <cfe-users(a)lists.llvm.org> Hi, I'm running clang-tidy 7.0 (also tried 5.0) to modernise some aspects of Boost.GIL (https://github.com/boostorg/gil) source code. I've noticed, clang-tidy 7.0 (also 5.0) does not apply fixes for some of modernize-use-* checks, especially modernize-use-using. I run it this way: ``` cd ${BOOST_ROOT}/libs/gil cmake -S . -B _build -DCMAKE_EXPORT_COMPILE_COMMANDS=ON .. run-clang-tidy.py -p=_build -header-filter='boost\/gil\/.*' -checks='-*,modernize-use-using' -fix ``` Then, I see huge number of "The new replacement overlaps with an existing replacement." diagnostics. Below, I copied an extract that hopefully is useful to figure out what is happening and going wrong. Basically, there are two class templates and a bunch of tag types: 1. file_stream_device https://github.com/boostorg/gil/blob/e0288ece9ec50534e7d02166863d6799a5932e… 2. get_write_device with partial specialisations, `enable_if`-ed https://github.com/boostorg/gil/blob/e0288ece9ec50534e7d02166863d6799a5932e… The file_stream_device is specialised for a tag and final get_write_device specialisation is matched. And, clang-tidy tries to substitute this alias in get_write_device typedef detail::file_stream_device< FormatTag > type; not with using type = detail::file_stream_device< FormatTag > ; but with `using type` for each FormatTag-based specialisation ``` New replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<bmp_tag>" Existing replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<FormatTag>" The new replacement overlaps with an existing replacement. New replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<bmp_tag>" Existing replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<FormatTag>" The new replacement overlaps with an existing replacement. New replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<jpeg_tag>" Existing replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<FormatTag>" The new replacement overlaps with an existing replacement. New replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<png_tag>" Existing replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<FormatTag>" The new replacement overlaps with an existing replacement. New replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<png_tag>" Existing replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<FormatTag>" The new replacement overlaps with an existing replacement. New replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<png_tag>" Existing replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<FormatTag>" The new replacement overlaps with an existing replacement. New replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<pnm_tag>" Existing replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<FormatTag>" The new replacement overlaps with an existing replacement. New replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<targa_tag>" Existing replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<FormatTag>" The new replacement overlaps with an existing replacement. New replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<targa_tag>" Existing replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<FormatTag>" The new replacement overlaps with an existing replacement. New replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<tiff_tag>" Existing replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<FormatTag>" The new replacement overlaps with an existing replacement. New replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<tiff_tag>" Existing replacement: /mnt/d/boost.wsl/libs/gil/include/boost/gil/io/get_write_device.hpp: 1885:+52:"using type = detail::file_stream_device<FormatTag>" The new replacement overlaps with an existing replacement. ``` Why clang-tidy tries to re-fix the typedef with new replacement instead of keeping the existing one, the generic one? i.e. using type = detail::file_stream_device<FormatTag> I've tried to prepare a minimal example, but I couldn't reproduce this issue. I observed, that if I manually prepare compile_database.json with single .cpp file that just `#include <boost/gil/io/device.hpp>`, that is the header with definition of the base templates and no definitions with higher level specialisations for format tags are included, then clang-tidy applies the expected fixes without any warnings. Could anyone share any insights about this issue? Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

1 1

How to install boost core
by Nipun Ramani 11 Dec '18

11 Dec '18

I am very new to boost and I have been wanting to build the library from scratch. I am using CMake with VS2017. I successfully created the project files of boost-core using CMake however I am unable to locate .lib file or .dll file after I run the build in VS2017.

2 1

[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

1 1

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

4 3

Will the boost::asio::streambuf keep in sequency order when ostream write to boost::asio::streambuf multiple time?
by hh h 10 Dec '18

10 Dec '18

Hi, Are there any problems in following statements? The receiver works a few minutes, then got wrong number in header field. std::shared_ptr<boost::asio::streambuf> buffer = std::make_shared<boost::asio::streambuf>(); std::ostream os(buffer.get()); os.write((char *) &sendHeader, sizeof(sendHeader)); os.write((char *) sb.data(), sb.size()); boost::asio::async_write(socket_, *buffer.get(), .....); Thank you. - JHH

2 1

Is the async_read more reliable than async_read_some?
by hh h 09 Dec '18

09 Dec '18

Hi, I have been using asio::async_read with protobuf for some time, it is relative easy to use protobuf function SerializeToOstream to attach a packet header and send the packet header along with to protobuf message, with fixed packet header size and message size in the header, I was able to use async_read. But I have to change to use msgpack which I could not find a way like protobuf to attach a packet header to msgpack message. The only way I could do is to use async_read_some, but I am very concerning the remark in the async_read_some document. Appreciate your comments. "The read operation may not read all of the requested number of bytes. Consider using the async_read function if you need to ensure that the requested amount of data is read before the asynchronous operation completes." Thank you. - JH

3 9

Re: [boost] Can we skip the __boost_check_library__.test ?
by Rene Rivera 07 Dec '18

07 Dec '18

Rerouting to appropriate lists.. On Sun, Dec 2, 2018 at 6:00 PM Kuhl, Brian via Boost-build < boost-build(a)lists.boost.org> wrote: > Hi Boost builders, > > We currently running the Boost test suite using ./b2 in the status > directory. > > We run nightly on several simulators and real boards using ARM, PowerPC, > Intel processors compiling Boost 1.68 with clang and GCC > > Our test results are being peppered with the occasional failure of > __boost_check_library__ > > I’m pretty sure we don’t care about the results of this test in the > context cross-compiling VxWorks? > Probably not. > What exactly is it testing for? > It checks various requirements and guidelines of the library structure. > And assuming it isn’t relevant, how do we “turn it off”? > Add the "--no-check-libs" per < https://github.com/boostorg/boost/blob/develop/status/Jamfile.v2#L18> (I believe running b2 --help in that dir would have shown you that info also). > The library Jam files don’t have an explicit reference to this that I can > find? > It's added here < https://github.com/boostorg/boost/blob/develop/status/Jamfile.v2#L119>. And it runs this script < https://github.com/boostorg/boost/blob/master/status/boost_check_library.py >. -- -- Rene Rivera -- Grafik - Don't Assume Anything -- Robot Dreams - http://robot-dreams.net

2 1

[release] Boost 1.69.0 Release Candidate 1
by Marshall Clow 07 Dec '18

07 Dec '18

The release candidates for the 1.68.0 release are now available at: <https://dl.bintray.com/boostorg/release/1.69.0/source/> The SHA256 checksums are as follows: af05616f71006f97833e130aad886c96136457511ace4b5496d6566e69cbe0ca boost_1_69_0_rc1.7z 8f32d4617390d1c2d16f26a27ab60d97807b35440d45891fa340fc2648b04406 boost_1_69_0_rc1.tar.bz2 9a2c2819310839ea373f42d69e733c339b4e9a19deab6bfec448281554aa4dbb boost_1_69_0_rc1.tar.gz d074bcbcc0501c4917b965fc890e303ee70d8b01ff5712bae4a6c54f2b6b4e52 boost_1_69_0_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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Executable files in Boost git repostories
by Edward Diener 06 Dec '18

06 Dec '18

We have again run into the situation where files with a Linux executable permission have been committed to various Boost git repositories, with Jim King creating a PR and list of these files in Boost Admin. I have fixed these for the repositories for which I have write access, and created PRs for the other repositories. But this begs the question as to what Boost's stance should be about adding actual executable files to a Boost git repository ? As an example a Linux bash command file was added to a particular repository and I created a PR to remove the executable file permission from the file. But the maintainer of the repository feels this is wrong and the Linux bash file should retain the executable file permissions and that the file should be part of the repository. But of course I am more interested here about the general principal of the matter. Obviously operating system command/batch files are executable files, but should they be so in a repository. Finally should be not have some sort of git hook that somehow eliminates this recurring problem of files with executable permissions being periodically committed to a Boost git repository ? Most all of the files I "fixed" or created PRs for are clearly source files what can not be "executed" in any way. But this happening again is a real problem to have to clean up each time.

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Reminder: Boost Master branch will close for release tomorrow (12/5)
by Marshall Clow 05 Dec '18

05 Dec '18

Calendar at https://www.boost.org/development -- Marshall

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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] [graph] Tree data structure
by Bjorn Reese 02 Dec '18

02 Dec '18

On 11/28/18 11:51 AM, Jeremy Murphy via Boost wrote: > long ago, back in 2002 and 2009, Kasper Peeters proposed adding his tree > data structure to Boost. There is also Rene's proposal, which sounds like a useful Boost library: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2013/n3700.html

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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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