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JSON and no-alloc
by Marc Oscar Singer 14 Aug '23

14 Aug '23

Greetings, I'm targeting the boost JSON library for an embedded target. There appears to be one place where there could be either a beneficial new feature, or the feature exists and I'm not seeing it. The section about Avoiding Dynamic Allocation is close to what we'd like to see, except that we don't want to depend on a stack buffer for value data. All of the text of the JSON message is present in the string view. It would be desirable to reference the values from there. Let me be a little more explicit. We receive a message in JSON format. The whole of this message must be received before we can pass it to the JSON parser. It's /possible/ to let the JSON parser manage the message as it arrives and manage both the parse and storage of the content. Doing so would require shifting some responsibilities within the firmware that are difficult to change. We parse out the fields we care about and then want to hold onto these values for some time without retaining the memory necessary for the parse itself. Since all of the values and keys are present in the original source buffer passed to parse() as a string_view, we could simply save the string_views for the values and discard the JSON parser. Except, this parser copies the value to another buffer s.t. discarding the parser invalidates the value string_views. Alternatively, if the values themselves were returned as string_views into the source buffer, these string_views would (could) survive destruction of the parser. If we are missing the method by which this can be implemented with the current parser, we'd be delighted to hear it. Cheers -- /Marc Oscar Singer/ *Woollysoft* +1.206.328.1718

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Abwesenheitsnachricht: JSON and no-alloc
by Sören Textor 14 Aug '23

14 Aug '23

Derzeit bin ich nicht im Hause Ihre E-Mail wird nicht weitergeleitet. In dringenden Fällen bitte support(a)ditec-gmbh.de oder Telefonhotline +49-6221-31698-110 oder die Zentrale +49-6221-31698-0 kontaktieren. Mit freundlichen Grüßen Dr. Sören Textor ----------------------------------------------- DiTEC Dr. Siegfried Kahlich & Dierk Langer GmbH Im Breitspiel 19 | 69126 Heidelberg | Germany Handelsregister | Mannheim | HRB 341229 Dieses Dokument ist vertraulich zu behandeln. Die Weitergabe, sowie Vervielfältigung, Verwertung und Mitteilung seines Inhalts ist nur mit unserer ausdrücklichen Genehmigung gestattet. Alle Rechte vorbehalten, insbesondere für den Fall der Schutzrechtsanmeldung. This document has to be treated confidentially. Its contents are not to be passed on, duplicated, exploited or disclosed without our express permission. All rights reserved, especially the right to apply for protective rights.

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Full-Text Search is LIVE!
by Vinnie Falco 10 Jul '23

10 Jul '23

Greetings. I am proud to announce that Mohammad’s excellent work on implementing a full-text search which looks into all the Boost libraries and their documentation is now complete, and has been published to the live website. You can access the search by pressing the Search button in the top right of the page: https://boost.org Please note that this is only the first iteration of this search tool and as such it will probably not give the perfect results that everyone expects every time. But now that we have something in place we can feedback, brainstorm on how to make it better, and iterate on it so that it evolves into something that consistently enhances the Boost user experience. To report problems or suggestions related to the search including the user interface, and the indexed contents, please open an issue in the Boost website repository: https://github.com/boostorg/website/issues There is also a “Report Issue” button in the search UI. Thanks!

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[Boost.TypeErasure] - Issue compiling under Windows with Embarcadero C++ Builder 11.3
by Andy Bell 07 Jul '23

07 Jul '23

Hi I'm using the type erasure library but have an issue (which I can workaround) when compiling in Windows 10 using Embarcadero C++ Builder 11.3. My problem is that C++ Builder brings in the Windows SDK Windows.h include file in every Windows VCL UI project it creates *before* any of my code has compiled and it's causing conflicts in boost header member11.hpp. This code is enough to cause the error: #include <boost/type_erasure/any.hpp> #include <boost/type_erasure/any_cast.hpp> #include <boost/type_erasure/builtin.hpp> #include <boost/type_erasure/operators.hpp> #include <boost/type_erasure/member.hpp> #include <boost/type_erasure/free.hpp> #include <boost/mpl/vector.hpp> namespace mynamespace { BOOST_TYPE_ERASURE_MEMBER(ReadStatus) } The error is because Windows.h defines 'interface' but this code from member11.hpp also uses 'interface': template<class P, template<class ...> class interface, class Sig, class Concept, class Base, class ID> using choose_member_interface = typename ::boost::mpl::if_c< ::boost::is_reference<P>::value, typename ::boost::mpl::if_c< ::boost::type_erasure::detail::is_non_const_ref<P>::value, interface<Sig, Concept, Base, const ID>, Base >::type, interface<Sig, Concept, Base, ID> >::type; and the compiler complains of conflicts. Embarcadero support have told me that I can't prevent Windows.h being included in my project before my boost-using code is compiled and attempts I've made to circumvent the problem, such as adding these lines to codegear.hpp: #ifdef interface #undef interface #endif don't work because C++ Builder is still including Windows.h before my code is compiled. To get around the problem, I changed member11.hpp in my boost installation to template<class P, template<class ...> class interface_, class Sig, class Concept, class Base, class ID> using choose_member_interface = typename ::boost::mpl::if_c< ::boost::is_reference<P>::value, typename ::boost::mpl::if_c< ::boost::type_erasure::detail::is_non_const_ref<P>::value, interface_<Sig, Concept, Base, const ID>, Base >::type, interface_<Sig, Concept, Base, ID> >::type; which I don't think will have side effects as 'interface/interface_' here is self-contained, but it doesn't feel like a good long term solution. Embarcadero support said: "Boost brings windows.h in because boost pulls it, *IF* the application is compiled for multi-threading then boost needs to access the OS threading functions, this is when you compile *without* the VCL." and I have confirmed this by creating a simple, multi-threaded Windows console application in C++ Builder... My question is: Is there a better way to work around this issue? My tests indicate that the Type Erasure library is working properly with my change, but it feels more like a hack than a fix... Thanks, Andy Bell Control Systems & Software Engineer Tel: +44 (0)1903 891700 Fax: +44 (0)1903 893888 Web: www.thermcosystems.com<http://www.thermcosystems.com/> www.csd-epi.com<http://www.csd-epi.com/> [cid:image002.png@01D9ADAA.693C8600] [Logo, company name Description automatically generated] P Please consider the environment before printing this email. This email and any files transmitted with it are confidential and intended solely for the intended recipient. If you are not the named addressee you should not disseminate, distribute, copy or alter this email. Any views or opinions presented in this email are solely those of the author and might not represent those of Tetreon Technologies Limited. Warning: Although Tetreon Technologies Limited has taken reasonable precautions to ensure no viruses are present in this email, the company cannot accept responsibility for any loss or damage arising from the use of this email or attachments. Tetreon Technologies Ltd is a limited company registered in England and Wales. Company Registration No. 4966845 Registered Offices: Highfield, Rock Road, Washington, West Sussex, RH20 3BH, England

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[asio] monitoring io_context load
by Dmitry 07 Jul '23

07 Jul '23

Hello, I would like to have a metric that measures time spent for work (executing completion handlers) vs time spent waiting for work in thread pool executing io_context::run(). It will help to estimate service capacity (i.e. how many more requests per second it can handle). It is similar to the system's CPU usage metric but CPU usage metric does not include waiting for mutex locks or sync io performed from completion handlers. In our performance tests io_context becomes overloaded (the queue grows faster than it's processed) when CPU usage is about 85%. I would like to have a metric that shows 100% in this case. There is BOOST_ASIO_CUSTOM_HANDLER_TRACKING macro that allows to intercept handler invocations and to measure execution time. But in the case of many lightweight handlers measuring time can bring significant overhead. I'm considering adding similar macros before and after waiting for the condition variable and epoll to measure wait time and then calculate execution time. I'm writing to ask if there is a better alternative? If not, would you be interested in a patch that adds "Handler Tracking" macros around wait calls? Thank you, Dmitry

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Please remove me from this list
by Vitaly Budovski 03 Jul '23

03 Jul '23

The web and email unsubscribe methods do not seem to work.

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[python][shared_ptr_from_python.hpp] looks like copy/paste or merge error
by Ran Regev 29 Jun '23

29 Jun '23

Hi, The code in construct() seems to surfer from copy/paste or merge error. It seems as though the following lines are duplicated in the else clause: void *const storage = ((converter::rvalue_from_python_storage<SP<T> >*)data)->storage.bytes; // Deal with the "None" case. if (data->convertible == source) new (storage) SP<T>(); Please take a look at: https://www.boost.org/doc/libs/1_82_0/boost/python/converter/shared_ptr_fro… Ran.

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[multiprecision] why 128 bit numbers isn't used in msvc?
by shar yashuv Giat 29 Jun '23

29 Jun '23

msvc added 128 bit numbers(in the header __msvc_int128.hpp). I know multiprecision uses __128 to improve performance so why doesn't it use msvc version? it's seems easy to change and will probably improve performance.

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assign a large integer to a cpp_int
by Matthew Mawson 27 May '23

27 May '23

I want to assign a large number to a cpp_int variable like this: cpp_int large = 30414093201713378043612608166064768844377641568960512000000000000; and I get this: error: integer literal is too large to be represented in any integer type. Thanks!

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Abwesenheitsnachricht: assign a large integer to a cpp_int
by Sören Textor 27 May '23

27 May '23

Derzeit bin ich nicht im Hause Ihre E-Mail wird nicht weitergeleitet. In dringenden Fällen bitte support(a)ditec-gmbh.de oder Telefonhotline +49-6221-31698-110 oder die Zentrale +49-6221-31698-0 kontaktieren. Mit freundlichen Grüßen Dr. Sören Textor ----------------------------------------------- DiTEC Dr. Siegfried Kahlich & Dierk Langer GmbH Im Breitspiel 19 | 69126 Heidelberg | Germany Handelsregister | Mannheim | HRB 341229 Dieses Dokument ist vertraulich zu behandeln. Die Weitergabe, sowie Vervielfältigung, Verwertung und Mitteilung seines Inhalts ist nur mit unserer ausdrücklichen Genehmigung gestattet. Alle Rechte vorbehalten, insbesondere für den Fall der Schutzrechtsanmeldung. This document has to be treated confidentially. Its contents are not to be passed on, duplicated, exploited or disclosed without our express permission. All rights reserved, especially the right to apply for protective rights.

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