April 2025 - Boost-users - lists.stage.boost.cppalliance.org

Issues with boost executor_work_guard
by João Fernando Silva 22 Apr '25

22 Apr '25

Hello all, We are facing some issues with boost::asio::executor_work_guard. We are spawning some threads which are bound to a boost::asio::io_context and proteced by a boost::asio::executor_work_guard so that they do not exit even if there is no work to be done. However, despite the work_guard still being valid, we see that the threads exit because boost::asio::detail::scheduler::outstanding_work reaches 0. All operations added to the queue are posted asynchronously. The boost version in use is 1.75 (also tested with 1.78 and the behaviour is the same). Could you help us on the following topics so that we can understand what the root cause may be? 1 - We created an implementation to track the number of elements on boost::asio::detail::op_queue, is this implementation valid? uint32_t size() { auto tmp_op = front_; uint32_t size{0}; while (tmp_op != 0) { ++size; tmp_op = op_queue_access::next(tmp_op); } return size; } 2 - Assuming the approach above is correct, we are trying to compare the values of outstanding_work with the returned value of op_queue.size(). However, these values do not seem to correlate, is this to be expected? 3 - Was this issue observed by someone else? If so what were the root causes? Thanks! Kind Regards, João Silva The information in this communication may contain confidential or legally privileged information. It is intended solely for the use of the individual or entity it addresses and others authorized to receive it. If you are not an intended recipient, you are hereby notified that any disclosure, copying, distribution or action in reliance on the contents of this information is strictly prohibited and may be unlawful. If you have received this communication by error, please notify us immediately by responding to this e-mail and then delete it from your system. Critical TechWorks is not liable for the proper and complete transmission of the information in this communication nor for any delay in its receipt This e-mail is environmentally friendly, just like Critical TechWorks, which lives in a paper-free atmosphere. Therefore, please consider the environment before printing it!

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boost.parser parse int or double?
by kila suelika 12 Apr '25

12 Apr '25

``` #include <boost/parser/parser.hpp> #include <iostream> #include <string> #include <variant> namespace bp = boost::parser; auto numeric_parser = bp::int_ | bp::double_; //auto numeric_parser = bp::double_ | bp::int_; void parse_number(const std::string& input) { auto result = bp::parse(input, numeric_parser); if (result) { std::visit([](auto&& arg) { using T = std::decay_t<decltype(arg)>; if constexpr (std::is_same_v<T, int>) std::cout << "Integer: " << arg << std::endl; else if constexpr (std::is_same_v<T, double>) std::cout << "double: " << arg << std::endl; }, *result); } else { std::cout << "Parsing failed:" << " (" << input << ")" << std::endl; } } int main() { parse_number("24"); parse_number("24.3"); return 0; } ``` Above code failed to parse "24.3" which makes me confused. First int should failed but why it didn't match double? If use ``` auto numeric_parser = bp::double_ | bp::int_; ``` then all number parsed to double.

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[release] Boost 1.88.0
by Marshall Clow 11 Apr '25

11 Apr '25

Release 1.88.0 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. The release contains two new libraries: * Hash2: An extensible hashing framework, from Peter Dimov and Christian Mazakas. * MQTT5: MQTT5 client library built on top of Boost.Asio, from Ivica Siladić, Bruno Iljazović, and Korina Šimičević. as well as numerous enhancements and bug fixes for existing libraries. For details, including download links, see <http://www.boost.org/users/news/version_1.88.0> You can also download directly from: <https://archives.boost.io/release/1.88.0/source/> To install this release on your system, see <http://www.boost.org/doc/libs/release/more/getting_started/index.html> Thanks to everyone who participated in this release. -- The Boost Release Team Marshall Clow, Glen Fernandes, Ion Ion Gaztañaga

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[boost] [OpenMethod] Boost.OpenMethod review scheduled
by Дмитрий Архипов 11 Apr '25

11 Apr '25

The review for the proposed Boost.OpenMethod library by Jean-Louis Leroy is scheduled to take place from April 28 to May 07. OpenMethods solve the Expression Problem by making it possible to define free virtual functions, i.e. virtual functions that exist outside of a class The library repository is here: https://github.com/jll63/Boost.OpenMethod. The documentation is here: https://jll63.github.io/Boost.OpenMethod.

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Re: [Boost-users] JSON Schema support in C++ with boost::json?
by Alex 08 Apr '25

08 Apr '25

> 3. Generate validation code that can emit informative messages about failed validation. Valijson ( https://github.com/tristanpenman/valijson ) apparently supports Boost.Json for schema validation, although I haven't used it personally. Most C++ implementations of schema validation don't support a lot of the newer JSON schema versions. You could take a look at some of the C++ tools at https://json-schema.org/tools?query=&sortBy=name&sortOrder=ascending&groupB… Regards, Alex Simpson

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JSON Schema support in C++ with boost::json?
by Nigel Stewart 07 Apr '25

07 Apr '25

Hello all, There are a couple of things I'd like to do with JSON Schema in C++, which are similar to protobuf, but JSON-centric. 1. Generate a C++17 struct from a JSON Schema, names, types, optionality, nested data, arrays. 2. Generate C++17 code for serialising to/from the natve C++17 struct. 3. Generate validation code that can emit informative messages about failed validation. Seems to me this problem isn't specific to our application stack. Essentially we want to pass state between NodeJS and core C++ modules and have those interfaces evolve over time in a maintainable way. What's out there? - Nigel Stewart

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