December 2022 - Boost-users

receive handler priority
by Alexander Carôt 28 Dec '22

28 Dec '22

Hello all, I have a classical receive handling structure for an asynchronous UDP socket: void receiver::receive(){ mySocket->async_receive_from( boost::asio::buffer(input, maxInputLength), senderEndpoint, boost::bind(&receiver::handleReceiveFrom, this, boost::asio::placeholders::error, boost::asio::placeholders::bytes_transferred)); } void receiver::handleReceiveFrom(const boost::system::error_code &error, size_t bytes_recvd) { // SPECIFIC CODE HERE AND FINAK CALL OF RECEIVE FUNCTION this->receive(); } Besides this my app works with several realtime threads I have assigned maximum priority to via: pthread_t threadID = (pthread_t) sendThread.native_handle(); struct sched_param param; int policy = SCHED_FIFO; int max = sched_get_priority_max(policy); param.sched_priority = max; pthread_setschedparam(threadID, policy, &param); Now I wonder in how far these realtime threads can have an impact on the performance of my receiver process: So far I assumed that the receiver handle code is executed immediately when a packet arrives at the NIC but I am not sure if other realtime threads might possibly delay this process when scheduled first. In other words: If we think of the receiver handling process as a thread that is triggered by incoming packets does this thread also have realtime capabilities that can suffer from competing processes ? Thanks in advance for clarification, best Alex -- http://www.carot.de Email : Alexander(a)Carot.de Tel.: +49 (0)177 5719797

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Abwesenheitsnachricht: boost::detail::spinlock problem
by Sören Textor 21 Dec '22

21 Dec '22

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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boost::detail::spinlock problem
by Cliff Diamond 21 Dec '22

21 Dec '22

Hi I'm using boost::detail::spinlock (boost-1.81) in code that compiles on both Visual Studio and gcc. I've hit a problem on the gcc build where the underlying spinlock member (v_) in spinlock_gcc_atomic.hpp isn't an atomic variable and isn't explicitly initialised (BOOST_DETAIL_SPINLOCK_INIT is defined, but there's no initializer and no constructor). v_ is declared as a non-atomic unsigned char and atomic operations use gcc intrinsics in that file. So v_ needs to be explicitly initialized to 0. When the lock method is called, it just spins as a result. This may be work-in-progress or am I misunderstanding? It seems such a glaring omission. The STL version of the spinlock uses std::atomic which does initialize v_ because it's wrapped up in the atomic template. Also there is a scoped_lock nested class within the boost spinlock. Why have an additional lock guard? Surely std::scoped_lock should be sufficient (or is it there just for testing - if so please comment it). I can overcome the problem (without modifying spinlock_gcc_atomic.hpp) by trying to acquire the lock when I create it and releasing it regardless. Is this a bug in that file? Thanks Cliff

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Boost IOStreams with CMake (CPMAddPackage) and Windows
by Richard Haney 17 Dec '22

17 Dec '22

Good afternoon, Hello everyone, I am new to this forum and new to *Boost* and *CMake* but eager to learn. So please forgive if this is a dumb question, but I am new to *Boost* and *CMake*. I have had success using *Boost.Iostreams* with Linux OS and CMake using *CPMPackageAdd* call for *boost_iostreams* library using compression and decompression with the following C++ code (the exact line of code that generates the error is shown below): #include <boost/iostreams/device/array.hpp> #include <boost/iostreams/device/back_inserter.hpp> #include <boost/iostreams/filtering_stream.hpp> #include <boost/iostreams/filter/zlib.hpp> #include <vector> #include <string> #include <iostream> #include <cstdlib> using namespace boost::iostreams; int main(int argc, char *argv[]) { // --------------------------------- // - COMPRESS DATA - // --------------------------------- std::vector<char> v; back_insert_device<std::vector<char>> snk{v}; filtering_ostream os; os.push(zlib_compressor{}); // This results in the Windows error zlib os.push(snk); os << "Boost" << std::flush; os.pop(); // --------------------------------- // - DECOMPRESS DATA - // --------------------------------- array_source src{v.data(), v.size()}; filtering_istream is; is.push(zlib_decompressor{}); is.push(src); std::string s; is >> s; std::cout << s << '\n'; return EXIT_SUCCESS; } However, when I try to use the same code on a Windows machine with MSVC compiler it generates errors explaining that* boost::iostreams::zlib is undefined *during linking. I am using *CMakeLists.txt* and would like to know if I can use *CMake* to properly build/compile for both Windows OS and Linux such that I can use the boost iostreams library with maybe an option in the *CPMAddPackage* call (maybe?). Is this possible? Can anyone point me in the correct direction with some simple example(s) if possible or links to existing solutions/hints to this same issue? I appreciate any assistance with this. Thank you for your time.

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[release] Boost 1.81.0
by Marshall Clow 14 Dec '22

14 Dec '22

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

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missing relaxed constexpr macros
by Gero Peterhoff 09 Dec '22

09 Dec '22

Hi John, i miss these for C++17/20/23 in boost/config. Can you retrofit this? thx Gero It could look like this: see https://en.cppreference.com/w/cpp/feature_test#__cpp_constexpr #if (__cpp_constexpr < 201703L) #define BOOST_NO_CXX17_CONSTEXPR #endif #if defined(BOOST_NO_CXX17_CONSTEXPR) #define BOOST_CXX17_CONSTEXPR #else #define BOOST_CXX17_CONSTEXPR constexpr #endif #if (__cpp_constexpr < 202002L) #define BOOST_NO_CXX20_CONSTEXPR #endif #if defined(BOOST_NO_CXX20_CONSTEXPR) #define BOOST_CXX20_CONSTEXPR #else #define BOOST_CXX20_CONSTEXPR constexpr #endif #if (__cpp_constexpr < 202207L) #define BOOST_NO_CXX23_CONSTEXPR #endif #if defined(BOOST_NO_CXX23_CONSTEXPR) #define BOOST_CXX23_CONSTEXPR #else #define BOOST_CXX23_CONSTEXPR constexpr #endif

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Does Boost.Multiprecision have a forwards declaration header?
by Ivan Matek 04 Dec '22

04 Dec '22

I presume not since I could not find it in docs, but decided to double check. My motivation is that I would like to limit heavy includes in my header(since intrinsics for avx512 files are 20k+ LOC on my system), but I would still like to use proper types in signature of my functions (since none of them take .args by value fwd declarations would be enough). So I was hoping for something like iosfwd. If it matters what part of library I am using: cpp_int.hpp P.S. I checked if telling compiler that I do not want arch support for avx512 would help, but it looks like avx512 intrinsics headers are included regardless, and even if it was not I would still like to not get into issues when compiling for HW that supports avx512. :) regards, Ivan

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