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New video: Getting Started with Boost.Asio: Timers and Serial Ports
by Richard 15 Mar '23

15 Mar '23

Utah Cpp Programmers has released a new video Getting Started with Boost.Asio: Timers and Serial Ports <https://www.youtube.com/watch?v=XB3uEit5R_Y> I/O operations are inherently asynchronous -- we don't know when input will arrive and when output will be generated. Network I/O can be particularly bothersome because of the long delays between sending a request and obtaining the response. Boost.Asio is a cross-platform C++ library for network and low-level I/O programming that provides developers with a consistent asynchronous model using a modern C++ approach. Boost.Asio covers timers, serial ports, files, pipes and TCP/IP networking. This month, Richard Thomson will give us an introduction to Boost.Asio concepts and asynchronous programming with this library. We'll look at how to use timers to notify our application of time passing and how to talk to serial ports asynchronously. Other Utah Cpp Programmers videos: <https://www.youtube.com/@UtahCppProgrammers> -- "The Direct3D Graphics Pipeline" free book <http://tinyurl.com/d3d-pipeline> The Terminals Wiki <http://terminals-wiki.org> The Computer Graphics Museum <http://ComputerGraphicsMuseum.org> Legalize Adulthood! (my blog) <http://LegalizeAdulthood.wordpress.com>

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[release] Boost 1.82.0 beta 1 released
by Marshall Clow 15 Mar '23

15 Mar '23

Boost release 1.82.0 beta 1 is now available at: https://boostorg.jfrog.io/artifactory/main/beta/1.82.0.beta1/source/ The SHA256 checksums are: efe17bea3f0b2c11f34828f37d5777f30eb6fef57af355c6a6664b08a4339999 boost_1_82_0_b1.7z 0af2a60f76abb4f411b1bd9c1a553f64454d9414990e8cc12f02f3b431e2ac45 boost_1_82_0_b1.tar.gz 495b2ae2f6970ea1e635f80222d9f6978148496cdd163e87c37cdd6de3b5ccfc boost_1_82_0_b1.zip edf4cb9e8e5a14412b91311438478ef6ce12afe2a54714eb2f0632a454c3d8d5 boost_1_82_0_b1.tar.bz2 Release notes (still need updates): https://www.boost.org/users/history/version_1_82_0.html Please try the beta and report any problems you encounter. Thanks to everyone who contributed to the release. -- Boost Release Team

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ASIO: Support for SQPOLL in io_uring backend
by Cyan Reddish 15 Mar '23

15 Mar '23

Hi. I was wondering if anything like that is planned. I am also interested in other general io_uring options like setting affinity masks for IO worker threads.

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Boost Asio help
by Richard, Charles 01 Mar '23

01 Mar '23

Hi, I've been tasked with trying to figure out why we are getting an error in our log file, the error is "error: End of file". I'm still fairly new to doing real-world C++ development and I struggle with understanding why the code does what it does. The errors in our log file specifically are: 2023.02.20 08:45:49.470[UTC] [19626:140486796130176] TRACE - Process::CmdRunner::AsyncReadStdout<0x7fc594013b20> len = 0 2023.02.20 08:45:49.470[UTC] [19626:140486796130176] TRACE - Process::CmdRunner::AsyncReadStdout<0x7fc594013b20> error: End of file At a high level, my understanding is that we use Boost Asio to run python scripts where our C++ process will fork a new child process to run these python scripts. What I don't understand is why the code we have like the below was chosen to implement that functionality and to handle error handling. I've looked at some Asio boost tutorials but I still have gaps between our implementation and the Boost Asio tutorials and documentation. I'm also wondering why the a_errCode == boost::asio::error::eof is not seemingly catching the end of file. The code in the method CmdRunner::AsyncReadStdout does the following: void CmdRunner::AsyncReadStdout(boost::system::error_code a_errCode, size_t a_readSize) { DoLOG(TRACE, "Process::CmdRunner::%s<%p> len = %zu", __func__, this, a_readSize); if ( a_errCode ) { DoLOG(TRACE, "Process::CmdRunner::%s<%p> error: %s", __func__, this, a_errCode.message().c_str()) } if ( a_readSize > 0 ) { DoLOG(TRACE, "Process::CmdRunner::%s<%p> - read this: %zu bytes", __func__, this, a_readSize) _stdoutBufList.Copy(_stdoutReadBuf, a_readSize); // Call user callback to push out bytes Daemon::Service::DispatchEvent([this]() { _cbHandler(_cbCtxt, false); }); } else if ( a_errCode == boost::asio::error::eof ) { // Read done, call user callback function! DoLOG(TRACE, "Process::CmdRunner::%s<%p> - Child process (%d) STDOUT reached EOF", __func__, this, _childPid) _cmdDone = _eofStdout = true; _procStdout->close(); _procStderr->close(); Daemon::Service::DispatchEvent([this]() { _cbHandler(_cbCtxt, true); }); } else { // Async-read more, until EOF seen _procStdout->async_read_some(boost::asio::buffer(_stdoutReadBuf, PROC_READ_BUF_SIZE), [this](boost::system::error_code ec, std::size_t a_readSize) { AsyncReadStdout(ec, a_readSize); }); } } Any hints or specific links to look at to further clarify my understanding would be appreciated. Thanks! Chach Internal Use - Confidential

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Precompiled Windows ARM/ARM64 binaries
by Stephan Brunner 01 Mar '23

01 Mar '23

Hi, are there any plans to ship precompiled windows binaries for ARM and/or ARM64 at some time on SourceForge [1]? Currently only a x86 and a x64 build is available there. If not, I'll look into building my own version for those architectures. Thanks a lot! [1] https://sourceforge.net/projects/boost/files/boost-binaries/1.81.0/ -- Mit freundlichen Grüßen / Best regards Stephan Brunner, M.Sc. Matrix: @boomer41:boomer41.net PGP: 5FB325E81E548282D458A65114A30C9CE3AE4CE2

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Boost Libraries and Dropping C++ Language Support
by Glen Fernandes 23 Feb '23

23 Feb '23

*Boost library authors and maintainers are free to drop support for old C++ standards in their libraries, at any time. * This includes libraries that other Boost libraries depend on. It even includes core libraries like Boost.Core or Boost.Static_Assert. We ask that maintainers do the right thing by all our users (which may include other Boost libraries) by announcing a future breakage *at least two Boost releases in advance*. When that eventual release time arrives, if Boost libraries are broken in older standards modes due to another Boost library dropping support, it will not block the Boost release. This means that we do not need to announce "Boost is dropping C++03" because Boost doesn't "support C++03" now as it is. It means that you, maintainer of Boost.X, should realize that you are free to announce that "Boost.X is dropping C++XY in version 1.Z" as you see fit. Boost in its infancy thrived because its libraries were on the cutting edge. Boost libraries today should similarly not be confined simply because other Boost libraries have chosen to depend on them. Furthermore, as Boost release managers we support authors exercising this freedom, and do not intend to impose any restrictions on what language support they must maintain. We will add a page to the Boost website stating the above formally. -- The release team (Glen Fernandes, Marshall Clow)

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[iostreams] When plan to move to C++20
by Seyyed Soroosh Hosseinalipour 17 Feb '23

17 Feb '23

ITNOA I have question about the plan to migrate code base from C++03 to C++20 for iostreams library I think iostreams library have very more clean if using modern C++ features, such as Concept Did you have any plan about that? thanks

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Abwesenheitsnachricht: Re: [iostreams] When plan to move to C++20
by Sören Textor 17 Feb '23

17 Feb '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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boost serialization of non-POD 16bit float : Half
by Nicholas Yue 17 Feb '23

17 Feb '23

Hi, I am trying to serialize out the value of OpenEXR's Half type values. I came across mention that custom types requires something like the following ``` namespace boost { namespace serialization { template<class Archive> void serialize(Archive & ar, half & h, const unsigned int version) { ar & boost::serialization::make_nvp("value", h); } } // namespace serialization } // namespace boost ``` The code compiles but when I run it, it segfaults. Is boost serializer a suitable for such use case ? Cheers -- Nicholas Yue https://www.linkedin.com/in/nicholasyue/

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Unable to compile when using BOOST_DETAIL_SPINLOCK_INIT
by radiatejava 09 Feb '23

09 Feb '23

I have an existing code for an application that uses BOOST_DETAIL_SPINLOCK_INIT from boost/smart_ptr/detail/spinlock.hpp. It is all fine when using with boost ver 1.53. I am trying to migrate to boost ver 1.66 and now this compilation fails. To isolate the issue, I have a sample program: #include <iostream> #include <boost/smart_ptr/detail/spinlock.hpp> class BoostTest { public: BoostTest(int v): val(v), bLock(BOOST_DETAIL_SPINLOCK_INIT) { std::cout << "constructor called" << std::endl; } int getValue() { std::cout << "getValue() called" << std::endl; return val; } private: int val; boost::detail::spinlock bLock; }; int main() { std::cout << "starting test" << std::endl; BoostTest bt(10); std::cout << "value now " << bt.getValue() << std::endl; } With ver 1.66, it now gives me the error. Why this error after upgrade to 1.66? How do I correct it? $ g++ -std=c++11 -I/data/hdd/code/mgmt/common/external/boost/ifc/dist/include -c boosttest.cc boosttest.cc: In constructor 'BoostTest::BoostTest(int)': boosttest.cc:6:63: error: use of deleted function 'boost::detail::spinlock::spinlock(boost::detail::spinlock&&)' BoostTest(int v): val(v), bLock(BOOST_DETAIL_SPINLOCK_INIT) { ^ In file included from /data/hdd/code/mgmt/common/external/boost/ifc/dist/include/boost/smart_ptr/detail/spinlock.hpp:47:0, from boosttest.cc:2: /data/hdd/code/mgmt/common/external/boost/ifc/dist/include/boost/smart_ptr/detail/spinlock_std_atomic.hpp:27:7: note: 'boost::detail::spinlock::spinlock(boost::detail::spinlock&&)' is implicitly deleted because the default definition would be ill-formed: class spinlock ^ /data/hdd/code/mgmt/common/external/boost/ifc/dist/include/boost/smart_ptr/detail/spinlock_std_atomic.hpp:27:7: error: use of deleted function 'std::atomic_flag::atomic_flag(const std::atomic_flag&)' In file included from /usr/include/c++/4.8/atomic:41:0, from /data/hdd/code/mgmt/common/external/boost/ifc/dist/include/boost/smart_ptr/detail/spinlock_std_atomic.hpp:19, from /data/hdd/code/mgmt/common/external/boost/ifc/dist/include/boost/smart_ptr/detail/spinlock.hpp:47, from boosttest.cc:2: /usr/include/c++/4.8/bits/atomic_base.h:275:5: error: declared here atomic_flag(const atomic_flag&) = delete; ^

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boost::process : write both stdout and stderr to the same stream ?
by Nicholas Yue 02 Feb '23

02 Feb '23

Hi, Is it possible to write both the stdout and stderr stream to the same output file/stream ? I am hoping to emulate ``` bp_stdout_stderr_app > output.txt 2>&1 ``` I tried doing something like that but get a runtime error Run output ``` terminate called after throwing an instance of 'boost::process::process_error' what(): dup3() failed: Bad file descriptor stdout : 000 stdout : 020 stdout : 040 Aborted (core dumped) ``` Source code ``` #include <boost/process.hpp> #include <iostream> using namespace boost::process; int main() { ipstream pipe_stream; child c("bp_stdout_stderr_app", std_out > pipe_stream, std_err > pipe_stream); std::string line; while (pipe_stream && std::getline(pipe_stream, line) && !line.empty()) std::cerr << line << std::endl; c.wait(); } ``` Cheers -- Nicholas Yue https://www.linkedin.com/in/nicholasyue/

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boost::log - tmp output log with decorated name ?
by Nicholas Yue 26 Jan '23

26 Jan '23

Hi, I plan to use boost::log for my C++ application logging needs. Does boost log have a convenient function for generating decorated filename in /tmp ? Something along the line of <app_name>_<timestamp>_<process_id>_<thread_id>.log This allows me to accumulate logs between runs to capture and compare. Cheers -- Nicholas Yue https://www.linkedin.com/in/nicholasyue/

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Fwd: [boost.interprocess] Are there pitfalls using managed_shared_memory?
by M L 10 Jan '23

10 Jan '23

Are there common pitfalls when using boost::interprocess::managed_shared_memory in order to share a variable in the following way (Cpp,Windows OS)? managed_shared_memory managed_shm(open_or_create, "my_shm", 1024); // Write int *i = managed_shm.construct<int>("Integer")(42); // Read std::pair<int*, std::size_t> p = managed_shm.find<int>("Integer"); - Is the shared memory deleted, when the application is stopped? - Do other programs or services can bear with this method without crashing? -is there a danger that shared memory could be accumulated with some kind of overflow? Question: what does one have to consider when using this method? Thanks for help.

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ASIO openSSL 3 support
by Ofer Lent 03 Jan '23

03 Jan '23

Hi, https://www.boost.org/users/history/version_1_80_0.html, "Asio" section, states: "Fixed compatibility with OpenSSL 3.0.4 and later." However, API-s which were deprecated in openSSL 3 still exist in boost_1_80_0.tar.gz<https://boostorg.jfrog.io/artifactory/main/release/1.80.0/source/boost_1_80…> --> boost/asio/ssl/impl/context.ipp: · RSA_free · DH_free · d2i_RSAPrivateKey_bio · PEM_read_bio_RSAPrivateKey · SSL_CTX_use_RSAPrivateKey · SSL_CTX_use_RSAPrivateKey_file · PEM_read_bio_DHparams Is there a plan to update them? BTW - It is possible to build an application with these deprecated API-s by using CFLAGS += -Wno-deprecated-declarations, but in my understanding it is not acceptable for FIPS compliance. Thanks! ------------------------------------------- This message is confidential. If you believe you received this message in error, please inform the sender and delete this message and all attachments.

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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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[release] Boost 1.81.0 beta 1 released
by Marshall Clow 17 Nov '22

17 Nov '22

Boost release 1.81.0 beta 1 is now available at: https://boostorg.jfrog.io/artifactory/main/beta/1.81.0.beta1/source/ The SHA256 checksums are: 135f03965b50d05baae45f49e4b7f2f3c545ff956b4500342f8fb328b8207a90 boost_1_81_0_b1.tar.gz 736b041748d04c573d145613161cf2e54beb210c5511b67e6fac5510b82b6646 boost_1_81_0_b1.7z 941c568e7ac79aa448ac28c98a5ec391fd1317170953c487bcf977c6ee6061ce boost_1_81_0_b1.tar.bz2 c58d50acf58a98d4f5a7d891257d154efa50ca90312ca446586c7b4f9b7d3f14 boost_1_81_0_b1.zip Release notes (still need updates): https://www.boost.org/users/history/version_1_81_0.html Please try the beta and report any problems you encounter. Thanks to everyone who contributed to the release. -- Boost Release Team

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Partial serialization of a program
by Markus Lavin 06 Nov '22

06 Nov '22

I have a simulator type program where I want to be able to save (and load) the current simulation state using Boost serialization. The program, as with most programs, consists of a part that is static during run-time and a part that is dynamic. Ideally I would like to serialize only the dynamic part but this however raises the following problem. If a serialized object in the dynamic part contains a pointer to a non-seralized object in the static part then how do I deal with that. Clearly the address cannot be serialized since it may change between builds and even between runs (ASLR). The program does contain a 'registry' though where all relevant static objects are registered with a unique identifier. So question is would it somehow be possible to have Boost serialization use this registry to serialize the unique identifier instead of trying to serialize the entire object when one of those pointers are serialized? As far as I can tell the documentation does not mention this situation and extensive web searching yields very little as well. Any advice appreciated! -Markus

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Question about boost::multi_index emplace operations
by Pavel Vazharov 03 Nov '22

03 Nov '22

Hi there, Is there a way to emplace (key, value) in boost multi_index hashed index in such a way that the value is not moved/stolen if the key is already present? As far as I checked the implementation for emplace (and emplace_) the node is eagerly created and the key and the value are moved into the node and then the insertion operation takes place. If the insertion fails the node is destroyed but the outside value is lost/stolen in all cases. What I actually need is to create the value only if the key is not present, because the creation is expensive, and I'd like to avoid the find+emplace or insert empty value + modify call. (As far as I checked, the value can't be modified directly from the returned iterator because it's const and will need const_cast to work). I thought to use emplace with some machinery for lazy creation struct creator { operator value_type () { return ...; } // create the value lazily, on demand }; The creator is passed to emplace instead of the actual value. However, this doesn't help because the node is eagerly created and the above operator is always called. Thanks, Pavel.

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Re: [Boost-users] Cannot open boost lib file when building CLI dll
by Michael Pogue 28 Oct '22

28 Oct '22

> > I am trying to build a CLR dll file in VS22 and dotnet 6.0 that references >> boost. When I build, I get the following error. >> LNK1104 cannot open file 'libboost_program_options-vc142-mt-x64-1_76.lib' >> >> - This file does exist. >> - I have restarted to make sure the file isn't locked. >> - I have tried building as 32 and 64 bit. >> - I have tried 3 different versions of boost >> >> The problem is reproduced by this project: >> https://github.com/MajorMajor0/boostRepro. >> Any help would be much appreciated. >> >

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Norms methods
by General Magic - Teodora Bogdan 26 Oct '22

26 Oct '22

Hello, I was using the Boost library and I wanted to call the l2_norm() method from "boost/math/tools/norms.hpp", but is says that the namespace boost::math::tools doesn't contain l2_norm() method. When I looked into it, I saw that the namespaces at the beginning of the file were written"boost::math::tools" instead of "namespace boost { namespace math { namespace tools {...". Can this be fixed? Have a nice day, Teodora Bogdan CONFIDENTIALITY NOTICE: This e-mail and any attachments hereto may contain information that is privileged or confidential, and is intended for use only by the individual or entity to which it is addressed. Any disclosure, copying or distribution of the information by anyone else is strictly prohibited. If you have received this document in error, please notify us promptly by responding to this e-mail. DISCLAIMER: General Magic accepts no liability for the content of this email, or for the consequences of any actions taken on the basis of the information provided, unless that information is subsequently confirmed in writing and duly signed on behalf of General Magic by an authorized officer. Any views or opinions presented in this email are solely those of the author and do not necessarily represent those of General Magic. No employee or agent is authorized to conclude any binding agreement on behalf of General Magic with another party by email without express written confirmation which is duly signed on behalf of General Magic by an authorized officer. Thank you.

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Boost::serialization detection of Cxx Standard
by Georg Gast 14 Oct '22

14 Oct '22

Hi, I developed a patch and a test to serialize std::pmr::(w)strings in all 3 archive types. The test I set the requirement to <cxxstd>17. It works so far but when I compile the library for using it in my application the "hidden" functions behind "BOOST_NO_CXX17_MEMORY_RESOURCE" are not found by the linker as the define is set when the library is compiled. How to work around this? Bye Georg

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Is there any official documentation on shutdown procedure for ASIO SSL socket?
by Ivan Matek 11 Oct '22

11 Oct '22

There is this SO answer https://stackoverflow.com/a/25703699/ with Vinnie comment from 8y ago that it should be added to documentation. :) I can not find anything in the documentation so I presume the documentation/example does not exist, but I decided to double check. regards, Ivan

3 2

Very slow destructors of binary_oarchive and filtering_streambuf
by boost.5nyej＠simplelogin.com 03 Oct '22

03 Oct '22

Hello, I just posted a question on StackOverflow, but I realised that this mailing list might be a better place. The link to the question is: https://stackoverflow.com/questions/73938656/very-slow-destructors-of-binar… Tl;dr; I have a code that serializes a big object by using binary_oarchive and filtering_bufstream. The writing on its own takes around 28 minutes, but the deconstructors of the mentioned classes take 37 and 36 minutes, respectively. It is very strange to me that they would take so much time to run, as the first deconstructor adds only 2KiB of data, and the second deconstructor doesn't change anything. Could you help me find the root cause of those execution times?

1 0

[serialisation] Strange "direct access" warning on OSX for basic_text_oprimitive
by Marco Craveiro 29 Sep '22

29 Sep '22

Hi Boost Users, First, a great thanks to the authors of the boost serialisation library, which I have used successfully across projects and has proven invaluable. Now to my problem. I have been investigating for a little while a strange warning I get when linking on OSX; the results of my investigation can be found here [1]. The TL; DR of it is as follows: my OSX debug build has a warning (indented for ease of reading): ld: warning: direct access in function 'boost::archive::basic_text_oprimitive< std::__1::basic_ostream<char, std::__1::char_traits<char> > >::~basic_text_oprimitive()' from file 'vcpkg_installed/x64-osx/debug/lib/libboost_serialization.a(basic_text_oprimitive.o)' to global weak symbol 'std::__1::basic_ostream<char, std::__1::char_traits<char> >& std::__1::endl<char, std::__1::char_traits<char> > (std::__1::basic_ostream<char, std::__1::char_traits<char> >&)' This warning is caused by a mismatch in visibility settings between my project and vcpkg's build of boost. However, as far as I can see, both projects are using "-fvisibility=default", meaning there should be no mismatch. Also, no other warnings show up but if I change the project settings I then get hundreds of warnings (again, for details see ticket). What I find even more puzzling is that I am using all three types of archives (Text, XML and Binary). Of these three, only Text produces this warning. As the problem is with the destructors, I did a quick inventory of the destructors to see how they differ: basic_xml_oarchive.hpp: [2] BOOST_ARCHIVE_OR_WARCHIVE_DECL ~basic_xml_oarchive() BOOST_OVERRIDE; basic_text_oarchive.hpp: [3] ~basic_text_oarchive() BOOST_OVERRIDE {} basic_binary_oarchive.hpp: [4] no destructor. So my question is, should text archive also have a BOOST_ARCHIVE_OR_WARCHIVE_DECL macro, and would that fix my warning? If so I can submit a PR. Many thanks for your time. Marco [1] https://github.com/Microsoft/vcpkg/issues/4497 [2] https://github.com/boostorg/serialization/blob/develop/include/boost/archiv… [3] https://github.com/boostorg/serialization/blob/develop/include/boost/archiv… [4] https://github.com/boostorg/serialization/blob/develop/include/boost/archiv… -- Marco Craveiro MD, Domain Driven Consulting blog: https://mcraveiro.github.io/index.html twitter: https://twitter.com/MarcoCraveiro That the Ideas are themselves manifestations (of the Idea-Idea) and that the Idea-Idea is a-kind-of Manifestation-Idea—which is a-kind-of itself, so that the system is completely self-describing— would have been appreciated by Plato as an extremely practical joke [Plato]. -- Alan Key

1 0

Re: [Boost-users] [boost] [signals2][variant] inline warning with MSVC 2022
by Frank Mori Hess 22 Sep '22

22 Sep '22

On Thu, Sep 22, 2022 at 8:57 AM Peter Dimov <pdimov(a)gmail.com> wrote: > > That's complete nonsense. First, Microsoft invented __forceinline, so > making BOOST_FORCEINLINE be a no-op on the very compiler for which > the feature has been added would be ridiculous. Second, it does force > inlining, that's why it's called __forceinline. The whole point of the warning > is to warn about the rare cases where the compiler does not honor the > command; it exists because people want to know whether their "force > inline" orders are ignored. But no boost user wants to be warned about some internal implementation detail of a boost library. So every boost usage of BOOST_FORCEINLINE needs to add a #pragma warning(disable: 4714), awesome! Who is the maintainer of variant anyways? -- Frank

1 0

TSan error with boost::interprocess::message_queue on macOS ARM
by vl01＠jens-carl.de 22 Sep '22

22 Sep '22

Hello List, I'm using the boost::interprocess::message_queue in a project and to verify everything is working I created a test case. In that test case I'm sending and receiving data via threads. The test passes on Linux, Windows with no sanitizer and also with AddressSanitizer and ThreadSanitizer. I recently added Apple Silicon (M1) to the test matrix and now the test run with ThreadSanitizer enabled fails. Is boost::interprocess::message_queue thread-safe? Can the reported TSan error be an false-positive? If it that case, what test can I run to verify that? I looked at code of atomic_cas32() and it uses the legacy built-in __sync_val_compare_and_swap(). Can it be that that built-in isn't supported on ARM? Is there a newer built-in which should be used? The reported TSan error: -- snip ================== WARNING: ThreadSanitizer: data race (pid=4146) Atomic write of size 4 at 0x000104af4028 by thread T2: #0 __tsan_atomic32_compare_exchange_val <null>:81245684 (libclang_rt.tsan_osx_dynamic.dylib:arm64e+0x57854) #1 boost::interprocess::ipcdetail::atomic_cas32(unsigned int volatile*, unsigned int, unsigned int) atomic.hpp:581 (tsan_boost:arm64+0x100005b30) Previous read of size 4 at 0x000104af4028 by thread T1: #0 boost::interprocess::ipcdetail::spin_mutex::try_lock() mutex.hpp:100 (tsan_boost:arm64+0x100006eb0) #1 void boost::interprocess::ipcdetail::try_based_lock<boost::interprocess::ipcdetail::spin_mutex>(boost::interprocess::ipcdetail::spin_mutex&) common_algorithms.hpp:62 (tsan_boost:arm64+0x100006e28) SUMMARY: ThreadSanitizer: data race atomic.hpp:581 in boost::interprocess::ipcdetail::atomic_cas32(unsigned int volatile*, unsigned int, unsigned int) -- snap Here is a code example which demonstrates the test case -- snip #include <boost/interprocess/ipc/message_queue.hpp> #include <iostream> #include <vector> #include <thread> #include <memory> struct MessageQueueImpl { MessageQueueImpl() { boost::interprocess::permissions file_permissions; file_permissions.set_permissions(0660); queue = std::make_unique<boost::interprocess::message_queue>(boost::interprocess::create_only, "tsanqueue", 10, 15, file_permissions); } std::unique_ptr<boost::interprocess::message_queue> queue; }; class MessageQueue { public: MessageQueue() : m_impl(std::make_unique<MessageQueueImpl>()) {} void send(const std::vector<uint8_t>& buffer) { m_impl->queue->send(buffer.data(), buffer.size(), 0); } void receive(std::vector<uint8_t>& buffer) { boost::interprocess::message_queue::size_type received_size = 0; buffer.resize(m_impl->queue->get_max_msg_size()); uint32_t prio; m_impl->queue->receive(buffer.data(), buffer.size(), received_size, prio); buffer.resize(received_size); } private: std::unique_ptr<MessageQueueImpl> m_impl; }; int main() { auto uut = std::make_unique<MessageQueue>(); std::thread sender([&uut]{ for(uint8_t i = 0; i < 3; ++i) { const std::vector<uint8_t> send_buffer = {i}; uut->send(send_buffer); } }); std::thread receiver([&uut]{ for(uint8_t i = 0; i < 3; ++i) { std::vector<uint8_t> receive_buffer; uint32_t prio; uut->receive(receive_buffer); std::cout << "buffer received:\n"; for (const auto i : receive_buffer) { std::cout << i << '\n'; } } }); if(sender.joinable()) { sender.join(); } if(receiver.joinable()) { receiver.join(); } return 0; } -- snap Cheers, Jens

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Re: [Boost-users] [boost] [signals2][variant] inline warning with MSVC 2022
by Frank Mori Hess 22 Sep '22

22 Sep '22

On Wed, Sep 21, 2022 at 12:32 PM Peter Dimov <pdimov(a)gmail.com> wrote: > > That's not very user friendly; maybe the user _wants_ the warning in his code, > and the above would disable it even if no Boost header that uses > BOOST_FORCEINLINE (and generates a warning) has been included. > Okay, then maybe BOOST_FORCEINLINE shouldn't be defined as __force_inline on compilers where it doesn't actually force inlining. If the compiler is just going to treat it as a suggestion, I don't see the point of boost headers using it and then suppressing the warning. -- Frank

1 0

[signals2][variant] inline warning with MSVC 2022
by Gavin Lambert 21 Sep '22

21 Sep '22

This may not be a new issue, as I'm trying to update a project from Boost 1.68 to 1.80 (big jump!), but in trying to compile I'm being hit with this lengthy warning (and this particular project is building with warnings as errors, so this is problematic): warning C4714: function 'class boost::variant<class boost::shared_ptr<void>,class boost::signals2::detail::foreign_void_shared_ptr> __cdecl boost::detail::variant::visitation_impl<struct boost::mpl::int_<0>,struct boost::detail::variant::visitation_impl_step<struct boost::mpl::l_iter<struct boost::mpl::l_item<struct boost::mpl::long_<3>,class boost::weak_ptr<class boost::signals2::detail::trackable_pointee>,struct boost::mpl::l_item<struct boost::mpl::long_<2>,class boost::weak_ptr<void>,struct boost::mpl::l_item<struct boost::mpl::long_<1>,class boost::signals2::detail::foreign_void_weak_ptr,struct boost::mpl::l_end> > > >,struct boost::mpl::l_iter<struct boost::mpl::l_end> >,class boost::detail::variant::invoke_visitor<class boost::signals2::detail::lock_weak_ptr_visitor const ,0>,void const *,struct boost::variant<class boost::weak_ptr<class boost::signals2::detail::trackable_pointee>,class boost::weak_ptr<void>,class boost::signals2::detail::foreign_void_weak_ptr>::has_fallback_type_>(int,int,class boost::detail::variant::invoke_visitor<class boost::signals2::detail::lock_weak_ptr_visitor const ,0> &,void const *,struct boost::mpl::bool_<0>,struct boost::variant<class boost::weak_ptr<class boost::signals2::detail::trackable_pointee>,class boost::weak_ptr<void>,class boost::signals2::detail::foreign_void_weak_ptr>::has_fallback_type_,struct boost::mpl::int_<0> *,struct boost::detail::variant::visitation_impl_step<struct boost::mpl::l_iter<struct boost::mpl::l_item<struct boost::mpl::long_<3>,class boost::weak_ptr<class boost::signals2::detail::trackable_pointee>,struct boost::mpl::l_item<struct boost::mpl::long_<2>,class boost::weak_ptr<void>,struct boost::mpl::l_item<struct boost::mpl::long_<1>,class boost::signals2::detail::foreign_void_weak_ptr,struct boost::mpl::l_end> > > >,struct boost::mpl::l_iter<struct boost::mpl::l_end> > *)' marked as __forceinline not inlined I'm not sure whether the Real Bug™ is in signals2 or in variant, but I don't think it's in any of my code since it doesn't name any of my types above that I can see. I tried the big stick of setting all of Boost to "external" (and set the external warning level to 0), but sadly this did not suppress the warning. Wrapping it in a #pragma suppression does hide the warning, which makes me sufficiently happy. But perhaps someone might be interested to poke at it?

2 2

version 1.78.0 compile failed on centos 7 with compiler clang
by David Frank 15 Sep '22

15 Sep '22

error message: boost/spirit/home/classic/phoenix/closures.hpp:274:30: error: default initialization of an object of const type 'const index<0>' without a user-provided default constructor Thanks.

1 0

version 1.78.0 compile failed on centos 7
by David Frank 15 Sep '22

15 Sep '22

error message: boost/spirit/home/classic/phoenix/closures.hpp:274:30: error: default initialization of an object of const type 'const index<0>' without a user-provided default constructor Thanks.

1 0

version 1.78.0 compile failed on centos 7
by David Frank 15 Sep '22

15 Sep '22

error message: boost/spirit/home/classic/phoenix/closures.hpp:274:30: error: default initialization of an object of const type 'const index<0>' without a user-provided default constructor On Saturday, September 3, 2022 at 08:48:54 PM PDT, David Frank <david_frank95(a)yahoo.com> wrote: I'm currently using version 60, it failed to compile with openssl 3.0.5. So I need to upgrade to a version that works. Thanks.

1 0

Redefined macro on Solaris, OmniOS, and SmartOS
by Camden Narzt 11 Sep '22

11 Sep '22

Building code (on Solaris, OmniOS, and SmartOS, using gcc) which includes boost, produces warnings such as the following: In file included from src/boost/config/platform/solaris.hpp:17:0, from src/boost/config.hpp:57, from src/boost/cstdint.hpp:36, from src/code_that_includes_boost.cpp:43: src/boost/config/posix_features.hpp:27:0: warning: "BOOST_HAS_STDINT_H" redefined [enabled by default] # define BOOST_HAS_STDINT_H ^ Not a big deal, but figured I’d report it in case it hadn’t been reported yet.

1 0

which version works with openssl 3.0.5?
by David Frank 04 Sep '22

04 Sep '22

I'm currently using version 60, it failed to compile with openssl 3.0.5. So I need to upgrade to a version that works. Thanks.

2 1

How to build Boost with static ICU via Msys2 / mingw-w64 / gcc on Windows?
by crillion＠tiscali.it 03 Sep '22

03 Sep '22

Hello, I'm trying to build boost 1.80 on windows 10 with the icu provided with msys2 (my goal in particular is that boost locale will build using my installed version of icu). My build platform is msys2 with mingw-w64 / gcc 12.2. By launching pacman -Q on the msys2-msys shell I have seen that I have icu 71.1-2 : (...) glib2 2.72.2-2 gmp 6.2.1-2 gnupg 2.2.36-1 grep 1~3.0-3 gzip 1.12-2 heimdal-libs 7.7.0-3 icu 71.1-2 inetutils 1.9.4-5 info 6.8-4 less 590-2 (...) on my system I have msys2 installed in the following folder C:programsmsys64 and in C:programsmsys64mingw64 there are the following folders : bin etc include lib libexec sbin share ssl var x86_64-w64-mingw32 in the lib folder I have found that there are lib files like libicuio.a, libicudt.a and libicutest.a . I extracted boost and then I've given the usual sequence of commands from the normal cmd shell of windows : for creating b2 : bootstrap.bat gcc for the actual build of boost, I've made the following attempts : b2 --toolset=gcc address-model=64 -sICU_PATH=C:programsmsys64mingw64 b2 --toolset=gcc address-model=64 include=C:programsmsys64mingw64include library-path=C:programsmsys64mingw64lib b2 --toolset=gcc address-model=64 -sICU_PATH=C:programsmsys64mingw64 include=C:programsmsys64mingw64include library-path=C:programsmsys64mingw64lib but none of these works : the build process always writes in its initial phase : (...) has_lzma_cputhreads builds : yes [2] cxx11_decltype : yes [2] cxx11_basic_alignas : yes [2] iconv (libc) : no [2] iconv (separate) : yes [2] icu : no [2] icu (lib64) : no [2] native atomic int32 supported : yes [2] has message compiler : no [2] native syslog supported : no [2] (...) what am I supposed to do to let b2 see the ICU lib files that I have in my msys2 distribution ? Thanks, Marco Voucher MISE per P.IVA e PMI: fino a 2500€ per la Banda Ultralarga. https://casa.tiscali.it/promo/?u=https://promozioni.tiscali.it/voucher_busi…..

1 0

suspendable/resumable/prioritizable task dispatcher
by chris-boostusers＠stankevitz.com 31 Aug '22

31 Aug '22

Hi, Unfortunately I don't have the vocabulary needed to ask this question, but hopefully I'll learn it here. Does Boost have something that will help me with this problem: I have a list of CPU-bound tasks I need to perform. I'll list two of them here: a) compute first zillion digits of pi (low priority) b) add two plus two (high priority) I co_spawn (a). Later, while (a) is running, I co_spawn (b). (a) will be suspended at a "co_suspension_point" so that (b) can take over. Of course when (b) completes, (a) will resume. For bonus points, it will support multiple threads (probably easy) and a task's priority can change over time (probably hard). Thank you! Chris PS: I was recently blown away by the coroutine capability of ASIO: Talking Async Ep1: Why C++20 is the Awesomest Language for Network Programming https://www.youtube.com/watch?v=icgnqFM-aY4

3 3

memory fault when passing var to a coroutine
by Piotr Gosławski 23 Aug '22

23 Aug '22

Hello, Using GCC 10.1 and Boost 1.77 I get a mem fault when executing the following code: #include <iostream> #include <boost/asio.hpp> #include <boost/asio/awaitable.hpp> struct TestStruct { std::string strField; }; boost::asio::awaitable<bool> TestFunction(TestStruct param) { std::cout << param.strField << std::endl; co_return true; } boost::asio::awaitable<void> TestCoroutine() { // This causes mem issue co_await TestFunction(TestStruct{"some string"}); } int main() { boost::asio::io_context io_context; boost::asio::co_spawn( io_context, []() { return TestCoroutine(); }, boost::asio::detached); io_context.run(); return 0; } Also tested with GCC 12.1 and Boost 1.79 - the result is the same ( https://godbolt.org/z/69MKbz7qE) Works if I use a temp variable: boost::asio::awaitable<void> TestCoroutine() { auto testStruct = TestStruct{"some string"}; co_await TestFunction(testStruct); } Or if I add a constructor to test struct: struct TestStruct { explicit TestStruct(const std::string& str) : strField(str) {} std::string strField; }; boost::asio::awaitable<void> TestCoroutine() { co_await TestFunction(TestStruct("some string")); } Is there any coroutines rule that I am violating here? If yes - is there any compiler option I can use to get a warning / error message? Full code with cmake can be found here: https://github.com/piotrgoslawski/mem_issue Thank you

1 0

re：question about compile the boost head file.
by zyx_xzy＠sina.com 23 Aug '22

23 Aug '22

Respeced Mr.Emil, Thank you for your kindly reply. >I can't reproduce this with msvc versions available on godbolt: >https://godbolt.org/z/E8vYWTPf6 Exactly on godbolt,the compilers work well. I test this by myself. Once again, I change to the Microsoft Visual Studio Community 2019 ver. 16.11.18. And compile the program ,the error still exist. >Can you provide a complete error log, including source file and line of the >error? soruce file:info.hppsource code line no:145soruce code:error_info_container_impl * c=new error_info_container_impl;error log:C2259 “boost::exception_detail::error_info_container_impl”: cannot instantiate abstract class, test_boost D:\boost_1_79_0\boost\exception\info.hpp 145 Best regards, zhiyong

2 1

question about compile the boost head file.
by zyx_xzy＠sina.com 20 Aug '22

20 Aug '22

hi anybody, I meet a problem when I try to compile the following program. #include <boost\exception\info.hpp> void main() { return; } The compile environment is Microsoft Visual Studio Community 2022 (64 位) - ver. 17.2.6.Compile error information is that C2259 “boost::exception_detail::error_info_container_impl”: cannot instantiate abstract class.I try many Boost versions,e.g.,boost 79,boost 65,boost64,boost60. They all give errors. Anybody can give me some suggestions? Best regards, zhiyong --------------------------------

2 1

Abwesenheitsnachricht: question about compile the boost head file.
by Sören Textor 20 Aug '22

20 Aug '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. ----------------------------------------------- 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.

1 0

[Boost.GIL] GCC 12.1.1 fails to compile boost.gil examples with -std=c++20
by B Aleck 18 Aug '22

18 Aug '22

Source: https://www.boost.org/doc/libs/1_80_0/libs/gil/doc/html/_downloads/resize.c… Compile with: g++ -std=c++20 -c gcc version: 12.1.1 The compile successes with -std=c++14 and -std=c++17, only fails with -std=c++20 Same error does not occur on clang Is this a boost bug or gcc bug?

2 1

Enumerating network interfaces and querying their properties
by Kenneth Porter 14 Aug '22

14 Aug '22

Is there a portable way to enumerate network interfaces and query their properties? I don't see anything in ASIO for that. Any recommendations for other libraries? So far the closest I've come is Python's netifaces library. (Maybe someone would like to fork the Python library's C source and bring it into Boost?) <https://github.com/al45tair/netifaces> I've got an app that configures a remote IoT device on the same segment and then opens UDP listeners to listen for a stream of data from the device. The user specifies the hostname or address of the device. I'd like to be able to restrict the listeners to just the interface that the device is connected to. I have two interfaces, one for the LAN and one for devices, and I don't want to listen on the LAN interface. So ideally I'd get the list of interfaces and their addresses and netmasks. I think I also need the routing table. I can then identify which interface will receive the incoming UDP stream.

1 0

Boost support for Arm64/Windows
by Jonathon Penix 12 Aug '22

12 Aug '22

Hi, I am interested in using Boost as a dependency on the Arm64/Windows platform but have been struggling to find information about the status for Boost libraries in general for Arm64/Windows. I am aware of a few specific libraries that directly mention their support status for Arm64/Windows (Boost.Atomic and Boost.Context, for example) or have had Arm64 related patches in their release notes (Boost.Build, for example). Are there any public boards/trackers for the current Boost status or outstanding issues for Boost on Arm64/Windows that I may have missed? Or should platform support be generally assumed to work outside of specific cases like Boost.Context so long as a conformant compiler is provided for the platform? Thanks!

2 1

[release] Boost 1.80.0
by Glen Fernandes 11 Aug '22

11 Aug '22

Release 1.80.0 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_1.80.0> You can also download directly from: <https://boostorg.jfrog.io/artifactory/main/release/1.80.0/> 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

3 2

Broken link to latest code from old ASIO example
by Kenneth Porter 11 Aug '22

11 Aug '22

The directory structure of ASIO changed a bit and now the website pages of samples in old versions no longer direct to the correct page in the latest version: <https://www.boost.org/doc/libs/1_51_0/doc/html/boost_asio/example/icmp/ping…> I wanted to see how to code a ping so I googled for "boost asio ping" and the top result was for 1.51.0. (I never get the latest code, but I can always jump to an older version and then jump from there to the latest. It just didn't work this time.) It did work for 1.67.0 (later in the google search results) which led to the current page: <https://www.boost.org/doc/libs/1_79_0/doc/html/boost_asio/example/cpp03/icm…>

1 0

Fwd: [boost] Upcoming Boost.URL review
by Mateusz Loskot 06 Aug '22

06 Aug '22

---------- Forwarded message --------- From: Klemens Morgenstern via Boost <boost(a)lists.boost.org> Date: Sat, 6 Aug 2022, 15:30 Subject: [boost] Upcoming Boost.URL review To: <boost(a)lists.boost.org> Cc: Klemens Morgenstern <klemensdavidmorgenstern(a)gmail.com> This is a reminder that the boost.url review will start in a week on the 13th. The source code can be found here https://github.com/CPPAlliance/url and the documentation here https://master.url.cpp.al/ . I am looking forward to plenty of reviews. _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost

1 0

Boost.Graph: user survey
by Jeremy Murphy 05 Aug '22

05 Aug '22

Dear Boost.Graph users, I'd like to know how you use Boost.Graph. If you know someone that uses Boost.Graph but is not on this mailing list, please forward this survey to them. The purpose of this survey is to help prioritize work on the areas of Boost.Graph that will have the most benefit to the users. I was planning to make a very sophisticated Google Forms survey, but that is so time consuming. These questions should all be taken in the context of using Boost.Graph. - Which operating systems do you use? - Which toolchains do you use? - What is the minimum C++ standard that you require support for? (e.g. 03, 11, 14, etc) - Which features of Boost.Graph are you using? - Which features do you think Boost.Graph is missing? - What are the biggest problems with using Boost.Graph? Purely out of curiosity: - What do you use it for? - If you use it in business (or research), how critical is it? Thanks! Jeremy

4 5

Help with a compilation error [Boost/Math]
by Peder Lon Hauge 04 Aug '22

04 Aug '22

Hi, I'm trying to use Boost in order to find values of a 2F3 hypergeometric function. Just to check that I am using the package the correct way, I tried to compile the small test file below (using the example from the pFq docs), with the command $ g++ -o test.exe test.cpp -I /home/peder/boost/boost_1_79_0 As far as I understand, the library is header-only, so I didn't expect the compilation error below. I don't where I've made a mistake, and I'd greatly appreciate any help with figuring out the error. I'm running Ubuntu 20.04.04 on WSL and using gcc 9.4.0. Best regards, Peder Test program: #include <iostream> #include <boost/math/special_functions/hypergeometric_pFq.hpp> int main() { double z = -9; double h = boost::math::hypergeometric_pFq({2,3,4}, {5,6,7,8}, z); // Calculate 3F4 std::cout << h << std::endl; return 0; } Error message: $ g++ -o test.exe test.cpp -I /home/peder/boost/boost_1_79_0 /usr/bin/ld: /tmp/ccp4Lm8m.o: in function `std::pair<long double, long double> boost::math::detail::hypergeometric_pFq_checked_series_impl<std::initializer_list<int>, long double, boost::math::policies::policy<boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy>, boost::math::detail::iteration_terminator>(std::initializer_list<int> const&, std::initializer_list<int> const&, long double const&, boost::math::policies::policy<boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy> const&, boost::math::detail::iteration_terminator const&, long long&)': test.cpp:(.text._ZN5boost4math6detail38hypergeometric_pFq_checked_series_implISt16initializer_listIiEeNS0_8policies6policyINS5_14default_policyES7_S7_S7_S7_S7_S7_S7_S7_S7_S7_S7_S7_EENS1_20iteration_terminatorEEESt4pairIT0_SB_ERKT_SF_RKSB_RKT1_RKT2_Rx[_ZN5boost4math6detail38hypergeometric_pFq_checked_series_implISt16initializer_listIiEeNS0_8policies6policyINS5_14default_policyES7_S7_S7_S7_S7_S7_S7_S7_S7_S7_S7_S7_EENS1_20iteration_terminatorEEESt4pairIT0_SB_ERKT_SF_RKSB_RKT1_RKT2_Rx]+0xeef): undefined reference to `boost::math::tools::promote_args<long double, float, float, float, float, float>::type boost::math::lgamma<long double, boost::math::policies::policy<boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy> >(long double, boost::math::policies::policy<boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy> const&)' /usr/bin/ld: test.cpp:(.text._ZN5boost4math6detail38hypergeometric_pFq_checked_series_implISt16initializer_listIiEeNS0_8policies6policyINS5_14default_policyES7_S7_S7_S7_S7_S7_S7_S7_S7_S7_S7_S7_EENS1_20iteration_terminatorEEESt4pairIT0_SB_ERKT_SF_RKSB_RKT1_RKT2_Rx[_ZN5boost4math6detail38hypergeometric_pFq_checked_series_implISt16initializer_listIiEeNS0_8policies6policyINS5_14default_policyES7_S7_S7_S7_S7_S7_S7_S7_S7_S7_S7_S7_EENS1_20iteration_terminatorEEESt4pairIT0_SB_ERKT_SF_RKSB_RKT1_RKT2_Rx]+0xfe5): undefined reference to `boost::math::tools::promote_args<long double, float, float, float, float, float>::type boost::math::expm1<long double, boost::math::policies::policy<boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy> >(long double, boost::math::policies::policy<boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy> const&)' /usr/bin/ld: /tmp/ccp4Lm8m.o: in function `int boost::math::detail::log_pochhammer<int, boost::math::policies::policy<boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy> >(int, unsigned int, boost::math::policies::policy<boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy>, int*)': test.cpp:(.text._ZN5boost4math6detail14log_pochhammerIiNS0_8policies6policyINS3_14default_policyES5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_EEEET_S7_jT0_Pi[_ZN5boost4math6detail14log_pochhammerIiNS0_8policies6policyINS3_14default_policyES5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_EEEET_S7_jT0_Pi]+0x3d): undefined reference to `boost::math::tools::promote_args<int, float, float, float, float, float>::type boost::math::lgamma<int, boost::math::policies::policy<boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy> >(int, int*, boost::math::policies::policy<boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy> const&)' /usr/bin/ld: test.cpp:(.text._ZN5boost4math6detail14log_pochhammerIiNS0_8policies6policyINS3_14default_policyES5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_EEEET_S7_jT0_Pi[_ZN5boost4math6detail14log_pochhammerIiNS0_8policies6policyINS3_14default_policyES5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_S5_EEEET_S7_jT0_Pi]+0x57): undefined reference to `boost::math::tools::promote_args<int, float, float, float, float, float>::type boost::math::lgamma<int, boost::math::policies::policy<boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy> >(int, int*, boost::math::policies::policy<boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy, boost::math::policies::default_policy> const&)' collect2: error: ld returned 1 exit status

3 3

[Query] Does boost support concurrent hash map, for ip fragment reassemble
by Jiany Wu 02 Aug '22

02 Aug '22

Hello, I want to use boost concurrent hash map to do fragment reassemble, does it support concurrent hash map? Or is there any similar concurrent data structure, which can support it? Thanks in advance! Best regards Dave

1 0

sgn/sign-function
by Gero Peterhoff 31 Jul '22

31 Jul '22

Hi John, i think your sign-function (boost/math/special_functions/sign.hpp) is incomplete. Because the resulttype is int, not all cases can be covered correctly (nan, inf, -0). With my implementation this works and it follows the std-conventions (sgn(FP) -> FP, sgn(INT/BOOL) -> double). I also tried to optimize them (branch-free, vectorizable). sgn(FP) -> FP ±0/±1 sgn(FP nan/inf) -> FP nan/inf sgn(INT) -> double +0/±1 sgn(UINT/BOOL) -> double +0/+1 regards Gero

1 0

C++11 or C++14?
by Vinnie Falco 29 Jul '22

29 Jul '22

I'm considering bumping up the C++ language requirement for Boost.URL from C++11 to C++14. I have concerns about doing this, because it affects all my downstream libraries (HTTP.Proto, HTTP.IO, Websocket.Proto, Websocket.IO, and any examples or complete clients/servers that I write). My main fear is that there are still a considerable number of individuals or corporations who, for whatever reason, cannot build with -std=c++14 or later despite having access to newer compilers. I don't mind if there is a small percentage of loss but I do mind if 20% or more of potential users will be locked out. The questions are: 1. Would you or your company be prevented from using Boost.URL if it required C++14? 2. Do you know any other organizations who cannot use C++14 or later? 3. Do you know of any regional or global metrics on who _cannot_ use libraries which require C++14? See also, this reddit thread on r/cpp: <https://www.reddit.com/r/cpp/comments/w6zuo5/c11_or_require_c14/> -- Regards, Vinnie Follow me on GitHub: https://github.com/vinniefalco

6 6

gcc 12 and clang 14
by Matt Hurd 28 Jul '22

28 Jul '22

Curious as to if gcc-12 and clang-14 may make it to the release compiler list for 1.80? (https://www.boost.org/users/history/version_1_80_0.html) Is that just a formality? I see the regression tests for both look in pretty good shape: https://www.boost.org/development/tests/develop/developer/summary.html Thanks all for your great work. Much appreciated, --Matt _______________ matthurd(a)acm.org

1 0

boost::asio::ssl::context::use_certificate_chain_file and boost::asio::ssl::context::use_certificate_file Methods Give "bad method" Error
by Osman Zakir 21 Jul '22

21 Jul '22

Hello. Message for update to previously-reported issue. It turns out that the "bad method" error was because of the boost::asio::ssl::context object methods I mentioned in the subject of this email. Reading the certs in from the files into std::strings manually and using use_certificate and use_certificate_chain instead is better, at least from what I saw. I still have an error in the browser (code: ERR_SSL_PROTOCOL_ERROR) when I try to visit my running app saying that the connection for the site isn't secure and that it gave back an invalid response. And running the command openssl s_client -connect <ip_address>:5501 -servername dragonosman.dynu.net gave this result: CONNECTED(00000148) 11784:error:1409442E:SSL routines:ssl3_read_bytes:tlsv1 alert protocol version:ssl\record\rec_layer_s3.c:1544:SSL alert number 70 --- no peer certificate available --- No client certificate CA names sent --- SSL handshake has read 7 bytes and written 322 bytes Verification: OK --- New, (NONE), Cipher is (NONE) Secure Renegotiation IS NOT supported Compression: NONE Expansion: NONE No ALPN negotiated Early data was not sent Verify return code: 0 (ok) and when command exits, I see this error in my server console window: Lines 625 and 626: handshake: unsupported protocol (SSL routines, tls_early_post_process_client_hello) Lines 646 and 647: read: unspecified system error I'm assuming this is a HTTP/2 upgrade request inside a TLS ClientHello message, but is that enough reason for the SSL error I'm getting in my browser? Anyway, I've sent an email on the OpenSSL users mailing list to ask how to parse the ClientHello message, so hopefully I'll get something from there.

1 0

[container] flat_set using a reversed small_vector
by Phil Endecott 20 Jul '22

20 Jul '22

Dear Experts, I currently have: template <typename KEY, typename VALUE, size_t SZ> using small_flat_map = boost::container::flat_map< KEY, VALUE, std::less<KEY>, boost::container::small_vector< std::pair<KEY,VALUE>, SZ > >; This works OK, but one thing that I do with it quite often is auto i = m.upper_bound(...); m.erase(m.begin(),i); Erasing items at the start of the vector is of course the worst thing you can do for performance with a flat_map. So I was wondering if I can have a flat_map that stores its elements in the reverse order in the underlying vector. Question: can anyone think of a way to do this that doesn't require changing all of the downstream code? For a few milliseconds I thought I could just change std::less for std::greater but that reverses the externally-visible behaviour. Is there some Boost utility that can wrap the implementation vector to work in reverse? Thanks, Phil.

1 0

Server App using Boost.Beast, Sending Only One Certificate out of Chain
by Osman Zakir 16 Jul '22

16 Jul '22

Hi, everyone. I upgraded my server app to Boost 1.79.0 and tried running it, but there are issues: 1. I renewed my Let's Encrypt certs, but when I try to check them, I see it's only sending one cert out of a chain of three. And I'm loading the certs and the RSA private key using the SSL context methods to load the cert chain and key from files, too. 2. The read operation on line 640 in the do_session function in currency_converter.cpp gave a "bad method" error before, but mostly gives "the connection was forcibly closed by the remote host" error. I have the source code on GitHub here: https://github.com/DragonOsman/currency_converter.

1 0

[release] Boost 1.80.0 beta 1 released
by Glen Fernandes 14 Jul '22

14 Jul '22

Boost release 1.80.0 beta 1 is now available at: https://boostorg.jfrog.io/artifactory/main/beta/1.80.0.beta1/source/ The SHA256 checksums are: boost_1_80_0_b1.tar.bz2 - b29191c1bd4504511f9b1155c6f79f06cc7044444780392ed7358f5778ac7d16 boost_1_80_0_b1.tar.gz - ad3df9f63acd667dcf13375fa0e90e7303f851251e91d1505974bdbbf1f94907 boost_1_80_0_b1.7z - 7bfdf705b1d058c3525be90ed5cb47aacf919cd74aa7d5752d55e78aa60880ba boost_1_80_0_b1.zip - 1b509ed848f153086984658d4d4a57af6230f496a53bf88aba805bb49039012d Release notes (still need updates): https://www.boost.org/users/history/version_1_80_0.html Please try the beta and report any problems you encounter. Thanks, -- Boost Release Team

1 0

Higher than expected memory usage by boost::iostreams::gzip_compressor
by Alex Petty 13 Jul '22

13 Jul '22

Hello, I'm looking at adopting boost::iostreams for reading/writing compressed streams. I'm testing with textual files commonly on the order of a couple of GB uncompressed, and a couple hundred MB compressed. I noticed during some initial testing that using a gzip_compressor to write a compressed stream through boost::iostreams results in significant memory usage, I'm seeing hundreds of MB per compressed stream. It looks like internally the gzip_compressor must be doing some GC-type behavior, because I see its memory usage increase to just under 1GB per stream with a gzip_compressor, and then decrease again. Is there any way to control the memory that gzip_compressor is using? I've tried both increasing and decreasing the buffer size when gzip_compressor is constructed, but that buffer is tiny and cannot be what's driving the increased memory usage. Thanks, Alex

1 0

[Graph] Can users on Xcode 7-10 help out?
by Jeremy Murphy 12 Jul '22

12 Jul '22

Dear Boost.Graph users, Is anyone that uses old Xcode 7-10 able to help out with some curious compilation errors? https://github.com/boostorg/graph/issues/298 We'll do our best to fix them but I assume it might be easier for someone that actually uses these particular platforms. Thanks, cheers. Jeremy

1 0

xpressive: How to combine vector of regex to one?
by Anton Sergunov 08 Jul '22

08 Jul '22

Hello Boost Users! I'm seeking some help from the community because can't see answer in documentation or in source code. I need to find which regex of N my string matches. I don't like to compare them one by one, to speed up the process. It's easy to implement if I have them compile time: ```cpp sregex re = (s1 = re1)|(s2 = re2)|(s3=re3); ... std::set<int> foo(const std::string& str) { std::set<int> result; smatch match; if(regex_match(str, match, re)) { for(int i = 0; i<3; ++i) if(match[i+1]) result.insert(i); } return result; } ``` But I have a vector: ```cpp std::set<int> foo(const std::string& str, const std::vector<sregex>& reVector) { sregex re; int index = 1; for(auto&& item : reVector) { re |= (mark_tag(index++) = item); // (1) } std::set<int> result; smatch match; if(regex_match(str, match, re)) { for(int i = 0; i<reVector; ++i) if(match[i+1]) result.insert(i); } } return result; } ``` There at (1) `|=` doesn't work as I expect for some reson, It didn't catch some values. If I replace it with ```cpp re = re | (mark_tag(index++) = item); ``` it just crashes. If I replace with: ```cpp auto t = re; re = t | (mark_tag(index++) = item); ``` it making captures of previous tags to be subexpresions matches. So code doesn't work as I want. Is it any way to prevent sub-expression capture isolation? As I understand it should be some intermediate type before sregex to express expression under construction. So it will not isolate matches of existing part. I'm using v1.65.1 https://github.com/boostorg/xpressive/issues/24

1 0

Embedded install paths in CMake files for Boost 1.79
by Alex 05 Jul '22

05 Jul '22

Apologies if this is the wrong list. I tried boost-build but I'm not sure if my message was verified (I don't see it in the archive). I'm trying to make a build of Boost that includes the generated CMake files. For my case, I need to install the files to a staging area before packaging them up for installation in the target environment. I've tried "b2 --stagedir <dir> stage" but the generated CMake files still include the stagedir path in them, instead of the install prefix specified during bootstrap, which triggers errors in the packaging system I need to use. I'm also not sure if it's then possible to just install the headers to the same staging location. Is there a way to install to a staging location while the CMake files have the paths to the final install location? CMake uses CMAKE_STAGING_PREFIX for this but I can't find an equivalent for b2. I guess it must be required for cross-compiling though, if you want to support CMake on the target? Regards, Alex

1 0

Excessive dynamic allocation when using boost::split(..., boost::is_any_of(", "))?
by Dominique Pellé 05 Jul '22

05 Jul '22

Hi This following program shows many allocations coming from boost::split(..., boost::is_any_of(",")): ``` $ cat split.cpp #include <string> #include <cstdio> #include <boost/algorithm/string.hpp> #include <boost/container/small_vector.hpp> int main() { std::string str = "foo,bar,foobar,quux"; std::size_t s = 0; for (int i = 0; i < 100; ++i) { boost::container::small_vector<std::string, 4> v; #ifdef USE_IS_ANY_OF boost::split(v, str, boost::is_any_of(",")); #else boost::split(v, str, [](const char c) { return c == ',';}); #endif s += v.size(); } fprintf(stderr, "%zu\n", s); } ``` When using boost::is_any_of(","), there are 7 dynamic allocations per loop iteration whereas when using the lambda predicate, there are 0 dynamic allocation per loop as shown below: ``` $ clang++ -std=c++14 -DUSE_IS_ANY_OF split.cpp $ heaptrack ./a.out ... allocations: 702 $ clang++ -std=c++14 split.cpp $ heaptrack ./a.out ... allocations: 2 ``` I suspect that there are potential optimizations in Boost here to avoid so many allocations when boost::is_any_of(",") is used. Regards Dominique

3 2

Boost.URL review planned for 13-22 August 2022
by Mateusz Loskot 29 Jun '22

29 Jun '22

Folks, Klemens Morgenstern kindly volunteered [1] as the Review Manager (thanks Klemens!) for the Boost.URL [2], so we have planned the review shortly after the upcoming release of the Boost 1.80. Check the Review Schedule [3] for details! [1] https://lists.boost.org/Archives/boost/2022/06/253225.php [2] https://lists.boost.org/Archives/boost/2022/04/252814.php [3] https://www.boost.org/community/review_schedule.html Best regards, -- The Boost Review Wizards Mateusz Loskot

2 2

Boost Twitter is Blowing Up!!!
by Vinnie Falco 21 Jun '22

21 Jun '22

Greetings fellow users, library authors, maintainers, review wizards, release wizards, and Boost Foundation Board members! As part of our ongoing effort to continue the revitalization of Boost, a handful of us have taken the reins to post about Boost on social media. We have postings on Reddit and Hacker news, blog posts about the new efforts in Boost.Unordered, and new tweets. However, we could use your help! Right now the Boost Twitter account has a measly 957 followers. It would be great to increase our reach, so I'm asking everyone if they could be so kind as to Follow the official Boost Twitter account here: <https://twitter.com/Boost_Libraries> and then amplify our messages by Liking and Retweeting. Starting with this pinned tweet, which everyone will see when they visit the Boost Libraries Twittter profile page: <https://twitter.com/Boost_Libraries/status/1539003321939202048> Following the Boost Twitter account will give you up-to-date information about what is going on with Boost, including articles and mentions on other social media sites. Here is what we have so far: <https://www.reddit.com/r/cpp/comments/vfdcrz/advancing_the_state_of_the_art…> <https://www.reddit.com/r/cpp/comments/vbdr3z/new_boostunordered_containers_…> <https://twitter.com/hackernewstop10/status/1538622706035343364> <https://news.ycombinator.com/item?id=31801814> To summarize, engaging with Boost related content on social media will enhance our profile - any help is appreciated! -- Regards, Vinnie Follow me on GitHub: https://github.com/vinniefalco

7 9

[JSON] Vote for Boost.JSON in this poll!
by Vinnie Falco 21 Jun '22

21 Jun '22

There's an online poll asking about which JSON library you use. If you use Boost.JSON consider voting for it: <https://meetingcpp.com/mcpp/survey/?q=2> Also, consider voting for it if you _don't_ use Boost.JSON, but you want to. -- Regards, Vinnie Follow me on GitHub: https://github.com/vinniefalco

1 0

[Locale] IBM437 encoding not supported in wconv
by Arnold, Stefan 14 Jun '22

14 Jun '22

Why is the IBM437 encoding not supported in boost::locale with the Win32 API ("wconv") backend? The following call will fail with a boost::locale::conv::invalid_charset_error when using the Win32 API backend: boost::locale::conv::to_utf<char>("abc", "IBM437") This is because "ibm437" is not contained in the all_windows_encodings variable in wconv_codepage.ipp (nor is "cp437" or another alias). As per Win32 API documentation (https://docs.microsoft.com/en-us/windows/win32/api/stringapiset/nf-stringap…, https://docs.microsoft.com/en-us/windows/win32/intl/code-page-identifiers) this encoding is supported in Win32 API. Furthermore, IBM437 is the legacy encoding of filenames in ZIP files, so it should be quite common.

1 1

Any objections to making C++14 the current baseline for Boost support and testing?
by John Maddock 10 Jun '22

10 Jun '22

Pursuant of discussion elsewhere: Does anyone have any concrete objections to Boost moving to a C++14 baseline? This would mean: * Library authors can drop and remove all support for pre-C++14 compilers after a suitable deprecation notice in place for say 3 releases. * The community maintenance team can likewise drop pre-C++14 support from community maintained / orphan libaries. * CI tests no longer need report pre-C++14 results. * From the next release onward, the boost super-project should clearly announce in our release notes, that C++11 and earlier support may no longer be available from the start of 2023. Thoughts? Thanks, John Maddock.

8 11

[thread] attribute constructor failing to compile
by Jeanette C. 07 Jun '22

07 Jun '22

Hey hey, using boost 1.78 from the Archlinux repository, using the thread constructor with boost::thread::attributes as first argument fails to compile. The relevant code from the small test program is this: void work(bool& done) // simple main function for the thread int main() { bool done = false; boost::thread::attributes attr; // all changes commented out in the program boost::thread th1(attr, work, std::ref(done)); // some code, sleep and set done to true th1.join(); return 0; } g++ 11.2.0 reports the following error: In file included from /usr/include/boost/thread/detail/thread.hpp:33, from /usr/include/boost/thread/thread_only.hpp:22, from /usr/include/boost/thread/thread.hpp:12, from thread_prio.cpp:1: /usr/include/boost/bind/bind.hpp: In instantiation of 'void boost::_bi::list2<A1, A2>::operator()(boost::_bi::type<void>, F&, A&, int) [with F = boost::thread_attributes; A = boost::_bi::list0; A1 = boost::_bi::value<int (*)(bool&)>; A2 = boost::_bi::value<std::reference_wrapper<bool> >]': /usr/include/boost/bind/bind.hpp:1273:18: required from 'boost::_bi::bind_t<R, F, L>::result_type boost::_bi::bind_t<R, F, L>::operator()() [with R = void; F = boost::thread_attributes; L = boost::_bi::list2<boost::_bi::value<int (*)(bool&)>, boost::_bi::value<std::reference_wrapper<bool> > >; boost::_bi::bind_t<R, F, L>::result_type = void]' /usr/include/boost/thread/detail/thread.hpp:120:18: required from 'void boost::detail::thread_data<F>::run() [with F = boost::_bi::bind_t<void, boost::thread_attributes, boost::_bi::list2<boost::_bi::value<int (*)(bool&)>, boost::_bi::value<std::reference_wrapper<bool> > > >]' /usr/include/boost/thread/detail/thread.hpp:118:18: required from here /usr/include/boost/bind/bind.hpp:298:35: error: no match for call to '(boost::thread_attributes) (int (*&)(bool&), std::reference_wrapper<bool>&)' 298 | unwrapper<F>::unwrap(f, 0)(a[base_type::a1_], a[base_type::a2_]); | ~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The syntax is based on this part of the manual: https://www.boost.org/doc/libs/1_79_0/doc/html/thread/thread_management.htm… Is that perhaps a feature only introduced in version 1.79 of the Boost libraries? Best wishes and thanks for any pointers, Jeanette -- * Website: http://juliencoder.de - for summer is a state of sound * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * Audiobombs: https://www.audiobombs.com/users/jeanette_c * GitHub: https://github.com/jeanette-c Don't care about money It doesn't give me half the thrill <3 (Britney Spears)

3 3

[Compute] Auto-determine work group size
by Stephan Menzel 12 May '22

12 May '22

Hi everyone, perhaps someone can answer a question about Boost.Compute. I have recently switched to it from using native OpenCL. Most of the things work fine except for one quirk: OpenCL allows for auto-determining the work group size when using enqueue_kernel(). As the correct work group size is still a mystery to me after using OpenCl for almost a year now I normally left this parameter to 0 to let OpenCL figure it out. With Boost.Compute and the equivalent function enqueue_nd_range_kernel() this doesn't seem to be possible. I have to use a parameter like boost::compute::extents<2>{ 8, 2 } as local_work_size. Leaving it 0 or using extents<2>{ 0, 0 } doesn't do the trick and I'm getting "Invalid work group size". This forces me to guess values until one works, which is extremely error prone and breaks all the time with images of different resolutions. Does anyone know how I can use OpenCL's auto-work-group-size feature in Boost.Compute? Cheers, Stephan

1 0

Iterating over each point within a geometry::box
by Keith Bennett 11 May '22

11 May '22

I want to iterate over every point within a geometry::model::box<point>. I want to be able to do that with iterators so that I can also use all (or most of) the standard algorithms like for_each or all_of or etc. Initially my code used several loops, one for each axis, like so for a 2d point: for (int x = box.min_corner().template get<0>(); x <= box.max_corner().template get<0>(); ++x) { for (int y = box.min_corner().template get<1>(); y <= box.max_corner().template get<1>(); ++y) { callback(point(x,y)) } } There are several places where this occurs. Some loops have the x axis first, others the y axis first -- and this has performance issues when translating the point to a container. Some loops were erroneously considering right-open intervals with less-than instead of less-than-or-equal-to comparisons. So I've had to fix bounding bugs and performance issues in multiple places that are caused by these manual loops. I've gone and unified a lot of that to use templated functions that basically duplicate some of the functionality in the standard. But that's not tractable and still doesn't use iterators so most of <algorithm> is still off-limits: namespace mynamespace { template <class box, enable_if vomit, blah blah> void for_each(const box& b, const std::function<void(const typename box::point_type&)> callback) { // the manual loops here, not repeated for brevity } } Then I've replaced most of those manual loops with calls to: mynamespace::for_each(box, [](const point& p){ // do some work here }); So I want to instead do: for (const auto& point : box) { callback(point); } Satisfying that would make a lot of places simpler and easier to read. I think it should also help to enable use of a lot of the stuff in the standard <algorithm> I understand that it might be difficult for, eg, a box containing a point with floating point types. But that's fine ... I'm only looping over integral points anyway. I'd also prefer to have the ability to control the axis order ... eg do I want x or y on the inner/outer loop? Do I want to only iterate over the y axis? I'm using C++14 and boost 1.70 at the moment. There's some friction against upgrading. But if this problem is solved in a future version -- like with C++20 ranges -- then that would be a strong point for me to convince my team to upgrade. I could go and write up some iterators myself of course. But before I do that I wondered if someone else has already solved this problem and I just haven't found the solution. Thoughts? -- Keith Bennett

1 0

Fwd: [boost] Boost MySQL Review Starts Today
by Mateusz Loskot 10 May '22

10 May '22

FYI ---------- Forwarded message --------- From: Richard Hodges via Boost <boost(a)lists.boost.org> Date: Tue, 10 May 2022 at 09:14 Subject: [boost] Boost MySQL Review Starts Today To: boost(a)lists.boost.org List <boost(a)lists.boost.org>, <boost-announce(a)lists.boost.org> Cc: Richard Hodges <hodges.r(a)gmail.com> Dear All, The Boost formal review of the MySQL library starts Today, taking place from May 10th, 2022 to May 19th, 2022 (inclusive) - We are starting one day after the announced date and extending the period by one day to compensate. The library is authored by Rubén Pérez Hidalgo (@anarthal in the CppLang slack). Documentation: https://anarthal.github.io/mysql/index.html Source: https://github.com/anarthal/mysql/ The library is built on the bedrock of Boost.Asio and provides both synchronous and asynchronous client connectors for the MySQL database system. Boost.MySQL is written from the ground up, implementing the entire protocol with no external dependencies beyond the Boost library. It is compatible with MariaDB. Connectivity options include TCP, SSL and Unix Sockets. For async interfaces, examples in the documentation demonstrate full compatibility with all Asio completion handler styles, including: Callbacks:- https://anarthal.github.io/mysql/mysql/examples/query_async_callbacks.html Futures :- https://anarthal.github.io/mysql/mysql/examples/query_async_futures.html Boost.Coroutine :- https://anarthal.github.io/mysql/mysql/examples/query_async_coroutines.html C++20 Coroutines :- https://anarthal.github.io/mysql/mysql/examples/query_async_coroutinescpp20… Rubén has also implemented the Asio protocols for deducing default completion token types :- https://anarthal.github.io/mysql/mysql/examples/default_completion_tokens.h… Reviewing a database connector in depth will require setting up an instance of a MySQL database. Fortunately most (all?) Linux distributions carry a MySQL and/or MariaDB package. MySQL community edition is available for download on all platforms here: https://dev.mysql.com/downloads/ Rubén has spent quite some time in order to bring us this library candidate. The development process has no doubt been a journey of discovery into Asio, its concepts and inner workings. I am sure he has become a fount of knowledge along the way. >From a personal perspective, I was very happy to be asked to manage this review. I hope it will be the first of many more reviews of libraries that tackle business connectivity problems without further dependencies beyond Boost, arguably one of the most trusted foundation libraries available. Please provide in your review information you think is valuable to understand your choice to ACCEPT or REJECT including Describe as a Boost library. Please be explicit about your decision (ACCEPT or REJECT). Some other questions you might want to consider answering: - Will the library bring additional out-of-the-box utility to Boost? - What is your evaluation of the implementation? - What is your evaluation of the documentation? - Will the choice of API abstraction model ease the development of software that must talk to a MySQL database? - Are there any immediate improvements that could be made after acceptance, if acceptance should happen? - Did you try to use the library? With which compiler(s)? Did you have any problems? - How much effort did you put into your evaluation? A glance? A quick reading? In-depth study? - Are you knowledgeable about the problem domain? More information about the Boost Formal Review Process can be found at: http://www.boost.org/community/reviews.html The review is open to anyone who is prepared to put in the work of evaluating and reviewing the library. Prior experience in contributing to Boost reviews is not a requirement. Thank you for your efforts in the Boost community. They are very much appreciated. Richard Hodges - review manager of the proposed Boost.MySQL library Rubén is often available on CppLang Slack and of course by email should you require any clarification not covered by the documentation, as am I. -- Richard Hodges hodges.r(a)gmail.com tg: @rhodges office: +44 2032 898 513 mobile: +376 380 212 _______________________________________________ Unsubscribe & other changes: http://lists.boost.org/mailman/listinfo.cgi/boost -- Mateusz Loskot, http://mateusz.loskot.net

1 0

[Boost.Asio] [SSL] Can I set the host name before performing a handshake?
by B Aleck 04 May '22

04 May '22

In openssl you call SSL_set_tlsext_host_name to set that Can I do that in boost?

2 2

boost.org domain expired?
by Warren Weckesser 03 May '22

03 May '22

(Hit enter too soon in my last email.) FYI: Attempting to visit https://www.boost.org results in a Network Solutions page, with links for "Renew Now" and "Backorder Domain". Warren

3 3

Re: [Boost-users] boost.org domain expired?
by Kenneth Porter 03 May '22

03 May '22

Confirmed. Here's a site snapshot from yesterday in case someone needs it: https://web.archive.org/web/20220502193202/https://www.boost.org/

1 0

boost.org domain expired?
by Warren Weckesser 03 May '22

03 May '22

1 0

[Math / Distributions] How do mean, variance, etc end up in scope?
by Warren Weckesser 02 May '22

02 May '22

This is probably more of a C++ question than a Boost/Math question. I think the answer comes down to a (surprising?) Boost namespace convention. In a program like this: ``` #include <boost/math/distributions/beta.hpp> using boost::math::beta_distribution; int main() { float a = 1.5f; float b = 3.0f; beta_distribution<float> dist(a, b); auto m = mean(dist); } ``` how does the name 'mean' end up in scope in 'main()'? I would have expected (and preferred!) something like 'using boost::math::mean;' to be required. Warren

3 3

[statechart] non-virtual unconsumed_event
by Alexandre Bouchu 26 Apr '22

26 Apr '22

Hello, Looking for guidance regarding best practices using boost statechart. When it came time to have a mechanism to catch unhandled events and pass that information back to clients, my first choice has been to override unconsumed_event public function in state_machine class. Given that the static code analysis tool we run complains about the dangers of overriding a non-virtual function, I came here to get more background into maybe why this function was not made virtual in the first place. Is there for example a better implementation practice that would see this "catch all" function stay empty, as is the case with state_machine implementation, and instead use another technique to provide meaningful feedback to clients when the action or state transition requested is invalid/unsupported? I feel I can justify and waive this code analysis tool warning up the food chain, but yet wanted some feedback from this user group first. Thanks, Alexandre

1 0

constexpre limits
by Gero Peterhoff 21 Apr '22

21 Apr '22

Hello John, i switched std::numeric_limits<float128> completely to constexpr because it bothered me a lot. Especially: - quiet_NaN (removed sqrt) - has/signaling_NaN adjusted Hope that's ok. regards Gero

1 0

Unable to run example code "line_interpolate"
by Ajay Kumar G 19 Apr '22

19 Apr '22

Hello, First of all, thank you for your contributions. Indeed it was a greatly useful library with very detailed documentation. While trying to run a sample example code "line_interpolate" from following link: https://www.boost.org/doc/libs/1_79_0/libs/geometry/doc/html/geometry/refer… There is an error that appears saying " error: ‘line_interpolate’ was not declared in this scope" but i dint understand the reason. While other examples from the reference( https://www.boost.org/doc/libs/1_79_0/libs/geometry/doc/html/geometry/matri…) work fine without any issues. May I know the actual cause of this issue? Working platform: Ubuntu 18.04 Boost Version: 1.65.1.0 Regards, Ajay

2 1

[release] Boost 1.79.0
by Marshall Clow 18 Apr '22

18 Apr '22

Release 1.79.0 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_1.79.0> You can also download directly from: <https://boostorg.jfrog.io/artifactory/main/release/1.79.0/> 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, Michael Caisse, Glen Fernandes

5 5

Boost.Intrusive: getting the next element
by Gonzalo Arana 16 Apr '22

16 Apr '22

Hi, Given an element (contained in a list), how may I get the next one, without requiring access to the list itself? I only found this way to get the next element: auto iterator = list.iterator_to(value); ++iterator; return *iterator; But it requires access to the list itself. Best regards, -- Gonzalo A. Arana

2 1

Boost.Text is looking for a (mini-)review manager
by Mateusz Loskot 15 Apr '22

15 Apr '22

Hi, A reminder from the review wizards: The Boost.Text library developed by Zach Laine is still looking for a (mini-)review manager, see details at: https://lists.boost.org/Archives/boost//2020/08/249594.php and https://www.boost.org/community/review_schedule.html Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

1 2

MySQL library scheduled for review
by Mateusz Loskot 15 Apr '22

15 Apr '22

Hi, A brief announcement from the review wizards: Following the proposal [1] and search for the review manager, formal review of the MySQL library [2] has been scheduled to take place between May 9, 2022 - May 18, 2022. Details and links available here https://www.boost.org/community/review_schedule.html We'd like to thank Richard Hodges for volunteering to act as the review manager, again! [1] https://lists.boost.org/Archives/boost/2022/03/252584.php [2] https://github.com/anarthal/mysql/ Best regards, -- Mateusz Loskot, http://mateusz.loskot.net

1 0

[Math / Special Functions] Use more than one user_error function?
by Warren Weckesser 14 Apr '22

14 Apr '22

I am wrapping some boost special functions as NumPy "ufuncs" for the Python library SciPy, and I am setting a policy to control how errors are handled. For example, the wrapper of erf_inv (for C++ types float, double and long double) is wrapped as the function scipy.special.erfinv (i.e. the Python function is erfinv in the module scipy.special). The actual core instantiation of the function for type, say, double, in C++ that is called by the ufunc implementation is double erfinv_double(double x) { return erf_inv(x, special_policy()); } where erf_inv is the Boost function, and special_policy is created as template <class T> T user_domain_error(const char *function, const char * message, const T& val) { sf_error("erfinv", SF_ERROR_DOMAIN, NULL); return std::numeric_limits<T>::quiet_NaN(); } typedef policy< domain_error<user_error>, overflow_error<ignore_error> > special_policy; Note that the error handler is calling sf_error(), a function in the SciPy special library. The first argument is the name of the SciPy Python function. That function might generate a Python warning or set a Python exception, and the name displayed in the error message should be the name of the SciPy function, and not something like "boost::math::erf_inv[...]". This leads to the problem. The above code, with a hard-coded string "erfinv" passed to sf_error(), works for erfinv, but obviously I can't use the same implementation of user_domain_error for a wrapper of, say, tgamma_ratio. So the question is, can different policies be created that have different user-defined error handlers? Or is there a clever way to get the SciPy name into the user_domain_error() function? (I hope there is something simple--I am not a C++ guru, so I may have missed something obvious.) I am considering creating a mapping from some parsed version of the function argument of user_domain_error to the SciPy names. E.g. the function argument could be scanned for the occurrence of "erf_inv", and know that the name "erfinv" should be passed to sf_error(). A table of regex patterns with corresponding SciPy names might do the trick. But I'm wondering if there is a more elegant (and more maintainable) solution. Regards, Warren

2 3

Re: [Boost-users] [boost] [release] Boost 1.79.0
by Glen Fernandes 14 Apr '22

14 Apr '22

On Wed, Apr 13, 2022 at 3:17 PM Andrey Semashev wrote: > > On 4/13/22 21:04, Vinnie Falco via Boost wrote: > > The thing that I absolutely LOVE about a new release of Boost, is that > > someone always reports a crashing bug just after the release is > > published: > > > > <https://github.com/boostorg/json/issues/692> > > We have a practice of adding post-release patches to release notes. Updated: https://github.com/boostorg/website/commit/0752dee32f149db385ea0f635886221b… Added /patches/1_79_0/0001-json-array-erase-relocate.patch and release notes updated. Glen

1 0

Unlock / free a boost::asio::strand in beast?
by Markus Bonk 13 Apr '22

13 Apr '22

Hi, The application is using beast / websockets to communicate with a websocket server. A specific onread handler which is initially running on the stream strand needs to read another value from the websocket server to proceed. It sends a message and then waits on a future. This deadlocks the websocket communication. If instead of a strand a mutex were being used could unlocking the mutex before sending the message after the data that needs to be protected / requires synchronization has been already acquired and the resources would be available for the next handler. Is there any way of 'unlocking' the strand i.e. setting the state of the handler's thread so that 'isrunning_on_strand' = false and the stream can continue servicing the incoming messages? Thanks for any pointers. Markus ________________________________ Markus Bonk Senior Software Engineer [cid:3dconnexion_bd84aa85-40b4-4789-87b1-4c8f703d9ae6.gif] Clarita-Bernhard-Str. 18 81249 M?nchen Germany markus_bonk(a)3dconnexion.com<mailto:markus_bonk@3dconnexion.com><mailto:%7BE-mail%7D> www.3dconnexion.com<http://www.3dconnexion.com> Gesch?ftsf?hrer: Antonio Pascucci Sitz der Gesellschaft: M?nchen Registergericht: M?nchen HRB 99232 This email and any files transmitted with are from 3Dconnexion GmbH. The contents of this email and any attachments are confidential to the intended recipient. They may not be disclosed to or used by or copied in any way by anyone other than the intended recipient. If this email is received in error, please contact 3Dconnexion GmbH by calling +49 89 8974542-0 and then delete it. Please note that neither 3Dconnexion GmbH nor the sender accepts any responsibility for viruses and it is your responsibility to scan or otherwise check this email and any attachments. Any opinion expressed in this email are those of the individual and not necessarily those of 3Dconnexion GmbH. 3Dconnexion GmbH processes and stores for commercial purposes your personal data, collected upon your consent, in accordance with its privacy policy available at https://www.3dconnexion.eu/privacy.html, which has been drafted in accordance with Regulation (EU) no. 679/2016 and all applicable local data protection laws and regulations of the countries where the company operates. To revoke your consent or exercise all your rights with regards to personal data, please contact us at privacy(a)3dconnexion.com<mailto:privacy@3dconnexion.com>.

2 1

Reading a large compressed .gz file without uncompressing it
by bharath pagadala 05 Apr '22

05 Apr '22

Hi Team, My requirement is I want a read a large .gz file and stream data without uncompressing it. Does the boost library help me to achieve this. Is there any function in the boost library which help me stream data directly without uncompressing the input .gz file. Please respond on this thank you in advance. Cheers, Bharat Pagadala

1 0

The Boost Statechart Library AND boost::bind
by Jinlong Shen 05 Apr '22

05 Apr '22

Can the statechart library be updated to treat the boost::bind warning about namespace. See here for details. https://stackoverflow.com/questions/53203970/why-boostbind-insists-pulling-…

1 0

[Nowide] Nowide and Property Tree file IO
by William Kappler 03 Apr '22

03 Apr '22

I'm trying to sidestep some issues with unicode filenames on Windows (MSYS64) using Boost.Nowide. Specifically, my program operates in UTF-8, and providing that to std/Boost functions yields incorrect filenames due to them being interpreted as UTF-16 (or something along those lines). However, the primary functions I have issues with are from Boost.PropertyTree. Specifically, read_json and write_json. These functions don't seem to be Nowide-friendly. I tried just calling boost::nowide::nowide_filesystem() before my json calls, hoping it would work; it did not, I got the same mangled filenames. My next thought was to see if a nowide stream could be substituted into the stream-taking variants of read_json/write_json; it cannot be, they aren't compatible. The only option that seems to leave is something along these lines: https://stackoverflow.com/a/21537818, but using Nowide to read in the file. That adds a lot of steps (and possibly memory usage). It feels like I'm missing something. Any suggestions would be appreciated. Thanks in advance. :-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:- *William E. Kappler II* Software Designer and Programmer william-kappler.com

1 0

boost python AttributeError
by Chien-Yu Chen 03 Apr '22

03 Apr '22

hi I followed the basic boost python examples, both hello_ext.greet() and hello.World() and both are giving me AttributeError error, like AttributeError: module `hello` has no attribute 'greet' dumpbin does show that I have PyInit_hello exported out. Please let me know if I am doing something wrong as this should be trivial. thx -- Any MicroSoft extension file will directly go to trash without any warning and regret.

1 0

Fwd: Concatenated input streams
by Robert Dodier 29 Mar '22

29 Mar '22

Hi, I'm interested in working with an input stream which comprises multiple input streams. The resulting stream comprises all of the input from the first stream (until EOF), then all of the input from the second, etc. For what it's worth, such an input stream is called a concatenated input stream in at least one other context (namely Common Lisp). The input streams in question are file input streams, although conceptually I don't know if that changes anything. I am hoping to find something equivalent to $ cat file1 file2 file3 ... > alldata and then reading alldata. Is there a Boost class which implements such a thing? I know that this is a pretty simple concept, and therefore it's just a small matter of programming, but I'm hoping that someone has already worked out the details. If there is such a thing in some library other than Boost, I would be interested to hear about that too. Thank you for your time, I appreciate your help very much. Robert Dodier

2 6

[Boost.Asio] Can I move io_context away while having sockets bound to it?
by B Aleck 22 Mar '22

22 Mar '22

You created serveral sockets and bound them to an io_context Is it safe to std::move the io_context away? Will those sockets be affected, or even be invalidated?

3 2

Curious definition of beast::file_mode::append
by Senthil Cheetancheri 18 Mar '22

18 Mar '22

Hi All, The current definition of append seems to be identical to that of write. Both are defined as follows: 1. Create a new file if it doesn't exist. 2. Truncate to zero bytes, if it exists. The comment for append says, "The current file position shall be set to the end of the file prior to each write." However, if the file is always truncated to zero, implementing the above comment achieves nothing significant. Shouldn't append simply open an existing file or create a new one for writing and set the file-pointer to the end of the file? This will also obviate the need for append_existing. Following the same line of reasoning for write: The comment says that this mode permits random-access reading and writing for the specified file. However again, if the size is always truncated to zero bytes, random-access reading or writing becomes a moot point. On the other hand, if write is defined not to truncate (as I expected originally), it will obviate the need for write_existing as well. Am I misunderstanding these definitions? Is there a sound reason behind the current definitions? Thanks, Senthil.

1 0

numeric_cast should work with enum's
by Frederick Virchanza Gotham 16 Mar '22

16 Mar '22

(Sometimes Gmail changes white space so I hope this post is indented properly) I think that "numeric_cast" should be able to cast to and from enum types, so that it can be used as follows: #include <cstdint> #include <iostream> using std::cout; using std::endl; enum class Frog { Blue, Yellow, Pink = 0xFFFFu }; enum class Toad : std::uint8_t { Purple, Orange = 0x7f }; int main(void) { try { numeric_cast<Toad>( Frog::Pink ); } catch(std::exception const &e) { cout << e.what() << endl; } std::uint32_t my_32_bit_var = 0xffffffffU; try { numeric_cast<std::uint16_t>(my_32_bit_var); } catch(std::exception const &e) { cout << e.what() << endl; } try { numeric_cast<std::uint8_t>( Frog::Pink ); } catch(std::exception const &e) { cout << e.what() << endl; } try { numeric_cast<Toad>(0x1FFu); } catch(std::exception const &e) { cout << e.what() << endl; } } In order to achieve this behaviour, I've created my own "numeric_cast" in the global namespace as follows: #include <type_traits> // is_enum, underlying_type #include <boost/numeric/conversion/cast.hpp> // numeric_cast template<bool T_is_an_enum, typename T> struct numeric_cast_helper { typedef T type; }; template<typename T> struct numeric_cast_helper<true, T> { typedef typename std::underlying_type<T>::type type; }; template<typename A, typename B> A numeric_cast(B const b) { return static_cast<A>( boost::numeric_cast<typename numeric_cast_helper<std::is_enum<A>::value, A>::type> ( static_cast<typename numeric_cast_helper<std::is_enum<B>::value, B>::type>(b) ) ); } Should the Boost Numeric library be changed so that numeric_cast can work with enum's?

1 0

[release] Boost 1.79.0 beta 1 released
by Marshall Clow 16 Mar '22

16 Mar '22

Boost release 1.79.0 beta 1 is now available at: <https://boostorg.jfrog.io/artifactory/main/beta/1.79.0.beta1/source/> The SHA256 checksums are as follows: 8985105623f48d55be01076d98ca4e7a8cb548a8d7f9ad0e1fc3c710d2c75fcf boost_1_79_0_b1.tar.bz2 4b58e4d3b6ff1176b3c6cb9eec496c1f6d2535270e97ec140da533d68766ca39 boost_1_79_0_b1.tar.gz 4d05b458cd039afe86003cf7e1e6c3a358b5b2d031892e620eedc344ab200246 boost_1_79_0_b1.7z 768875ad5c77763445e8b119072cfa1e64854b071a353dd44c3c73ff46df910b boost_1_79_0_b1.zip For details of what's in the release, see <https://www.boost.org/users/history/version_1_79_0.html>. Please download the beta, give it a try, and report any problems you encounter. Thanks, -- The Boost Release Team

1 0

container: static_vector and type traits
by MM 15 Mar '22

15 Mar '22

Hello Should static_vector be of standard layout and/or trivially copyable? depending on the element type I see this outputs false std::cout << std::is_standard_layout_v<boost::container::static_vector<char,32>> << std::endl; std::cout << std::is_trivially_copyable_v<boost::container::static_vector<char,32>> << std::endl; Rds,

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