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Serialization over UDP
by Álvaro Cebrián Juan 11 Jun '18

11 Jun '18

Hello everyone, I have no prior experience with Boost. I need to serialize an object and send it over UDP to a remote machine. I already have a completely functional serialization mechanism over TCP and I would like to convert it to UDP. The member function that I use to serialize the objects over TCP looks like this: /// Asynchronously write a data structure to the socket. > template <typename T, typename Handler> > void async_write(const T& t, Handler handler) > { > // Serialize the data first so we know how large it is. > std::ostringstream archive_stream; > boost::archive::text_oarchive archive(archive_stream); > archive << t; > outbound_data_ = archive_stream.str(); > > // Format the header. > std::ostringstream header_stream; > header_stream << std::setw(header_length) > << std::hex << outbound_data_.size(); > if (!header_stream || header_stream.str().size() != header_length) > { > // Something went wrong, inform the caller. > boost::system::error_code > error(boost::asio::error::invalid_argument); > socket_.get_io_service().post(boost::bind(handler, error)); > return; > } > outbound_header_ = header_stream.str(); > > // Write the serialized data to the socket. We use "gather-write" to > send > // both the header and the data in a single write operation. > std::vector<boost::asio::const_buffer> buffers; > buffers.push_back(boost::asio::buffer(outbound_header_)); > buffers.push_back(boost::asio::buffer(outbound_data_)); > boost::asio::async_write(socket_, buffers, handler); > } > As you can see in the code, it makes use of streams to write the serialized data asynchronously to the remote machine. This is fine for TCP, since this protocol is stream-oriented. However, as far as I know, this does not work for UDP because it is message-oriented and therefore it does not support streams. Thus, I would be very grateful if someone could shed some light on which tools does Boost provide that would make serialization feasible over UDP. Thank you. Best Regards, Álvaro

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Bug when using boost::optional with boost::program_options?
by Jim Porter 06 Jun '18

06 Jun '18

Before I spend too long tracking this down (I'm only seeing it in an Appveyor Windows build, since I do most of my work on Linux), I wanted to see if anyone else has experienced this issue. I'm trying to use boost::program_options to parse a command line arg and store it into a boost::optional, however I get a surprising compilation error[1]. This appears to have been introduced sometime between Boost 1.60 and 1.62 (Appveyor doesn't have Boost 1.61). I see that there were some significant changes to boost::optional between those revisions, so maybe that's the cause? The following test case *might* reproduce the issue, but sadly, rextester only has Boost 1.60, so it works there[2]. If it fails for someone with Boost 1.62+, then great! (Well, not "great", but you know what I mean.) Interestingly, it's not until Boost 1.65[3] that boost::program_options claims to support storing values into boost::optional; it's worked for me since long before that, possibly because I `#include <boost/optional/optional_io.hpp>`. If this isn't enough for others to help confirm this issue, that's ok; I'll try to get a Windows dev environment set up to provide more details in the coming week. I just wanted to send this out before I forgot about it... If it matters, the Appveyor build I'm seeing this with uses Visual Studio 2015 Update 3. Thanks, - Jim [1] https://hastebin.com/awutivawew.txt [2] http://rextester.com/QGBH48883 [3] https://www.boost.org/users/history/version_1_65_0.html

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Can't build Boost sgd libraries using VC
by Ed Bronkowski 05 Jun '18

05 Jun '18

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boost::process::win32_launch(...) with unicode working directory - Urgent
by Chandrasekhar B 04 Jun '18

04 Jun '18

Dear Users, I have trouble using the following boost api. I am developing application for Non English OS. The working directory is non-english for this case. If I set the working directory to Japanese or any other non-english language, the process does not start. I have few files that need to be read from the working directory. however, if I launch the process from the cmd line (whose path is again some Unicode text) the process launches fine. boost::process:win32_launch(const Executable &exe, const Arguments &args, const Win32_Context &ctx) is there any way to support unicode path for working directory within boost? Regards Chandrasekhar

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How to build shared boost with clang-win?
by JR Cary 03 Jun '18

03 Jun '18

Windows 7 VSS2017 (1911) LLVM-6.0.0-win64 ./bootstrap.bat (works) ./b2 -d+2 -q toolset=clang-win runtime-link=shared link=shared cxxflags='/std:c++14 /EHsc /MD' address-model=64 threading=multi variant=release -s NO_COMPRESSION=1 --layout=system --abbreviate-paths -j1 --without-python --without-mpi --without-log --without-math stage fails at clang-linux.link.dll bin.v2\libs\atomic\build\clng-lnx-win\rls\thrd-mlt\boost_atomic.dll "clang++" -o "bin.v2\libs\atomic\build\clng-lnx-win\rls\thrd-mlt\boost_atomic.dll" -Wl,-soname -Wl,boost_atomic.dll -shared -Wl,--start-group "bin.v2\libs\atomic\build\clng-lnx-win\rls\thrd-mlt\lockpool.obj" -Wl,-Bstatic -Wl,-Bdynamic -Wl,--end-group -m64 -pthread It looks like clang-win is trying to use clang++ to link? Should it no use clang-cl? Thanks....John Cary

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Plans to add parameter parsing in Beast?
by David Demelier 30 May '18

30 May '18

Hello, I'm trying to use Beast, it works fine and looks promising. Unfortunately, it looks like (unless I'm wrong) that there is no facilities to parse URL parameters or POST data. Such as /foo&option1=1&option2=2 Or simply form data: option1=1&option2=2 Are there plans to add such things or is definitely a non-goal of Boost Beast? Regards, -- David

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Boost::Log memory allocation
by Olivier Tristan 29 May '18

29 May '18

Hi, I was wondering if it is possible to avoid allocation in the thread trying to log stuff ? I thought that using asynchronous_sink and bounded_fifo_queue with drop_on_overflow would be enough but it do not look like to be the case. Thanks ! -- Olivier Tristan Research & Development www.uvi.net

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boost-iostreams problem
by Theodore Papadopoulo 28 May '18

28 May '18

Hi, I'm trying to use boost_iostream in a way that is probably not intented. My use case is the following, I have a C++ stream. I want to read its first bytes to determine if its gzip or Bzip2 or none of those, putback the characters to the stream and then create the appropriate pipeline to read the stream. Ideally, I'd then restart the procedure, so that I can incrementally build a pipeline based on the successive magic numbers read at the begining of the stream after different level of decoding. Imagine a file that has been gzipped and uuencoded. Let's call its stream ifs. Reading the first bytes of ifs, I would detect that it's an uuencoded file, so I construct a pipeline ifs1 = ifs | uudecode. Reading the first bytes of ifs1, I would detect that it's a gzipped file, and will construct a new pipeline ifs2 = ifs | uuencode | gzip (the reverse ordering for reading pipelines does not help here, but I can manage that). And so on.... Unfortunately, this does not work as I'm expecting it. The attached code is a small example showing the problem. When, reading the stream after having pushed the gzip filter (line 23), I get an exception. boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::iostreams::gzip_error> > Digging a little with gdb seems to show that the putback buffer is somehow lost, so the gzip filter does not read the proper header and hence the exception. The raw in.read does not throw exceptions but returns random bytes after the first 1f.... What is strange is that if I do the sequence: in.push(file); read(in,buffer,1); putback(in,buffer[0]); in.pop(); in.push(file); read(in,buffer,1); std::cout << std::hex << static_cast<int>(static_cast<unsigned char>(buffer[0])) << std::endl; putback(in,buffer[0]); The second read correctly reads the character put back (1f), but the second putback triggers an exception (putback buffer full). If the first read/putback is done directly on file, everything works as expected. I'm really stuck at this point, so any help would be welcome.... I hope there is a way to use boost_iostreams to achieve what I want to do. Thank's in advance for any clue on how to solve this... Theo.

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[asio] continuous reads into streambuf
by Stephan Menzel 25 May '18

25 May '18

Hello all, once again I find myself struggling with asio streambufs but wanted to ask here before chicken out to char buffers again. My problem is that I cannot read more than one protocol loop successfully. I got a TCP connection here that continuously receives messages on a simple protocol like that: header_size CRLF header (contains payload size) payload <repeat> I thought this is a prime use case for reading into a streambuf as I can easily deal with additional data being in there and the client pushing as fast as it can. Here is what I do (simplified quite a bit, sorry for copy and paste and simplify errors): (m_socket and m_streambuf are only used by one io_context, one thread, no races as far as I can tell) void read_header_size() { asio::async_read_until(m_socket, m_streambuf, "\r\n", [self](const boost::system::error_code, const std::size_t) { // < handle error skipped > std::string hsizestr; hsizestr.reserve(32); { std::istream is(&self->m_streambuf); std::getline(is, hsizestr); } std::size_t header_size = parse(hsizestr); self->read_header(header_size); }); } void read_header(const std::size_t n_header_size) { asio::async_read(m_socket, m_streambuf, boost::asio::transfer_exactly(n_header_size), [self, packet, n_header_size](const boost::system::error_code, const std::size_t) { // < handle error skipped > // Tried two versions of parsing the header (manual consume and istreams of various sorts) // manual consume: size_t payload_size = parse_header(n_streambuf.data().data(), n_header_size)) { n_streambuf.consume(n_header_size); self->read_payload(payload_size); }); } void read_payload(const std::size_t n_payload_size) { asio::async_read(m_socket, m_streambuf, boost::asio::transfer_exactly(payload_size), [self, n_packet, packet_size](const boost::system::error_code, const std::size_t) { // < handle error skipped > { std::istream is(&self->m_streambuf, std::ios::binary); is.read(target_buffer, target_buffer_size); // target buffer is elsewhere and well guarded } // read next message self->read_header_size(); }); } When I run this and make sure the client pushes at least 2 packets I can safely receive and process the first but after that the next asnc_read() in read_header never returns. As in never calls its handler. From debugging and looking at the streambuf I can reasonably assume the buffer contains all the data after the first async_read_until because the packages are very small (only about 60 bytes total). This leads me to believe the transfer_exactly don't return unless something is actually really transferred. But if such is the case, why does the first loop succeed? I am quite lost here. If anybody has some suggestion it is much appreciated. Thanks a bunch! Stephan

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Boost Process continuously read output
by Surya Kiran Gullapalli 16 May '18

16 May '18

Hi, I'm trying to read outputs/logs from different processes and display them in a GUI. The processes will be running for long time and produce huge output. I'm planning to stream the output from those processes and display them according to my needs. All the while allow my gui application to take user inputs and perform other actions. What I've done here is, from main thread launch two threads for each process. One for launching the process and another for reading output from the process. This is the solution I've come up thus far. // Process Class class MyProcess { namespace bp = boost::process; boost::asio::io_service mService; // member variable of the class bp::ipstream mStream // member variable of the class std::thread mProcessThread, mReaderThread // member variables of the class. public void launch(); }; void MyProcess::launch() { mReaderThread = std::thread([&](){ std::string line; while(getline(mStream, line)) { std::cout << line << std::endl; } }); mProcessThread = std::thread([&]() { auto c = boost::child ("/path/of/executable", bp::std_out > mStream, mService); mService.run(); mStream.pipe().close(); } } // Main Gui class class MyGui { MyProcess process; void launchProcess(); } MyGui::launchProcess() { process.launch(); doSomethingElse(); } The program is working as expected so far. But I'm not sure if this is the correct solution. Please let me know if there's any alternative/better/correct solution Thanks, Surya

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