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[release] 1.69.0 closed for major changes
by Marshall Clow 01 Nov '18

01 Nov '18

The master branch is now closed for new libraries and breaking changes, and will be closing for the beta in one week. Also, if you're ready, you can also add your libraries' changes to the release notes at: < https://github.com/boostorg/website/blob/master/feed/history/boost_1_69_0.q… > After editing the release notes, you should get a form to create a pull request, remember to submit it, otherwise I won't see your change. Thanks, -- The Boost Release Team

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Web based C++ compiler with Boost support
by Michael Powell 01 Nov '18

01 Nov '18

Hello, Does anyone happen to know of a decent web based C++ compiler with Boost support? Specifics, if possibly, include support for MSVC, especially VS2017 C++, Spirit, probably C++17 as well, etc. I know that's probably asking for a lot, but my searches aren't turning up very much, or it is getting confused with literally "building Boost", which is a bit OT. :-) Thanks! Best regards, Michael Powell

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Roughed in Proto2 Spirit parser
by Michael Powell 31 Oct '18

31 Oct '18

Hello, I'm working on a Proto2 Spirit parser. Right now it's really roughed in. There is no AST at the moment. That's TBD; right now I am focused on just getting the build to work. https://gcc.godbolt.org/z/_nBsKi The code is there, but the compiler driving the web site is choking on Spirit. I put the rules in up front; probably ambitious on my part, and am finding an error on: _range %= _int_lit >> -(lit("to") >> (_int_lit | lit("max")); Severity Code Description Project File Line Suppression State Error C1075 '{': no matching token found Kingdom.OrTools.Sat.Params.Generator g:\source\kingdom software\kingdom.ortools\standard\src\kingdom.ortools.sat.params.generator\proto_parser.cpp 205 The Proto2 grammar states: range = intLit [ "to" ( intLit | "max" ) ] I'm considering pairing it back significantly and building the grammar up gradually to make sure it all builds. That's probably a sounder approach anyway. Eventually I want to build up the AST in such a way as to facilitate generating some boilerplate adapter code in my target language (C#). Thoughts? Best regards, Michael Powell https://developers.google.com/protocol-buffers/docs/reference/proto2-spec

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Error building Spirit parser in VS2017
by Michael Powell 31 Oct '18

31 Oct '18

Hello, I am receiving the following error building against the latest VS2017 ... 1>Version_Parser.cpp 1>d:\dev\boost.org\boost_1_68_0\boost\iostreams\positioning.hpp(96): error C4996: 'std::fpos<_Mbstatet>::seekpos': warning STL4019: The member std::fpos::seekpos() is non-Standard, and is preserved only for compatibility with workarounds for old versions of Visual C++. It will be removed in a future release, and in this release always returns 0. Please use standards-conforming mechanisms to manipulate fpos, such as conversions to and from streamoff, or an integral type, instead. If you are receiving this message while compiling Boost.IOStreams, a fix has been submitted upstream to make Boost use standards-conforming mechanisms, as it does for other compilers. You can define _SILENCE_FPOS_SEEKPOS_DEPRECATION_WARNING to acknowledge that you have received this warning, or define _REMOVE_FPOS_SEEKPOS to remove std::fpos::seekpos entirely. 1>c:\program files (x86)\microsoft visual studio\2017\enterprise\vc\tools\msvc\14.15.26726\include\iosfwd(59): note: see declaration of 'std::fpos<_Mbstatet>::seekpos' With my grammar: BOOST_FUSION_ADAPT_STRUCT(NS_VERSION_H::version, _major, _minor, _patch, _build); template <typename It> struct version_parser : qi::grammar<It, NS_VERSION_H::version()> { version_parser() : dot_('.'), version_parser::base_type(_start) { using qi::lit; using qi::hold; using qi::short_; _major_part = short_; _minor_part = lit(dot_) >> short_; _patch_part = lit(dot_) >> short_; _build_part = lit(dot_) >> short_; _start = hold[_major_part >> _minor_part >> -(_patch_part >> -_build_part)]; } private: qi::rule<It, NS_VERSION_H::version()> _start; const char dot_; qi::rule<It, short()> _major_part; qi::rule<It, short()> _minor_part; qi::rule<It, short()> _patch_part; qi::rule<It, short()> _build_part; }; bool try_parse_version(const std::string& s, NS_VERSION_H::version& v) { using It = std::string::const_iterator; using qi::parse; It first = s.begin(), last = s.end(); if (!parse(first, last, version_parser<It>{}, v)) { std::cout << "Failed to parse: '" << s << "'" << std::endl; return false; } const auto dot_ = "."; std::cout << "version: " << v._major << dot_ << v._minor << dot_ << v._patch << dot_ << v._build << std::endl; return true; } At present I have not furnished any Spirit flags or anything of that sort; pretty much taking the includes, grammar, building as-is. Secondary to the error, I want the parser to reject spaces, should just be numeric (short) and the dot delimiter. Best regards, Michael Powell

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Boost "Application" concept?
by Michael Powell 30 Oct '18

30 Oct '18

Hello, I know Boost has within its repo the elements of bits that comprise a typical application; i.e. program options, for starters, etc. However, I was curious, is there a library in the Boost repo that wraps it all up in a prescribed format? Or a handle of recipes? Things I would expect to find include the program options, ability to run, with some arguments, etc. Not an exhaustive set of expectations, to be sure. Thanks for the feedback! Cheers, Michael W Powell

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Boost 1.68.0 - boost hashing changed ?
by Shailja Prasad 28 Oct '18

28 Oct '18

Hello there, I was trying to upgrade boost 1.53.0 to boost 1.68.0. But, it looks like hashing code generation has changed, since the following line gives two different hashcode for same string input. boost::hash<string> namehash; size_t hashCode = namehash( name); Where name is string, an e.g “abcdefg” With boost 1.53.0 the hashCode is 168904 And with boost 1.68.0 the hashCode is 69530. I am giving just sample random number here, those two numbers are never equal, with everything remain the same, only change boost version on EL6 Linux machine with GCC 4.9 compiler. This is blocking me to upgrade to newer version of boost. I appreciate if anyone has some info on this. Thanks

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Mailman upgrade
by Brad Johnson 27 Oct '18

27 Oct '18

Happy Late October all. Just a quick notification that mailman upgraded from 2.1.26 -> 2.1.29 at 27-Oct-2018 02:50 UTC. Release notes for 2.1.27, 2.1.28, and 2.1.29: https://launchpad.net/mailman/2.1/2.1.27 https://launchpad.net/mailman/2.1/2.1.28 https://launchpad.net/mailman/2.1/2.1.29 Sanity checks on test mailing list shows mail is still flowing and archiving. Any questions or concerns, please let me know at this address or sysadmin(a)boost.org. Thanks, -- Brad Johnson Ciere Consulting 916.877.6030 brad.johnson(a)ciere.com ciere.com

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Boost Multiprecision list.
by A Z 26 Oct '18

26 Oct '18

I am aware the the boost multiprecision library is a headers library. -Is Boost multiprecision accurately arbitrary precision, ie. can have its number precisions and scales always made to a larger number, contingent only to the amount of available OS memory? -If I want to use boost Boost multiprecision on its own, what is the name of the Boost .dll or .lib files that have all the headers in it? I need a minimal set of files in order to run multiprecision on its own. ?

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Boost iterator facade implementation
by rmawatson rmawatson 26 Oct '18

26 Oct '18

https://github.com/boostorg/iterator/blob/boost-1.63.0/include/boost/iterat… I was wondering about is_non_proxy_reference<Reference,Value> in this metafunction. It appears to select between postfix_increment_proxy<Iterator> and writable_postfix_increment_proxy<Iterator> based on whether Reference is the same type as Value ignoring cv& what is the case that writable_postfix_increment_proxy<Iterator> is selected. So when is Reference going to be a different 'base type' to Value? is this to support user returning their own proxy or something?

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[asio] Advice on implementing rate-limiting for async_write
by Kyle Ketterer 25 Oct '18

25 Oct '18

Hello fellow Boost friends, I am looking into some advice on implementing rate-limiting using using Boost ASIO with async_write. I am working on a Enterprise File Backup solution named Vessel @ https://github.com/VesselEnterprise/vessel-backup. My project uses Boost through and through. The use case is as follows: - Many users on the same network/subnet may be transferring files at once - I want to add the feature of being able to limit upload speed to the storage provider (AWS, Azure, etc) The request starts as follows: (pseudo code) Let's say we have a string of 1000 bytes we want to send to a server: const std::string& request //Passed to member function and make_shared<>() > to member var on stack to ensure lifetime of async operation Let's also say we want to limit the transfer speed to 100 bytes/second size_t transfer_max = 100; Should we start the request with async_write() on the socket? //Ensure that no more than transfer_max bytes are sent during the first write > boost::asio::async_write(*m_socket, boost::asio::buffer(http_request, > transfer_max), boost::bind(&HttpClient::handle_write, this, > boost::asio::placeholders::error, > boost::asio::placeholders::bytes_transferred )) ; > Here is where I have questions. In the completion handler handle_write(...), we need to continue to call async_write() until all bytes have been written and determine the current transfer rate, and sleep the thread if necessary. When sending the next set of bytes, is it best to explicitly declare a buffer and consume or use a pointer to the char array? void HttpClient::handle_write( const boost::system::error_code& e, size_t > bytes_transferred ) > { > /** > ** Do some stuff here to determine transfer rate, and sleep if > necessary... > */ > > //Pseudocode > if ( transfer_rate > transfer_max ) > { > //Possibility 1? > auto buffer = boost::asio::buffer(request, transfer_max); > buffer.consume(total_bytes_transferred_so_far); > boost::asio::async_write(*m_socket, buffer, > boost::bind(&HttpClient::handle_write, this, > boost::asio::placeholders::error, > boost::asio::placeholders::bytes_transferred )) ; > //Possibility 2? > boost::asio::async_write(*m_socket, > boost::asio::buffer(&request[total_bytes_transferred_so_far], > transfer_max), boost::bind(&HttpClient::handle_write, this, > boost::asio::placeholders::error, > boost::asio::placeholders::bytes_transferred )) ; > return; > > } > //...eof > } Advice on the topic is greatly appreciated. If I am way off, just let me know :) Thanks! -- Kyle Ketterer <reminisc3(a)gmail.com>

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