January 2013 - Boost-users - lists.boost.org

narrowing conversion warning in boost's regex_traits_defaults.hpp when trying to initialize wregex object
by rsk82 29 Jan '13

29 Jan '13

The first line compiles ok. The second also produces working EXE, but in addition I get this large error: In file included from d:\boost/boost/regex/v4/regex_traits.hpp:35:0, from d:\boost/boost/regex/regex_traits.hpp:27, from d:\boost/boost/regex/v4/regex.hpp:39, from d:\boost/boost/regex.hpp:31, from test.cpp:4: d:\boost/boost/regex/v4/regex_traits_defaults.hpp: In instantiation of 'const charT* boost::re_detail::get_escape_R_string() [with charT = wchar_t]': d:\boost/boost/regex/v4/basic_regex_parser.hpp:804:54: required from 'bool boost::re_detail::basic_regex_parser<charT, traits>::parse_extended_escape() [with charT = wchar_t; traits = boost::regex_traits<wchar_t>]' d:\boost/boost/regex/v4/basic_regex_parser.hpp:308:36: required from 'bool boost::re_detail::basic_regex_parser<charT, traits>::parse_extended() [with charT = wchar_t; traits = boost::regex_traits<wchar_t>]' d:\boost/boost/regex/v4/basic_regex_parser.hpp:134:10: required from 'void boost::re_detail::basic_regex_parser<charT, traits>::parse(const charT*, const charT*, unsigned int) [with charT = wchar_t; traits = boost::regex_traits<wchar_t>]' d:\boost/boost/regex/v4/basic_regex.hpp:215:7: required from 'void boost::re_detail::basic_regex_implementation<charT, traits>::assign(const charT*, const charT*, boost::re_detail::basic_regex_implementation<charT, traits>::flag_type) [with charT = wchar_t; traits = boost::regex_traits<wchar_t>; boost::re_detail::basic_regex_implementation<charT, traits>::flag_type = unsigned int]' d:\boost/boost/regex/v4/basic_regex.hpp:661:4: required from 'boost::basic_regex<charT, traits>& boost::basic_regex<charT, traits>::do_assign(const charT*, const charT*, boost::basic_regex<charT, traits>::flag_type) [with charT = wchar_t; traits = boost::regex_traits<wchar_t>; boost::basic_regex<charT, traits>::flag_type = unsigned int]' d:\boost/boost/regex/v4/basic_regex.hpp:382:33: required from 'boost::basic_regex<charT, traits>& boost::basic_regex<charT, traits>::assign(const charT*, const charT*, boost::basic_regex<charT, traits>::flag_type) [with charT = wchar_t; traits = boost::regex_traits<wchar_t>; boost::basic_regex<charT, traits> = boost::basic_regex<wchar_t, boost::regex_traits<wchar_t> >; boost::basic_regex<charT, traits>::flag_type = unsigned int]' d:\boost/boost/regex/v4/basic_regex.hpp:367:48: required from 'boost::basic_regex<charT, traits>& boost::basic_regex<charT, traits>::assign(const charT*, boost::basic_regex<charT, traits>::flag_type) [with charT = wchar_t; traits = boost::regex_traits<wchar_t>; boost::basic_regex<charT, traits> = boost::basic_regex<wchar_t, boost::regex_traits<wchar_t> >; boost::basic_regex<charT, traits>::flag_type = unsigned int]' d:\boost/boost/regex/v4/basic_regex.hpp:336:7: required from 'boost::basic_regex<charT, traits>::basic_regex(const charT*, boost::basic_regex<charT, traits>::flag_type) [with charT = wchar_t; traits = boost::regex_traits<wchar_t>; boost::basic_regex<charT, traits>::flag_type = unsigned int]' test.cpp:15:37: required from here d:\boost/boost/regex/v4/regex_traits_defaults.hpp:329:73: warning: narrowing conversion of ''\37777777605'' from 'char' to 'const wchar_t' inside { } [-Wnarrowing] d:\boost/boost/regex/v4/regex_traits_defaults.hpp:331:64: warning: narrowing conversion of ''\37777777605'' from 'char' to 'const wchar_t' inside { } [-Wnarrowing] code : #include <iostream> #include <boost/regex.hpp> int main() { boost::regex narrow_str_regex("a+"); boost::wregex wide_str_regex(L"a+"); } boost: http://sourceforge.net/projects/boost/files/boost/1.52.0/boost_1_52_0.7z compiler: http://sourceforge.net/projects/mingwbuilds/files/host-windows/releases/4.7… ( and I know that this is the bug: https://svn.boost.org/trac/boost/ticket/7263 ) so, any tricks to get around this (some compiler switches?, I dunno) ? Or can I just ignore this error ? (Yes I need regex matching on wide strings.) -- View this message in context: http://boost.2283326.n4.nabble.com/narrowing-conversion-warning-in-boost-s-… Sent from the Boost - Users mailing list archive at Nabble.com.

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[1.53.0] Beta release candidates 2 now available for testing
by Marshall Clow 28 Jan '13

28 Jan '13

Updated release candidate files for 1.53.0 beta 1 are available at http://boost.cowic.de/rc/ As always, the release managers would appreciate it if you download the candidate of your choice and give building it a try. Please report both success and failure, and anything else that is noteworthy. This helps ensure the candidates build OK before we push them out to SourceForge. The files (and associated md5s) are: 579b680bf55f53cd6d50adc391cb6c23 *boost_1_53_0_beta1_rc2.tar.gz 02098bb6da0e9c10712ae63c16e6aeea *boost_1_53_0_beta1_rc2.tar.bz2 998e2616a66c50e5693f563afb899002 *boost_1_53_0_beta1_rc2.zip e4fde6a869a3e21f8751ba8b7fd471a8 *boost_1_53_0_beta1_rc2.7z There were three changes between rc1 and rc2: * Fixes for compilation errors in Boost.Serialization * Documentation updates for Boost.SmartPtr * Updates to Boost.Threads Thanks, --The release managers

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Re: [Boost-users] boost random in 2 dimensions
by Robert Patterson 28 Jan '13

28 Jan '13

@Gabriel >From your answer I understand that, the uniform distributed values are >generated seperately for x and y axis. Then both should be combined to >form a point over a plane. @Norbert i think this could do uniform distribution only over one co-ordinates. I am assuming you want to sample a point uniformly at random from a rectangular subset of the plane with the sides of the rectangle parallel to the axes. If not, the problem is a little more complex, but still soluble. However, for a square of size 1 Norbert is correct. The extension to a general rectangle is simple - just use two uniform_real_distributions (this will also give you floating point numbers as per your first post). Calls to two different uniform_real_distributions (or successive calls to one object) using the same engine object will give a point uniformly distributed in the rectangle. You are correct to point out that the individual coordinates are also uniformly distributed, but since they are independent they also yield a uniformly distributed point on the rectangle. Robert

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Assertion `invariant_()' failed. in boost multi index
by Sunil S Nandihalli 28 Jan '13

28 Jan '13

Hi Everybody, Boost multi index is a very nice library. But I have a situation where the invariant_() assertion fails. One of the indices is ordered based on a score which is computed with a function. The score of the same element can change when computed at different times. but however, the scores change, score decay over time, such that the previously computed order will always be right. While I don't know if this is the issue, I wanted to make sure that this kind of scoring functions does not cause a problem because of some caching that boost may be doing internally .. and also, the return value of the scoring function is a double which I can imagine can introduce some comparison issues. I am digging into the code to make sure that that is not the problem .. any pointers from the community is greatly appreciated. Thanks, Sunil.

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[spirit/qi] Error handler not called
by Szymon Gatner 28 Jan '13

28 Jan '13

Hi, I am trying to develop a JSON parser using spirit/qi so far it is not going bad but I am having serious problem with on_error and error handler. This is my code: namespace qi = boost::spirit::qi; namespace ascii = boost::spirit::ascii; namespace phoenix = boost::phoenix; template <typename Iterator> struct error_handler { template <typename, typename, typename, typename> struct result { typedef void type; }; void operator()(Iterator first, Iterator last, Iterator err_pos, const boost::spirit::info& info) const { std::cout << "never called"; } }; template <class Iterator> struct JsonGrammar : public qi::grammar<Iterator, Value(), ascii::space_type> { JsonGrammar() : JsonGrammar::base_type(json, "json"), error(error_handler<Iterator>()) { using qi::double_; using qi::lexeme; using qi::char_; using qi::int_; using qi::on_error; using qi::fail; using phoenix::construct; using phoenix::val; using namespace qi::labels; qi::on_error<qi::fail>(json, error(_1, _2, _3, _4)); string %= lexeme['"' >> +(char_ - '"') >> '"']; number = int_; member = string >> ':' >> value; array = '[' >> value % ',' >> ']'; object = '{' >> member >> *(',' >> member) >> '}'; value = array | object | number | string | qi::bool_ | "null"; json = array | object; json.name("json"); } phoenix::function<error_handler<Iterator> > const error; qi::rule<Iterator, std::string(), ascii::space_type> string; qi::rule<Iterator, int(), ascii::space_type> number; qi::rule<Iterator, Value(), ascii::space_type> json; qi::rule<Iterator, Array(), ascii::space_type> array; qi::rule<Iterator, Value(), ascii::space_type> value; qi::rule<Iterator, Object(), ascii::space_type> object; qi::rule<Iterator, std::pair<std::string, Value>(), ascii::space_type> member; }; now when i try to parse std::string json = "[1, 2, 3, 4, t]"; parising result is false. but error handelr is never called. What am I doing wrong? Regards, Simon -- Szymon Gatner The Lordz Games Studio www.thelordzgamesstudio.com

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boost random in 2 dimensions
by Danny 28 Jan '13

28 Jan '13

I am trying to use a boost random generator to make random points uniformly distributed over a plane surface. In the the following link, the code for doing it in a single dimension is available: http://stackoverflow.com/questions/2254909/boost-random-number-generator Here they use boost::uniform_int<> to generate numbers as int in a single dimension. But in my case I wish to generate numbers as float in two dimensions over a plane. Is there any distribution type available to use it in two dimensions? (I have seen boost::uniform_on_sphere, but it is for spherical surfaces.) Is it possible to to this using boost library? -- View this message in context: http://boost.2283326.n4.nabble.com/boost-random-in-2-dimensions-tp4641761.h… Sent from the Boost - Users mailing list archive at Nabble.com.

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[ICL] interval_map::find returns only const iterator
by CarlosRoVe 27 Jan '13

27 Jan '13

Hi, I am using boost v.1.49.0 and I have a question about ICL. We are building a system that stores information associated with time intervals. For this we are using the interval_map container, and every element that we insert in the map contains a right_open interval as the key, and an instance of the structure that holds the information as the value. Some of the features of the system are: 1. Minimum interval length is one second. 2. We have seen that the default behavior for interval_map is aggregate on overlap, but in our case we enforce that overlapping time intervals are not allowed. To achieve this, every time we try to insert an element we perform a check if the time interval overlaps with any of the existing intervals in the map, and if so, we ignore the element. 3. We should be able to modify the data associated with a time interval. We have seen that the find method of the interval_map container returns only a const iterator, but we would like to have a version of find that returns a non-const iterator as well. We want to be able to search for an element whose time interval contains a certain timestamp, and change its content. With the given requirements, find should return one element at most. For us it would be handy if ICL could also provide a version of find that returns a non-const iterator, but maybe I this would break the philosophy behind the design of ICL. We would be glad to hear ideas suggesting what we could do, or alternatives ways of dealing with other problem. Thank you very much. -- View this message in context: http://boost.2283326.n4.nabble.com/ICL-interval-map-find-returns-only-const… Sent from the Boost - Users mailing list archive at Nabble.com.

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boost::asio async
by huvcbo 26 Jan '13

26 Jan '13

Hello, I have a problem I hope I can get some help with. I use boost http-server3, I have a number of tcp/ip-client started and connects to a server, every 15 seconds sending tcp/ip-client a keepalive message. When an HTTP client connects get tcp/ip-client from a container, and from the http message, a new message must be sent via the tcp/ip-client, when the reply is received how can I return it to the http-session? When i send the message to the tcp/ip-client the http-session goes out of scope. Both http-server and tcp/ip-client use async_write and read. Appriciate any help. /Christer

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[accumulators] accumulator "adapters"?
by Pete Bartlett 25 Jan '13

25 Jan '13

Dear all, The accumulators library is a very nice way to get a set of statistics for a stream of numbers, doubles, say. Now let’s suppose I’m receiving a stream of boost::optional<double>s – e.g. let’s suppose I’m receiving simulation results and some simulations fail. It would be neat if I could somehow write and “adaptor accumulator” that took this stream of optionals and then, if they are not empty, pass them to an underlying accumulator. In rough terms: template<typename UnderlyingAccumulator , typename Sample > struct accumulator_adaptor { template<typename Args> void operator()( Args const& args) { Sample const& s = args[sample]; if( s ) { m_underlying_accumulator( *s ) ; //doesn’t compile UnderlyingAccumulator expects an Args, not a Sample } } private: UnderlyingAccumulator m_underlying_accumulator; }; (we might also define another accumulator that just counts the number of “bad” samples. Then by adding an appropriate feature adaptor, one could write something like accumulator_set< boost::optional<double> , tag::accumulator_adaptor< mean > , tag::bad_samples_count > For the data 1.0,2.0,boost::optional<double>(),4.0 This would return a mean of 7/3 and a bad_samples_count of 1. Is it possible for me to implement such an adaptor that would work for an arbitrary underlying accumulator? Thanks for your interest, Pete

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Does Boost have polymorphic functors as named-operators?
by TONGARI 25 Jan '13

25 Jan '13

Hi all, Is there something like -- functional::identity, functional::plus (not std::plus<T>), functional::assign...etc -- in Boost? I know I can use Phoenix _1, _1 + _2, _1 = _2..., but I'd expect something more basic. Sometimes I just need something like that but not willing to have all the ET things... Maybe they're just provided within Phoenix or Proto? Thanks for any help.

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