November 2013 - Boost-users - lists.preview.boost.org

Converting Timestamp into hex of 8 bytes
by Rahul Mathur 09 Nov '13

09 Nov '13

Sorry for wrong post. I have a string Timestamp of 1383889129 which on ONLINE conversion from string to hex gives a 10 bytes as "31 33 38 33 38 38 39 31 32 39". But, the need is to have the TIMEStamp in 8 bytes only. OR any other way using either C++ or Boost where I can convert the string Timestamp of 1383889129 into 8 bytes hex value. Any clue ..!!

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Handling JSON with Boost
by Jauhien Piatlicki 07 Nov '13

07 Nov '13

Hi all, I'm interested whether there exists a library for working with JSON in Boost that preserves data types? I know about property_tree, but if I read a valid JSON with it and then write it out it results in all fields being strings. This is because property_tree internally does not distinguish different value types. But I need something that can read e.g. {"number":42} get access to it and write it then in the same form. Thanks for answering, regards, Jauhien

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Boost API System or Library Calls ..
by Rahul Mathur 06 Nov '13

06 Nov '13

Out of curiosity, wish to know if BOOST ASIO calls like - boost::asio::read() boost::asio::transfer_all() boost::asio::write() BOOST LEXICAL calls like - boost::lexical_cast<std::string>() BOOST POSIX TIME calls like - boost::posix_time::microsec_clock::universal_time() boost::posix_time::microsec_clock::ptime() are LIBRARY or SYSTEM calls. How to know which calls of BOOST are SYSTEM and LIBRARY calls? Thanks.

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Safe to pass dereferenced anonymous shared_ptr?
by Chris Stankevitz 06 Nov '13

06 Nov '13

Q1: Is the below code dangerous? A1: Only if the anonymous shared_ptr is deleted before function f returns. Q2: Is the anonymous shared_ptr deleted before function f returns? A2: ? Thank you, Chris === #include <iostream> #include <boost/make_shared.hpp> void f(const int& i) { std::cout << "i = " << i << std::endl; } int main() { f(*boost::make_shared<int>(42)); return 0; }

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[Containter] Compilation errors with 1.55 and VC2013
by Szymon Gatner 05 Nov '13

05 Nov '13

Hi, I am getting compilation errors with Container library after trying to build with Visual Studio 2013 and Boost 1.55 RC: Error 1 error C2228: left of '.select_on_container_copy_construction' must have class/struct/union c:\devel\boost_1_55_0\boost\intrusive\detail\has_member_function_callable_with.hpp 200 1 ConsoleApplication2 Minimalistic example to reproduce: #include <boost/signals2/connection.hpp> #include <boost/container/slist.hpp> #include <boost/container/vector.hpp> int main() { typedef boost::signals2::connection Connection; boost::container::vector<Connection> connections_; } Error happens wheter vector or slist is used (didn't try more containers) Regards, Szymon Gatner

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[LOG]: set_filter error in tutorial_filtering.cpp and per-sink instance filtering
by Johan Lundberg 05 Nov '13

05 Nov '13

Dear all, (this is my first post to this list) I'm trying to make a boost log sink that would filter on a severity level which should be thread-safely modifiable while logging is ongoing. On my way there I get errors while trying to compile this tutorial example: http://www.boost.org/doc/libs/1_54_0/libs/log/example/doc/tutorial_filterin… The file as-is compiles and runs fine, but if I switch on the user-provided filtering function example by activating the block in #if 0 (and commenting out the other definition of init()) I get errors related to phoenix bind: The offending line is 155: sink->set_filter(phoenix::bind(&my_filter, severity, tag_attr)); I would be grateful for advice on how to get that working. More details on that at the end of the mail. Now, assuming I get past the errors, what is a good way to add a per-sink log level filter? I may have several instances of the sink. To clarify: I know this is not the right syntax, but If I could use a custom functor or a C++11 lambda for a filter I would do something like this: using ATseverity=std::atomic<severity_level> ; // (severity is an enum) shared_ptr<ATseverity> shared_log_level = std::make_shared<ATseverity>(warning); sink->set_filter( [=shared_log_level]->bool(severity_level const& level, std::string const& tag){ return level >= shared_log_level->get(); }); I could then store and modify the shared_log_level from elsewhere. Is there a right way to do this? cheers /Johan Details on the compilation error: I think this is the relevant part of the error message: /myboost154/include/boost/phoenix/core/preprocessed/expression_10.hpp:140:17: error: could not convert ‘boost::proto::make_expr<boost::phoenix::detail::tag::function_eval, boost::proto::domainns_::basic_default_domain, boost::phoenix::detail::function_ptr<2, bool, bool (*)(const boost::log::v2_mt_posix::value_ref<severity_level>&, const boost::log::v2_mt_posix::value_ref<std::basic_string<char> >&)>, boost::log::v2_mt_posix::expressions::attribute_keyword<tag::severity>, boost::log::v2_mt_posix::expressions::attribute_keyword<tag::tag_attr> >((* & a0), (* & a1), (* & a2))’ from ‘const type {aka const boost::proto::exprns_::basic_expr<boost::phoenix::detail::tag::function_eval, boost::proto::argsns_::list3<boost::proto::exprns_::basic_expr<boost::proto::tagns_::tag::terminal, boost::proto::argsns_::term<boost::phoenix::detail::function_ptr<2,bool, bool (*)(const boost::log::v2_mt_posix::value_ref<severity_level>&, const boost::log::v2_mt_posix::value_ref<std::basic_string<char>>&)> >, 0l>, boost::log::v2_mt_posix::expressions::attribute_keyword<tag::severity>, boost::log::v2_mt_posix::expressions::attribute_keyword<tag::tag_attr> >, 3l>}’ to ‘boost::proto::exprns_::basic_expr<boost::proto::tagns_::tag::terminal, boost::proto::argsns_::term<boost::phoenix::detail::function_ptr<2, bool, bool (*)(const boost::log::v2_mt_posix::value_ref<severity_level>&, const boost::log::v2_mt_posix::value_ref<std::basic_string<char> >&)> >, 0l>::proto_child0 { aka boost::phoenix::detail::function_ptr<2, bool, bool (*)(const boost::log::v2_mt_posix::value_ref<severity_level>&, const boost::log::v2_mt_posix::value_ref<std::basic_string<char> >&)>}’ }; I tried boost 1.54 and compiled with gcc 4.7.1 and 4.8.1 under Linux, with and without C++11 mode: g++ -std=gnu++11 -DBOOST_ALL_DYN_LINK boostlogexample.cpp -L $BOOST/lib/ -I $BOOST/include/ -pthread -lboost_system -lboost_log_setup -lboost_log \ -lboost_date_time -lboost_thread -lrt -lboost_filesystem

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container with large number of elements and a small number of invalide elements
by MM 05 Nov '13

05 Nov '13

Hello, I have a need for a container where I can store 10^6 elements of type T (PODs) , a small number of which (say 100) can be invalid elements (ie special value of T) The 100 elements can be randomly distributed throughout the 10^6 elements. The container should be as close to a sequence container as possible. The required usages: 0. invalid elements can be set = 10^6 - 100 1. get number of valid elements in O(1) 2. get the max/min element of all valid elements 3. have a bidrectional iterator that iterators only over valid elements On a separate note, is there a version of multi_array where the number of dimensions is known at runtime? regards,

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[1.55.0] Release candidate 2 available
by Marshall Clow 05 Nov '13

05 Nov '13

RC2 files for 1.55.0 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: 93780777cfbf999a600f62883bd54b17 *boost_1_55_0_rc2.tar.gz d6eef4b4cacb2183f2bf265a5a03a354 *boost_1_55_0_rc2.tar.bz2 8aca361a4713a1f491b0a5e33fee0f1f *boost_1_55_0_rc2.zip 4e5bbc15fc8c80df8be428f8a5b5a823 *boost_1_55_0_rc2.7z Thanks! -- The release managers === Changes to release since rc1 === ---- Author: bemandawes Date: 2013-10-28 13:16:50 EDT (Mon, 28 Oct 2013) New Revision: 86503 URL: http://svn.boost.org/trac/boost/changeset/86503 Log: Merge 86426 from trunk. This should fix msvc test failures. ---- Author: bemandawes Date: 2013-10-29 09:15:03 EDT (Tue, 29 Oct 2013) New Revision: 86514 URL: http://svn.boost.org/trac/boost/changeset/86514 Log: Merge 84443 from trunk, to fix mpl assert failures for msvc in many libraries. ---- Author: eric_niebler Date: 2013-10-29 12:53:08 EDT (Tue, 29 Oct 2013) New Revision: 86516 URL: http://svn.boost.org/trac/boost/changeset/86516 Log: merge [86460] from trunk, fix bootstrap on mingw --- Author: jhunold Date: 2013-10-29 13:19:33 EDT (Tue, 29 Oct 2013) New Revision: 86519 URL: http://svn.boost.org/trac/boost/changeset/86519 Log: Merge 84402 from ^/trunk ------------------------------------------------------------------------ r84402 | jhunold | 2013-05-21 14:23:20 +0200 (Di, 21 Mai 2013) | 4 lines Fix: cache file loading and saving must use native paths Fixes caching at least on Windows platform ------------------------------------------------------------------------ --- Author: johnmaddock Date: 2013-11-01 05:32:55 EDT (Fri, 01 Nov 2013) New Revision: 86532 URL: http://svn.boost.org/trac/boost/changeset/86532 Log: Merge fix for dependency tracking. --- Author: danieljames Date: 2013-11-03 14:20:09 EST (Sun, 03 Nov 2013) New Revision: 86551 URL: http://svn.boost.org/trac/boost/changeset/86551 Log: Merge Visual C++ 12 fix for Unordered. --- Author: viboes Date: 2013-11-03 15:43:42 EST (Sun, 03 Nov 2013) New Revision: 86552 URL: http://svn.boost.org/trac/boost/changeset/86552 Log: Thread: merge [86540] to fix #9319.

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boost::statechart "custom::reaction"
by rahul baruah 05 Nov '13

05 Nov '13

I am using boost::statechart. Instead of simple_state , using boost:: statechart::state. Now i am able to access the state_machine member variable. but when i am using custom::reaction or mpl::list it throught error. Code Snippet: struct NotReady : StateBase< NotReady, TopState > { //typedef NotReadyStateList reactions; NotReady (my_context ctx) : my_base( ctx ){ outermost_context().maxPairedDevices = 3; cout << outermost_context().maxPairedDevices << endl; } template< class MostDerived > sc::result react( const PairingBaseEvents< MostDerived > & ); public: typedef sc::custom_reaction< StartEvent > reactions; }; Error: ndefined reference to `boost::statechart::detail::safe_reaction_result NotReady::react<StartEvent>(PairingBaseEvents<StartEvent> const&)' regards Rahul Baruah

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Concatenating int value to string ..??
by Rahul Mathur 05 Nov '13

05 Nov '13

All, I wish to have string (combination of string value and int value) which increments until 100. The code is as below - --- #include <iostream> #include <cstdlib> #include <string> #include <boost/lexical_cast.hpp> using namespace std; int main() { std::string TID = "Apple"; int TagID = 01, Value = 000 /* 100 IDs*/; std::string TagName, TagInitial, TagUId; TagName = TID + boost::lexical_cast<std::string>(TagID); // Should be as -> Apple01 TagInitial = TagName + boost::lexical_cast<std::string>(Value); // Should be as -> Apple01000 int i = boost::lexical_cast<int>(TagInitial) + 1; // Should be as -> Apple01001 TagUId = boost::lexical_cast<std::string>(i); std::cout << "Tag ID .." << TagUId << endl; } I get below error message - -- terminate called after throwing an instance of 'boost::exception_detail::clone_impl<boost::exception_detail::error_info_injector<boost::bad_lexical_cast> >' what(): bad lexical cast: source type value could not be interpreted as target Aborted (core dumped) -- Any clue? ~ Thanks!!

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XML Serialization
by Lasse Laursen 05 Nov '13

05 Nov '13

Hey People, I'm having some issues using BOOST's serialization capabilities in version 1.53. To be honest, the capability provided by boost seem to involve a lot of macro usage here and there, and despite the fact that I've read a number of tutorials, I still don't feel like I've got a solid grasp on how it all works. Probably because I keep running into compilation problems that I can't seem to figure out how to fix logically, I usually just end up trying a number of different macro's that other people recommend until it just works. Not ideal, I know, but... All my logical deduction usually leads me to solutions that don't work as I keep expecting. Case in point, I want to serialize some data as XML. Essentially it's just a struct with a few strings in it that is used as 'settings' data. I get the following error message during compilation in VS2012: Error 47 error C2664: 'boost::mpl::assertion_failed' : cannot convert parameter 1 from 'boost::mpl::failed ************boost::serialization::is_wrapper<T>::* ***********' to 'boost::mpl::assert<false>::type' d:\sdks\cinder\boost\boost\archive\basic_xml_iarchive.hpp 70 I found out, it had to do with any XML serilization requiring an additional 'name' to be added, pertaining to how XML works via the 'BOOST_SERIALIZATION_NVP' macro. I added that to all my strings - still nothing. Then I proceeded to comment out everything, so my struct is now just an empty shell: struct AEMSettings { // Superfluous since structs are fully public? friend class boost::serialization::access; AEMSettings() { } /*** * Serialize handles both input/output as the & operator doubles as both << and >> */ template<class Archive> void serialize( Archive &ar, const unsigned version ) { //ar & BOOST_SERIALIZATION_NVP( mSpeakersDeviceName ); //ar & BOOST_SERIALIZATION_NVP( mSpeakersDeviceDriverName ); //ar & BOOST_SERIALIZATION_NVP( mHeadphonesDeviceName ); //ar & BOOST_SERIALIZATION_NVP( mHeadphonesDeviceDriverName ); //ar & BOOST_SERIALIZATION_NVP( mMicrophoneDeviceName ); //ar & BOOST_SERIALIZATION_NVP( mMicrophoneDeviceDriverName ); } //std::string mSpeakersDeviceName; //std::string mSpeakersDeviceDriverName; //std::string mHeadphonesDeviceName; //std::string mHeadphonesDeviceDriverName; //std::string mMicrophoneDeviceName; //std::string mMicrophoneDeviceDriverName; }; Can anyone tell me what I am missing here? Regards, Gazoo

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[Spirit] Parser omits certain characters
by beet 05 Nov '13

05 Nov '13

Dear all, For all of the following, please see the attached test-case. I would like to specify certain characterstics of variables in the following way: d(MY_DPAR_01,-10.3,12.8,100) . So in this case there is a type-identifyer (d stands for "double") and then, in parantheses, a variable name (or alternatively an index), a lower and upper boundary and some integer parameter. What is contained in the list depends on the parameter type. It should then be possible to specify any number of variables, including their properties, in a comma-separated list. So I need to dissect a string like the following: "d(MY_DPAR_01,-10.3,12.8,100), d(0,-10.3,12.8,100), i(SOME_IPAR_17, 0,5), b(SOME_BPAR)" The first step, as I see it, is to seperate the "outer" list and to store each variable description in a boost::tuple<char, std::string>, where the char holds the type identifier and the std::string the part inside the parantheses. Then, in the second step, I want to parse that string according to what is expected for this particular type. I have now run into the problem that the following rule in Boost.Spirit "swallows" all non-alphanumeric characters. qi::rule<std::string::const_iterator, std::string(), ascii::space_type> varSpec = +(alnum | '_' | ',' | '.' | '+' | '-'); varSpec stands for the text inside of the parantheses. I would have expected this to match any string of at least one of the listed character types (i.e. alpha-numeric, underscore, etc.). The rule qi::rule<std::string::const_iterator, boost::tuple<char, std::string>(), ascii::space_type> varString = char_("dfib") >> '(' >> varSpec >> ')'; is then meant to separate the type-descriptor from the description. Parsing with these yields the output d: MYDPAR01103128100 d: 0103128100 i: SOMEIPAR1705 b: SOMEBPAR on a Mac (Mavericks, Boost 1.54) i.e., only the alpha-numeric characters remain. So clearly my assumption about the "varSpec" rule is wrong. On a Ubuntu 13.10 System (Boost 1.54, g++ 4.8.1) I get the output d: d: i: b: which is equally wrong. Funnily, if I define varSpec simply as +char_, varSpec gives the correct result on the Mac (haven't tried Ubuntu), but varString does not match anything. So I am at a loss here and would appreciate some help. Best Regards and thanks for any help you can provide, Beet

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[move] non-inline move constructor - won't compile
by Krzysztof Czainski 03 Nov '13

03 Nov '13

Hi, I've been trying to writhe a non-inline move constructor, to place its' implementation in a .cpp file. I'm having problems compiling my code, which I managed to simplify (after examining output of the preprocessor) down to this short code snippet: #include <boost/move/core.hpp> struct X { X( ::boost::rv< X >& x ); operator ::boost::rv<X>&() { return *static_cast< ::boost::rv<X>* >(this); } }; X::X( ::boost::rv< X >& x ) {} Compiling a .cpp file with the above contents gives me: a.cpp:41:1: error: prototype for 'X::X(boost::rv<X>&)' does not match any in class 'X' X::X( ::boost::rv< X >& x ) {} ^ a.cpp:35:8: error: candidates are: X::X(const X&) struct X ^ a.cpp:37:5: error: X::X(boost::rv<X>&) X( ::boost::rv< X >& x ); ^ I'm using MinGW gcc 4.8.1 in default -std mode (not-C++11 mode), boost-1.54. Am I doing something wrong here, or is it a bug in the compiler? Regards, Kris

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Status of smart_assert
by Daan Baas 03 Nov '13

03 Nov '13

Howdy, I was searching for an intelligent assert facility with serveral debug levels, that asserts when it is run debug mode and throws in release mode. That is how i ran into Boost's SMART_ASSERT ( http://www.drdobbs.com/cpp/enhancing-assertions/184403745) However, I cannot find anything about it that was posted after 2003 nor can I find it on the Boost site. Does anyone know what happened to the project? Was is cancelled or did it make it into Boost under another name? Kind regards, Dano

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[MSM] Parse error in Visual Studio 2012, not in Visual Studio 2013.
by Vincent N. Virgilio 02 Nov '13

02 Nov '13

Hello, In the code below, VS 2012 (target v110) underlines the macro name BOOST_MSM_EUML_EVENT_WITH_ATTRIBUTES in the last line with a wavy red line. Hovering a mouse over it shows a tooltip with error report: "Error: not a class or struct name" And if I recall correctly, the code does not compile. The error disappears in VS 2013 (v120). Though in VS 2013 (target v120), if I remove line "namespace msm = boost::msm;", the last line triggers an error again. This time with a different tooltip error report: "Error: name followed by '::' must be a class or namespace name." Am I using MSM incorrectly? Thanks, Vince // BEGIN euml.h #include <boost/msm/back/state_machine.hpp> #include <boost/msm/front/state_machine_def.hpp> #include <boost/msm/front/euml/euml.hpp> using namespace boost::msm::front::euml; namespace msm = boost::msm; BOOST_MSM_EUML_DECLARE_ATTRIBUTE(char*, charp_attr) BOOST_MSM_EUML_ATTRIBUTES((attributes_ << charp_attr), found_attrS) // next line gives error in VS 2012 (target v110), "Error: not a class or struct name". Not in VS 2013 (targ. v12). BOOST_MSM_EUML_EVENT_WITH_ATTRIBUTES(found, found_attrS) // END euml.h

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[1.55.0] Release candidates available
by Marshall Clow 01 Nov '13

01 Nov '13

Release candidate files for 1.55.0 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: ba1ae723b8b4d1edeca684bb14b3213b *boost_1_55_0_rc1.tar.gz 66e01be2f328c556835c42be7b6d17d5 *boost_1_55_0_rc1.tar.bz2 925bb6c96082033687e5742b4e77af7b *boost_1_55_0_rc1.zip 830d61075ecf7d5ebf7c0843033393bf *boost_1_55_0_rc1.7z Thanks! -- The release managers

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Connecting signals where one is a member
by Chris Stankevitz 01 Nov '13

01 Nov '13

Hello, "Connect 4" fails to compile in the code below on g++ 4.6.3. Why does "Connect 4" not work while "Connect 2" does work? Connect 4 and 2 are the same thing as far as I can see. Thank you, Chris #include <boost/signals2/signal.hpp> typedef boost::signals2::signal<void( )> TDSignalA; typedef boost::signals2::signal<void(int)> TDSignalB; TDSignalA SignalA1; TDSignalB SignalB1; struct TSItem { TDSignalA SignalA2; TDSignalB SignalB2; }; int main() { TSItem Item; // Connect 1 SignalA1.connect(Item.SignalA2); // Connect 2 SignalA1.connect(TDSignalA::slot_type(&TSItem::SignalA2, &Item)); // Connect 3 SignalB1.connect(Item.SignalB2); // Connect 4 //SignalB1.connect(TDSignalB::slot_type(&TSItem::SignalB2, &Item, _1)); return 0; }

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VS2005 compiler error in swap() definition after including flat_map.hpp
by Фёдор Трушкин 01 Nov '13

01 Nov '13

Dear All, I encountered a strange problem recently. It's perfectly reproducable under VS2005 even with the latest boost 1_55 rc. Here's the minimal reproducable example: // ----- //#include <boost/container/flat_map.hpp> #include <boost/container/detail/config_begin.hpp> #include <boost/intrusive/detail/memory_util.hpp> #include <boost/container/detail/memory_util.hpp> void swap(); // ------ In VS2005 this innocent piece of code yields: // ------ error C2365: 'swap' : redefinition; previous definition was 'formerly unknown identifier' // ------ VS2010 and GCC 4.5.2 have no complaints. Looks like VS2005 compiler is entangled somehow by BOOST_INTRUSIVE_HAS_MEMBER magic. Actually, it's quite a headache that with VS2005 one can't introduce swap() after, say, flat_map is included. Should this incompatibility be regarded as a bug? Best regards, Fedor Trushkin

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