November 2013 - Boost-users

XML Serialization
by Lasse Laursen 04 Nov '13

04 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

3 3

[Spirit] Parser omits certain characters
by beet 04 Nov '13

04 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

3 4

[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

3 4

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

2 2

[MSM] Parse error in Visual Studio 2012, not in Visual Studio 2013.
by Vincent N. Virgilio 01 Nov '13

01 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

3 3

[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

9 16

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; }

2 2

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

2 1