February 2006 - Boost-users - lists.preview.boost.org

Re: [Boost-users] problem with serialization of pure virtual
by Nat Goodspeed 01 Mar '06

01 Mar '06

> -----Original Message----- > From: boost-users-bounces(a)lists.boost.org [mailto:boost-users- > bounces(a)lists.boost.org] On Behalf Of Tobias Combe > Sent: Tuesday, February 28, 2006 7:18 AM > To: boost-users(a)lists.boost.org > Subject: [Boost-users] problem with serialization of pure virtual > > When i use "ar.register<derived>();" in the template of the base-class > to register the derived classes, i get a syntax error. [Nat] What compiler are you using?

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[iostreams] array_sink
by Jeff Flinn 28 Feb '06

28 Feb '06

My reading of the docs states that array_sink models the concept sink, meaning that the following should compile: #include <boost/iostreams/device/array.hpp> #include <boost/iostreams/operations.hpp> namespace io = boost::iostreams; int main( int argc, char* argv[] ) { char x[4] = {}; io::array_sink lSink(x,4); const char* y = "abc"; io::write( lSink, y, 4 ); return 0; } I must be doing something obviously wrong, on VC7.1 I get: c:\boost\boost_1_33_1\boost\iostreams\write.hpp(118) : error C2039: 'write' : is not a member of 'boost::iostreams::basic_array_sink<Ch>' with [ Ch=char ] c:\boost\boost_1_33_1\boost\iostreams\write.hpp(52) : see reference to function template instantiation 'std::streamsize boost::iostreams::detail::write_device_impl<boost::iostreams::output>::write<boost::unwrap_reference<T>::type>(T &,const boost::iostreams::detail::member_char_type<T>::type *,std::streamsize)' being compiled with [ T=boost::iostreams::array_sink ] c:\dev\AAA - Advantage New\DasNew\DasClientTest\DasClientTest.cpp(36) : see reference to function template instantiation 'std::streamsize boost::iostreams::write<boost::iostreams::array_sink>(T &,const boost::iostreams::detail::member_char_type<T>::type *,std::streamsize)' being compiled with [ T=boost::iostreams::array_sink ] Any thoughts are appreciated. Thanks, Jeff

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Re: [Boost-users] [mpl] newbie question
by Gottlob Frege 28 Feb '06

28 Feb '06

Top posting because I'm going to remark about this thread in general, but this message is a fine example. Andy seems to be speaking (mostly) about int_<>, integral_c, etc (I'll just say the incorrect 'int<>') and plus; David is talking about transform. I think, but can't say for sure, that Andy wants plus to work 'as expected' and always return int<>, not just 'concept-identical' to int. Maybe it does, I'm not sure. And/or he wants transform ***when applied to int<> with plus, etc*** to return int<>. David, says, that ***in general*** transform can't make the return type "match" (in Andy's stricter sense) the inputs. Maybe it could for the special case of int<>? IMO, that would be quite hard, as the point of the templates is to be general. Do I have this right, in any sense? P.S. for David, below: Date: Sat, 25 Feb 2006 10:22:57 -0500 > From: David Abrahams <dave(a)boost-consulting.com> > Subject: Re: [Boost-users] [mpl] newbie question > To: boost-users(a)lists.boost.org > Message-ID: <uoe0v799q.fsf(a)boost-consulting.com> > Content-Type: text/plain; charset=us-ascii > > "Andy Little" <andy(a)servocomm.freeserve.co.uk> writes: > > > I think we need a little bit more context here. > > > >> > > OP > >>> David Abrahams > >> > >> Andy Little (me) > >> > >> > > Just trying to use mpl::transform on a vector of int's and I can't > seem to > >> > > get > >> > > it working properly. Can anyone see what's wrong?? I'm trying to > perform > >> > > > >> > > vector_c<int, 1, 2, 3> + vector_c<int, 1, 1, 1> = vector_c<int, 2, > 3 ,4> > >> > > > >> > > The is_same function always returns false when I compile and run > it. > >> > > >> > The result of the transform is only required to be > "concept-identical" the line above says "the transform" >> > to the result you're looking for. > >> > > >> IMO that behaviour is sloppy. I see no reason why (at least) > >> > >> boost::is_same < plus< int_<1> ,int_<1> >::type, int_<2> > shouldnt > >> be true. > > > > Your change from "the transform" to "being about transform" above is > > problematic for me. I don't know what you mean. Nobody wrote "the transform" above. as mentioned, he did, but that doesn't mean I understand the point he is trying to make. Don't make this complicated. It is very simple: I made a statemnt > *about the behavior of transform*, and you replied "that behavior is > sloppy," and then proceeded to go on about something only distantly > related (the type of results of arithmetic operations). > > The behavior I was describing is not sloppy. To make the library > behave differently would introduce a huge overhead in implementation > code that is more likely than not to slow down compilation of user > programs. > > Let me be a little more explicit: > > transform<vector_c<int, ...> >::type > > is likely to be a specialization of vectorN where N is a numeral. > Therefore, testing it against a vector_c specialization using is_same > will always fail. That is the behavior I was referring to. > > I wouldn't care much what you said, except for that you're doing this > in a thread where impressionable "newbies" are reading, and I don't > want them to misunderstand the library design or the implementation > decisions and their costs/benefits. Your statement above not only > unfairly maligns Aleksey's work, it is misleading. > > -- > Dave Abrahams > Boost Consulting > www.boost-consulting.com > >

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Re: [Boost-users] problem with serialization of pure virtual
by RIVASSEAU Jean Noel 28 Feb '06

28 Feb '06

You should send a code snippet. What are the syntax error you get, and the error you get when doing a "BOOST_CLASS_EXPORT(derived);" ? I also have a problem with an abstract base class (although at link time, not compile time). Try removing the pure virtual function (just to see if it works). Another hint too would be to try to serialize a constant member; sometimes I had strange ASSERTION_FAILURE related to serialization of non-constants (this is also explained in the docs). Jean-Noël -----Message d'origine----- De : boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] De la part de Tobias Combe Envoyé : mardi 28 février 2006 13:18 À : boost-users(a)lists.boost.org Objet : [Boost-users] problem with serialization of pure virtual Hello I read the documention and some prior postings to related topics. But none of the proposed solutions seems to work for me. My problem: I have an abstarct base class(with pure vitual function) and several derived from that. All are written in the same source/header -file. I want to serialize an object via a pointer to the base-class. When i use "ar.register<derived>();" in the template of the base-class to register the derived classes, i get a syntax error. When i export them with "BOOST_CLASS_EXPORT(derived);" or BOOST_CLASS_EXPORT_GUID(derived,"derived") it doesn't work (i think because they are all in the same file). I'm also using "BOOST_IS_ABSTRACT(base);" When i comment "oa << object;" ervything compiles fine. Uncommented i get a: boost/archive/detail/oserializer.hpp:567: error: incomplete type ` boost::STATIC_ASSERTION_FAILURE<false>' does not have member `value' error... So is there a solution (without seperating the derived classes into different files) for this problem? _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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[serialization] problem building libs
by Federico Feller 28 Feb '06

28 Feb '06

Hi, I am trying to use the serialization library with borland 6, but when i try to link a program that uses it, the linking fails to find the libboost_serialization-bcb-mt-d-1_33_1.lib file. I checked the libraries generated when i built the library (using bjam) and i found out that the 'mt' version of the library wasnt there. I generated the files ejecuting 'bjam -sTOOLS=borland' under the serialization/build directory. How can i get the mt libraries generated? thanks Federico __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com

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problem with serialization of pure virtual
by Tobias Combe 28 Feb '06

28 Feb '06

Hello I read the documention and some prior postings to related topics. But none of the proposed solutions seems to work for me. My problem: I have an abstarct base class(with pure vitual function) and several derived from that. All are written in the same source/header -file. I want to serialize an object via a pointer to the base-class. When i use "ar.register<derived>();" in the template of the base-class to register the derived classes, i get a syntax error. When i export them with "BOOST_CLASS_EXPORT(derived);" or BOOST_CLASS_EXPORT_GUID(derived,"derived") it doesn't work (i think because they are all in the same file). I'm also using "BOOST_IS_ABSTRACT(base);" When i comment "oa << object;" ervything compiles fine. Uncommented i get a: boost/archive/detail/oserializer.hpp:567: error: incomplete type ` boost::STATIC_ASSERTION_FAILURE<false>' does not have member `value' error... So is there a solution (without seperating the derived classes into different files) for this problem?

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Re: [Boost-users] problem with serialization of pure virtual
by RIVASSEAU Jean Noel 28 Feb '06

28 Feb '06

>From the code snippet, I can say that you are not serializing via a pointer to base class, since you serialize tmp which is an object, not a pointer (by the way, tmp is just an object of the base class... you would lose the information of *event if event pointed to a derived class). Try changing: SENSOR_Event tmp = *event; oa << tmp; to just: oa << event; And also, include the BOOST_CLASS_EXPORT macro for the base class. Or, you can try doing (to see what it does): const SENSOR_Event tmp = *event; oa << tmp; but there, you are serializing a pointer, not an object. Jean-Noël -----Message d'origine----- De : boost-users-bounces(a)lists.boost.org [mailto:boost-users-bounces@lists.boost.org] De la part de Tobias Combe Envoyé : mardi 28 février 2006 16:51 À : boost-users(a)lists.boost.org Objet : Re: [Boost-users] problem with serialization of pure virtual Jean Noel wrote: >You should send a code snippet. > Event.h: #include <boost/archive/text_oarchive.hpp> #include <boost/archive/text_iarchive.hpp> #include <boost/serialization/base_object.hpp> #include <boost/serialization/vector.hpp> #include <boost/serialization/shared_ptr.hpp> #include <boost/serialization/export.hpp> #include <fstream> class SENSOR_Event{ friend class Sensor; friend class AODVRTSensor; friend class OLSRRTSensor; private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar.register<NodeEvent>(); ""// for each derived class ar & time; ar & sourceId; ar & sourceType; ar & eventType; ar & *data; } protected: double time; int sourceId; std::string sourceType; std::string eventType; DataNode *data; public: ... }; class NodeEvent : public SENSOR_Event{ private: friend class boost::serialization::access; template<class Archive> void serialize(Archive & ar, const unsigned int version) { ar & boost::serialization::base_object<SENSOR_Event>(*this); } public: NodeEvent(); NodeEvent(double nodeId, double x, double y, double z, double speed); }; ...//other derived Events BOOST_CLASS_EXPORT(NodeEvent); ""// for each derived class BOOST_IS_ABSTRACT(SENSOR_Event); Sensor.cc: #include "Event.h" void Sensor::send(const SENSOR_Event *event){ ... // serialize to string std::stringstream s; boost::archive::text_oarchive oa(s); SENSOR_Event tmp = *event; oa << tmp; std::string p = s.str(); ... } Error: ... boost/archive/detail/oserializer.hpp: In function `void boost::archive::save(Archive&, T&) [with Archive = boost::archive::text_oarchive, T = SENSOR_Event]': boost/archive/basic_text_oarchive.hpp:78: instantiated from `void boost::archive::basic_text_oarchive<Archive>::save_override(T&, int) [with T = SENSOR_Event, Archive = boost::archive::text_oarchive]' boost/archive/detail/interface_oarchive.hpp:78: instantiated from `Archive& boost::archive::detail::interface_oarchive<Archive>::operator<<(T&) [with T = SENSOR_Event, Archive = boost::archive::text_oarchive]' IDSNet/Sensor.cc:24: instantiated from here boost/archive/detail/oserializer.hpp:567: error: incomplete type ` boost::STATIC_ASSERTION_FAILURE<false>' does not have member `value' >What are the syntax error you get, and the error you get when doing a "BOOST_CLASS_EXPORT(derived);" ? > "syntax error before `;' token" for that line >I also have a problem with an abstract base class (although at link time, not compile time). Try removing the pure virtual function (just to see if it works). > this doesn't help >Another hint too would be to try to serialize a constant member; sometimes I had strange ASSERTION_FAILURE related to serialization of non-constants (this is also explained in the docs) > I'm serializing a constant member... _______________________________________________ Boost-users mailing list Boost-users(a)lists.boost.org http://lists.boost.org/mailman/listinfo.cgi/boost-users

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serialization: errata: even manual instantiation is impossible
by RIVASSEAU Jean Noel 28 Feb '06

28 Feb '06

Hello : Regarding my last post : Even a manual template instantiation is in fact impossible since it would require including the necessary archive headers (else, the boost ::archive ::xml_iarchive is not recognized). Since you forbid to include any archive headers in the classes, I do not understand how you can follow your own advice. This seems impossible to me. Would you have code to illustrate ? Jean-Noël

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Re: [Boost-users] Serialization : unregistered_cast & otherquestions
by RIVASSEAU Jean Noel 28 Feb '06

28 Feb '06

Hello, CommonSerialize.h - remove the following #include <boost/archive/xml_oarchive.hpp> #include <boost/archive/xml_iarchive.hpp> and add the following: #include <boost/serialization/export.hpp> test_independent.cc - change the top to look like the following: // INDEPENDENT TEST #include <boost/archive/xml_oarchive.hpp> #include <boost/archive/xml_iarchive.hpp> #include <MObject.h> #include <MObject_serialization.hh> #include <MemberVariableSpecification.h> #include <MemberVariableSpecification_serialization.hh> #include <fstream> This won't work. Since you now have the archive headers in only one place, there is no multiple definition problem. However serialization code is *not* instantiated for MObject or MemberVariableSpecification. This is normal since when compiling the .cc that contains this code, there is no archive header included and so the export.hpp has no effect. The code is here but is not instantiated. So in order to follow this advice: a) include all boost/serialization/.. headers in each class file. b) include NO boost/archive/... headers in any class file c) make a "template instantiation module" which instanticiates code for all archives I plan to use. This can be either in the app or in a library. d) lihk and execute without problem. I have to explicitly instantiate the serialization code for the needed archive in the .cc files. That is, do: template void save<boost::archive::xml_oarchive>( boost::archive::text_oarchive & ar, const MObject & m, const unsigned int file_version ); And same for load. This is what you do in demo_pimpl.cpp. Is that what you usually do and recommend to do? This has the advantage to avoid big compilations (these code instantiations will only occur when the class to serialize has indeed changed). However this has the inconvenience of manually instantiating every template (and if you want to change your archive format , eg from text to xml for example, everything needs to be changed). Jean-Noël

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[BGL] graph without parallel edges
by Alejandro Aragón 28 Feb '06

28 Feb '06

Hi everyboty, Can someone point to a concrete example of a graph without parallel edges??? I am using setS as my container for the edges but I still insert edges twice in my graph algorithm. Thank you, aa

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