Re: [Boost-users] xml serialization : compilation fails

From: Cyril (cyril.delmas_at_[hidden])
Date: 2007-05-04 10:33:21

Hughes, James a écrit :
>  
>
>   
>> -----Original Message-----
>> From: boost-users-bounces_at_[hidden] 
>> [mailto:boost-users-bounces_at_[hidden]] On Behalf Of Cyril
>> Sent: 04 May 2007 15:02
>> To: boost-users_at_[hidden]
>> Subject: [Boost-users] xml serialization : compilation fails
>>
>> Hello all,
>> I have a problem while attempting to serialize a simple 
>> object using xml (text works fine !).
>>
>> This is my code :
>>
>> // SomeData.h
>> #include <boost/serialization/utility.hpp> #include 
>> <boost/serialization/base_object.hpp>
>>
>> class OBJECTS_API InternalData {
>> public:
>>     InternalData();
>>     virtual ~InternalData();
>>     virtual int getInternals() const = 0;
>> private:
>>     friend class boost::serialization::access;
>>     template<class Archive>
>>     void serialize(Archive & ar, const unsigned int version)
>>     {
>>     }
>> };
>>
>> class OBJECTS_API RealData : public InternalData {
>> public:
>>     RealData(int internals=0);
>>     int getInternals() const;
>> private:
>>     int _internals;
>>
>>     friend class boost::serialization::access;
>>     template<class Archive>
>>     void serialize(Archive & ar, const unsigned int version)
>>     {
>>         ar & BOOST_SERIALIZATION_BASE_OBJECT_NVP(InternalData)
>>            & BOOST_SERIALIZATION_NVP(_internals);
>>     }
>> };
>>
>> class OBJECTS_API SomeData {
>> public:
>>     SomeData(int internals=0);
>>     ~SomeData();
>>     InternalData* getInternals() const;
>> private:
>>     InternalData* _data;
>>     static InternalData* createData(int internals);
>>
>>     friend class boost::serialization::access;
>>     template<class Archive>
>>     void serialize(Archive & ar, const unsigned int version)
>>     {
>>         //ar.register_type(static_cast<RealData*>(0));
>>         ar & BOOST_SERIALIZATION_NVP(_data);
>>     }
>> };
>> //////////////////
>> // somewhere else
>> const SomeData data(4);
>> boost::archive::xml_oarchive xoa(archive); //archive is a 
>> file stream xoa << data;
>>
>> ////////////////////
>>
>> This fails to compile because :
>> // basic_xml_oarchive.hpp
>> // Anything not an attribute and not a name-value pair is an 
>> // error and should be trapped here.
>> template<class T>
>> void save_override(T & t, BOOST_PFTO int) {
>>         // If your program fails to compile here, its most 
>> likely due to
>>         // not specifying an nvp wrapper around the variable to
>>         // be serialized.
>>         BOOST_STATIC_ASSERT(0 == sizeof(T)); }
>>
>> I can't see why my code isn't correct according to that 
>> constraint. Any help ?
>>
>> Thanks in advance.
>>     
>
> I just had a very similar (if not the same) problem - I spent some time
> assigning GUID's to all the classes, and ensuring all base classes were
> correctly serialised using BOOST_SERIALIZATION_BASE_OBJECT_NVP and that
> seems to have fixed the problem. Whether it was that or something else
> that got changed during the figuring out period is anyones guess!!
>
> See BOOST_CLASS_EXPORT_GUID
>
> James
>
>
>
>
>
>   
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>>
>>     
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>   

Found this :
xoa << BOOST_SERIALIZATION_NVP(data);

the code compiles, but is it the right way to proceed ?