Re: [Boost-users] Subject: Serialization, text_Xarchive Why doesn't work?

3 Aug 2006

      That is not a greate problem.

The problems start then...

The reason of the problem can be follow:
one of the operator [](int Index) has two versions, which have only one difference:
const OTCValue& and OTCValue&.

Maybe the compiler cannot choose the necessary.

But now I have another problem:
I have such a class, which shouldn't be saved normally (OTCData).
The reason for this: this class has a member, which should be rerialized via string, more then that, it cannot be copied (OTCDataID and OTCDataHeaderID).

So I've tried to do following:

#include <boost/serialization/tracking.hpp>
#include <boost/serialization/split_member.hpp>
namespace DataManagement
{
    class OTCData : public IOTCData
    {
        friend class boost::serialization::access;
        template<class Archive>
            void save(Archive & ar, const unsigned int version) const
        {
            const std::string own_id=m_own_id->save_to_string();
            ar & own_id;
            const std::string header_id=m_header_id->save_to_string();
            ar & header_id;
            ar & m_rows;
            ar & m_cols;
        }
        template<class Archive>
                void load(Archive & ar, const unsigned int version)
        {
            std::string own_id;
            std::string header_id;
            ar & own_id;
            m_own_id->load_from_string(own_id);
            ar & header_id;
            m_header_id->load_from_string(header_id);
            ar & rows;
            ar & m_cols;

        }
        BOOST_SERIALIZATION_SPLIT_MEMBER();

        std::auto_ptr<OTCDataID>    m_own_id;
        std::auto_ptr<OTCDataHeaderID>    m_header_id;
        std::vector<OTCRow>        m_rows;
        int            m_cols;
// shouldn't be serialized
        const IOTCDataHeader *    m_header;
        };
}

Then function to save instance of OTCData:

namespace DataManagement{
  class DataController
  {
     void save_otcdata(const OTCData&data)const;
  };

  void DataManagement::DataController::save_otcdata(const OTCData& data) const
  {
	std::string file_name=set_file_name(data);
	std::ofstream	ofs(file_name.c_str());
	boost::archive::text_oarchive oa(ofs);
	oa << data; // Here I have very long compiler error messages
        // which are very like the messages by trying to save nonconstant object 	
  }
}

I have no idea any more. I save only constants and the compilation fails!

Thanks to all!

-------- Original-Nachricht --------
Datum: Thu, 3 Aug 2006 08:14:41 -0700
Von: "Robert Ramey" <ramey@rrsd.com>
An: boost-users@lists.boost.org
Betreff: Re: [Boost-users] Subject: Serialization,	text_Xarchive Why doesn\'t work?
...
Is it possible that m_value is uninitialized?  It is a known
problem that many compilers can can write uninitialized
floating/double values to a text stream and then cannot
read them.  This topic is currently being discussd on
the developer's list - as it arises all the time.
Take a look a test_serial.txt with a text editor.
What does it look like?
Robert Ramey
tkachenkok@gmx.de wrote:
...
I've tried to write my first application with Boost.Serialization
library.
Here is the part of code, where the boost::text_iarchive throws an
exception "boost::archive::archive_exception" "what():  stream
error":
[code]
enum Origin {
    UNKNOWN=0,
    MEASURED,
    AVERAGE };
class OTCValue
{
friend class boost::serialization::access;
template<class Archive>
void serialize(Archive & ar, const unsigned int version)
{
ar & m_value;
ar & m_orig;
}
double m_value;
Origin m_orig;
        ...
};
         ...
const OTCValue val1=(*loaded.second.begin())->get_row(0)[0];
{
std::ofstream ofs("test_serial.txt");
boost::archive::text_oarchive oa(ofs);
oa << val1;
}
OTCValue val;
{
std::ifstream ifs("test_serial.txt");
boost::archive::text_iarchive ia(ifs);
ia >> val; // here is this exceptions thrown
}
        ...
[/code]
And here is a little bit different code, which works great:
[code]
enum Origin {
    UNKNOWN=0,
    MEASURED,
    AVERAGE };
class OTCValue
{
friend class boost::serialization::access;
template<class Archive>
void serialize(Archive & ar, const unsigned int version)
{
ar & m_value;
ar & m_orig;
}
double m_value;
Origin m_orig;
        ...
};
         ...
const OTCValue val1(5.5, MEASURED);
{
std::ofstream ofs("test_serial.txt");
boost::archive::text_oarchive oa(ofs);
oa << val1;
}
OTCValue val;
{
std::ifstream ifs("test_serial.txt");
boost::archive::text_iarchive ia(ifs);
ia >> val;
}
        ...
[/code]
What is the problem? The construction
(*loaded.second.begin())->get_row(0)[0] returns an OTCValue .
I have compiled the boost-1.33.1 from the sources (www.boost.org).
The project I've made is under KDevelop 3.2.2 (initially consol
"Hello World" application)
Operating System: SuSe Linux 10.0
Compiler: gcc version 4.0.2
I hope, that I've gave enouph information. If not, ask what aou need,
you are welcome.
Best regards,
and thanks to all!
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Re: [Boost-users] Subject: Serialization, text_Xarchive Why doesn't work?

Konstantin Tkachenko