Re: [Boost-users] Boost serializer: incomplete type error reported

From: Diego Molla (diego_at_[hidden])
Date: 2006-06-22 05:28:12

Thanks for your advice, Gennaro.

I had to move the following includes to the beginning of the file:

#include <boost/archive/text_oarchive.hpp>
#include <boost/archive/text_iarchive.hpp>

I also realised that the following gives the same error of incomplete type:

void
SetOfRules::save(const string &fileName)
// Save into a file
{
    ofstream fout(fileName.c_str());
    boost::archive::text_oarchive oa(fout);
    oa << *this;
    fout.close();
}

I had to use a helper function like this:

void
_save(const SetOfRules &sor, const string &fileName);

void
SetOfRules::save(const string &fileName)
// Save into a file
{
   _save(*this,fileName);
}

void _save(const SetOfRules &sor, const string &fileName)
{
   std::ofstream fout(fileName.c_str());
   boost::archive::text_oarchive oa(fout);
   oa << sor;
   fout.close();
} // save

And similarly to load a class.

Diego

>>Hello,
>>
>>I have an error that is puzzling me. I have defined serialization of
>>several custom classes, and everything worked perfectly until we've
>>changed to a new Linux OS and had to reinstall Boost. Now the program
>>doesn't compile and the error given is:
>>
>> error: incomplete type
>>'boost::serialization::extended_type_info_null<SetOfRules>' used in
>>nested name specifier
>>
>>I don't really understand why it says there is an incomplete type when
>>there used to be no errors. The same error happens with all the classes
>>where I've defined serialization.
> 
> I'm not too much into the latest gcc developments (certainly others
> will give a more accurate reply) but it looks like a two-phase lookup
> issue: at the time your function is parsed SetOfRules is actually
> incomplete, but the old gcc version you had didn't diagnose it and
> delayed analisys to instantiation time.
> 
> This is just my feeling. You might try moving SetOfRules' #include
> before.
> 
> --Gennaro. 

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Diego MOLLA ALIOD                                 diego_at_[hidden]
Department of Computing               http://www.ics.mq.edu.au/~diego
Macquarie University