Robert Ramey wrote:
It SHOULD work but this is an area still in flux.
You might expand on the explanation of how it fails:
It throws "unregistered class", but when I use it as statically linked
lib then everything works as expected.
Some observations:
There should be no need to include the header
The serialization code will be instantiated only when code like ar <<
session_record
is encountered. Since your DLL code doesn't include your any archives no
code
is generated.
Yes, there's no need to include ,
it could be removed from the export.h, but it doesn't mean that my DLL
code doesn't include archives' code. Inside implementation of this
(de)serialize functions (somewhere inside export.cpp, or whatever) I
include all the archives code etc.
basicly, here's export.cpp
/////
//all needed includes & using namespace ...
#include "export.h"
session_record::~session_record(){}
session_record::operator session_record *(){
return this;
}
void serialize(session_record* derived, const char* file_name){
ofstream out(file_name);
if(!out || !out.is_open()) throw std::runtime_error(std::string("failed
to open \"")+file_name+'"');
text_oarchive oa(out, no_header | no_codecvt);
oa & derived;
}
session_record* deserialize(const char* file_name){
ifstream in(file_name);
text_iarchive ia(in, no_header | no_codecvt);
session_record *derived;
ia & derived;
return derived;
}
/////////
then in another app, that links to export.dll I have:
/// needed includes & using declarations ...
#include "export.h"
class client_record : public virtual session_record {
friend class boost::serialization::access;
template<class Archive> void serialize(needed args...){
serialization::base_object(*this);
ar & name;
ar & address;
ar & amount;
}
virtual void print_on(std::ostream &os)const{
os <<
"client record: \n"
"\tname: " << name << "\n"; //....
}
public:
std::string name, address;
double amount;
};
BOOST_CLASS_EXPORT(client_record);
main()try{
client_record x;
x.name = "John Doe";
x.amount = 129.99;
x.address = "2080 Wellington, apt. 13";
serialize(&x, "xxx.txt");
}catch (const exception &e) {
cout << "error: " << e.what() << endl;
}
/////////
I get unregistered class exception. I use vc71 and if I now in settings
for the export.dll change project type from Dll to static library, and
recompile my test program, everything works as expected.
and this error I get is from serializing from base pointer, not from
deserializing...
The first step to making this work is to look at the demo which
compiles serialization code in separate modules. This shows
how to instantiate the required code. Also look at
polymorphic archives which permit application
code to be compiled to a common interface.
