具有序列化嵌套類的類的序列化奇怪的編譯錯誤

Question

我想了解一些boost序列化的基礎知識。所以我跟着the tutorial創建了簡單的class A和class B和class C，它有A a_;和B b_;作爲私人成員。

#include <boost/serialization/serialization.hpp> 
#include <boost/archive/text_oarchive.hpp> 
#include <boost/archive/text_iarchive.hpp> 
#include <string> 
#include <fstream> 

class A{ 
private: 
     friend class boost::serialization::access; 

     template<class Archive> 
     void serialize(Archive & ar, const unsigned int version) 
     { 
       ar & a_; 
     } 

     int a_; 

public: 
     A(){ std::cout << "A constructed" << std::endl; } 
     A(int a): a_(a) { std::cout << "A constructed with 'a' ==" << a << std::endl; } 
}; 
class B{ 
private: 
     template<class Archive> 
     void serialize(Archive & ar, const unsigned int version) 
     { 
       ar & b_; 
     } 

     std::string b_; 
public: 
     B(){ std::cout << "B constructed" << std::endl; } 
     B(std::string b): b_(b) { std::cout << "B constructed with 'b' ==" << b << std::endl; } 
}; 

class C{ 
private: 
     template<class Archive> 
     void serialize(Archive & ar, const unsigned int version) 
     { 
       ar & a_; 
       ar & b_; 
       ar & d_; 
     } 

     A a_; 
     B b_; 
     double d_; 

public: 
     C(){ std::cout << "C constructed" << std::endl; } 
     C(int a, std::string b, double d): a_(a), b_(b), d_(d) { std::cout << "C constructed with 'd' == " << d << std::endl; } 
}; 

int main() { 
    // create and open a character archive for output 
    std::ofstream ofs("filename"); 

    // create class instance 
    C c(15, "rock and roll", 25.8); 

    // save data to archive 
    { 
      boost::archive::text_oarchive oa(ofs); 
      // write class instance to archive 
      oa << c; 
      // archive and stream closed when destructors are called 
    } 

    C c_recreated; 
    { 
      // create and open an archive for input 
      std::ifstream ifs("filename"); 
      boost::archive::text_iarchive ia(ifs); 
      // read class state from archive 
      ia >> c_recreated; 
      // archive and stream closed when destructors are called 
    } 

    std::cin.get(); 
} 

在IDEone生活是here所有的陌生和可怕的編譯器錯誤。雖然在我的VS2010我只拿到了2個相同的錯誤：

Error 2 error C2248: 'C::serialize' : cannot access private member declared in class 'C' 
Error 3 error C2248: 'C::serialize' : cannot access private member declared in class 'C'  

我做了什麼錯，我怎樣才能使class C序列化有class A和class B後？

Answer 1

對於B和C，您沒有friend class boost::serialization::access;。