c++ - boost::archive::text_oarchive 的简单扩展

Question

我正在尝试将成员变量添加到 Boost 存档类。正在关注this ，我想到了:

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

#include <fstream>

class MyOArchive : public boost::archive::text_oarchive_impl<MyOArchive>
{
public:
    bool MyData;

    friend class boost::archive::detail::common_oarchive<MyOArchive>;
    friend class basic_text_oarchive<MyOArchive>;
    //friend class boost::serialization::save_access; // save_access in namespace boost::serialization does not name a type

    MyOArchive(std::ostream& os, unsigned int flags = 0) : boost::archive::text_oarchive_impl<MyOArchive>(os, flags) {}

};

class MyClass
{
public:

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

    double Value;

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

};


int main()
{
    MyClass myClass;

    std::ofstream outputStream("test.txt");
    //boost::archive::text_oarchive outputArchive(outputStream);
    MyOArchive outputArchive(outputStream);
    outputArchive << myClass;
    outputStream.close();

    return 0;
}

但是，我收到链接器错误:

undefined reference to boost::archive::text_oarchive_impl<MyOArchive>::text_oarchive_impl(std::ostream&, unsigned int)

谁能解释这里出了什么问题？我不需要重新实现存档的任何功能，只需附加此成员MyData .

Answer 1

啊。发现了。

您需要在链接到最终产品的一个 TU 中包含用于基本实现的 ipp。

#include <boost/archive/impl/basic_text_oarchive.ipp>
#include <boost/archive/impl/text_oarchive_impl.ipp>

此外，save_access 位于不同的 caSTLe 命名空间中:

friend class boost::archive::save_access;

Live On Coliru

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

#include <boost/archive/impl/basic_text_oarchive.ipp>
#include <boost/archive/impl/text_oarchive_impl.ipp>
#include <fstream>

class MyOArchive : public boost::archive::text_oarchive_impl<MyOArchive> {
  public:
    bool MyData;

    friend class boost::archive::detail::common_oarchive<MyOArchive>;
    friend class basic_text_oarchive<MyOArchive>;
    friend class boost::archive::save_access;

    MyOArchive(std::ostream &os, unsigned int flags = 0) : boost::archive::text_oarchive_impl<MyOArchive>(os, flags) {}
};

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

    double Value;

    template <class Archive> void serialize(Archive &ar, unsigned) { ar &Value; }
};

int main() {
    MyClass myClass;

    {
        std::ofstream outputStream("test.txt");

        MyOArchive outputArchive(outputStream);
        outputArchive << myClass;
    }
}

输出是

22 serialization::archive 13 0 0 6.95328877045326431e-310