如何序列化包含指向原语类？ [英] How do I serialize a class containing pointers to primitives?

问题描述

我想使用升压的功能用于序列指向原语（这样我就不必去参考，并做了深刻的店我自己）。不过，我得到了一堆错误，当我尝试这样做。下面是应该包含哪些写保存和负荷方法和阅读类内容类的简单例子从一个文件。这个程序不能编译：

I am trying to use boost's functionality for serializing pointers to primitives (so that I don't have to de-reference and do a deep store myself). However, I get a pile of errors when I try to do it. Here is a simple example of a class that is supposed to contain save and load methods which write and read the class content from a file. This program does not compile:

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

#include <boost/serialization/shared_ptr.hpp>
#include <boost/shared_ptr.hpp>

#include <fstream>

class A
{
public:
    boost::shared_ptr<int> sp;
    int const * p;

    int const& get() {return *p;}

    void A::Save(char * const filename);
    static A * const Load(char * const filename);

        //////////////////////////////////
        // Boost Serialization:
        //
    private:
        friend class boost::serialization::access;
        template<class Archive>
        void serialize(Archive & ar,const unsigned int file_version)
        {
            ar & p & v;
        }
};

// save the world to a file:
void A::Save(char * const filename)
{
    // create and open a character archive for output
    std::ofstream ofs(filename);

    // save data to archive
    {
        boost::archive::text_oarchive oa(ofs);

        // write the pointer to file
        oa << this;
    }
}

// load world from file
A * const A::Load(char * const filename)
{
    A * a;

    // create and open an archive for input
    std::ifstream ifs(filename);

    boost::archive::text_iarchive ia(ifs);

    // read class pointer from archive
    ia >> a;

    return a;
}

int main()
{

}

请注意，我的不可以感兴趣的是取消引用指针的解决方案;我想提振照顾，对我（很多这些类的可能会指向同一个底层对象）。

Note that I am not interested in a solution that dereferences the pointer; I want boost to take care of that for me (many of these classes might be pointing to the same underlying object).

推荐答案

在 http://www.boost.org/doc/libs/1_54_0/libs/serialization/doc/index.html ：

在默认情况下，数据类型指定由执行层面基本
  类的序列化特质，无需跟踪。如果期望以跟踪
  通过指针的共享原始对象（例如一长用作
  引用计数），它应被包裹在一类/结构，以便它
  可识别的类型。改变了执行的替代
  水平长期将影响整个程序序列化的所有多头
   - 可能不是什么人会打算

By default, data types designated primitive by Implementation Level class serialization trait are never tracked. If it is desired to track a shared primitive object through a pointer (e.g. a long used as a reference count), It should be wrapped in a class/struct so that it is an identifiable type. The alternative of changing the implementation level of a long would affect all longs serialized in the whole program - probably not what one would intend.

因此​​：

struct Wrapped {
    int value;
    private:
    friend class boost::serialization::access;
    template<class Archive>
    void serialize(Archive & ar,const unsigned int file_version)
    {
        ar & value;
    }
};

boost::shared_ptr<Wrapped> sp;
Wrapped const * p;

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