我有一个类，它的一个成员是一个指向二维整数数组的指针。我想在serialize函数中传递此成员，但收到以下错误：error: request for member ‘serialize’ in ‘t’, which is of non-class type ‘int’我读了documentation，我发现他们使用了

ar.register_type(static_cast<type *>(NULL));

所以我也做了同样的事但我还是有问题
我正在附加我试图序列化的代码段：

#include <iostream>
#include<set>
#include<map>
#include <boost/mpi/datatype.hpp>
#include <boost/mpi/environment.hpp>
#include <boost/mpi/communicator.hpp>
#include <boost/mpi.hpp> 

class Dummy 
{
private: 
    int m_N;
    int** array; 
    friend class boost::serialization::access;
    template <class Archive>
    void serialize(Archive &ar, const unsigned int /*version*/)
    {
        ar &m_N; 
        ar.register_type(static_cast<int**>(NULL));
        ar &array; 
    }
public:
    Dummy(){}; 
    Dummy(const int N) 
    {
        m_N=N; 

        array = new int*[N+1];
        for(auto i=0;i<N+1;i++)
        {
            array[i] = new int[N+1];
        }
    };
    ~Dummy()
    {
        for(auto i=0;i<m_N+1;i++)
        {
            delete[]array[i];
        }delete[]array;
    }; 
    
};
namespace boost { namespace mpi {
    template <>
struct is_mpi_datatype<Dummy> : mpl::true_ { };
} }

int main(int argc, char* const argv[]) 
{
    boost::mpi::environment   env; 
    boost::mpi::communicator  world; 
    std::map<int,std::vector<Dummy>> IdToVecObject;
    std::vector<Dummy> vec; 
    std::set<int> neigbours; 
    if(world.rank()==0)
    {   
        Dummy obj(1); 
        vec.push_back(obj); 
        neigbours.insert(1); 
        IdToVecObject.emplace(1,vec); 

    }
    if(world.rank()==1)
    {
        Dummy obj(1); 
        vec.push_back(obj); 
        neigbours.insert(0); 
        IdToVecObject.emplace(0,vec); 
    }
    for(auto it:IdToVecObject)
    {
        int target= it.first;
        Dummy obj(1); 
        world.send(target,0,obj); 
    }
    for(auto i:neigbours)
    {
        int source= i ;  
        Dummy obj(1); 
        std::vector<Dummy> objects; 
        world.recv(source,0,obj); 
    }
    return 0; 
}