c++ - boost serialization std::unique_ptr support

Question

Does the boost serialization library support serialization of std::unique_ptr? I tried to compile the code below, but if I include the boost::archive::text_oarchive oa(ofs); oa << g; line,

the compiler (btw gcc4.7 with -std=c++11 flag) throws an error

/usr/include/boost/serialization/access.hpp:118:9: error: ‘class std::unique_ptr’ has no member named ‘serialize’

#include <iostream>
#include <memory>
#include <fstream>
#include <boost/archive/text_oarchive.hpp>
#include <boost/archive/text_iarchive.hpp>
class MyDegrees
{
public:
  void setDeg(int d){deg = d;}
  int getDeg()const {return deg;}
private:
  friend class boost::serialization::access;
    template<class Archive>
    void serialize(Archive & ar, const unsigned int version)
    { ar & deg; }
  int deg;
};
class gps_position
{
private:
    friend class boost::serialization::access;
    template<class Archive>
    void serialize(Archive & ar, const unsigned int version)
    { ar & degrees; }
    std::unique_ptr<MyDegrees> degrees;
public:
    gps_position(): degrees(std::unique_ptr<MyDegrees>(new MyDegrees)){};
    void setDeg(int d){degrees->setDeg(d);}
    int getDeg() const {return degrees->getDeg();}
};
int main()
{
    std::ofstream ofs("filename");
    gps_position g;
    g.setDeg(45);
    std::cout<<g.getDeg()<<std::endl;
    {// compiler error, fine if commented out
        boost::archive::text_oarchive oa(ofs); oa << g;
    }
  return 0;
}

Answer 1

I'm not sure how to interpret this list, but it seems like support for this was added sometime after 1.48. I am using 1.58 and it is included. Just

#include <boost/serialization/unique_ptr.hpp>

and then it will work as follows:

#include <memory>

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

#include <fstream>

class Point
{
public:
    Point() { }

    float x = 1.;
    float y = 2.;
    float z = 3.;

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

    template<class TArchive>
    void serialize(TArchive & archive, const unsigned int version)
    {
        archive & x;
        archive & y;
        archive & z;
    }
};

void ValidUniquePointer()
{
    std::unique_ptr<Point> p(new Point());

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

    // read from a text archive
    std::unique_ptr<Point> pointRead;
    std::ifstream inputStream("test.txt");
    boost::archive::text_iarchive inputArchive(inputStream);
    inputArchive >> pointRead;

    std::cout << pointRead->x << " " << pointRead->y << " " << pointRead->z << std::endl;

}

void NullUniquePointer()
{
    std::unique_ptr<Point> p;

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

    // read from a text archive
    std::unique_ptr<Point> pointRead;
    std::ifstream inputStream("test.txt");
    boost::archive::text_iarchive inputArchive(inputStream);
    inputArchive >> pointRead;

    if(pointRead != nullptr) {
        std::cout << pointRead->x << " " << pointRead->y << " " << pointRead->z << std::endl;
    }
    else {
        std::cout << "Pointer is null!" << std::endl;
    }

}

int main()
{
    ValidUniquePointer();
    NullUniquePointer();
    return 0;
}