Предупреждение при создании динамической библиотеки

#include "../export/myclass_export.h"
#include "../core/core.h"
 
#include <Eigen/Dense>
 
#include <optional>
 
class MYCLASS_EXPORT MyClass
{
  MyClass();
 
private:
  HighFive::Group devCurveGroup;    // warning: C4251: 'MyClass::devCurveGroup': class 'HighFive::Group' needs to have dll-interface to be used by clients of class 'MyClass' 
  HighFive::DataSet devDataD;    // warning: C4251: 'MyClass::devCurveGroup': class 'HighFive::Group' needs to have dll-interface to be used by clients of class 'MyClass' 
};

#ifndef MYCLASS_EXPORT_H
#define MYCLASS_EXPORT_H
 
#ifdef MYCLASS_STATIC_DEFINE
#  define MYCLASS_EXPORT
#  define MYCLASS_NO_EXPORT
#else
#  ifndef MYCLASS_EXPORT
#    ifdef MYCLASS_EXPORTS
        /* We are building this library */
#      define MYCLASS_EXPORT __declspec(dllexport)
#    else
        /* We are using this library */
#      define MYCLASS_EXPORT __declspec(dllimport)
#    endif
#  endif
 
#  ifndef MYCLASS_NO_EXPORT
#    define MYCLASS_NO_EXPORT 
#  endif
#endif
 
#ifndef MYCLASS_DEPRECATED
#  define MYCLASS_DEPRECATED __declspec(deprecated)
#endif
 
#ifndef MYCLASS_DEPRECATED_EXPORT
#  define MYCLASS_DEPRECATED_EXPORT MYCLASS_EXPORT MYCLASS_DEPRECATED
#endif
 
#ifndef MYCLASS_DEPRECATED_NO_EXPORT
#  define MYCLASS_DEPRECATED_NO_EXPORT MYCLASS_NO_EXPORT MYCLASS_DEPRECATED
#endif
 
#if 0 /* DEFINE_NO_DEPRECATED */
#  ifndef MYCLASS_NO_DEPRECATED
#    define MYCLASS_NO_DEPRECATED
#  endif
#endif
 
#endif /* MYCLASS_EXPORT_H */

class DLL_EXPORTS MyClass
{
  MyClass(){};
 
  template <typename D>
  Eigen::MatrixX<D::Scalar> getMtx(const Eigen::DenseBase<D> &M)
  {
    return M.derived();
  }
};

#ifndef SURF_H
#define SURF_H
 
#include "../h5geo_export.h"
#include "../core/core.h"
 
#include <Eigen/Dense>
 
#include <optional>
 
class H5GEO_EXPORT Surf
{
private:
  explicit Surf(HighFive::Group &surfGroup);
  static bool isSurf(HighFive::Group &surfGroup);
 
public:
  static std::optional<Surf>
  create(HighFive::Group &surfGroup);
 
  bool writeData(
      const Eigen::Ref<const Eigen::MatrixXd>& M);
 
  Eigen::MatrixXd getData();
 
public:
  HighFive::Group surfGroup;
  HighFive::DataSet surfDataD;
};
 
#endif // SURF_H

#include "surf.h"
 
Surf::Surf(HighFive::Group &surfGroup) :
  surfGroup(surfGroup),
  surfDataD(surfGroup.getDataSet("surf_data"))
{
 
}
 
std::optional<Surf>
Surf::create(HighFive::Group &surfGroup){
  if (isSurf(surfGroup))
    return Surf(surfGroup);
  else
    return  std::nullopt;
}
 
bool Surf::isSurf(HighFive::Group &surfGroup){
  try {
    surfGroup.getDataSet("surf_data");
  } catch (HighFive::Exception e) {
    return false;
  }
 
  return true;
}
 
bool Surf::writeData(
    const Eigen::Ref<const Eigen::MatrixXd>& M)
{
  if (M.size() == 0)
    return false;
 
  std::vector<size_t> dims = {size_t(M.cols()), size_t(M.rows())};
  try {
    surfDataD.resize(dims);
    surfDataD.write_raw(M.data());
  } catch (HighFive::Exception e) {
    return false;
  }
 
  return true;
}
 
Eigen::MatrixXd Surf::getData(){
  std::vector<size_t> dims(surfDataD.getDimensions());
  Eigen::MatrixXd M(dims[1], dims[0]);
  try {
    surfDataD.read(M.data());
  } catch (HighFive::Exception e) {
    return Eigen::MatrixXd();
  }
 
  return M;
}