‘make

../UniqueStrTest/main.cpp: In function ‘int main(int, char**)’:
../UniqueStrTest/main.cpp:35:25: error: ‘make_unique’ is not a member of ‘std’
           auto p = std::make_unique(); // p 是占有 D 的 unique_ptr
                         ^~~~~~~~~~~

make_unique从c++14开始，c++11不支持，但是可以自己实现make_unique

  /// std::make_unique for single objects
  template
    inline typename _MakeUniq<_Tp>::__single_object
    make_unique(_Args&&... __args)
    { return unique_ptr<_Tp>(new _Tp(std::forward<_Args>(__args)...)); }

  /// std::make_unique for arrays of unknown bound
  template
    inline typename _MakeUniq<_Tp>::__array
    make_unique(size_t __num)
    { return unique_ptr<_Tp>(new remove_extent_t<_Tp>[__num]()); }

  /// Disable std::make_unique for arrays of known bound
  template
    inline typename _MakeUniq<_Tp>::__invalid_type
    make_unique(_Args&&...) = delete;