CUDA programming Doppia about the host-CodePudding

 # # ifndef GEOMETRY_HPP 
# define GEOMETRY_HPP 

#include  

//# include & lt; The boost/geometry/geometries'/point_xy. Hpp> 
//# include & lt; The boost/geometry/geometries'/box. Hpp> 

//little was catnip to get the proper compilation inside and outside the CUDA NVCC compiler 
# if defined (USE_GPU) 
#include  
# the else//not defined (USE_GPU) 
# if not defined (__device__) 
# define __device__ 
# endif 
# if not defined (__host__) 
# define __host__ 
# endif 
# endif//defined (USE_GPU) 

The namespace doppia {

The namespace geometry {
///This namespace contains simplified versions of 
///boost: : geometry: : model: : d2: : point_xy & lt;> And boost: : geometry: : model: : box<> 

//In order to reuse the same datastructures In the CUDA code, 
//we define our simplified point and box classes, which conform to the boost: : geometry API, 
//but do not include lexical_cast in one of its dark corners 
//typedef boost: : geometry: : model: : d2: : point_xy & lt; Coordinate_t & gt; Point_t; 
//typedef boost: : geometry: : model: : box
Template 
The class point_xy 
{
Public: 

Typedef CoordinateType coordinate_t; 

///the Default constructor, does not initialize anything 
__host__ __device__ inline point_xy () 
{} 

///Constructor with x/y values 
__host__ __device__ inline point_xy (CoordinateType const& X, CoordinateType const& Y) 
: m_x (x), m_y (y) 
{} 

///the Copy constructor 
__host__ __device__ inline point_xy (const point_xy & amp; Other) 
: m_x (other) (x)), m_y (other) y ()) 
{} 

///Get the x value 
 -__host__ __device__ inline CoordinateType const& (x) const 
{return m_x; } 

///Get y - value 
__host__ __device__ inline CoordinateType const& Y () const 
{return m_y; } 

///Set x - value 
__host__ __device__ inline void x (CoordinateType const& V) 
{m_x=v; } 

///Set y - value 
__host__ __device__ inline void y (CoordinateType const& V) 
{m_y=v; } 

Boolean operator==(const point_xy & amp; Other) const 
{
Return (m_x==other. M_x) and (m_y==other. M_y); 
} 

Boolean operator!=(const point_xy & amp; Other) const 
{
Return (* this==other)==false; 
} 

Protected: 

CoordinateType m_x, m_y; 
};

The above code to use GPU but the compiler complains error
Error C2485: "__host__" : unable to identify the extension feature
Hope to mention the great god, what is the cause of this error may be