python 调用 vc++生成的 dll 中的函数，出错求助，谢谢

// ----------------------------------------  MakeDll.h 代码如下 ----------------------------------------  
#define DLL_API __declspec(dllexport)
#include<iostream>
using namespace std;

DLL_API int add(int a, int b);
class DLL_API Point
{
private:
        float x, y;
public:
        Point();
};
// ----------------------------------------  MakeDll.cpp 代码如下 ----------------------------------------  
#include "stdafx.h"
#include <iostream>
using namespace std;
#include "MakeDll.h"

DLL_API int add(int a, int b)
{
        return a + b;
        cout << "a = " << a << "\tb = " << b << endl;
}
Point::Point()
{
        x = 0.0f;
        y = 0.0f;
        cout << "x = " << x << "\ty = " << y << endl;
}

# --------------------------------------- python 调用 dll 如下 ------------------------------------
from ctypes import *
api = CDLL('MakeDLL')
a = c_int(1)
b = c_int(2)
x = c_float(0.1)
y = c_float(1.2)
c = api.add(a,b)                      # 报错：AttributeError: function 'add' not found
p = api.Point(x,y)                     #报错：AttributeError: function 'Point' not found