#ifndef HELLO_WORLD_CALCULATOR_H
#define HELLO_WORLD_CALCULATOR_H
class Calculator {
public:
    double add(double first, double second);
};
#endif

#include "Calculator.h"
double Calculator::add(double first, double second) {
    return first + second;
}

#include <iostream>
#include <tr1/memory>
#include "Calculator.h"

using namespace std;

double add1(double first, double second){
    shared_ptr<Calculator>calculater(new Calculator());
    return calculater->add(first, second);
}

extern "C"
{
    double add(double f, double s){
        return add1(f,s);
    }
}

# coding=utf-8

import ctypes
from ctypes import *

if __name__ == "__main__":
    lib = ctypes.CDLL("./test.so")
    lib.add.argstype = [c_double, c_double]
    lib.add.restype = c_double
    print lib.add(c_double(12), c_double(36))

Traceback (most recent call last):
  File "test.py", line 9, in <module>
    lib = ctypes.CDLL("./test.so")
  File "/usr/lib/python2.7/ctypes/__init__.py", line 365, in __init__
    self._handle = _dlopen(self._name, mode)
OSError: ./test.so: undefined symbol: _ZN10Calculator6devideEdd