解析VC中创建DLL,导出全局变量,函数和类的深入分析

//stdafx.h
#pragma once
#define MATHLIB_EXPORT

//MathLib.h
#pragma once

#ifdef MATHLIB_EXPORT
#define MATHLIBAPI __declspec(dllexport)
#else
#define MATHLIBAPI __declspec(dllimport)
#endif

//macro
#define PI 3.14149

//Global variable
extern MATHLIBAPI int GlobalVariable;

//Function
MATHLIBAPI int Add(int a,int b);

//Class
class MATHLIBAPI Math
{
public:
int Multiply(int a,int b);
};

//MathLib.cpp
#include "stdafx.h"
#include "MathLib.h"

int GlobalVariable = 100;

int Add(int a,int b)
{
return a+b;
}

int Math::Multiply(int a,int b)
{
return a*b;
}

#include "stdafx.h"
#include <iostream>
using namespace std;

#include "../MathLib/MathLib.h"
#pragma comment(lib,"../Debug/MathLib.lib")

int _tmain(int argc, _TCHAR* argv[])
{
cout<<"Pi = "<<PI<<endl;

cout<<"GlobalVariable = "<<GlobalVariable<<endl;

int a = 20,b = 30;
cout<<"a="<<a<<", "<<"b="<<b<<endl;
cout<<"a+b = "<<Add(a,b)<<endl;

Math math;
cout<<"a*b = "<<math.Multiply(a,b)<<endl;

return 0;
}