VC中创建DLL，导出全局变量，函数和类（隐式调用）
一.创建DLL
1.在VC中新建一个Win32空项目MathLib；
2.添加预编译头文件stdafx.h，定义导入导出控制符号：
1: //stdafx.h
2: #pragma once
3: #define MATHLIB_EXPORT
3.添加包含要导出的全局变量,函数和类的头文件MathLib.h:
1: //MathLib.h
2: #pragma once
3:
4: #ifdef MATHLIB_EXPORT
5: #define MATHLIBAPI __declspec(dllexport)
6: #else
7: #define MATHLIBAPI __declspec(dllimport)
8: #endif
9:
10: //macro
11: #define PI 3.14149
12:
13: //Global variable
14: extern MATHLIBAPI int GlobalVariable;
15:
16: //Function
17: MATHLIBAPI int Add(int a,int b);
18:
19: //Class
20: class MATHLIBAPI Math
21: {
22: public:
23: int Multiply(int a,int b);
24: };
4.添加所导出元素的实现文件MathLib.cpp
1: //MathLib.cpp
2: #include "stdafx.h"
3: #include "MathLib.h"
4:
5: int GlobalVariable = 100;
6:
7: int Add(int a,int b)
8: {
9: return a+b;
10: }
11:
12: int Math::Multiply(int a,int b)
13: {
14: return a*b;
15: }
二,测试所创建的DLL
测试代码:
1: #include "stdafx.h"
2: #include <iostream>
3: using namespace std;
4:
5: #include "../MathLib/MathLib.h"
6: #pragma comment(lib,"../Debug/MathLib.lib")
7:
8: int _tmain(int argc, _TCHAR* argv[])
9: {
10: cout<<"Pi = "<<PI<<endl;
11:
12: cout<<"GlobalVariable = "<<GlobalVariable<<endl;
13:
14: int a = 20,b = 30;
15: cout<<"a="<<a<<", "<<"b="<<b<<endl;
16: cout<<"a+b = "<<Add(a,b)<<endl;
17:
18: Math math;
19: cout<<"a*b = "<<math.Multiply(a,b)<<endl;
20:
21: return 0;
22: }
注意：在测试lib的程序的开始可以不对全局变量进行声明直接用，要声明的话用 extern int _declspec(dllimport) a;
作者“菜鸟变身记”
补充：软件开发 , Vc ,
