C++ DLL 创建实例 导出类和函数

今天工作闲下来, 就试看DLL编程, 好久没玩DLL了,结果花了一个半小时才写出这个很简单的例子.

起初直接把子__declspec(dllexport) 放在类声明的地方. 发生 warning　C4273 DLL 链接不一致错误.

想了挺长时间才意识到是生成lib时并头文件和原文件中对函数的名字解析名字不一样而产生的.  才想到要定义一个宏.

有点感叹知识不用会也会老的. 下边是代码

//头文件:testClass.h

 

#ifndef TEST_CLASS_H__
#define TEST_CLASS_H__

#include <iostream>
using namespace std;

#ifdef SERVERDLL_EXPORTS //在创建产生DLL的工程中先把 SERVERDLL_EXPORTS 预定义上
#define SERVERDLL_API __declspec(dllexport)
#else
#define SERVERDLL_API __declspec(dllimport)
#endif

class SERVERDLL_API TestClass
{
public:
    virtual void VirtualFunction(void);

    void NormalFunction(void);
};

SERVERDLL_API void func(void);
#endif

#ifndef TEST_CLASS_H__ #define TEST_CLASS_H__ #include <iostream> using namespace std; #ifdef SERVERDLL_EXPORTS //在创建产生DLL的工程中先把 SERVERDLL_EXPORTS 预定义上 #define SERVERDLL_API __declspec(dllexport) #else #define SERVERDLL_API __declspec(dllimport) #endif class SERVERDLL_API TestClass { public: virtual void VirtualFunction(void); void NormalFunction(void); }; SERVERDLL_API void func(void); #endif

//实现文件.testClass.cpp 

#include "testClass.h"


void TestClass::VirtualFunction(void)
    {
        cout<< "this is VirtualFunction()!" <<endl;
        return;
    }
void TestClass::NormalFunction(void)
    {
        cout<< "this is NormalFunction()!" <<endl;
        return;
    }
void func(void)
{
    cout << "xixi haha" <<endl;
    return;
}

#include "testClass.h" void TestClass::VirtualFunction(void) { cout<< "this is VirtualFunction()!" <<endl; return; } void TestClass::NormalFunction(void) { cout<< "this is NormalFunction()!" <<endl; return; } void func(void) { cout << "xixi haha" <<endl; return; }

//调试代码

#include <iostream>
#include <windows.h>

#include <e://myself//MyProject//网络程序//ServerDLL//testClass.h>

using namespace std;
#pragma comment(lib, "E://myself//MyProject//网络程序//ServerDLL//Debug//ServerDLL.lib")

//TestClass类为DLL导出的类
class MY : public TestClass
{
public:
        virtual void VirtualFunction()
    {
        cout<< "my VirtualFunction()" <<endl;
        return;
    }
    void NormalFunction()
    {
        cout<< "my NormalFunction()" <<endl;
        return;
    }
};
int main(void)
{
    MY my;
    TestClass *tc = &my;

    tc->NormalFunction();
    tc->VirtualFunction();
    //调用导出的函数
    func();

    cout<<"liu zhiliang"<<endl;
    system("PAUSE");
    return 0;
}

#include <iostream> #include <windows.h> #include <e://myself//MyProject//网络程序//ServerDLL//testClass.h> using namespace std; #pragma comment(lib, "E://myself//MyProject//网络程序//ServerDLL//Debug//ServerDLL.lib") //TestClass类为DLL导出的类 class MY : public TestClass { public: virtual void VirtualFunction() { cout<< "my VirtualFunction()" <<endl; return; } void NormalFunction() { cout<< "my NormalFunction()" <<endl; return; } }; int main(void) { MY my; TestClass *tc = &my; tc->NormalFunction(); tc->VirtualFunction(); //调用导出的函数 func(); cout<<"liu zhiliang"<<endl; system("PAUSE"); return 0; }

输出：

this is NormalFunction()!
my VirtualFunction()
xixi haha
liu zhiliang
请按任意键继续. . .