c++调用DLL

示例一:
//dllTest.h file
#ifndef DLL_H
#define DLL_H

#if BUILDING_DLL
#define  DLLIMPORT _declspec(dllimport)
#else
#define  DLLIMPORT _declspec(dllexport)
#endif

class TestClass
{
private:
public:
    TestClass();
    virtual int add(int, int);
    virtual int sub(int, int);
    virtual ~TestClass();
};
#endif

//dllTest.cpp file
#include "dllTest.h"

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

TestClass::TestClass()
{
}

int TestClass::add(int i, int j)
{
    return (i+j);
}

int TestClass::sub(int i, int j)
{
    return (i-j);
}

TestClass::~TestClass()
{
}

extern "C" _declspec(dllexport) TestClass* MakeClass()
{
    return new TestClass();
}

//MainTest.cpp file
#include <iostream>
#include <windows.h>

#include "dllTest.h"

using namespace std;

int main(int argc, char** argv)
{
    HMODULE hDll = LoadLibrary("DLLTEST");

    if(NULL == hDll)
    {
        cout<<"Load Dll Faile!"<<endl;
        return 1;
    }

    cout<<"Load Dll Success!"<<endl;

    typedef TestClass* (*MakeClassPtr)();

    MakeClassPtr ptr = (MakeClassPtr)GetProcAddress(hDll, "MakeClass");
    TestClass*pTestClass = ptr();

    cout<<pTestClass->add(10, 20)<<endl;

    delete pTestClass;
    FreeLibrary(hDll);

    system("pause");

    return 0;
}