DLL静态（显示）调用，动态（隐式）调用

静态调用：

需要dll文件，lib文件，头文件

lib文件在编译时用到，在主程序加载时，会装载dll，主程序运行期，dll不能卸载

动态调用：

需要dll文件

使用LoadLibrary-> GetProcAddress调用，只有在LoadLibrary执行时，dll才被装载，dll可以随时被卸载

动态调用代码例子

#ifndef _IKPERSON_H_
#define _IKPERSON_H_
#ifdef DLL_EXPORT
#define DLL_API	extern "C" __declspec(dllexport)
#else
#define DLL_API extern "C" __declspec(dllimport)
#endif
/*
	设计这个接口类的作用：
	能采用动态调用方式使用这个类
*/
class IKPerson
{
public:
	virtual ~IKPerson(void)	//对于基类，显示定义虚析构函数是个好习惯（注意，为什么请google）
	{
	}
	virtual int GetOld(void) const = 0;
	virtual void SetOld(int nOld) = 0;
	virtual const char* GetName(void) const = 0;
	virtual void SetName(const char* szName) = 0;
};
/* 导出函数声明 */
DLL_API IKPerson* _cdecl GetIKPerson(void);
typedef IKPerson* (__cdecl *PFNGetIKPerson)(void);
#endif

#pragma once
#define DLL_EXPORT
#include "ikperson.h"
class CKChinese :
	public IKPerson
{
public:
	CKChinese(void);
	~CKChinese(void);
	virtual int GetOld(void) const;
	virtual void SetOld(int nOld);
	virtual const char* GetName(void) const;
	virtual void SetName(const char* szName);
private:
	int m_nOld;
	char m_szName[64];
};

#include "StdAfx.h"
#include "KChinese.h"
CKChinese::CKChinese(void) : m_nOld(0)
{
	memset(m_szName, 0, 64);
}
CKChinese::~CKChinese(void)
{
}
int CKChinese::GetOld(void) const
{
	return m_nOld;
}
void CKChinese::SetOld(int nOld)
{
	this->m_nOld = nOld;
}
const char* CKChinese::GetName(void) const
{
	return m_szName;
}
void CKChinese::SetName(const char* szName)
{
	strncpy(m_szName, szName, 64);
}
/* 导出函数定义 */
IKPerson* __cdecl GetIKPerson(void)
{
	IKPerson* pIKPerson = new CKChinese();
	return pIKPerson;
}

// callclassExportDll.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include <iostream>
using namespace std;
#include "../../classExportDll/classExportDll/IKPerson.h"
int _tmain(int argc, _TCHAR* argv[])
{
	HMODULE hDll = ::LoadLibrary(_T("classExportDll.dll"));
	if (NULL != hDll)
	{
		PFNGetIKPerson pFun = (PFNGetIKPerson)::GetProcAddress(hDll, "GetIKPerson");
		if (NULL != pFun)
		{
			IKPerson* pIKPerson = (*pFun)();
			if (NULL != pIKPerson)
			{
				pIKPerson->SetOld(103);
				pIKPerson->SetName("liyong");
				cout << pIKPerson->GetOld() << endl;
				cout << pIKPerson->GetName() << endl;
				delete pIKPerson;			
			}
		}
		::FreeLibrary(hDll);
	}
	return 0;
}