组件接口调用IDL IUnknown 14.5.22

IDL math.idl文件如下：

import "objidl.idl";

[
	object,
	uuid(C9BAF4B4-0637-404e-824A-631F5B80FED5)
]
//生成的时候要在项目设置里面MIDL选项里吧MKTYPLIB..兼容给取消
interface IMath:IUnknown
{
	HRESULT Add(long nAdd1,long nAdd2,long *pnAdd);
	HRESULT Sub(long nSub1,long nSub2,long *pnSub);
}

实现:

// ImpMath.cpp: implementation of the CImpMath class.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "ImpMath.h"
#include "math_i.c"
//////////////////////////////////////////////////////////////////////
// Construction/Destruction
//////////////////////////////////////////////////////////////////////

CImpMath::CImpMath()
{
    m_nRef=0;
}

CImpMath::~CImpMath()
{

}
//IUnknown函数实现
STDMETHODIMP CImpMath::QueryInterface(REFIID iid,void** ppiObject)
{

    
    if(iid==IID_IUnknown){
    
        *ppiObject=static_cast<IUnknown *>( this );
    }else if(iid==IID_IMath)
    {
        *ppiObject=static_cast<IMath *>(this);
    }else{
        *ppiObject=NULL;
          return E_FAIL;
    }
    AddRef();
    return S_OK;

}
STDMETHODIMP_(ULONG) CImpMath::AddRef(){
    //使用原子锁 避免多线程访问出错 
    InterlockedIncrement(&m_nRef);
    return m_nRef;
}
STDMETHODIMP_(ULONG) CImpMath::Release(){
    InterlockedIncrement(&m_nRef);
    if(m_nRef==0){
        delete this;
    }
    return m_nRef;
}

STDMETHODIMP CImpMath::Add(long nAdd1,long nAdd2,
                           long * pnAdd)
{
    if(pnAdd==NULL){
        return E_INVALIDARG;
    }
    *pnAdd=nAdd1+nAdd2;
    return S_OK;
}
STDMETHODIMP CImpMath::Sub(long nSub1,long nSub2,
                           long * pnSub)
{
    *pnSub=nSub1+nSub2;
    return S_OK;
}

接口创建:

// COMInterface.cpp : Defines the entry point for the DLL application.
//

#include "stdafx.h"
#include "ImpMath.h"
BOOL APIENTRY DllMain( HANDLE hModule, 
                       DWORD  ul_reason_for_call, 
                       LPVOID lpReserved
					 )
{
    return TRUE;
}

IUnknown * CreateInstance() {
    //创建对象
    CImpMath *pMath=new CImpMath;
    //获取接口
    IUnknown *piUnknown = NULL;
    pMath->QueryInterface(IID_IUnknown,(LPVOID*)&piUnknown);
    //返回接口
    return piUnknown;
}

def文件

LIBRARY "COMInterface"
EXPORTS 
	CreateInstance @1

接口的使用

// UserComIf.cpp : Defines the entry point for the console application.
//

#include "stdafx.h"
#include "../COMInterface/math.h"
#include "../COMInterface/math_i.c"

typedef IUnknown *(*CREATEINSTANCE)();
IMath * GetMath(){
    HMODULE hDll=(HMODULE)LoadLibrary("COMInterface.dll");
    CREATEINSTANCE CreateInstance=(CREATEINSTANCE)GetProcAddress(hDll,"CreateInstance");
    //创建接口
    IUnknown * piUnknown=CreateInstance();
    IMath * piMath=NULL;
    HRESULT nRet=piUnknown->QueryInterface(IID_IMath,(LPVOID*)&piMath);

    //释放接口 判断返回值
    piUnknown->Release();
    if(FAILED(nRet)){
        printf("cannt find IMath\n");
        return NULL;
    }
    //返回IMath接口
    return piMath;
}

int main(int argc, char* argv[])
{
    //获取接口
    IMath *piMath=GetMath();
    //使用接口
    long nAdd=0;
    piMath->Add(100,100,&nAdd);
    printf("%d\n",nAdd);
    //释放接口
    //piMath->Release();
	return 0;
}

程序下载 :http://pan.baidu.com/s/1i3A6U25