函数指针传递的问题,为什么我返回的指针总是null呢?

[xhwu3721]

定义BOOL SearchDir(WCHAR strDestDir[],IWMDMStorage** pIStorageDir);
调用:
IWMDMStorageControl* pIWMDMStorageControl;
SearchDir(strDestDirectory,&pIStorage);
但pIStorage总是返回0,我试过在SearchDir函数体中pIStorageDir指针却很正常.



BOOL SearchDir(WCHAR strDestDir[],IWMDMStorage** pIStorageDir)
{
IWMDMEnumStorage* pIEnumStorage, *pIEnumStorageFile; //枚举存储器
IWMDMStorage* pIStorage ;// *pIStorageFile; //用于访问存储媒体内容
ULONG ulNumStorage;
IWMDMStorageControl* pIWMDMStorageControl;

IWMDMEnumStorage* pEnumStorageTest = NULL;
BOOL bFoundDirectory=FALSE;
// Assume that the parameter pMetaData is a valid.
WCHAR wDeviceName[256];
memset(wDeviceName,'\0',sizeof(wDeviceName));

///////////////////////
hr = pIDevice->EnumStorage(&pIEnumStorage);
pIDevice->GetName(wDeviceName,256);

DWORD pdwAttributes = 0;
_WAVEFORMATEX *pFormat = NULL;

hr = pIEnumStorage->Next(ulNumStorage, &pIStorage, &ulNumFetched);
pIStorage->GetAttributes(&pdwAttributes,pFormat);

pIStorageDir = &pIStorage; //在这里都很正常
}

[xhwu3721]

指教得是,多谢!结贴了.

[thisisll]

*pIStorageDir = pIStorage;

[tufaqing]

楼上正解，楼主要好好学学指针和函数参数。