vc 查看硬盘盘符剩余空间

string strtemp = "c:\\123\\456\\789.txt";
    char uuu[2] = {0};
    uuu [0]= strtemp[0];
    CString firstchar = uuu;
    CString strRootPath=firstchar + ":\\";
    /*CString strRootPath="E:\\123.txt";*///带根目录标记的磁盘符号
    DWORD dwSectorsPerCluster=0;//每簇中扇区数
    DWORD dwBytesPerSector=0;//每扇区中字节数
    DWORD dwFreeClusters=0;//剩余簇数
    DWORD dwTotalClusters=0;//总簇数
    if (GetDiskFreeSpace(strRootPath,&dwSectorsPerCluster,&dwBytesPerSector,
        &dwFreeClusters,&dwTotalClusters))
    {
        //m_dwVolSize=dwTotalClusters*dwSectorsPerCluster*dwBytesPerSector;//不能这样，否则越界
        double dd=dwSectorsPerCluster*dwBytesPerSector/(1024.*1024.);
        dd=dd/1024.;
        double m_dFree=dwFreeClusters*dd;//该磁盘剩余容量总大小
        if (m_dFree < 1)
        {
            WriteToLogAndTime("硬盘空间小于1G，请清理空间");
            AfxMessageBox("硬盘空间小于1G，请清理空间");
        }
    }