Getting ERROR_INSUFFICIENT_BUFFER error in DeviceIoControl Function

[learningvisualc]

Hi all, I am trying to get Logical drives of a hard disk(\\.\PhysicalDrive0). I have tried using DeviceIoControl function for it but i am getting GetLastError() = 122 i.e. ERROR_INSUFFICIENT_BUFFER error. My code is as follows:-

HANDLE hDevice;

hDevice = CreateFile("\\\\.\\PhysicalDrive0"    // drive 
                          0,                    // no access to the drive
                          FILE\_SHARE\_READ |    // share mode
                          FILE\_SHARE\_WRITE, 
                          NULL,              // default security attributes
                          OPEN\_EXISTING,    // disposition
                          0,               // file attributes
                          NULL);          // do not copy file attributes



PARTITION\_INFORMATION\_EX obj;
DWORD cb;


BOOL iu = DeviceIoControl(hDevice,                             // handle to a partition
			  IOCTL\_DISK\_GET\_PARTITION\_INFO\_EX,   // dwIoControlCode
			  NULL,                              // lpInBuffer
			  0,                                // nInBufferSize
			  &obj,			           // output buffer
			  sizeof(obj),                    // size of output buffer
			  &cb,                           // number of bytes returned
			  NULL                          // OVERLAPPED structure
			 );
if(iu == 0)
{
	DWORD err = GetLastError();
	CString str;
	str.Format("%d",err);
	AfxMessageBox(str);
}
CloseHandle(hDevice);

I am not getting where exactly is the problem... How can i do this.. Thanks in advance

[Andrew Brock]

Not sure if it is just the way u copied it to code project, but you need to escape each of the back slashes in the drive name like "\\\\.\\PhysicalDrive0" also add a comma in after that string. Once I applied those changes your code worked for me.