DeviceIoControl(..., FSCTL_LOCK_VOLUME,...); Issue

[Kronos86m]

Hello together,

I want to lock a volume (USB Device) but receive an ERROR_INVALID_HANDLE all the time:

HANDLE hDev = CreateFile(
	"\\\\.\\E:",
	0,
	(FILE_SHARE_READ | FILE_SHARE_WRITE),
	NULL,
	OPEN_EXISTING,
	FILE_FLAG_OVERLAPPED,
	NULL
	);

if (hDev == INVALID_HANDLE_VALUE)
{
	cout << "CreateFile() failed!" << endl;
	cout << "GetLastError(): " << GetLastError() << endl;
	return -1;
}
DWORD bytesReturned;
OVERLAPPED overlapped;

BOOL retDevIoCtrl = DeviceIoControl(
	hDev,              // handle to a volume
	FSCTL_LOCK_VOLUME, // dwIoControlCode
	NULL,              // lpInBuffer
	0,                 // nInBufferSize
	NULL,              // lpOutBuffer
	0,                 // nOutBufferSize
	&bytesReturned,    // number of bytes returned
	&overlapped        // OVERLAPPED structure
);
if (!retDevIoCtrl)
{
	cout << "FSCTL_LOCK_VOLUME failed!" << endl;
	cout << "GetLastError(): " << GetLastError() << endl;

The output is always "FSCTL_LOCK_VOLUME failed! GetLastError(): 6"

I've tried a few variations of the CreateFile parameters but didn't find a solution so far. Maybe somebody can help? Am I using the wrong parameters? As far as I understand the MSDN documentation I use them as advised.

Cheers

[Computergeek01]

The 'hEvent' data member in your OVERLAPPED struct was never initialized or set to zero, that's the "Invalid Handle" that the error code is referring to: http://msdn.microsoft.com/en-us/library/windows/desktop/ms684342(v=vs.85).aspx


Remember that C objects don't have constructors so stuff like this has to be done by hand.

[Null]

Is asynchronous I/O really needed in this situation? I think &overlapped can be replaced with NULL and the code will work fine.

[Kronos86m]

Thanks a lot to both of you.
You were absolutely right: I forgot to initialize the OVERLAPPED struct.
Nevertheless there had been another error after that. I had to modify the access rights of the CreateFile funtion.

HANDLE hDev = CreateFile(
	"\\\\.\\E:",
	(GENERIC_READ | GENERIC_WRITE),
	(FILE_SHARE_READ | FILE_SHARE_WRITE),
	NULL,
	OPEN_EXISTING,
	FILE_FLAG_OVERLAPPED,
	NULL
	);