FSCTL_LOCK_VOLUME
The FSCTL_LOCK_VOLUME
DeviceIoControl
operation locks a volume. A locked volume can be accessed only through
handles to the file object (*hDevice) that locks the volume.
dwIoControlCode = FSCTL_LOCK_VOLUME; // operation code
lpInBuffer = NULL; // pointer to input buffer; not
used; must be NULL
nInBufferSize = 0; // size of input buffer; not
used; must be zero
lpOutBuffer ;
// pointer to output buffer; not used; must be NULL
nOutBufferSize ;
// size of output buffer; not used; must be zero
lpBytesReturned ;
// pointer to DWORD used by DeviceIoControl function
Parameters
lpInBuffer
Points to an
input buffer. Not used with this operation. Set to NULL.
nInBufferSize
Specifies the
size, in bytes, of the buffer pointed to by lpInBuffer. Not used with
this operation. Set to zero.
lpOutBuffer
Points to an
output buffer. Not used with this operation. Set to NULL.
nOutBufferSize
Specifies the
size, in bytes, of the buffer pointed to by lpOutBuffer. Not used with this
operation. Set to zero.
lpBytesReturned
Pointer to a DWORD.
This value cannot be NULL. Although the FSCTL_LOCK_VOLUME operation
produces no output data and lpOutBuffer should be NULL, the DeviceIoControl function uses the variable
pointed to by lpBytesReturned. After the operation, the value of this
variable is without meaning.
Return Values
If the
operation succeeds, DeviceIoControl returns TRUE.
If the
operation fails, DeviceIoControl returns FALSE. To get extended error
information, call GetLastError.
Remarks
The hDevice
handle passed to DeviceIoControl must be a handle to a volume,
opened for direct access. An application can obtain such a handle by calling CreateFile
with lpFileName set to a string that looks like this:
\\.\X:
where X is a
hard-drive partition letter, floppy disk drive, or CD-ROM drive. The
application must also specify the FILE_SHARE_READ and FILE_SHARE_WRITE flags in
the dwShareMode parameter of CreateFileXN35YD.
The FSCTL_LOCK_VOLUME
operation fails if there are any open files on the volume. Conversely, success
of this operation indicates there are no open files.
The operation
is useful for applications that need exclusive access to a volume for a period
of time for example, disk utility
programs.
A locked volume
remains locked until one of the following occurs:
The application invokes the FSCTL_UNLOCK_VOLUME DeviceIoControl operation
to unlock the volume.
The handle closes, either
directly through CloseHandle, or indirectly when a process terminates.
The system
flushes all cached data to the volume before locking it. For example, any data
held in a lazy-write cache is written to the volume.
See Also