FSCTL_SET_OBJECT_ID_EXTENDED

Using the FSCTL_SET_OBJECT_ID_EXTENDED control code modifies user data in the object identifier of an existing, open object in a Windows 2000 NTFS file system.

To perform this operation, call the DeviceIoControl function with the following parameters.

BOOL DeviceIoControl(
  (HANDLE) hDevice,              // handle to device
  FSCTL_SET_OBJECT_ID_EXTENDED,  // dwIoControlCode operation
  (LPVOID) lpInBuffer,           // input buffer
  (DWORD) nInBufferSize,         // size of input buffer
  NULL,                          // lpOutBuffer; must be NULL
  0,                             // nOutBufferSize; must be zero
  (LPDWORD) lpBytesReturned,     // number of bytes returned
  (LPOVERLAPPED) lpOverlapped    // OVERLAPPED structure
);

Parameters

hDevice

[in] Handle to the directory, file, or alternate stream on which object identifier user data is to be set. The process must have write access to or restore privilege for the object. To obtain a device handle, call the CreateFile function.

dwIoControlCode

[in] Control code for the operation. This value identifies the specific operation to be performed and the type of device on which to perform it. Use FSCTL_SET_OBJECT_ID_EXTENDED for this operation.

lpInBuffer

[in] Pointer to the input buffer, a FILE_OBJECTID_BUFFER structure. The ObjectId member of the structure is ignored. Only the user data, in the ExtendedInfo member of the structure, is applied to the object identifier.

nInBufferSize

[in] Size, in bytes, of the input buffer, FILE_OBJECTID_BUFFER.

lpOutBuffer

[out] Pointer to the output buffer. Not used; must be NULL.

nOutBufferSize

[in] Size, in bytes, of the output buffer. Not used; must be zero.

lpBytesReturned

[out] Pointer to a variable that receives the actual count of bytes returned by the function in the output buffer. The lpBytesReturned value is meaningless because there is no output buffer. With an asynchronous call, the programmer must provide a non-NULL pointer to a valid value.

If lpOverlapped is NULL (nonoverlapped I/O), lpBytesReturned is used internally and cannot be NULL.

If lpOverlapped is not NULL (overlapped I/O), lpBytesReturned can be NULL.

lpOverlapped

[in] Pointer to an OVERLAPPED structure.

If hDevice was opened with the FILE_FLAG_OVERLAPPED flag, lpOverlapped must point to a valid OVERLAPPED structure. In this case, DeviceIoControl is performed as an overlapped (asynchronous) operation. If the device was opened with the FILE_FLAG_OVERLAPPED flag and lpOverlapped is NULL, the function fails in unpredictable ways.

If hDevice was opened without specifying the FILE_FLAG_OVERLAPPED flag, lpOverlapped is ignored and DeviceIoControl does not return until the operation has been completed, or until an error occurs.

Return Values

If the operation succeeds, DeviceIoControl returns a nonzero value.

If the operation fails, DeviceIoControl returns zero. To get extended error information, call GetLastError.

Remarks

Object identifiers are Windows 2000 internal objects used by the operating system to track other objects such as files and directories. They are invisible to most applications and should never be modified by applications. Modifying an object identifier can result in the loss of data from portions of a file, up to and including entire volumes of data. Also, there is no guarantee that code to manipulate object identifiers will be forward compatible with future versions of Windows. Therefore, use standard Win32 functions to manipulate object identifiers and other operating system objects.

This operation sets the user data only in the object identifier. The ObjectId member of the FILE_OBJECTID_BUFFER structure is ignored. There is no mechanism for modifying the ObjectId member. The user should not attempt to modify user data, as it is created and used internally by Windows 2000 system services.

To set the object identifier on an object that does not already have one, use the FSCTL_SET_OBJECT_ID operation. To have NTFS generate an object identifier if one does not exist, use the FSCTL_CREATE_OR_GET_OBJECT_ID operation.

The typical use of the FSCTL_SET_OBJECT_ID_EXTENDED operation is where the application program does not use the user data generated by NTFS when the FSCTL_CREATE_OR_GET_OBJECT_ID operation is used. The FSCTL_SET_OBJECT_ID_EXTENDED operation would be used to install user-provided data in place of the data generated by NTFS.

Requirements

  Windows NT/2000: Requires Windows 2000.
  Windows 95/98: Unsupported.
  Header: Declared in Winioctl.h.

See Also

Device Input and Output Overview, Device Input and Output Control Codes, DeviceIoControl, CreateFile, FILE_OBJECTID_BUFFER, FSCTL_CREATE_OR_GET_OBJECT_ID, FSCTL_GET_OBJECT_ID, FSCTL_SET_OBJECT_ID, FSCTL_SET_OBJECT_ID_EXTENDED