FSCTL_TXFS_READ_BACKUP_INFORMATION control code

[Microsoft strongly recommends developers utilize alternative means to achieve your application’s needs. Many scenarios that TxF was developed for can be achieved through simpler and more readily available techniques. Furthermore, TxF may not be available in future versions of Microsoft Windows. For more information, and alternatives to TxF, please see Alternatives to using Transactional NTFS.]

Returns Transactional NTFS (TxF) specific information for the specified file.

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


BOOL DeviceIoControl(
  (HANDLE) hDevice,              // handle to device
  FSCTL_TXFS_READ_BACKUP_INFORMATION, // dwIoControlCode
  NULL,                          // lpInBuffer
  0,                             // nInBufferSize
  (LPVOID) lpOutBuffer,          // output buffer
  (DWORD) nOutBufferSize,        // size of output buffer
  (LPDWORD) lpBytesReturned,     // number of bytes returned
  NULL    // OVERLAPPED structure
);

Parameters

hDevice

A handle to the file to retrieve metadata for.

dwIoControlCode

The control code for the operation. Use FSCTL_TXFS_READ_BACKUP_INFORMATION for this operation.

lpInBuffer

Not used with this operation; set to NULL.

nInBufferSize

Not used with this operation; set to 0 (zero).

lpOutBuffer

A pointer to the output buffer, a TXFS_READ_BACKUP_INFORMATION_OUT structure.

nOutBufferSize

The size of the output buffer, in bytes.

lpBytesReturned

A pointer to a variable that receives the size of the data stored in the output buffer, in bytes.

If lpOverlapped is NULL, lpBytesReturned cannot be NULL. Even when an operation returns no output data and lpOutBuffer is NULL, DeviceIoControl makes use of lpBytesReturned. After such an operation, the value of lpBytesReturned is meaningless.

If lpOverlapped is not NULL, lpBytesReturned can be NULL. If this parameter is not NULL and the operation returns data, lpBytesReturned is meaningless until the overlapped operation has completed. To retrieve the number of bytes returned, call GetOverlappedResult. If hDevice is associated with an I/O completion port, you can retrieve the number of bytes returned by calling GetQueuedCompletionStatus.

lpOverlapped

A pointer to an OVERLAPPED structure.

If hDevice was opened without specifying FILE_FLAG_OVERLAPPED, lpOverlapped is ignored.

If hDevice was opened with the FILE_FLAG_OVERLAPPED flag, the operation is performed as an overlapped (asynchronous) operation. In this case, lpOverlapped must point to a valid OVERLAPPED structure that contains a handle to an event object. Otherwise, the function fails in unpredictable ways.

For overlapped operations, DeviceIoControl returns immediately, and the event object is signaled when the operation has been completed. Otherwise, the function does not return until the operation has been completed or an error occurs.

Return value

If the operation completes successfully, DeviceIoControl returns a nonzero value.

If the operation fails or is pending, DeviceIoControl returns 0 (zero). To get extended error information, call GetLastError.

Remarks

FSCTL_TXFS_READ_BACKUP_INFORMATION is a synchronous operation.

This control code can be used by backup functions and applications, such as Win32 BackupRead, and by Volume Shadow Copy Service (VSS) writers that support secondary resource managers. For more information, see Volume Shadow Copy Service.

ReFS:  This code is not supported.

Requirements

Minimum supported client

Windows Vista [desktop apps only]

Minimum supported server

Windows Server 2008 [desktop apps only]

Header

WinIoCtl.h (include Windows.h)

See also

DeviceIoControl
TXFS_READ_BACKUP_INFORMATION_OUT
Volume Shadow Copy Service

 

 

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