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ZwSetInformationFile routine

The ZwSetInformationFile routine changes various kinds of information about a file object.


NTSTATUS ZwSetInformationFile(
  _In_  HANDLE                 FileHandle,
  _Out_ PIO_STATUS_BLOCK       IoStatusBlock,
  _In_  PVOID                  FileInformation,
  _In_  ULONG                  Length,
  _In_  FILE_INFORMATION_CLASS FileInformationClass


FileHandle [in]

Handle to the file object. This handle is created by a successful call to ZwCreateFile or ZwOpenFile.

IoStatusBlock [out]

Pointer to an IO_STATUS_BLOCK structure that receives the final completion status and information about the requested operation. The Information member receives the number of bytes set on the file.

FileInformation [in]

Pointer to a buffer that contains the information to set for the file. The particular structure in this buffer is determined by the FileInformationClass parameter. Setting any member of the structure to zero tells ZwSetInformationFile to leave the current information about the file for that member unchanged.

Length [in]

The size, in bytes, of the FileInformation buffer.

FileInformationClass [in]

The type of information, supplied in the buffer pointed to by FileInformation, to set for the file. Device and intermediate drivers can specify any of the following FILE_INFORMATION_CLASS values.

FileInformationClass ValueMeaning


Change the information that is supplied in a FILE_BASIC_INFORMATION structure. The caller must have opened the file with the FILE_WRITE_ATTRIBUTES flag set in the DesiredAccess parameter.


Usually, sets the DeleteFile member of a FILE_DISPOSITION_INFORMATION to TRUE, so the file can be deleted when ZwClose is called to release the last open handle to the file object. The caller must have opened the file with the DELETE flag set in the DesiredAccess parameter.


Change the current end-of-file information, supplied in a FILE_END_OF_FILE_INFORMATION structure. The operation can either truncate or extend the file. The caller must have opened the file with the FILE_WRITE_DATA flag set in the DesiredAccess parameter.


Change the current default IRP priority hint for the file handle. The new value is supplied in a FILE_IO_PRIORITY_HINT_INFORMATION structure.

Note   This structure must be 8-byte aligned.


Create a hard link to an existing file, which is specified in a FILE_LINK_INFORMATION structure. Not all file systems support hard links; for example NTFS does while FAT does not.


Change the current file information, which is stored in a FILE_POSITION_INFORMATION structure.


Change the current file name, which is supplied in a FILE_RENAME_INFORMATION structure. The caller must have DELETE access to the file.


Change the current short file name, which is supplied in a FILE_NAME_INFORMATION structure. The file must be on an NTFS volume, and the caller must have opened the file with the DesiredAccess DELETE flag set in the DesiredAccess parameter.


Change the current valid data length for the file, which is supplied in a FILE_VALID_DATA_LENGTH_INFORMATION structure. The file must be on an NTFS volume, and the caller must have opened the file with the FILE_WRITE_DATA flag set in the DesiredAccess parameter. Non-administrators and remote users must have the SeManageVolumePrivilege privilege.


Change or remove the I/O completion port for the specified file handle. The caller supplies a pointer to a FILE_COMPLETION_INFORMATION structure that specifies a port handle and a completion key. If the port handle is non-NULL, this handle specifies a new I/O completion port to associate with the file handle. To remove the I/O completion port associated with the file handle, set the port handle in the structure to NULL. To get a port handle, a user-mode caller can call the CreateIoCompletionPort function.


Return value

ZwSetInformationFile returns STATUS_SUCCESS or an appropriate error status.


ZwSetInformationFile changes information about a file. It ignores any member of a FILE_XXX_INFORMATION structure that is not supported by a particular device or file system.

If you set FileInformationClass to FileDispositionInformation, you can subsequently pass FileHandle to ZwClose but not to any other ZwXxxFile routine. Because FileDispositionInformation causes the file to be marked for deletion, it is a programming error to attempt any subsequent operation on the handle other than closing it.

If you set FileInformationClass to FilePositionInformation, and the preceding call to ZwCreateFile included the FILE_NO_INTERMEDIATE_BUFFERING flag in the CreateOptions parameter, certain restrictions on the CurrentByteOffset member of the FILE_POSITION_INFORMATION structure are enforced. For more information, see ZwCreateFile.

If you set FileInformationClass to FileEndOfFileInformation, and the EndOfFile member of FILE_END_OF_FILE_INFORMATION specifies an offset beyond the current end-of-file mark, ZwSetInformationFile extends the file and pads the extension with zeros.

For more information about working with files, see Using Files in a Driver.

Callers of ZwSetInformationFile must be running at IRQL = PASSIVE_LEVEL and with special kernel APCs enabled.

Note  If the call to this function occurs in user mode, you should use the name "NtSetInformationFile" instead of "ZwSetInformationFile".


Target platform



Available starting with Windows 2000.


Wdm.h (include Wdm.h, Ntddk.h, or Ntifs.h)






PASSIVE_LEVEL (see Remarks section)

DDI compliance rules

PowerIrpDDis, HwStorPortProhibitedDDIs

See also




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