FILE_ID_64_EXTD_DIR_INFORMATION structure (ntifs.h)
The FILE_ID_64_EXTD_DIR_INFORMATION structure is used to query 64-bit file reference number information for the files in a directory.
Syntax
typedef struct _FILE_ID_64_EXTD_DIR_INFORMATION {
ULONG NextEntryOffset;
ULONG FileIndex;
LARGE_INTEGER CreationTime;
LARGE_INTEGER LastAccessTime;
LARGE_INTEGER LastWriteTime;
LARGE_INTEGER ChangeTime;
LARGE_INTEGER EndOfFile;
LARGE_INTEGER AllocationSize;
ULONG FileAttributes;
ULONG FileNameLength;
ULONG EaSize;
ULONG ReparsePointTag;
LARGE_INTEGER FileId;
WCHAR FileName[1];
} FILE_ID_64_EXTD_DIR_INFORMATION, *PFILE_ID_64_EXTD_DIR_INFORMATION;
Members
NextEntryOffset
Byte offset of the next FILE_ID_64_EXTD_DIR_INFORMATION entry, if multiple entries are present in a buffer. This member is zero if no other entries follow this one.
FileIndex
Byte offset of the file within the parent directory. This member is undefined for file systems, such as NTFS, in which the position of a file within the parent directory is not fixed and can be changed at any time to maintain sort order.
CreationTime
Time when the file was created.
LastAccessTime
Last time the file was accessed.
LastWriteTime
Last time information was written to the file.
ChangeTime
Last time the file was changed.
EndOfFile
Absolute new end-of-file position as a byte offset from the start of the file. EndOfFile specifies the byte offset to the end of the file. Because this value is zero-based, it actually refers to the first free byte in the file. In other words, EndOfFile is the offset to the byte immediately following the last valid byte in the file.
AllocationSize
File allocation size, in bytes. Usually, this value is a multiple of the sector or cluster size of the underlying physical device.
FileAttributes
File attributes, which can be any valid combination of the following:
- FILE_ATTRIBUTE_READONLY
- FILE_ATTRIBUTE_HIDDEN
- FILE_ATTRIBUTE_SYSTEM
- FILE_ATTRIBUTE_DIRECTORY
- FILE_ATTRIBUTE_ARCHIVE
- FILE_ATTRIBUTE_NORMAL
- FILE_ATTRIBUTE_TEMPORARY
- FILE_ATTRIBUTE_COMPRESSED
FileNameLength
Specifies the length of the file name string, in bytes.
EaSize
Combined length, in bytes, of the extended attributes (EA) for the file.
ReparsePointTag
Tag value for the reparse point.
FileId
The 64-bit file reference number for the file. This number is generated and assigned to the file by the file system.
FileName[1]
Specifies the first character of the file name string. This is followed in memory by the remainder of the string.
Remarks
This information can be queried in either of the following ways:
Call ZwQueryDirectoryFile, passing FileIdExtdDirectoryInformation as the value of FileInformationClass and passing a caller-allocated, FILE_ID_EXTD_DIR_INFORMATION-structured buffer as the value of FileInformation.
Create an IRP with major function code IRP_MJ_DIRECTORY_CONTROL and minor function code IRP_MN_QUERY_DIRECTORY.
No specific access rights are required to query this information.
File reference numbers, also called file IDs, are guaranteed to be unique only within a static file system. They aren't guaranteed to be unique over time because file systems are free to reuse them, nor are they guaranteed to remain constant. For example, the FAT file system generates the file reference number for a file from the byte offset of the file's directory entry record (DIRENT) on the disk. Defragmentation can change this byte offset. Thus a FAT file reference number can change over time.
All dates and times are in absolute system-time format. Absolute system time is the number of 100-nanosecond intervals since the start of the year 1601.
This structure must be aligned on a LONGLONG (8-byte) boundary. If a buffer contains two or more of these structures, the NextEntryOffset value in each entry, except the last, falls on an 8-byte boundary.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows 11, version 23H2 |
| Header | ntifs.h |