A hard link is the file system representation of a
file by which more than one path references a single file in the same volume. To
create a hard link, use the CreateHardLink function. Many changes to that file
are instantly visible to applications that access it through the hard links that
reference it. However, the directory entry size and attribute information is
updated only for the link through which the change was made.
For example, in a system where C: and D: are local drives and Z: is a network drive mapped to \\fred\share, the
following reference is permitted as a hard link:
C:\dira\ethel.txt linked
to C:\dirb\dirc\lucy.txt
The following are not:
C:\dira linked to c:\dirbC:\dira\ethel.txt linked
to D:\dirb\lucy.txt
By creating
hard links you can:
- Use the same file name as the original file but appear in different folders.
- Use different file names from the original file but appear in the same folder.
- Use different file names from the original file and appear in different folders.
Because a hard link is a directory entry for a file, an application can modify a
file by using any of its hard links. Applications that use any other hard link
can detect the changes. However, directory entries for hard links are updated
only when a user accesses a file by using the hard link. For example, if a user
opens and modifies a file by using its hard link, and the size of the original
file changes, the hard link that is used to access the file also shows the new
size.
Hard links do not have security descriptors; instead, the security descriptor
belongs to the original file to which the hard link points. Thus, if you change
the security descriptor of any hard link, you actually change the underlying
file security descriptor. All hard links that point to the file allow the newly
specified access. You cannot give a file different security descriptors on a
per-hard-link basis.