Dfyjkt

I want to get short file path from a given Windows path.
For this reason I use the following JAVA code (with JNA library):

 char result = new char[65535];
 Kernel32.INSTANCE.GetShortPathName(file.toString(), result, result.length);
 System.out.println(Native.toString(result));

The above code works fine. However, in some cases the returned value is empty string. For example, using the following existing path on Windows yeilds an empty value:

C:UserssomeuserDownloadsGfl4AHIHf6SVMPMT9hjitNZOSXVofG1A9VJrv66YerqDfW8TW73O3VUb1wYYnOOB2l9CvSmTjfPLUvIwwvkddiL3sj7XNB1gqGGrUnmotsG4V3WR50SV1JAkXe2M0MpR4VDoYAUt5WgLpdLqoIdRlH4bd7OcZ3j0GOs90FGuZpZpjhEZBobNz1CwK50jJWYCwAHNmaYOYrC3JnOl6xtX4phNJmGfl4AHIHf6SVMPMT9hjitNZOSXVofG1A9VJrv66YerqDfW8TW73O3VUb1wYYnOOB2l9CvSmTjfPLUvIwwvkddiL3sj7XNB1gqGGrUnmotsG4V3WR50SV1JAkXe2M0MpR4VDoYAUt5WgLpdLqoIdRlH4bd7OcZ3j0GOs90FGuZpZpjhEZBobNz1CwK50jJWYCwAHNmaYOYrC3JnOl6xtX4phNJmdsMlll

The returned value of Kernel32.INSTANCE.GetShortPathName is 0, which according to javadoc is

If the function fails for any other reason, the return value is zero. To get extended error information, call GetLastError.

Calling GetLastError returns 3.

Now, using the following command:

dir /x

I'm able to see that the file actually has an alredy generated short name (GFL4AH~1).

What I've missed?

I found the solution:

 int returnCode = Kernel32.INSTANCE.GetShortPathName("\\?\" + file.toString(), result, result.length);

From MS docs:

To specify an extended-length path, use the "?" prefix. For example, "?D:very long path".