Your subscript 2 applies to NTFS. The only characters NTFS does not allow are NUL and "/". Beyond that, it is up to the API you're choosing to use to read the

Your subscript 2 applies to NTFS. The only characters NTFS does not allow are NUL and "/". Beyond that, it is up to the API you're choosing to use to read the volume. Win32 has of course many more restrictions than POSIX would, but since Windows NT supports multiple personalities, you could still RW illegal Win32 characters under NT, e.g. with SFU.