No, I mean Windows API honors UTF-16 surrogate pairs, and processes them correctly. It doesn't produce invalid UTF-16 strings either. Apps may not support UTF-1

No, I mean Windows API honors UTF-16 surrogate pairs, and processes them correctly. It doesn't produce invalid UTF-16 strings either. Apps may not support UTF-16 properly, and that's not on Windows, is it? NTFS, on the other hand, has no dictated format for filename encoding. It just stores raw bytes as filenames, so anything can be a filename on NTFS, including invalid strings if the caller decides to do so. That's not on Windows either, otherwise, we should add Linux to the list too as ext4 and most other file systems also don't care about filename encoding.