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Editorial Team
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Asked: 2026-05-19T05:49:51+00:00

(This question is a toughie… it might require knowledge of NTFS and/or the use

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(This question is a toughie… it might require knowledge of NTFS and/or the use of NT Native APIs; be warned.) 🙂

If I’m given two HANDLEs to two files, how can I definitively (not just with high probability) find out if the two HANDLEs belong to the exact same file and stream on the disk?

This means, for example, checking the 8-byte NTFS file IDs isn’t enough, because two HANDLEs with the same file ID can be pointing to different data streams of the same file, and I need to find out if the two streams are really the same and only differ by the name (hardlink).

(What’s the use? This way, if I want to perform an operation on all files inside a folder, I don’t do the operation twice on the same data stream with different names.)

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1 Answer

  1. Editorial Team

    This requires GetFileInformationByHandleEx(), asking for FileStreamInfo. That returns the stream name.

    This warning in the SDK docs should be noted:

    Certain file information classes
    behave slightly differently on
    different operating system releases.
    These classes are supported by the
    underlying drivers, and any
    information they return is subject to
    change between operating system
    releases.

    Avoid relying on recovering info that is (or should be) readily available in your program.

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