Hi Eugen,
HDF5 will maintain the consistency of the objects opened via two
different threads internal to the library. Modifications that one thread makes
to the object may make "derived" information in the other thread inconsistent,
but the library's perspective will be fine.
Quincey
On Aug 18, 2012, at 7:27 AM, Wintersberger, Eugen wrote:
> Thanks for the fast reply. I do not UUIDs to survive anything. In fact
> they should only be unique as long as a file is open. I am working on a
> thin, thread-safe C++ wrapper around HDF5. Locking the individual
> objects and make their interfaces thread-safe is one thing. But there is
> another problem with HDF5: consider two concurrent threads opening the
> same object in the file. Though the types returned would be thread-safe,
> the fact that both threads act on the same object in the file would lead
> to inconsistencies. To circumvent this problem I plan to establish a
> central registry where all objects are retrieved from. Each object is
> opened only once and appended to the registry using a unique identifier
> as a key (that's why I need a unique identifier for each object).
> Clearly these UUIDs must be only unique during the lifetime of a file
> object. The code itself only works with references to the objects stored
> in the registry. Thus, at least I think so, locking the objects should
> make sense again and two threads can safely work on the same object.
>
> regards
> Eugen
>
>
>
> On Fri, 2012-08-17 at 08:41 -0500, Gerd Heber wrote:
>> Eugen, how are you? Yes, you can concoct something that is unique in the
>> file scope using addresses, but I'd be hesitant to go down that path.
>> I'd invest in a few UUIDs (call it whatever you want) attributes and not
>> look back. They survive repacks and other machinations.
>> True, for existing read-only files, you'd have to maintain a mapping on the
>> side.
>> Addresses are not your friends, if you know what I mean...
>>
>> Best, G.
>>
>> -----Original Message-----
>> From: [email protected] [mailto:[email protected]]
>> On Behalf Of Wintersberger, Eugen
>> Sent: Friday, August 17, 2012 8:28 AM
>> To: [email protected]
>> Subject: [Hdf-forum] Unique object identifier
>>
>> Hi folks
>> I need to get a unique ID for each object in an HDF5 file (as the path to
>> an object is not unique). As far as I know there is nothing like this in
>> HDF5 out of the box. However, I have seen that one can retrieve the address
>> of an object within the file. Can this address be used as a unique
>> identifier?
>>
>> regards
>> Eugen
>> --
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>
> _______________________________________________
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> [email protected]
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