[Nexus] NXroot attribute

[Osborn, Raymond]

I have created an issue on the NeXus Github to fix this (https://github.com/nexusformat/definitions/issues/466). The answer to your question is that you should set ‘HDF5_Version' to the version number of the HDF5 library you use. The ‘HDF_version’ refers to the HDF v4 version (before HDF was rebranded as HDF5), and ‘NeXus_version’ refers to the version of the NeXus API, which presumably you don’t use.

The inconsistency in capitalization is regrettable. The NIAC will have to decide whether it’s worth harmonizing them, but both HDF4 and the NeXus API are gradually falling into disuse, so it’s a problem that will wither away if we do nothing about it. We should also probably add ‘h5py_version’ and possibly ‘nexusformat_version’ (for the Python API), so perhaps versioning is getting a bit too complicated.

Ray

> On Apr 23, 2016, at 5:52 PM, V. Armando Sole <sole at esrf.fr> wrote:
> 
> Hello,
> 
> In the web page concerning NXroot:
> 
> http://download.nexusformat.org/doc/html/classes/base_classes/NXroot.html
> 
> I guess one of the attributes is supposed to contain the HDF version.
> 
> However, I see
> 
> @NeXus_version: NX_CHAR
> 
>    Version of NeXus API used in writing the file
> 
> @HDF_version: NX_CHAR
> 
>    Version of NeXus API used in writing the file
> 
> @HDF5_Version: NX_CHAR
> 
>    Version of NeXus API used in writing the file. Note this attribute is spelled with uppercase “V”, different than other version attributes.
> 
> I guess cut and paste went too far :-)
> 
> Please, what attribute should contain the HDF version?
> 
> Best regards,
> 
> Armando
> 
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-- 
Ray Osborn, Senior Scientist
Materials Science Division
Argonne National Laboratory
Argonne, IL 60439, USA
Phone: +1 (630) 252-9011
Email: ROsborn at anl.gov