Hi Werner,

On May 21, 2010, at 2:26 PM, Werner Benger wrote:

> Hi,
> 
> I recently discovered the H5Literate() function of HDF5 1.8 being able to
> iterate over the entries of a group via indices specified on them:
> 
>       http://www.hdfgroup.org/HDF5/doc/RM/RM_H5L.html#Link-Iterate
> 
> but I could not find out yet how to specify such indices on the entries
> of a group? I would assume such an index might be a property of the
> group creation call H5Gcreate2(), but could not find information via
> the HDF5 reference manual how to specify indices there.
> 
> Where can I find information on indexed group entries? And, could such
> information be referenced from the respective functions in the reference
> documentation? That would be very helpful.

        All groups provide alpha-numeric indices, and if the 
H5Pset_link_creation_order() routine 
(http://www.hdfgroup.org/HDF5/doc/RM/RM_H5P.html#Property-SetLinkCreationOrder) 
is used, a group may also track and index the creation order of links within 
the group.  So, H5_INDEX_NAME can always be passed to H5Literate and 
H5_INDEX_CRT_ORDER could also be used on groups with links that have their 
creation order tracked.

        We discussed other types of indices or even some user-defined index 
order, but haven't had time/funding to implement anything in that direction yet.

> The H5Literate() only talks about indexed "links", but is it correct to
> assume that it would actually apply to any object within a group,
> i.e. datasets and groups, since they are formally links?

        Groups contain links, not objects.  So, iterating over those links will 
allow you to reach the object that the link references.

        Quincey


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