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[netCDF #MJR-379092]: more information about segmentation fault in ncdump when dumping HDF5 string

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  • Subject: [netCDF #MJR-379092]: more information about segmentation fault in ncdump when dumping HDF5 string
  • Date: Fri, 23 Mar 2012 11:31:38 -0600
Hi Kent,

Thanks for all your work on isolating the bug.

I think the problem may be that netCDF-4 has no such type 
as a "fixed length string", it only has the "string" type,
which is always variable length, and an "array of char"
type, which was in the netCDF-3 classic model, and for
which a dimension must be defined and named to identify
the langth of the char array.

When Ed added support for reading HDF5 files that were not 
netCDF-4 files, he may have not realized fixed-length chars
were a new type that the netCDF-4 data model does not support.
They either have to be converted to variable length strings
(perhaps with a hidden attribute indicating they are fixed
length) or as array of char, with a new dimension defined
that does not correspond to an associated HDF5 dataspace.

Or, we have to add support for a new type, which is a lot of
work.

The netCDF-4 data model supports fixed-size arrays as members
of structs, without having to define associated named dimensions.
But as far as I understand, it does not support fixed-size arrays
that have no associated, named dimensions.

I'll have to look at this a little more carefully to verify that 
the problem is in the netCDF-4 library layer rather than ncdump, 
but if so, the fix will have to be in the library.

--Russ

Russ Rew                                         UCAR Unidata Program
address@hidden                      http://www.unidata.ucar.edu



Ticket Details
===================
Ticket ID: MJR-379092
Department: Support netCDF
Priority: Normal
Status: Closed