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[netCDF #PEN-204681]: Problem reading NetCDF 4 classic files b/w NetCDF 4.0.1 and 4.1.1?

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  • Subject: [netCDF #PEN-204681]: Problem reading NetCDF 4 classic files b/w NetCDF 4.0.1 and 4.1.1?
  • Date: Thu, 13 May 2010 12:42:25 -0600
Hi Mary,

Sorry it has taken so long to respond to your question ...

> A user gave me a NetCDF 4 classic file that he created using NetCDF 
> 4.1.1/HDF5 1.8.4-patch1 on a little endian machine.
> 
> He tried to open it with a version of NCL that had been linked against NetCDF 
> 4.0.1 and HDF5 1.8.2, and got the following error:
> 
> fatal:Can't open HDF5 attribute
> 
> I saw this same problem using "ncdump" from NetCDF 4.0.1/HDF 1.8.2:
> 
> % ncdump slp.nc4Classic.1979.nc
> ncdump: slp.nc4Classic.1979.nc: Can't open HDF5 attribute
> 
> 
> If I use ncdump or ncl that was compiled against NetCDF 4.1.1 and 
> HDF5-1.8.4-patch1, it works fine.
> 
> Is this related to the fix that went into HDF5 1.8.4-patch1? There are more 
> than 10 attributes attached to one
> of the variables, but I thought the bug only applied to files that were 
> written on a big endian machine.

I'm assuming the errors occurred on a big-endian machine.  You're right that 
the original
report on the bug at

  http://www.hdfgroup.org/HDF5/release/known_problems/index.html

says it only occurs for files written on big-endian platforms and read on 
little-endian
platforms.  I thought we had tested that things work OK in the other direction.

But I just succeeded in duplicating the problem you report, creating a simple 
file with
a variable having 10 attributes on a big-endian platform using 4.1.1 and 
running a
4.0.1 version of ncdump built on a little-endian platform on that simple file, 
resulting
in a segmentation violation in an HDF5 function called from nc_open().  We will 
investigate
further.  Thanks for reporting the problem!

--Russ



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



Ticket Details
===================
Ticket ID: PEN-204681
Department: Support netCDF
Priority: Urgent
Status: Closed