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[netCDF #DMD-262410]: 4.3.3.1 -- Cannot read int variable into longlong data type.

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  • Subject: [netCDF #DMD-262410]: 4.3.3.1 -- Cannot read int variable into longlong data type.
  • Date: Mon, 06 Jul 2015 12:36:34 -0600
Hello,

Thank you for providing the information below; I had read your pull request 
(https://github.com/Unidata/netcdf-c/pull/120) while I was out of the office 
last week, and was trying to figure out the context where this check would 
cause problems.  This answers that question splendidly.

I will need to check for potential unintended effects of the pull request which 
applies the fix you describe below, but I should be able to do that in the next 
day or two.  

Thanks again for the detailed information!

-Ward


> In netcdf-4.3.2 and netcdf-4.3.1, we use the capability of calling
> nc_get_var_longlong to read an int dataset variable into a longlong
> client datatype.  This works in serial and in parallel.
> 
> I recently tested upgrading to netcdf-4.3.3.1 and am encountering errors
> when doing this.  The basic issue seems to be that the dispatcher in the
> 4.3.2 is NC_DISPATCH_NC3; however, in 4.3.3.1, the dispatcher is forced
> to be NC_DISPATCH_NC5 when run in parallel.  This is done at line 177
> of dfile.c.
> 
> The problem with this is that when I call nc_get_var_longlong, I get an
> NC_EINVAL return from line 569 in nc5dispatch.c.
> 
> If I remove that memtype check, then the code falls through to the switch
> statements and seems to correctly handle the NC_INT64 memory type at
> either line 598 or line 619 in the same file.
> 
> It looks like there is either a problem with forcing the dispatcher to be
> NC_DISPATCH_NC5 or the "memtype == NC_INT64" check needs to be removed.
> Note that the NC5_get_att and NC5_put_att functions do not have that
> check, but the NC5_get_vara and NC5_put_vara functions do.
> 
> Thanks,
> ..Greg
> 
> 

Ticket Details
===================
Ticket ID: DMD-262410
Department: Support netCDF
Priority: Normal
Status: Closed