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[netCDF #UAZ-383203]: number of variables possible

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  • Subject: [netCDF #UAZ-383203]: number of variables possible
  • Date: Tue, 23 Nov 2010 08:54:02 -0700
Hi Uli,

> I'm pretty new, using the netcdf format. I also work under IDL and use
> their implemented tools.
> 
> I was wondering if there is per netcdf definition a limit in the number
> of variables which can be defined within one file? The IDL version I use
> stops at 1024. Is this rather a IDL specific, or defined by the format?

In netCDF version 3.4 (1998), that was the limit, defined in the C 
include file netcdf.h as the value of the macro NC_MAX_VARS.  It was 
increased to 2000 in version 3.5.0 (2001), and to 8192 in version 3.6.1
(2005) and it has remained 8192 in all subsequent versions for netCDF
"classic" and 64-bit offset format files.  I would expect that a more
recent version of IDL would use the higher limits, but we don't have 
IDL installed here, so can't test that.

The limit was originally set to make Fortran development simpler, as
dynamic memory allocation was not possible in earlier Fortran standards.
In C and more recent versions of Fortran, this is not a problem, so we
are considering eliminating the upper limit in a future vesion of netCDF.

--Russ





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



Ticket Details
===================
Ticket ID: UAZ-383203
Department: Support netCDF
Priority: Normal
Status: Closed