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[netCDF #BIE-294861]: [netcdfgroup] as_double weaknesses

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  • Subject: [netCDF #BIE-294861]: [netcdfgroup] as_double weaknesses
  • Date: Wed, 10 Nov 2010 16:41:29 -0700
Hi Sjur,

Does the problem you reported a long(!) time ago with as_double() still
occur, and if so do you have a little example program that demonstrates
the bug?  I think the lack of an example of the bug is why it's still
open.

--Russ

> > I've come across two apparent properties of the as_double() function in the 
> > NetCDF C++ interface:
> > 1: as_double() does not check for data_mode, and creashes if the file is in 
> > definition mode
> > 2: as_double() does not check for dimension limits, returning whatever is 
> > in the calculated memory location.
> >
> > Are these checks left out intentionally to save time, or would it be 
> > advantageous to have them? Considering that the function allocates and 
> > deallocates memory on the fly, the extra time to perform these checks 
> > should not be dramatic.
> >
> > NetCDF 4 on Windows, precompiled C interface dll.
> 
> Thanks for reporting this problem.  I assume you are reporting
> the problem with the old netCDF-3 C++ interface in the cxx/ source
> directory rather than the experimental (and incomplete) netCDF-4
> interface in the cxx4/ source directtroy, but the problems may be in
> both.  A user is currently working on completing the cxx4/ interface
> and upgrading it to make use of more modern C++ idioms, exceptions,
> templates, and name spaces.
> 
> The C++ interface was designed so that
> 
> * No explicit nc_redef or nc_endef calls are needed for switching between
> define and data modes. Whenever a mode switch is required, it happens
> implicitly.
> 
> so if that's not working when as_double() is invoked, it's a bug.  Also
> as_double(n) should return a fill value when n is out of range, so that
> also looks like a bug.  We'll try to get them fixed before the next release.
> 
> Thanks for reporting the problems!
> 
> --Russ
> 
> 
> Russ Rew                                         UCAR Unidata Program
> address@hidden                     http://www.unidata.ucar.edu
> 
> 

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



Ticket Details
===================
Ticket ID: BIE-294861
Department: Support netCDF
Priority: Critical
Status: Closed