Re: Datatype Conversion Overflow Document (fwd)

• To: netcdf-hdf@xxxxxxxxxxxxxxxx
• Subject: Re: Datatype Conversion Overflow Document (fwd)
• From: Russ Rew <russ@xxxxxxxxxxxxxxxx>
• Date: Mon, 26 Apr 2004 09:28:20 -0600

Quincey Koziol <koziol@xxxxxxxxxxxxx> wrote:

>     We've thought about the changes to the overflow document and are leaning
> toward taking out the "fill value" parameter from the callback, since it can
> be easily set up by an application (or the netCDF library) as part of the
> "user_data" information for the callback.  With this revision, the overflow
> callback is more general purpose and less tailored to just the netCDF needs.
> Let me know what you think.

This seems fine to me.

The main use for data conversion, as far as netCDF is concerned, is in
requesting numeric data as double or float, without needing to know or
care what numeric type is actually used for storing the data.  For
example, a visualization application may present an interface that
lets users choose several datasets to visualize together, and it makes
the application writer's job easier to just get all the values as
doubles.

So although we have to handle the details of what happens in weird
cases such as when doubles are requested as ints and an overflow, loss
of precision, or truncation occurs, in practice this is rarely a
concern.

--Russ