about hdf/libnc-dap private netcdf.h

[Patrice Dumas]

> I believe there is backward compatibility: HDF4 uses the oldest netcdf.h.  NC
> can be almost anything. If it's above 2.0 it's probably OK. (Hoop?)

After I looked at the code it seems that gradsnc uses the netcdf 3 interface,
like gradsdods, and gradshdf uses the netcdf 2 interface.

> I don't know much about DODS except that it is using a newer version than HDF4.
>  HDF4's netcdf.h doesn't provide C++ support so trying to compile DODS with
> HDF's netcdf.h will most likely fail.  All this is just "educated guessing" and

My understanding of the DODS part is that nc-dods (or nc-dap) doesn't
specifically provide a C++ interface for netcdf. Still libnc-dap/libc-dods
must be linked against the C++ library libdap (so must be linked with a C++
compiler or with -lstdc++).

> For the autoconf macros this means, you either make sure you use the header
> file that comes the package or require a minimum version number for each of the
> HDF, NC and DODS components. Something like version 2.3 for HDF and NC and 3.5
> for DODS might work. I hope this helps.

Ok. As the netcdf 2 api is still present in the netcdf 3 api, the only
trouble is that gradsdods (and maybe gradsnc) cannot use the hdf netcdf.h.

Now I have to translate that into autoconf macros...

Thanks.

--
Pat