about hdf/libnc-dap private netcdf.h

[Matthias Munnich]

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Hi Pat,

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?)
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
needs to be checked.

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.

Matt

PS: Thanks for working on this!

Patrice Dumas wrote:
> Hi,
>
> hdf and libnc-dap ship their own netcdf.h file because (if I'm not wrong)
> they reimplement the netcdf api (at least for libnc-dap). When the
> netcdf.h include file is taken from the system it could be possible that
> a netcdf.h file coming from another package is used. The most common case is
> certainly that the netcdf.h from netcdf itself is used instead of the
> netcdf.h coming from the hdf or libnc-dap package. Is it an issue? If it
> is the other way around (gradsnc uses a netcdf.h coming from hdf or
> libnc-dap) is it an issue? And lastly is it problematic if hdf or libnc-dap
> use the netcdf.h file from the other package?
> Or are the different api versions compatible enough?
>
> I ask this question because netcdf.h detection is currently badly handled
> by the configure macros I send to the list (namely if the netcdf netcdf.h
> include file isn't detected, the hdf or libnc-dap netcdf.h are not picked up).
> So I would like to do something better, but if there are compatibility issues
> the cppflags would have to be isolated, if there are no compatibility issue
> it is much simpler, if a netcdf.h file has been detected it can be used.
>
> --
> Pat
>
>

- --
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Matthias Munnich
UC Los Angeles, IGPP & Dep. of Atmos. and Ocean. Sc.
Ph: +1-310-794 5899; Fax: +1-310-206 3051
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