Phil, > On Tue, 27 Dec 2011, Unidata netCDF Support wrote: > > > The C++ library version in 4.1.3, from the cxx directory, was intended for > > netCDF classic format files. Are you actually using the experimental cxx4 > > library from the cxx4 directory? > > The library was built (not by me!) using the --enable-netcdf-4 flag to > configure. The installation note toward the bottom of > > http://www.unidata.ucar.edu/software/netcdf/docs/cxx4/ > > is a bit cryptic, as the text says it is necessary to use the > --enable-netcdf-4 flag in configuring but the following example uses > --enable-cxx-4. Are these equivalent? No, --enable-netcdf-4 builds libraries that understand additional formats and have additional functions in the C or Fortran API, enabled by using the HDF5 library as a storage layer to support an enhanced data model. You may find this FAQ answer clarifies the relationships among the data formats, models, and APIs: http://www.unidata.ucar.edu/netcdf/docs/faq.html#formats-and-versions The --enable-cxx-4 flag requires the enable-netcdf-4 flag, but specifies that a new version of the old C++ API should be built and tested. This new version supports most of the the netCDF-4 enhanced data model and formats. It is not designed to be backward compatible with the C++ interface, which was designed before exceptions and templates were even in the C++ standard. > > So I assume "ncdump -k power_test1.nc" outputs "netCDF-4" for the file > > format. > > That's correct. > > > The "1L" type for the bolos:matrix attribute indicates an attribute of > > type int64 rather than int. NetCDF-4 files can use 6 primitive types that > > are not in the netCDF classic data model, including NC_INT64 which has the > > value 10. > > That's what I assumed it should be from ncdump (I didn't modify the > netcdf.cpp file, either; this problem just got kind of dumped in my lap). > I tried replacing it with as_double() - should that have worked? I don't know, as I'm not familiar with the new cxx4 API yet. > > From your use of the as_int() method, it looks like you're trying to use the > > old C++ code for classic format files on a new netCDF-4 format file which is > > making use of extended types in the netCDF-4 data model. I'm surprised that > > the old cxx API can even open a netCDF-4 file; it should just return an > > unrecognized file type of error when that is attempted. > > > The C++ API we have for netCDF-4 files is in the cxx4 directory and is only > > built if you use the --enable-cxx-4 flag to configure. There's a > > stand-alone > > version of the netCDF-4 C++ libraries, separated out from the C software, as > > announced here: > > > > > > http://www.unidata.ucar.edu/mailing_lists/archives/netcdfgroup/2011/msg00365.html > > > > and documented here: > > > > http://www.unidata.ucar.edu/software/netcdf/docs/cxx4/ > > What's the difference (if any) between the --enable-cxx-4 and > --enable-netcdf-4 flags? I hope that's clear from the explanation above. --Russ > > Ticket Details > > =================== > > Ticket ID: GPR-287619 > > Department: Support netCDF > > Priority: Normal > > Status: Closed > > > > Russ Rew UCAR Unidata Program address@hidden http://www.unidata.ucar.edu Ticket Details =================== Ticket ID: GPR-287619 Department: Support netCDF Priority: Normal Status: Closed
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