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Peter, I've heard of using double precision instead of floats in Fortran applications for numerical stability, but not 8-byte integers. Lots of people run models at NCAR specifying -r8 -i4 and call netCDF Fortran functions with 8-byte reals that correspond to doubles in the netCDF interface compiled with -r4 -i4, and that works. The netCDF-3 interface only has primitive integer types for integers of one, two, or four bytes. It uses an XDR representation for four-byte integers on disk to store signed integers between -2**32 and 2**32-1. If eight-byte integers are really required in the netCDF-3 file, they will have to be represented in some other way than using the primitive types netCDF-3 supports. The netCDF-4 interface supports eight-byte integers (C type "long long"), but the netCDF-4 software is still only in beta release. I also could not find a way to tell the Intel C or C++ compiler that the "int" type is supposed to be eight bytes, but I think that would be required if you want to use -i8 to compile the netCDF-3 Fortran interface that calls the netCDF-3 C interface. If you could compile the C library to use eight-byte ints, you would still have to make sure only four-bytes worth of the ints were used for data, since otherwise the data values would be truncated. NetCDF has been ported to Cray and NEC platforms with eight-byte integers, but the C and Fortran compilers support eight-byte integers natively on those platforms. Sorry I can't be of more help, but I don't know how to build a ifort netCDF-3 interface using the -i8 flag ... --Russ Russ Rew UCAR Unidata Program address@hidden http://www.unidata.ucar.edu Ticket Details =================== Ticket ID: ZTO-391659 Department: Support netCDF Priority: Normal Status: Closed