Cray T3E F90 interface

[Mark Hadfield]

Hello all

In case anyone is interested, I have got the netcdf-3.6.2 Fortran-90 
interface working on a Cray T3E (don't laugh!). The main obstacle to 
this was related to the usual T3E problem: the default REAL type has the 
same number of bytes (8) as the default DOUBLEPRECISION. However the 
netCDF Fortran 90 code defines two real kinds:

    FourByteReal = selected_real_kind(P=6, R=37)
    EightByteReal = selected_real_kind(P=13, R=307)

and then assumes that FourByteReal corresponds to REAL. This is an 
incorrect assumption, with the result that all the nf90_*_FourByteReal 
functions give SEGFAULTs. My solution was to strip out all references to 
these functions in the interface declarations in 
f90/netcdf_overloads.f90. The resulting library supports only 8-byte 
reals (as does the underlying Fortran 77 library).

The purpose of the current message is twofold:

    * To leave a record of this in the Googleverse, in the unlikely
      event that anyone else needs to use the netCDF Fortran-90
      interface on a Cray T3E.
    * To ask, is there any interest from the developers in incorporating
      my changes into the master code?

By the way, some time ago I explored the alternative approach of using 
the compiler's "-default32" switch, which makes the default REAL 4 bytes 
long. This turns out not to be a good idea, as it also affect the 
default integer size in a way that breaks a lot of other code.

-- 
Mark Hadfield          "Ka puwaha te tai nei, Hoea tahi tatou"
m.hadfield at niwa.co.nz
National Institute for Water and Atmospheric Research (NIWA)



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