anchor.diff:              ncid=-1
               varid=-1
               ! Open the file. NF90_NOCLOBBER tells netCDF we want append to existing files
  +            !   nf90_64bit_offset tells netCDF that this may be a really LARGE file and it needs to support >2GB
               if (present(open_new_file)) then
                   if (open_new_file) then
  -                    call check( nf90_create(filename, NF90_CLOBBER, ncid), filename)
  +                    call check( nf90_create(filename, or(NF90_CLOBBER,nf90_64bit_offset), ncid), filename)
                   endif
               endif
               if (ncid==-1) then
  
positive.code:             endif
  
              ! End define mode. This tells netCDF we are done defining metadata.
              call check( nf90_enddef(ncid) )
              ! write the actual data to the file
              if (error == 0) then
                  call check( nf90_put_var(ncid, varid, data_out), trim(filename)//":"//trim(varname))
  
negative.code:             ! Open the file. NF90_NOCLOBBER tells netCDF we want append to existing files
              if (present(open_new_file)) then
                  if (open_new_file) then
                      call check( nf90_create(filename, or(NF90_CLOBBER,nf90_64bit_offset), ncid), filename)
                  endif
              endif
              if (ncid==-1) then
  