! (C) Copyright 2005- ECMWF.
!
! This software is licensed under the terms of the Apache Licence Version 2.0
! which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
!
! In applying this licence, ECMWF does not waive the privileges and immunities granted to it by
! virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction.
!
!
!  Description: How to set missing a key value.
!
!
!
program set_missing
   use eccodes
   implicit none
   integer              :: infile, outfile
   integer              :: igrib, Ni, is_missing

   infile = 5
   outfile = 6

   call codes_open_file(infile, &
                        '../../data/reduced_gaussian_pressure_level.grib2', 'r')

   call codes_open_file(outfile, &
                        'f_out_surface_level.grib2', 'w')

   !     a new grib message is loaded from file
   !     igrib is the grib id to be used in subsequent calls
   call codes_grib_new_from_file(infile, igrib)

   call codes_set(igrib, 'typeOfFirstFixedSurface', 'sfc')
   call codes_set_missing(igrib, 'scaleFactorOfFirstFixedSurface')
   call codes_set_missing(igrib, 'scaledValueOfFirstFixedSurface')

   ! see GRIB-490
   call codes_get(igrib, 'Ni', Ni)
   call codes_is_missing(igrib, 'Ni', is_missing)
   if (is_missing == 0) then
      ! Ni should be missing in gribs with Reduced Gaussian grids
      call codes_check(-2, 'Ni_should_be_missing', '')
   end if
   call codes_set(igrib, 'Ni', Ni)

   call codes_write(igrib, outfile)
   call codes_release(igrib)
   call codes_close_file(infile)
   call codes_close_file(outfile)

end program