! (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 get values using keys.
!
program grib_read_message
   use eccodes
   implicit none
   integer                      ::  ifile, ofile
   integer                      ::  iret, igrib
   integer, dimension(50000)   :: buffer
   integer(kind=kindOfSize_t)   :: len1
   integer                      :: step, level

   call codes_open_file(ifile, '../../data/index.grib', 'r')
   call codes_open_file(ofile, 'out.readmsg.grib', 'w')

   ! a GRIB message is read from file into buffer
   len1 = size(buffer)*4
   call codes_read_from_file(ifile, buffer, len1, iret)

   do while (iret /= CODES_END_OF_FILE)

      ! a new GRIB message is created from buffer
      call codes_new_from_message(igrib, buffer)

      ! get as a integer
      call codes_get(igrib, 'step', step)
      write (*, *) 'step=', step

      call codes_get(igrib, 'level', level)
      write (*, *) 'level=', level

      call codes_release(igrib)

      call codes_write_bytes(ofile, buffer, len1)

      ! a message is read from file into buffer
      len1 = size(buffer)*4
      call codes_read_from_file(ifile, buffer, len1, iret)

   end do

   call codes_close_file(ifile)
   call codes_close_file(ofile)

end program grib_read_message