! (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 create a multi-field message in memory and write
!               it to a file. The multi-field messages can be created
!               only in GRIB edition 2.
!
!
!
program grib2_multi_write
   use eccodes
   implicit none
   integer                            :: infile, outfile
   integer                            :: in_gribid
   integer                            :: multi_gribid
   integer                            :: step, startsection

   ! Multi-field messages can be created only in edition 2
   call codes_open_file(infile, '../../data/sample.grib2', 'r')

   call codes_open_file(outfile, 'multi_created.grib2', 'w')

   ! A GRIB message is loaded from file
   ! in_gribid is the GRIB id to be used in subsequent calls
   call codes_grib_new_from_file(infile, in_gribid)

   startsection = 4
   do step = 0, 240, 12
      call codes_set(in_gribid, "step", step)
      call codes_grib_multi_append(in_gribid, startsection, multi_gribid)
   end do

   ! Write messages to a file
   call codes_grib_multi_write(multi_gribid, outfile)

   call codes_release(in_gribid)
   call codes_release(multi_gribid)

   call codes_close_file(infile)
   call codes_close_file(outfile)

end program grib2_multi_write