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! (C) Copyright 2005-2016 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 in 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,iret
  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)

  enddo

!  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

#
# (C) Copyright 2005-2016 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.
#

import traceback
import sys

from eccodes import *

INPUT = '../../data/sample.grib2'
OUTPUT = 'out.mw.grib'
VERBOSE = 1  # verbose error reporting


def example():
    fin = open(INPUT, 'rb')
    fout = open(OUTPUT, 'wwb')

    gid = codes_grib_new_from_file(fin)

    mgid = codes_grib_multi_new()

    for step in range(12, 132, 12):
        codes_set(gid, "step", step)
        codes_grib_multi_append(gid, 4, mgid)

    codes_grib_multi_write(mgid, fout)

    codes_grib_multi_release(mgid)
    codes_release(gid)
    fin.close()
    fout.close()


def main():
    try:
        example()
    except CodesInternalError, as err:
        if VERBOSE:
            traceback.print_exc(file=sys.stderr)
        else:
            print >>syssys.stderr, .write(err.msg + '\n')

        return 1


if __name__ == "__main__":
    sys.exit(main())

/*
 * (C) Copyright 2005-2016 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.
 */

/*
 * C Implementation: grib_multi_write
 *
 * Description: How to encode GRIB2 messages containing multiple fields
 *
 */
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include "eccodes.h"

static void usage(const char* prog) {
    printf("usage: %s in.grib out.grib\n",prog);
    exit(1);
}

int main(int argc, char** argv)
{
    int err = 0;
    FILE* in = NULL;
    FILE* of = NULL;
    long edition, step;
    char* filename=NULL;
    char* ofilename=NULL;
    codes_handle *h = NULL;
    codes_multi_handle *mh=NULL;
    const int start_section = 4; /* Grib2 Product Definition Section */

    if (argc < 3) usage(argv[0]);
    filename=argv[1];
    ofilename=argv[2];

    /* open input file */
    in = fopen(filename,"r");
    if(!in) {
        fprintf(stderr, "ERROR: unable to open input file %s\n",filename);
        return 1;
    }

    /* new grib handle from input file */
    h = codes_handle_new_from_file(0, in, PRODUCT_GRIB, &err);
    CODES_CHECK(err,0);
    CODES_CHECK(codes_get_long(h,"edition",&edition),0);
    if (edition != 2) {
        fprintf(stderr, "ERROR: Input grib must be edition 2 for multi fields\n");
        exit(1);
    }

    /* create a new empty multi field handle */
    mh=codes_grib_multi_handle_new(0);
    if (!mh) {
        fprintf(stderr,"ERROR: Unable to create multi field handle\n");
        exit(1);
    }

    for (step=12;step<=120;step+=12) {
        /* set step */
        codes_set_long(h,"step",step);
        /* append h to mh repeating from section 4 */
        /* i.e. starting from section 4 all the sections to the end of the message will be copied */
        codes_grib_multi_handle_append(h, start_section, mh);
    }

    /* open output file */
    of=fopen(ofilename,"w");
    if(!of) {
        fprintf(stderr, "ERROR: unable to open output file %s\n",ofilename);
        exit(1);
    }

    /* write multi fields handle to output file */
    codes_grib_multi_handle_write(mh,of);
    fclose(of);

    /* release memory */
    codes_handle_delete(h);
    codes_grib_multi_handle_delete(mh);

    fclose(in);
    return 0;
}