eccodes/examples/C/multi.c

/*
 * Copyright 2005-2014 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: multi  
 *
 * Description: How to decode grib messages containing multiple
 *              fields. Try to turn on and off multi support to
 *              see the difference. Default is OFF.
 *  			For all the tools defalut is multi support ON.
 *
 *
 */
#include <stdio.h>
#include <stdlib.h>

#include "grib_api.h"

int main(int argc, char** argv) {
	int err = 0;
	long parameterCategory=0,parameterNumber=0,discipline=0;
	FILE* in = NULL;
	char* filename = "../../data/multi.grib2";
	grib_handle *h = NULL;

	/* turn on support for multi fields messages */
	grib_multi_support_on(0);

	/* turn off support for multi fields messages */
	/* grib_multi_support_off(0); */

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

	while ((h = grib_handle_new_from_file(0,in,&err)) != NULL ) {

		GRIB_CHECK(err,0);

		GRIB_CHECK(grib_get_long(h,"discipline",&discipline),0);
		printf("discipline=%ld\n",discipline);

		GRIB_CHECK(grib_get_long(h,"parameterCategory",&parameterCategory),0);
		printf("parameterCategory=%ld\n",parameterCategory);

		GRIB_CHECK(grib_get_long(h,"parameterNumber",&parameterNumber),0);
		printf("parameterNumber=%ld\n",parameterNumber);

		if ( discipline == 0 && parameterCategory==2) {
			if (parameterNumber == 2) printf("-------- u -------\n");
			if (parameterNumber == 3) printf("-------- v -------\n");
		}
		grib_handle_delete(h);
	}

	fclose(in);
	return 0;
}