eccodes/examples/C/grib_set_keys.c

91 lines
2.6 KiB
C

/*
* (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.
*/
/*
* C Implementation: grib_set_keys
*
* Description: how to set key values in GRIB messages
*
*/
#include <stdio.h>
#include <stdlib.h>
#include "eccodes.h"
int main(int argc, char** argv)
{
int err = 0;
long centre = 80;
long long_value = 0;
char string_value[100];
size_t len = sizeof(string_value) / sizeof(char);
size_t size = 0;
FILE* in = NULL;
const char* infile = "../../data/regular_latlon_surface.grib1";
FILE* out = NULL;
const char* outfile = "out.set.grib1";
codes_handle* h = NULL;
const void* buffer = NULL;
size_t str_len = 0; /* See the call to codes_set_string later */
in = fopen(infile, "rb");
if (!in) {
fprintf(stderr, "Error: unable to open file %s\n", infile);
return 1;
}
out = fopen(outfile, "wb");
if (!out) {
fprintf(stderr, "Error: unable to open file %s\n", outfile);
fclose(in);
return 1;
}
/* create a new handle from a message in a file */
h = codes_handle_new_from_file(0, in, PRODUCT_GRIB, &err);
if (h == NULL) {
fprintf(stderr, "Error: unable to create handle from file %s\n", infile);
fclose(out);
return 1;
}
/* set centre as a long */
CODES_CHECK(codes_set_long(h, "centre", centre), 0);
/* set paramId and shortName - normally you would do one or the other */
CODES_CHECK(codes_set_long(h, "paramId", 500004), 0);
/* the value of str_len is not used, it can be anything! */
CODES_CHECK(codes_set_string(h, "shortName", "fis", &str_len), 0);
/* get centre as a long */
CODES_CHECK(codes_get_long(h, "centre", &long_value), 0);
printf("centre long value=%ld\n", long_value);
/* get centre as a string */
CODES_CHECK(codes_get_string(h, "centre", string_value, &len), 0);
printf("centre string value=%s\n", string_value);
/* get the coded message in a buffer */
CODES_CHECK(codes_get_message(h, &buffer, &size), 0);
/* write the buffer in a file*/
if (fwrite(buffer, 1, size, out) != size) {
perror(outfile);
exit(1);
}
codes_handle_delete(h);
fclose(in);
fclose(out);
return 0;
}