text: /*
   * Copyright 2005-2018 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_keys_iterator
   *
   * Description:
   * Example on how to use keys_iterator functions and the
   * codes_keys_iterator structure to get all the available
   * keys in a GRIB message.
   *
   */
  
  #include <assert.h>
  #include <stdlib.h>
  #include <stdio.h>
  #include <unistd.h>
  #include <string.h>
  
  #include "eccodes.h"
  
  #define MAX_KEY_LEN  255
  #define MAX_VAL_LEN  1024
  
  static void usage(char* progname);
  
  int main(int argc, char *argv[])
  {
    /* To skip read only and not coded keys
       unsigned long key_iterator_filter_flags=CODES_KEYS_ITERATOR_SKIP_READ_ONLY ||
       CODES_KEYS_ITERATOR_SKIP_COMPUTED;
    */
      unsigned long key_iterator_filter_flags=CODES_KEYS_ITERATOR_ALL_KEYS;
  
    /* Choose a namespace. E.g. "ls", "time", "parameter", "geography", "statistics" */
    char* name_space="ls";
  
    /* name_space=NULL to get all the keys */
    /* char* name_space=0; */
  
    FILE* f = NULL;
    codes_handle* h=NULL;
    
    int err=0;
    int msg_count=0;
  
    char value[MAX_VAL_LEN];
    size_t vlen=MAX_VAL_LEN;
  
    if (argc != 2) usage(argv[0]);
  
    f = fopen(argv[1],"r");
    if(!f) {
      perror(argv[1]);
      exit(1);
    }
  
    while((h = grib_handle_new_from_file(0,f,&err)) != NULL)
    {
      codes_keys_iterator* kiter=NULL;
      msg_count++;
      /*printf("-- GRIB N. %d --\n",msg_count);*/
      if(!h) {
        printf("ERROR: Unable to create grib handle\n");
        exit(1);
      }
  
          kiter=codes_keys_iterator_new(h,key_iterator_filter_flags,name_space);
      if (!kiter) {
        printf("ERROR: Unable to create keys iterator\n");
        exit(1);
      }
  
      while(codes_keys_iterator_next(kiter))
      {
        const char* name = codes_keys_iterator_get_name(kiter);
        vlen=MAX_VAL_LEN;
        bzero(value,vlen);
        CODES_CHECK(codes_get_string(h,name,value,&vlen),name);
        printf("%s = %s\n",name,value);
      }
  
      codes_keys_iterator_delete(kiter);
      codes_handle_delete(h);
    }
    fclose(f);
    return 0;
  }
  
  static void usage(char* progname)
  {
    printf("\nUsage: %s grib_file\n",progname);
    exit(1);
  }
  