#include <errno.h>
#include <stdio.h>

int compare_to_zero(FILE *fp){

  (void) ftell(fp);                /* 'Missing Test of Error Code' warning issued here
                                    * - errno is not checked between return from this call and the next call to ftell()
                                    */

  (void) ftell(fp);                                   /* ok: immediately followed by check errno!=0 */
  if (errno != 0){ return 1; }

  (void) ftell(fp);                                   /* ok: immediately followed by check errno==0 */
  if (errno == 0) {  }
  else {return 1;}

  (void) ftell(fp);                /* 'Missing Test of Error Code' warning issued here
                                    * - following check errno>0 is not a test for equality with zero
                                    */
  if (errno > 0){ return 1; }

  return 0;
}

int compare_to_nonzero(FILE *fp){
  (void) ftell(fp);                /* 'Missing Test of Error Code' warning issued here
                                    * - following check errno==15 is not a test for equality with zero
                                    */
  if (errno == 15){ return 1; }
  return 0;
}

int not_all_paths(FILE *fp, int i){
  (void) ftell(fp);                /* 'Missing Test of Error Code' warning issued here
                                    * - errno is not checked when i!=100
                                    */
  if (i == 100){
    if (errno!=0) {return 1;}
  }
  return 0;
}