add: default: fprintf(stderr, "%s: fileio: invalid operation=%d\n", progname, fio->op); return -1;
context: int fileio_rbin ( struct fioparms * fio,                  char * filename, FILE * f, unsigned char * buf, int size ){  int rc;  switch (fio->op) {    case FIO_READ:      rc = fread(buf, 1, size, f);      break;    case FIO_WRITE:      rc = fwrite(buf, 1, size, f);      break;  }  if (rc < size) {    fprintf(stderr,             "%s: %s error %s %s: %s; %s %d of the expected %d bytes\n",             progname, fio->iodesc, fio->dir, filename, strerror(errno),            fio->rw, rc, size);    return -1;  }  return rc;}