add: return ok;
context: head_file (const char *filename, uintmax_t n_units, int count_lines){  int fd;  if (STREQ (filename, "-"))    {      have_read_stdin = 1;      return head (_("standard input"), STDIN_FILENO, n_units, count_lines);    }  else    {      fd = open (filename, O_RDONLY);      if (fd >= 0)	{	  int errors;	  errors = head (filename, fd, n_units, count_lines);	  if (close (fd) == 0)	    return errors;	}      error (0, errno, "%s", filename);      return 1;    }}