rem: if (files_given == 0) { if ((*sum_func) ("-", files_given) < 0) errors = 1; }
add: if (files_given <= 0) ok = sum_func ("-", files_given);
context: main (int argc, char **argv){  int errors = 0;  int optc;  int files_given;  int (*sum_func) (const char *, int) = bsd_sum_file;  program_name = argv[0];  setlocale (LC_ALL, "");  bindtextdomain (PACKAGE, LOCALEDIR);  textdomain (PACKAGE);  atexit (close_stdout);  have_read_stdin = 0;  while ((optc = getopt_long (argc, argv, "rs", longopts, NULL)) != -1)    {      switch (optc)	{	case 0:	  break;	case 'r':		/* For SysV compatibility. */	  sum_func = bsd_sum_file;	  break;	case 's':	  sum_func = sysv_sum_file;	  break;	case_GETOPT_HELP_CHAR;	case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);	default:	  usage (EXIT_FAILURE);	}    }  files_given = argc - optind;  if (files_given == 0)    {      if ((*sum_func) ("-", files_given) < 0)	errors = 1;    }  else    for (; optind < argc; optind++)      if ((*sum_func) (argv[optind], files_given) < 0)	errors = 1;  if (have_read_stdin && fclose (stdin) == EOF)    error (EXIT_FAILURE, errno, "-");  exit (errors == 0 ? EXIT_SUCCESS : EXIT_FAILURE);}