exit (lose ? EXIT_FAILURE : EXIT_SUCCESS);
return lose ? EXIT_FAILURE : EXIT_SUCCESS;
main (int argc, char **argv){  static const char hello[] = "Hello, world.\n";  static const char replace[] = "Hewwo, world.\n";  static const size_t replace_from = 2, replace_to = 4;  char filename[FILENAME_MAX];  char *name = strrchr (*argv, '/');  char buf[BUFSIZ];  FILE *f;  int lose = 0;  if (name != NULL)    ++name;  else    name = *argv;  (void) sprintf (filename, "/tmp/%s.test", name);  f = fopen (filename, "w+");  if (f == NULL)    {      perror (filename);      exit (1);    }  (void) fputs (hello, f);  rewind (f);  (void) fgets (buf, sizeof (buf), f);  rewind (f);  (void) fputs (buf, f);  rewind (f);  {    size_t i;    for (i = 0; i < replace_from; ++i)      {	int c = getc (f);	if (c == EOF)	  {	    printf ("EOF at %Zu.\n", i);	    lose = 1;	    break;	  }	else if (c != hello[i])	  {	    printf ("Got '%c' instead of '%c' at %Zu.\n",		    (unsigned char) c, hello[i], i);	    lose = 1;	    break;	  }      }  }  {    long int where = ftell (f);    if (where == (long int) replace_from)      {	register size_t i;	for (i = replace_from; i < replace_to; ++i)	  if (putc(replace[i], f) == EOF)	    {	      printf ("putc('%c') got %s at %Zu.\n",		      replace[i], strerror (errno), i);	      lose = 1;	      break;	    }      }    else if (where == -1L)      {	printf ("ftell got %s (should be at %Zu).\n",		strerror (errno), replace_from);	lose = 1;      }    else      {	printf ("ftell returns %lu; should be %Zu.\n", where, replace_from);	lose = 1;      }  }  if (!lose)    {      rewind (f);      if (fgets (buf, sizeof (buf), f) == NULL)	{	  printf ("fgets got %s.\n", strerror(errno));	  lose = 1;	}      else if (strcmp (buf, replace))	{	  printf ("Read \"%s\" instead of \"%s\".\n", buf, replace);	  lose = 1;	}    }  if (lose)    printf ("Test FAILED!  Losing file is \"%s\".\n", filename);  else    {      (void) remove (filename);      puts ("Test succeeded.");    }  exit (lose ? EXIT_FAILURE : EXIT_SUCCESS);}