rem: for (i = 0; i < nfiles; ++i)
add: initbuf (&buf, sizeof (struct line), MAX (merge_buffer_size, sort_size)); temp.text = NULL;  while (fillbuf (&buf, fp, file_name))
context: check (char **files, int nfiles){  int i, disorders = 0;  FILE *fp;  for (i = 0; i < nfiles; ++i)    {      fp = xfopen (files[i], "r");      disorders += checkfp (fp, files[i]);    }  return disorders;}