rem: int i, disorders = 0; FILE *fp;
add: FILE *fp = xfopen (file_name, "r"); struct buffer buf;		 struct line temp;		 size_t alloc = 0; uintmax_t line_number = 0; struct keyfield const *key = keylist; bool nonunique = ! unique; bool ordered = true;
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;}