begin int fd = fopen ("../../ga68", file_o_rdonly);
      assert (fd /= -1);
      assert (errno = 0);
      long long int offset;
      offset := lseek (fd, long long 0, seek_cur);
      assert (offset = long long 0);
      assert (errno = 0);
      offset := lseek (fd, long long 0, seek_set);
      assert (offset = long long 0);
      assert (errno = 0);
      offset := lseek (fd, long long 0, seek_end);
      long long int offset2 = lseek (fd, offset, seek_set);
      assert (offset = offset2);
      long long int file_size = fsize (fd);
      assert (errno = 0);
      assert (offset = file_size)
end