fseek (fp, b->offset, SEEK_SET);
fseeko (fp, b->offset, SEEK_SET);
static int count_delete_lines (FILE *fp, BODY *b, long *length, size_t datelen){  int dellines = 0;  long l;  int ch;  if (b->deleted)  {    fseek (fp, b->offset, SEEK_SET);    for (l = b->length ; l ; l --)    {      ch = getc (fp);      if (ch == EOF)	break;      if (ch == '\n')	dellines ++;    }    dellines -= 3;    *length -= b->length - (84 + datelen);    /* Count the number of digits exceeding the first one to write the size */    for (l = 10 ; b->length >= l ; l *= 10)      (*length) ++;  }  else  {    for (b = b->parts ; b ; b = b->next)      dellines += count_delete_lines (fp, b, length, datelen);  }  return dellines;}