_IO_seek_set
dir = _IO_seek_set;
case _IO_seek_set:
dir = _IO_seek_set;
case _IO_seek_set:
if (dir != _IO_seek_cur && dir != _IO_seek_set && dir != _IO_seek_end)
dir = _IO_seek_set;
case _IO_seek_set:
dir = _IO_seek_set;