private static extern th_dec_ctx_ptr th_decode_alloc(ref Th_Info _info, th_setup_info_ptr _setup);
private static extern void th_info_clear(ref Th_Info _info);
private static extern int th_decode_headerin(ref Th_Info _info, ref Th_Comment _tc, ref th_setup_info_ptr _setup, ogg_packet_ptr _op);
private static extern void th_info_init(ref Th_Info c);