Since 6.3 IO protocol version.

typedef struct _PRL_IO_DISPLAY_ENCODING_LIST {
  PRL_UINT32 encodingListSz;
  PRL_UINT32 defaultEncodingIdx;
  PRL_IO_DISPLAY_ENCODING encodingList[PRL_IO_MAX_ENCODINGS];
} PRL_IO_DISPLAY_ENCODING_LIST;