NCD_IS_FIRST_OPERATION
EXT_NCD_OPEN_FOR_READ_COMMIT
EXT_NCD_OPEN_FOR_WRITE_COMMIT
EXT_NCD_IOCLOSE
EXT_NCD_IOSYNC
EXT_NCD_REDEF
EXT_NCD_ENDDEF
EXT_NCD_WRITE_FIELD
EXT_NCD_READ_FIELD
EXT_NCD_INQUIRE_OPENED
EXT_NCD_INQUIRE_FILENAME
EXT_NCD_SET_TIME
EXT_NCD_GET_NEXT_TIME
EXT_NCD_GET_PREVIOUS_TIME
EXT_NCD_GET_NEXT_VAR
EXT_NCD_END_OF_FRAME
EXT_NCD_GET_VAR_INFO