Questions about SDK-functions (Syntax, Parameters etc.)

[ReneMiner]

my question of today is about thinBasic_GetKeywordSpeficic

All i know is

'----------------------------------------------------------------------------
  'thinBasic_GetKeywordSpeficic
  '----------------------------------------------------------------------------
  ' Instruct parser to get next token, test if it a keyword and if yes,
  ' check if it is one of the possible keywords passed. If not, a RT-Error
  ' will be generated
  '----------------------------------------------------------------------------
DECLARE FUNCTION  thinBasic_GetKeywordSpeficic                  _
                          LIB "thinCore.DLL"                      _
                          ALIAS "thinBasic_GetKeywordSpeficic"    _
                          (                                       _
                                      BYVAL HideError   AS LONG , _
                                      BYVAL AutoPutBack AS LONG , _
                                      BYVAL lKey1   AS LONG     , _
                             OPTIONAL BYVAL lKey2   AS LONG     , _
                                      BYVAL lKey3   AS LONG     , _
                                      BYVAL lKey4   AS LONG     , _
                                      BYVAL lKey5   AS LONG     , _
                                      BYVAL lKey6   AS LONG     , _
                                      BYVAL lKey7   AS LONG     , _
                                      BYVAL lKey8   AS LONG     , _
                                      BYVAL lKey9   AS LONG     , _
                                      BYVAL lKey10  AS LONG     , _
                                      BYVAL lKey11  AS LONG     , _
                                      BYVAL lKey12  AS LONG     , _
                                      BYVAL lKey13  AS LONG     , _
                                      BYVAL lKey14  AS LONG     , _
                                      BYVAL lKey15  AS LONG     , _
                                      BYVAL lKey16  AS LONG     , _
                                      BYVAL lKey17  AS LONG     , _
                                      BYVAL lKey18  AS LONG     , _
                                      BYVAL lKey19  AS LONG     , _
                                      ByVal lKey20  As Long     , _
                                      ByVal lKey21  As Long     , _
                                      ByVal lKey22  As Long     , _
                                      ByVal lKey23  As Long     , _
                                      ByVal lKey24  As Long     , _
                                      ByVal lKey25  As Long       _
                          ) As Long

i guess i have to store up to 25 different keywords to lKey1 to lKey25 ?
What is the rule? why "As Long? Will it return the number 1 to 25 telling me the keyword? isn't it possible without to create an Error?