

'===================
'OPTIONAL PARAMETERS
'===================


  '---------------------------------------------------------
  function f(v as sys, optional a as sys, b as sys) external
  '=========================================================
  string opts
  '
  '
  'check to see if the address of b is null
  '
  if @a then
    opts+=" A = "+str(a)
  else
    opts+="  A is not specified  "
  end if

 if @b then
    opts+="  B = "+str(b)
  else
    opts+="  B is not specified  " 
  end if

  '
  print "V = " str(v) chr(13) chr(10) opts
  '
  end function


  'SOME DATA
  '=========

  sys vv=42


  '======
  'TESTS:
  '======

  f vv          'A AND B NOT SPECIFIED
  f vv,123      'A SPECIFIED
  f vv,,456     'B SPECIFIED (A SET TO 0)
  f vv,123,456  'BOTH SPECIFIED


