system/sysvarnt.pas

   1 unit sysvarnt;
   2 {X: this unit contains some definitions and initializations, needed to
   3     support variants. To use variants, just place reference to sysvarnt
   4     unit in your unit uses clause *first* }
   5
   6 interface
   7
   8 var
   9   Unassigned: Variant;    { Unassigned standard constant }
  10   Null: Variant;          { Null standard constant }
  11   EmptyParam: OleVariant; { "Empty parameter" standard constant which can be
  12                             passed as an optional parameter on a dual interface. }
  13
  14 implementation
  15
  16 initialization
  17
  18   VarAddRefProc := VariantAddRef;
  19   VarClrProc := VariantClr;
  20
  21   TVarData(Unassigned).VType := varEmpty;
  22   TVarData(Null).VType := varNull;
  23   TVarData(EmptyParam).VType := varError;
  24   TVarData(EmptyParam).VError := $80020004; //DISP_E_PARAMNOTFOUND
  25
  26   ClearAnyProc := @VarInvalidOp;
  27   ChangeAnyProc := @VarCastError;
  28   RefAnyProc := @VarInvalidOp;
  29
  30 finalization
  31
  32 end.