看到TVarData的定义,不明白record中包含case 的含意TVarData = packed record
case Integer of
0: (VType: TVarType;
case Integer of
0: (Reserved1: Word;
case Integer of
0: (Reserved2, Reserved3: Word;
case Integer of
varSmallInt: (VSmallInt: SmallInt);
varInteger: (VInteger: Integer);
varSingle: (VSingle: Single);
varDouble: (VDouble: Double); varCurrency: (VCurrency: Currency);
varDate: (VDate: TDateTime);
varOleStr: (VOleStr: PWideChar);
varDispatch: (VDispatch: Pointer);
varError: (VError: HRESULT);
varBoolean: (VBoolean: WordBool);
varUnknown: (VUnknown: Pointer);
varShortInt: (VShortInt: ShortInt);
varByte: (VByte: Byte); varWord: (VWord: Word);
varLongWord: (VLongWord: LongWord);
varInt64: (VInt64: Int64);
varString: (VString: Pointer);
varAny: (VAny: Pointer);
varArray: (VArray: PVarArray);
varByRef: (VPointer: Pointer);
);
1: (VLongs: array[0..2] of LongInt); );
2: (VWords: array [0..6] of Word);
3: (VBytes: array [0..13] of Byte);
);
1: (RawData: array [0..3] of LongInt);
end;
case Integer of
0: (VType: TVarType;
case Integer of
0: (Reserved1: Word;
case Integer of
0: (Reserved2, Reserved3: Word;
case Integer of
varSmallInt: (VSmallInt: SmallInt);
varInteger: (VInteger: Integer);
varSingle: (VSingle: Single);
varDouble: (VDouble: Double); varCurrency: (VCurrency: Currency);
varDate: (VDate: TDateTime);
varOleStr: (VOleStr: PWideChar);
varDispatch: (VDispatch: Pointer);
varError: (VError: HRESULT);
varBoolean: (VBoolean: WordBool);
varUnknown: (VUnknown: Pointer);
varShortInt: (VShortInt: ShortInt);
varByte: (VByte: Byte); varWord: (VWord: Word);
varLongWord: (VLongWord: LongWord);
varInt64: (VInt64: Int64);
varString: (VString: Pointer);
varAny: (VAny: Pointer);
varArray: (VArray: PVarArray);
varByRef: (VPointer: Pointer);
);
1: (VLongs: array[0..2] of LongInt); );
2: (VWords: array [0..6] of Word);
3: (VBytes: array [0..13] of Byte);
);
1: (RawData: array [0..3] of LongInt);
end;
即,4个LongInt的大小