function TIBDatabaseInfo.GetDBSQLDialect: Integer;
var
  local_buffer: array[0..IBLocalBufferLength - 1] of Byte;
  length: Integer;
  DatabaseInfoCommand: Byte;
begin
  DatabaseInfoCommand := Byte(isc_info_db_SQL_Dialect);
  Call(isc_database_info(StatusVector, @FDatabase.Handle, 1, @DatabaseInfoCommand,
                       IBLocalBufferLength, @local_buffer), True);
  if local_buffer[0] <> isc_info_db_SQL_dialect then
    result := 1
  else begin
    length := isc_vax_integer(@local_buffer[1], 2);
    result := isc_vax_integer(@local_buffer[3], length);
  end;
end;

function GetSQLDialect(AStatus: IStatus; AAttachment: IAttachment): Integer;
var
  LBuf: array[0..15] of Byte;
  LLen: Integer;
  LCmd: Byte;
begin
  LCmd := isc_info_db_SQL_Dialect;
  AAttachment.getInfo(AStatus, 1, @LCmd, Length(LBuf), @LBuf[0]);
  if LBuf[0] <> isc_info_db_SQL_dialect then
    result := 1
  else begin
//    LLen := isc_vax_integer(@LBuf[1], 2);
//    result := isc_vax_integer(@LBuf[3], LLen);
  end;
end;

function GetSQLDialect(AStatus: IStatus; AAttachment: IAttachment): Integer;
type
  TBuffer = packed record
    Cmd: Byte;
    case Len: SmallInt of
      1: (v1: ShortInt);
      2: (v2: SmallInt);
      4: (v4: Integer);
      8: (v8: Int64);
      -1: (reserved: array[0..12] of Byte);
  end;
var
  LBuf: TBuffer;
  LCmd: Byte;
  Li: Integer;
begin
  LCmd := isc_info_db_SQL_Dialect;
  AAttachment.getInfo(AStatus, 1, @LCmd, SizeOf(LBuf), @LBuf);
  if LBuf.Cmd <> isc_info_db_SQL_dialect then
    Result := 1
  else begin
    case LBuf.Len of
      SizeOf(LBuf.v1): Result := LBuf.v1;
      SizeOf(LBuf.v2): Result := LBuf.v2;
      SizeOf(LBuf.v4): Result := LBuf.v4;
      SizeOf(LBuf.v8): Result := LBuf.v8;
    else
      Result := 0;
      for Li := LBuf.Len - 1 downto 0 do
        Result := (Result shl 8) or LBuf.reserved[Li]
    end;
  end;
end;

function PortableInteger(APtr: Pointer; ASize: Integer): Int64;
type
  TValue = record
  case Byte of
    1: (v1: ShortInt);
    2: (v2: SmallInt);
    4: (v4: Integer);
    8: (v8: Int64);
    255: (reserved: array[0..7] of ShortInt);
  end;
var
  LValue: ^TValue absolute APtr;
  Li: Integer;
begin
  case ASize of
    SizeOf(LValue^.v1): Result := LValue^.v1;
    SizeOf(LValue^.v2): Result := LValue^.v2;
    SizeOf(LValue^.v4): Result := LValue^.v4;
    SizeOf(LValue^.v8): Result := LValue^.v8;
  else
    if LValue^.reserved[ASize - 1] < 0 then
      Result := -1
    else
      Result := 0;
    for Li := ASize - 1 downto 0 do
      Result := (Result shl 8) or LValue^.reserved[Li]
  end;
end;

type
  TValue = record
  case Byte of
    1: (v1: ShortInt);
    2: (v2: SmallInt);
    4: (v4: Integer);
    8: (v8: Int64);
    255: (reserved: array[0..7] of ShortInt);
  end;

procedure TForm1.Button1Click(Sender: TObject);
var
  LBuf: TValue;
begin
  LBuf.reserved[0] := 1;
  LBuf.reserved[1] := 2;
  LBuf.reserved[2] := 3;
  LBuf.reserved[3] := 4;
  ShowMessage(IntToHex(LBuf.v4));
end;

Result := (Result shl 8) or (LValue^.reserved[Li] and $FF)

Case: 1: 2312, 2: 2328, 4: 2312, 8: 2360, 
Loop: 1: 2344, 2: 4485, 4: 8484, 8: 16640,