anchor.diff:    TmCustomVirtualDataset = class(TDataSet)
     strict private
       FInternalOpen     : Boolean;
  -    FCurrentRecord    : Integer;      // current record (0 to FRecordCount - 1)
  +    FCurrentRecord    : Longint;      // current record (0 to FRecordCount - 1)
       FFilterBuffer     : TRecordBuffer;
       FReadOnly         : Boolean;
       FRecordBufferSize : Integer;      // data + housekeeping (TRecordInfo)
  
positive.code: function TmCustomVirtualDataset.Locate(const KeyFields: string;
    const KeyValues: Variant; Options: TLocateOptions): Boolean;
  var
    P: Integer;
  begin
    if Assigned(FOnLocate) then
    begin
  
negative.code: 
      { Standard public overrides }
      function BookmarkValid(ABookmark: TBookmark): Boolean; override;
      function CompareBookmarks(Bookmark1, Bookmark2: TBookmark): Longint; override;
  //    function CreateBlobStream(Field: TField; Mode: TBlobStreamMode)
  //      : TStream; override;
      {$IFNDEF FPC}
  