function SizeOfFile(const FileName: string): Windows.DWORD;
var
  FH: THandle;  // file handle
begin
  FH := SysUtils.FileOpen(
    FileName, SysUtils.fmOpenRead or SysUtils.fmShareDenyNone
  );
  try
    Result := Windows.GetFileSize(FH, nil);
  finally
    SysUtils.FileClose(FH);
  end;
end;
//delphi/2224