タイトル

function FileLen(const AFilename: WideString): Int64;
  var
    info: TWin32FileAttributeData;
begin
  Result := -1;

  if NOT GetFileAttributesExW(PWideChar(AFilename), GetFileExInfoStandard, @info) then
      EXIT;

  if (info.dwFileAttributes AND FILE_ATTRIBUTE_DIRECTORY > 0) then
      EXIT;
//    raise Exception.CreateFmt('Can not get file size : %s', [AFilename]);

  Result := Int64(info.nFileSizeLow) or Int64(info.nFileSizeHigh shl 32);
end;

function FileSize(const AFilename: WideString): Int64;
begin
  Result := FileLen(AFilename);
end;