uses
  FileCtrl;

function GetFiles(fileSpec: String; s: TStrings): Integer;
begin
  with TFileListBox.CreateParented(HWND(-3)) do
  try
    Mask := ExtractFileName(fileSpec);
    Directory := ExtractFilePath(fileSpec);
    FileType := [ftArchive];
    Result := Items.Count;
    s.Assign(Items);
  finally
    Free;
  end;
end;