Dir parameter of function DIR_OPEN should be mode out

procedure DIR_OPEN(
  Dir    : out DIRECTORY;
  Path   : STRING;
  Status : out DIR_OPEN_STATUS
);
impure function DIR_OPEN(
  Dir    : DIRECTORY;
  Path   : STRING
) return DIR_OPEN_STATUS;

In the function DIR_OPEN, the Dir parameter has the same purpose as the Dir parameter of the procedure DIR_OPEN. Hence, the Dir parameter of the function DIR_OPEN should be mode out.