MODULE TOpenFlattenByte;
(* M3: a 2-D array passed to VAR ARRAY OF BYTE; the byte view aliases the
   original payload. *)
TYPE Mat = ARRAY [0..1], [0..2] OF CARDINAL;
VAR ExitCode : INTEGER;
    m : Mat;

PROCEDURE Fill (VAR b : ARRAY OF BYTE);
BEGIN
  b[0] := 42;
  b[1] := 0;
  b[2] := 0;
  b[3] := 0
END Fill;

BEGIN
  Fill(m);
  IF m[0, 0] = 42 THEN ExitCode := 42 ELSE ExitCode := 1 END
END TOpenFlattenByte.