Producer and Consumer – Monitor Example

program prod_cons_mon;

monitor buffer;

var count, in, out: integer;

buf: array[0..n-1] of integer;

full, empty: condition;

procedure append(x: integer); procedure remove(var y: integer);

begin begin

if count > n then WAIT(full); if count = 0 then WAIT(empty);

buff[in] := x; y := buff[out];

in := (in + 1) mod n; out := (out + 1) mod n;

count := count + 1; count := count – 1;

SIGNAL(empty); SIGNAL(full);

end; end;

begin {monitor executable code}

count := 0;

in := 0;

out := 0;

end;

procedure producer; procedure consumer;

var item: integer; var item: integer;

while true do while true do

begin begin

generate item; buffer.remove(item);

buffer.append(item); use item;

end; end;

begin {main program}

cobegin

producer;

consumer;

coend;

end.