1C MP+poonceonces 2 3(* 4 * Result: Sometimes 5 * 6 * Can the counter-intuitive message-passing outcome be prevented with 7 * no ordering at all? 8 *) 9 10{ 11 int buf; 12 int flag; 13} 14 15P0(int *buf, int *flag) // Producer 16{ 17 WRITE_ONCE(*buf, 1); 18 WRITE_ONCE(*flag, 1); 19} 20 21P1(int *buf, int *flag) // Consumer 22{ 23 int r0; 24 int r1; 25 26 r0 = READ_ONCE(*flag); 27 r1 = READ_ONCE(*buf); 28} 29 30exists (1:r0=1 /\ 1:r1=0) (* Bad outcome. *) 31