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 12P0(int *buf, int *flag) // Producer 13{ 14 WRITE_ONCE(*buf, 1); 15 WRITE_ONCE(*flag, 1); 16} 17 18P1(int *buf, int *flag) // Consumer 19{ 20 int r0; 21 int r1; 22 23 r0 = READ_ONCE(*flag); 24 r1 = READ_ONCE(*buf); 25} 26 27exists (1:r0=1 /\ 1:r1=0) (* Bad outcome. *) 28