volatile required?

[Doug Gwyn]

In article <712 at Aragorn.dde.dk> ct at dde.dk (Claus Tondering) writes:
-	  int p=3, *q=&p;
-	  *q=4;
-	  printf("%d\n",p);
-Is it acceptable that this program prints 3 instead of 4? The variable
-p is not declared volatile, and therefore the fact that *q=4 assigns
-4 to p may be considered a side effect.

No, a correct implementation must print "4" (and a new-line).
You're confusing "volatile" with "noalias" (which is no longer
in the proposed standard).  C supports aliasing via pointers.