alt Hacker NewsWhat you are describing is implementation defined behavior. Using that is perfectly safe and reasonable. Undefined means this programs is malformed.
What you are describing is implementation defined behavior. Using that is perfectly safe and reasonable. Undefined means this programs is malformed.
No I'm just repeating what the original comment said, which is that it's explicitly UB:
"5.1.2.4.1 says any volatile access - including just reading it - is a side effect. 6.5.1.2 says that unsequenced side effects on the same scalar object (in this case, x) are UB. 6.5.3.3.8 tells us that the evaluations of function arguments are indeterminately sequenced w.r.t. each other."
If function arguments were sequenced with respect to each other, it wouldn't be a problem.
But actually, maybe the original comment is wrong. Presumably "indeterminately sequenced" and "unsequenced" mean different things, although I don't have a copy of the standard at hand to check.