c16rtombstate
struct c16rtombstate *S;
S = (struct c16rtombstate *)(void *)ps;
__CTASSERT(offsetof(struct c16rtombstate, mbs) <= sizeof(mbstate_t));
offsetof(struct c16rtombstate, mbs));
__CTASSERT(alignof(struct c16rtombstate) <= alignof(mbstate_t));