> It relies on struct layout, and if anything has wider alignment than ptrdiff_t, it's broken. I think you're wrong about this. I'm pretty certain a pointer to

> It relies on struct layout, and if anything has wider alignment than ptrdiff_t, it's broken. I think you're wrong about this. I'm pretty certain a pointer to a struct is always equivilent to a pointer to the first member, except for the type. I went and looked it up in C11 (6.7.2.1 point 15): > A pointer to a structure object, suitably converted, points to its initial member (or if that member is a bit-field, then to the unit in which it resides), and vice versa. There may be unnamed padding within a structure object, but not at its beginning. Edit: A duh, the + sizeof(ptrdiff_t) is the part that's wrong. Yeah, agreed.