Re: Documentation of memcpy and undefined behavior in memset

[Bartosz Brachaczek <b.brachaczek@gmail.com>]

On 7/6/2017 6:23 PM, Rich Felker wrote:
> I think you're correct, at least under a pessimistic interpretation of
> the standard. I can't find where they actually define "modifies", and
> you could argue that assignment of the same value twice "modifies" the
> object at most once, but I don't like relying on that kind of
> ambiguity and it's easy enough to fix just by adding a sequence point.

I don't have a copy of C11, but N1570 reads in a note to 3.1:

> ‘‘Modify’’ includes the case where the new value being stored is the same as the previous value.

Bartosz