On Fri, Feb 20, 2015 at 12:06:28PM +0100, Florian Weimer wrote: > On 02/19/2015 09:56 PM, Sandra Loosemore wrote: > > Hmmmm, Passing the additional option in user code would be one thing, > > but what about library code? E.g., using memcpy (either explicitly or > > implicitly for a structure copy)? > > The memcpy problem isn't restricted to embedded architectures. > > size_t size; > const unsigned char *source; > std::vector<char> vec; > … > vec.resize(size); > memcpy(vec.data(), source, size); > > std::vector<T>::data() can return a null pointer if the vector is empty, > which means that this code is invalid for empty inputs. > > I think the C standard is wrong here. We should extend it, as a QoI > matter, and support null pointers for variable-length inputs and outputs > if the size is 0. But I suspect this is still a minority view.
I disagree. If you want a function that will have that different property, don't call it memcpy. Jakub