On 02/20/15 05:10, Jakub Jelinek wrote:
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.
Right. If someone wants to take it up with the Austin group, that's
fine. But until/unless the Austin group blesses, I don't think we should
extend as a QoI matter.
jeff
