Why is `std::copy` 5x (!) slower than `memcpy` for reading one int from a char buffer, in my test program?

Question

This is a follow-up to this question where I posted this program:

#include 
#include 
#include 
#include 

        

Answer 1

memcpy and std::copy each have their uses, std::copy should(as pointed out by Cheers below) be as slow as memmove because there is no guarantee the memory regions will overlap. This means you can copy non-contiguous regions very easily (as it supports iterators) (think of sparsely allocated structures like linked list etc.... even custom classes/structures that implement iterators). memcpy only work on contiguous reasons and as such can be heavily optimized.