> A final interesting property of this code is that its be- haviour is undefined according to the C language standard. The reason is that it calls memcpy() across a range of memory comprising multiple distinct C objects, copying them all into memory-mapped storage in a single operation.

What's wrong with memcpy here? As long as dst and src are both non-zero and the ranges of memory are not overlapping, the behavior of memcpy is well defined.