In addition to what mfrost said, there's also no need because C++ assignment is member-by-member copy unless otherwise specifically implemented for the type. If you have a POD, then that's what you get with assignment; there's no need to call memcpy at all.

(The difference is that memcpy will copy padding bytes, and the assignment operator may not. But if you depend on the values of the padding bytes, you have major problems...)