See my reply to the parent poster for an example where RVO applies in C++ but not C, leading to better code in the C++ case. The key is to let the address of th

See my reply to the parent poster for an example where RVO applies in C++ but not C, leading to better code in the C++ case. The key is to let the address of the objects involved escape: otherwise "as if" will let C (and C++ even without RVO) optimize away the copies anyways, since they are not observable in that case.