Question

In C++ one cannot rely on the copy constructor being called from a return statement because of a special clause in the standard that allows a compiler to omit a call to the copy constructor resulting from a return statement, even if the copy constructor has side effects. Thus, it is bad style to write a copy constructor that does something else than just copy constructing the instance.

Are there similar statements in the C++11 standard that allow the compiler to eliminate a call to the move constructor under certain circumstances – and if so, what are those circumstances?

Answer 1

Copy-elision applies just the same to move construction, it’s the exact same clause and both the elision of copy construction and move construction is collectively called “copy-elision”.

§12.8 [class.copy] p31

When certain criteria are met, an implementation is allowed to omit the copy/move construction of a class object, even if the copy/move constructor and/or destructor for the object have side effects. […]