[bluGill]

there is a lot wrong but your analisys misses the elephant: the function takes a copy and so a copy must be generated. std::move will move if possible but in this case move isn't possible and so a copy will be made.

Move is allowed to not move because in generic code you don't want to have to check for if move is possible for the type in question.

[GrantMoyer]

In the case of the example, there is a move, and std::move works in the example.

The function, show, doesn't take a copy, it takes a Person object. Persons can be copy constructed or move constructed (both constructors are implicit, since there's no user-defined constructors). std::move returns an r-value reference to main's p, so Person's implicit move constructor is called, and show's p argument is move constructed from main's p. The reported address changes because moving creates a new object in C++, but the moved-to object may take ownership of the heap allocated memory and other resources from the moved-from object.

In this case, the moved-to Person takes ownership of the heap allocation from the moved-from Person's string member and sets the moved-from Person's string member to an empty string. Without std::move, show's p is copy constructed, including its string member.

[littlestymaar]

C++ making the most inscrutable semantic possible, speedrun any %.