Discussion: Moving Out
Execute the code to understand the output and gain insights into the behavior of moved-from objects.
Run the code
Now, it’s time to execute the code and observe the output.
#include <iostream>#include <string>int main(){std::string hello{"Hello, World!"};std::string other(std::move(hello));std::cout << "'" << hello << "'";}
Understanding the output
A moved-from object should no longer be used, as resources will have been moved out of it, pointers might point to destroyed objects, and so on.
How a particular moved-from object behaves is up to the implementer of that class. The implementer has a lot of freedom here, but at a minimum, the object should be safe to destroy so nothing breaks when, for instance, a moved-from local variable goes out of scope. Unless explicitly documented, we, as a user, should not assume that a class makes any further guarantees.
Standard library guarantee
The C++ standard provides an additional guarantee for the classes in the standard library, though:
Objects of types defined in the C++ standard library may be moved ...