c++ - Return lvalue reference from temporary object -

is, returning lvalue reference *this, allowed when *this rvalue?

#include <iostream> #include <string> using namespace std;  class { public:     a& f() {         return *this;     }     string val() const {         return "works";     } };  int main() {     cout << a{}.f().val(); } 

is there scenario value returned f() dangling reference @ point?

does calling f() prolongs lifetime of caller if rvalue in example?

*this never rvalue in case, (a reference to) temporary. temporaries valid objects until statement defined completed, i.e. until code reaches terminating ;, or until end of controlling expression for, if, while, do, , switch statements, e.g. in if (a{}.f()) { something; }, temporary valid until last ) before body of condition ({ something; }).