Is that sample code correctly?

[stosha]

Could you say me is that code fully correctly?

A Fun()
{
A a = 0;
return a;
}

const A& a = Fun();
A b = a;

[superbonzo]

to say it's "fully" correct, you should show us the definition of A ...

anyway, supposing that A is non-explictly constructible from an int and that it is also copy constructible, it's correct.

if you have doubts about the line "const A& a = Fun();", note that a temporary bound to a const reference will survive up to the end of the scope in which the reference is defined; so, again, it's ok.