Question

Generally this discussion is up to the local function variable only:

void foo (const int &i)
{
  // use i till foo() ends
}
foo(3);

But, does this rule applies to the class member also ?

struct A {
  const int &a;
  A () : a(3) {}  // version 1
  A (const int &i) : a(i) {} // version 2
};

Now A used as,

{
  return ()? new A : new A(3) : new A(some_local_variable);
}

Will the contents of a remain same through out the life time of the all 3 newly allocated A ?

Answer 1

The C++03 standard (Section “12.2/5 Temporary objects”) answers your question aptly:

The temporary to which the reference is bound or the temporary that is the complete object to a subobject of which the temporary is bound persists for the lifetime of the reference except as specified below. A temporary bound to a reference member in a constructor’s ctor-initializer (12.6.2) persists until the constructor exits. A temporary bound to a reference parameter in a function call (5.2.2) persists until the completion of the full expression containing the call.