Is taking the address of a member of an uninitialized object well defined?

Question

Consider the following example. When bar is constructed, it gives it\'s base type (foo) constructor the address of my_member.y where <

Answer 1

Yes you are allowed to pass &my_member.y to foo's constructor, and even copy the pointer - which you do with x(p_x).

The behaviour on dereferencing that pointer though in foo's constructor is undefined. (But you don't do that.)