pieniek writes:
Hello,I have always though, that given a pointer to an object, members are at (this) + (member-offset). But this cannot be true for multiple inheritance, no?Example: struct A { int x,y; } struct B { int a, b, c; } struct C : public A, public B {} int func (B* b, B* actuallyCinstance) { return b->b + actuallyCinstance->b; }How is the B::b member accessed, especially b->b when b is B? What is the cost of that (x86_64)?
Both pointers received by func() are pointers to an instance of the B class. The offset is the same.
If the caller invokes func() with the second argument being a pointer to an instance of C, the caller adjust the pointer to point to C's superclass, and invokes func() with two pointers to an instance of B.
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