Is this defined

Question

Suppose I have a class A:

class A : virtual SomeOtherClass{
  //Stuff here
};

Suppose I have do this somewhere:

A thing;
alignas(A) uint8_t arr[sizeof(A)];
for (int x = 0; x < sizeof(A); x++)
{
  //Copy into array
  arr[x] = reinterpret_cast<uint8_t*>(&A)[x];
}

A* otherThing = reinterpret_cast<A*>(arr);

Is what I am doing here defined behavior, or am I killing myself in someway that I am unaware?

`reinterpret_cast` is almost always a bad idea. – πάντα ῥεῖ Jul 05 '16 at 01:08 — πάντα ῥεῖ, Jul 05 '16 at 01:08

score 2 · Accepted Answer · edited May 23 '17 at 12:08

2

The shown code executes something that's equivalent to memcpy().

As such, this is undefined behavior. Classes with virtual base classes are not trivially-copyable.

edited May 23 '17 at 12:08

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answered Jul 05 '16 at 01:13

Sam Varshavchik

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Is this defined

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