Would a copy constructor be at work here?

Question

void setCurrentTransformations(const NodeTransformations& theSet){
    m_currentTransformations=theSet;
}

I want to confirm that I am understanding this exactly because theSet is going out of scope just after this function gets called.

This is going to actually copy theSet into m_currentTransformations, right? In other words, it is safe, regardless of the scope of theSet in the caller.

It's the fact that if this was a pointer instead of a reference, I know it would not be safe. But I assume here that it is perfectly fine, and m_currentTransformations will copy theSet so that it will not matter what happens to the original value that theSet references, right?

This has nothing to do with safety. It's far more fundamentally about *correctness*. — Kerrek SB, Apr 24 '13 at 18:26
@KerrekSB that is a rather cryptic comment you made there. care to elaborate? — johnbakers, Apr 24 '13 at 18:30

Sergey Kalinichenko · Accepted Answer · 2013-04-24T18:58:52.387

4

This is going to actually copy theSet into m_currentTransformations, right?

Absolutely, this is going to make a copy. However, it is going to do so using the assignment operator of the NodeTransformations class, so you may need to be careful of how it is defined. If you define a copy constructor, you usually need an assignment operator and a destructor, too (that is commonly known as the rule of three).

edited Apr 24 '13 at 18:58

answered Apr 24 '13 at 18:25

Sergey Kalinichenko

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"Need" is a little strong. I have several classes that need copy constructors and assignment but don't need destructors. – Ryan Witmer Apr 24 '13 at 18:49
@RyanWitmer You're right, there are [exceptions to the rule of three](http://stackoverflow.com/q/15557406/335858), so I should have said "usually need" instead of just "need". Thanks! – Sergey Kalinichenko Apr 24 '13 at 18:59

Would a copy constructor be at work here?

1 Answers1