[bregma]

The "zero-cost abstraction" concept is that you don't pay for something you don't use. If you use a smart pointer, you pay for it. If you don't use a smart pointer, it's zero cost.

Any argument that smart pointers are not zero cost to the language because they have a cost when you use them is a classic straw man argument.

[mehrdadn]

I think there might be a terminology mixup here but he probably meant zero-overhead abstraction. And in any case, the point he's making is not a strawman argument.

[bregma]

OK, let's substitute "overhead" for "cost in the argument.

Premise one: C++ has zero overhead for most of its features, like smarts pointers: if you don't use them, they cost nothing.

Premise two: using features like smart pointers adds a cost to your C++ program.

Conclusion (due to the strawman logical fallacy): C++ is not zero overhead because there exists a feature that has a cost if you use it.

I'd like to see the reasoning that leads to the same conclusion without resorting to the strawman logical fallacy.

[mehrdadn]

He talked about more than just unique_ptr if you actually watch the video, but I don't even get why you're dying to have such a pointless argument here. When you see free lunches offered somewhere, do you start arguing with people how everyone is wrong and there is such a thing as a free lunch too? Is it so hard to actually take the point and just move on instead of dissecting it like a mathematical theorem?