[neutronicus]

I strongly disagree. Move Semantics allow you to communicate ownership information at API boundaries with the type system.

C APIs come, of necessity, with tons of documentation about who is deleting what, when. Or, you know, maybe they don't and you have to learn the hard way. std::unique_ptr (implemented with move semantics) largely solves this problem.

And you can imagine notions of ownership more complex than "I'm deleting this at some point" (maybe "I'm versioning this object now, don't worry about it"). If you want to encode these transfers of ownership into your API, that's Move Semantics!

[jfkebwjsbx]

If you read carefully, I said use move semantics to implement containers. That includes std::unique_ptr (a container for pointers with a deleter).

The point is that you shouldn't be using rvalue ref parameters, std::forward, etc. in most of your code. Even std::move should be fairly rare.

[neutronicus]

Any time you want to pass a named unique_ptr across an API boundary, you'll need to std::move it

[jfkebwjsbx]

...which you should avoid as much as possible do.

Passing std types across API boundaries is a code smell.

[MauranKilom]

What? That's one of the primary motivations!

"I have created an object and will pass its unique ownership to you." -> std::unique_ptr

"This routine needs a function that takes two ints and returns a float (without putting all my code into headers)." -> std::function<float(int, int)>.

Can you elaborate in what circumstance you should not pass std::types across API boundaries?

[jfkebwjsbx]

The heap allocation is an implementation detail.

std::function is useful in some situations, but "without putting all my code into headers" is not a good argument.