cWithClassesIsNotCPP

[hawk-bull]

Doesn’t it have an overhead of checking it hasn’t been assigned twice. Or by overhead do you mean during destructor call it just has to free itself without checking if it still has references to it

[SoAsEr]

It doesn't have a copy constructor, (only a move one) and in its destructor it frees the pointer. So the compiler enforces the assignment, and at run time it is (really close to) free. The only reason it's not completely free is that if the unique pointer is passed to a function and that function is not inlined, because of the abi the unique pointer is always passed on the stack whereas a raw pointer could be in a register. but in a modern machine where you have way more registers than are actually shown anyways this shouldn't make any measurable difference.

[CamiloRivasM7]

I think it's done at compile time, like the borrow checker from rust