How do I pass smart pointers into functions?

Question

When passing objects into functions, do the same rules apply to smart pointers as to other objects that contain dynamic memory?

When I pass, for example, a std::

Answer 1

A smart pointer is an object that refer to another object an manages its lifetime.

Passing a smart pointer reuquires to respect the semantics the smart poitner support:

• Passing as const smartptr& always work (and you cannot change the pointer, but can change the state of what it points to).
• Passing as smartptr& always work (and you can change the pointer as well).
• Passing as smartptr (by copy) works only if smartptr is copyable. It works with std::shared_ptr, but not with std::unique_ptr, unless you "move" it on call, like in func(atd::move(myptr)), thus nullifying myptr, moving the pointer to the passed parameter. (Note that move is implicit if myptr is temporary).
• Passing as smartptr&& (by move) imposes the pointer to be moved on call, by forcing you to explicitly use std::move (but requires "move" to make sense for the particular pointer).