When and how to pass smart pointer (C++)

This post is based on a post from Herb Sutter.

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When

if (The ownership of the object isn't shared or moved &&
    The lifetime of the object is guaranteed 1)
{
    Pass the object itself by value, raw pointer or reference
}
else
{
    Pass the smart pointer either by value or reference
}

¹ The passed object lives longer than it can be used by the receiver.

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How

	unique_ptr	shared_ptr / weak_ptr
By value	To move the ownership	To share the ownership
By reference	To modify the smart pointer (e.g. reset)
By const ref.	Don’t, better use a raw pointer / ref.	To share the ownership 2

² Faster than by value, but you have to guarantee the lifetime while passing.