Use a `unique_ptr<T>` to transfer ownership where a pointer is needed

Reason

Using unique_ptr is the cheapest way to pass a pointer safely.

See also: C.50 regarding when to return a shared_ptr from a factory.

Example

unique_ptr<Shape> get_shape(istream& is)  // assemble shape from input stream
{
    auto kind = read_header(is); // read header and identify the next shape on input
    switch (kind) {
    case kCircle:
        return make_unique<Circle>(is);
    case kTriangle:
        return make_unique<Triangle>(is);
    // ...
    }
}

Note

You need to pass a pointer rather than an object if what you are transferring is an object from a class hierarchy that is to be used through an interface (base class).

Enforcement

(Simple) Warn if a function returns a locally allocated raw pointer. Suggest using either unique_ptr or shared_ptr instead.