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Closes #836

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hsutter 2017-03-13 12:05:51 -07:00
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CppCoreGuidelines.md
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@ -3064,6 +3064,8 @@ When I call `length(s)` should I test for `s == nullptr` first? Should the imple
Using `unique_ptr` is the cheapest way to pass a pointer safely.
See also [C.50](#Rc-factory) regarding when to return a `shared_ptr` from a factory.
##### Example
unique_ptr<Shape> get_shape(istream& is) // assemble shape from input stream
@ -5058,6 +5060,10 @@ An initialization explicitly states that initialization, rather than assignment,
If the state of a base class object must depend on the state of a derived part of the object, we need to use a virtual function (or equivalent) while minimizing the window of opportunity to misuse an imperfectly constructed object.
##### Note
The return type of the factory should normally be `unique_ptr` by default; if some uses are shared, the caller can `move` the `unique_ptr` into a `shared_ptr`. However, if the factory author knows that all uses of the returned object will be shared uses, return `shared_ptr` and use `make_shared` in the body to save an allocation.
##### Example, bad
class B {
@ -5091,7 +5097,7 @@ If the state of a base class object must depend on the state of a derived part o
virtual void f() = 0;
template<class T>
static shared_ptr<T> Create() // interface for creating objects
static shared_ptr<T> Create() // interface for creating shared objects
{
auto p = make_shared<T>();
p->PostInitialize();