Difference between boost::scoped_ptr<T> and std::unique_ptr<T>

c++ unique-ptr scoped-ptr
moshbear picture moshbear · Nov 20, 2011 · Viewed 30.1k times · Source

Is the sole difference between boost::scoped_ptr<T> and std::unique_ptr<T> the fact that std::unique_ptr<T> has move semantics whereas boost::scoped_ptr<T> is just a get/reset smart pointer?

Answer

Nicol Bolas picture Nicol Bolas · Nov 20, 2011

No, but that is the most important difference.

The other major difference is that unique_ptr can have a destructor object with it, similarly to how shared_ptr can. Unlike shared_ptr, the destructor type is part of the unique_ptr's type (the way allocators are part of STL container types).

A const unique_ptr can effectively do most of what a scoped_ptr can do; indeed, unlike scoped_ptr, a const unique_ptr cannot be rebound with a reset call.

Also, unique_ptr<T> can work on a T which is an incomplete type. The default deleter type requires that T be complete when you do anything to the unique_ptr that potentially invokes the deleter. You therefore have some freedom to play games about where that happens, depending on the situation.

Related questions

Differences between unique_ptr and shared_ptr

Possible Duplicates: pimpl: shared_ptr or unique_ptr smart pointers (boost) explained Could someone explain differences between shared_ptr and unique_ptr?

Read More
How do I pass a unique_ptr argument to a constructor or a function?

I'm new to move semantics in C++11 and I don't know very well how to handle unique_ptr parameters in constructors or functions. Consider this class referencing itself: #include <memory> class Base { public: typedef unique_ptr<Base&…

Read More
Returning unique_ptr from functions

unique_ptr<T> does not allow copy construction, instead it supports move semantics. Yet, I can return a unique_ptr<T> from a function and assign the returned value to a variable. #include <iostream> #…

Read More