www.boost.org/libs/smart_ptr/scoped_ptr.htm
The scoped_ptr template is a simple solution for simple needs. It supplies a basic "resource acquisition is initialization" facility, without shared-ownership or transfer-of-ownership semantics.
noncopyable, it is safer than shared_ptr or std::auto_ptr for pointers which should not be copied. Because scoped_ptr is simple, in its usual implementation every operation is as fast as for a built-in pointer and it has no more space overhead that a built-in pointer. scoped_ptr cannot be used in C++ Standard Library containers.
Free Functions swap template<class T> void swap(scoped_ptr<T> & a, scoped_ptr<T> & b); hpp> #include <iostream> struct Shoe { Shoe() { std::cout << "Buckle my shoe\n"; A secondary reason to use scoped_ptr is to prevent a later maintenance programmer from adding a function that transfers ownership by returning the auto_ptr, because the maintenance programmer saw auto_ptr, and assumed ownership could safely be transferred. We all know that under the covers bool is usually just an int. Indeed, some argued against including bool in the C++ standard because of that. But by coding bool rather than int, you tell your readers what your intent is. It has been suggested that scoped_ptr<T> is equivalent to std::auto_ptr<T> const. Ed Brey pointed out, however, that reset will not work on a std::auto_ptr<T> const. Handle/Body Idiom One common usage of scoped_ptr is to implement a handle/body (also called pimpl) idiom which avoids exposing the body (implementation) in the header file.
Frequently Asked Questions Q Why doesn't scoped_ptr have a release() member? A When reading source code, it is valuable to be able to draw conclusions about program behavior based on the types being used. If scoped_ptr had a release() member, it would become possible to transfer ownership of the held pointer, weakening its role as a way of limiting resource lifetime to a given context. Use std::auto_ptr where transfer of ownership is required. Permission to copy, use, modify, sell and distribute this document is granted provided this copyright notice appears in all copies. This document is provided "as is" without express or implied warranty, and with no claim as to its suitability for any purpose.
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