+ |
+
+ |
+
+ enable_shared_from_this.hpp+ |
+
| + | |
+ The header <boost/enable_shared_from_this.hpp> defines + the class template enable_shared_from_this. It is used as a + base class that allows a shared_ptr to the current + object to be obtained from within a member function. +
+enable_shared_from_this<T> defines two member functions + called shared_from_this that return a shared_ptr<T> + and shared_ptr<T const>, depending on constness, to this.
+
+class Y: public enable_shared_from_this<Y>
+{
+public:
+
+ shared_ptr<Y> f()
+ {
+ return shared_from_this();
+ }
+}
+
+int main()
+{
+ shared_ptr<Y> p(new Y);
+ shared_ptr<Y> q = p->f();
+ assert(p == q);
+ assert(!(p < q || q < p)); // p and q must share ownership
+}
+
+
+namespace boost
+{
+
+template<class T> class enable_shared_from_this
+{
+public:
+
+ shared_ptr<T> shared_from_this();
+ shared_ptr<T const> shared_from_this() const;
+}
+
+}
+
+ +++ Requires: enable_shared_from_this<T> must be an + accessible base class of T. *this must be a subobject + of an instance t of type T. There must have + existed at least one shared_ptr instance p pointing + to t. +
++ Returns: A shared_ptr<T> instance r that shares + ownership with p. +
++ Postconditions: r.get() == this. +
+
+
+ Copyright © 2002 by Peter Dimov. 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.