On 16/04/2012 20:06, Igor R wrote:
just started playing with boost::shared_ptr. How do I get a const iterator pointing to a shared_ptr pointing to a const object? See code below, I'd like to prevent a MyItem being changed through const iterators.
IIUC, the following answers your question: http://www.boost.org/doc/libs/1_49_0/libs/smart_ptr/shared_ptr.htm#FAQ <<Q. Why is operator->() const, but its return value is a non-const pointer to the element type? A. Shallow copy pointers, including raw pointers, typically don't propagate constness. It makes little sense for them to do so, as you can always obtain a non-const pointer from a const one and then proceed to modify the object through it.shared_ptr is "as close to raw pointers as possible but no closer".>>
Got a recommendation as to how to get this const-correct? I'm kinda clueless right now... Or does the above faq mean it just cant be done? struct MyItem { int value; }; struct MyContainer { protected: typedef std::set<boost::shared_ptr<MyItem> > MySet; MySet set; public: MySet::iterator stuff_begin(); // should not change ptr nor MyItem nor set XXX::const_iterator stuff_begin() const; };