shared_ptr and container iterators

16 Apr 2012

      Hi all,

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.

struct MyItem
{
	int	value;
};

struct MyContainer
{
	typedef std::set	MySet;
	MySet	set;
};

int main(int argc, char* argv[])
{
	MyContainer	mc;

	boost::shared_ptr<MyItem>	p(new MyItem);
	p->value = 5;
	mc.set.insert(p);

	MyContainer::MySet::const_iterator	i = mc.set.begin();
	// cannot mutate shared_ptr pointed to by iterator: ok
	//(*i).reset(new MyItem);
	// cannot change ptr but can change value: ok
	(*i)->value = 6;

	MyContainer::MySet::iterator	j = mc.set.begin();
	(*j).reset(new MyItem);

	// how to do this?
	// should not change ptr nor MyItem
	std::set::const_iterator k =
mc.set.begin();

	return 0;
}

Johannes Totz

Igor R

Johannes Totz

Jeffrey Lee Hellrung, Jr.

Igor R

Thorsten Ottosen

Johannes Totz

Thorsten Ottosen

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