Re: [Boost-users] scoped_ptr faq

25 Nov 2005


      On Thu, 24 Nov 2005 07:10:41 -0200, Daniel Krügler  wrote:
...
Bruno Martínez wrote:
...
I know.  The problem is that I want incomplete types support *and*  
release
member function.
Use std::auto_ptr and ensure that you obey Peter Dimov's
recommendations. I know, that the standard says, in 5.3.5
"If the object being deleted has incomplete class type at the point of
deletion and the complete class has a
non-trivial destructor or a deallocation function, the behavior is
undefined."
and in 17.4.3.6
"if an incomplete type (3.9) is used as a template argument when
instantiating a template component."
There exists no special restriction on std::auto_ptr for incomplete
classes
I don't understand.  There is a restriction.  It's 17.4.3.6!
...
and the main difference between std::auto_ptr and
boost::scoped_ptr in this point is that the standard says, that "no
diagnose is required", while boost will diagnose that due a safety belt
in boost::checked_delete.
Yes, scoped_ptr is very well the behaved.
...
...
I don't seem to require a destructor in this case, for vc71 or gcc3.4:
#include 
struct node {
     boost::scoped_ptr<node> next;
};
int main()
{
     node n;
}
This snippet does not proof, that no d'tor is needed, because node::next
is empty for the complete program run-time. Just assign a node to next,
and you will see...
I did, but it still works:

#include 

struct node {
     boost::scoped_ptr<node> next;
     node(node* next = 0) : next(next) {}
};

int main()
{
     node n;
     n.next.reset(new node);
}

Bruno