Hi Joaquín, I'm using the scope_guard from multi_index/detail/scope_guard.hpp. It seems like a revision has made the destructor and copy-constructor protected instead of private. This is in some sense more idiomatic, but it breaks a use that I have in my upcomming auto_buffer class. Basically I'm only constructing a scope_guard object when I know the code can throw, otherwise I construct a "null" scope_guard which is simply an instance of scope_guard_impl_base. Here's the code: namespace auto_buffer_detail { typedef boost::multi_index::detail::scope_guard_impl_base null_guard; } #define BOOST_AUTO_BUFFER_CONSTRUCTOR_SCOPE_GUARD() \ boost::has_nothrow_copy<T>::value ? boost::auto_buffer_detail::null_guard() : \ boost::multi_index::detail::make_obj_guard( *this, \ &auto_buffer::deallocate, \ buffer_, members_.capacity_ ) and use it like so: boost::multi_index::detail::scope_guard guard = BOOST_AUTO_BUFFER_CONSTRUCTOR_SCOPE_GUARD(); ... guard.dismiss(); Any chance you make the two members public again? -Thorsten