El 25/01/2013 21:47, Matias Capeletto escribió:
On Fri, Jan 25, 2013 at 9:30 PM, Ion Gaztañaga <igaztanaga@gmail.com> wrote:
If Bimap exports a pointer type (say Bimap::pointer or similar) that can be offset_ptr or raw pointer (I think multiindex exports it), then you just need to use:
typedef boost::pointer_to_other <typename Bimap::pointer, Bimap>::type bimap_ptr;
typedef boost::intrusive::pointer_traits <typename Bimap::pointer>:: rebind_pointer<Bimap>::type bimap_ptr;
Thanks for the answer Ion. Ok, so doing this I will only pay for the offset_ptr in case the allocator needs it. That is good.
But still when users will select an interprocess allocator they will be paying for every call to the views:
left_type& left = bm.left; left.size(); // needs to use offset_ptr
Have this problem also with iterators. Containers with interprocess allocators will return an iterator that can be placed in shared memory (contains offset_ptr) but when you use it to iterate in your process, you pay the price of offset_ptr. I think multiindex also pays this price.
What MultiIndex is doing is creating the index views with a pointer to (this) every time the user ask them. I could do the same if I deprecate .left and .right and include get_left() and get_right() functions. But as I said I will like to keep the current interface... is something like the rewire extension impossible? (I am afraid it is if you are pointing to read only memory).
I don't fully understand what do you achieve with "rewire", can you elaborate, please? Best, Ion