Asger Mangaard wrote:
Tobias Schwinger wrote:
o save a few lines for "deep compare" (it seems unlikely to me that this feature will be very useful)
Unfortunately the context got lost, here: That point is from my summary of what the library seems to buy me in its current state.
Would you rather compare on the pointers themselves, or?
Not neccessarily (but it seems a more approriate default to me, while we're at it). Why bother with comparison in the first place?
o stack allocation using SBO
Could be interresting.
...and can probably done with STL-style allocator support. Something like that namespace my_project { // customize boost::body_ptr for my_project's memory management template<typename T> struct body_ptr : boost::body_ptr<T, my_custom_allocator<T> > { }; } should work, however, so the user does not have to repeat the parametrization all over the place.
o COW (copy on non const access)
Could you give an example?
Let's see (untested and incomplete code for illustration only): class my_class { struct heavy_body; body_ptr< heavy_body > ptr_body; public: state get_state() const; void set_state(state); }; // ... my_class my_instance; // ... my_class my_second_instance(my_instance); // no copy, both instances share the same body #if case1 my_second_instance.set_state(some_state); // non-const access of shared body ==> need a copy // my_second_instance gets a brand new copy #elif case2 my_instance.set_state(some_state); // non-const access of shared body ==> need a copy // my_instance gets a brand new copy #endif Works for you? Note that you have to synchronize the reference counter and also the copy operation in a multithreaded environment. Regards, Tobias