A Large Number of sp_counted_impl_p Objects

Question

I just performed Allocation Profiling about how many objects of each type are in my application. I am using boost::shared_ptr extensively.

I found a large number of sp_counted_impl_p objects allocated, each occupying 16 bytes. How many of sp_counted_impl_p objects can be expect per shared_ptr? Does someone have an idea?

Answer 1

For what I can see in the implementation, just one per shared_ptr. However, note that there are more objects used by boost internally, that may use this counted class directly or shared_ptr itself. Also, if you use the boost.serialization framework, it is also based on this class/mechanism. Anyway, by "a large number", how many of them are there?

Answer 2

There should be one per object you point to with a shared_ptr. If there are more of them, you're probably not using shared_ptr properly and you're begging for troubles like double-free errors.