You have some code that creates a HardwareContext object representing a hardware resource.
You need to do some specialized cleanup tasks associated with this object when the destructor of the shared_prt 
referencing if executes when  the reference count reaches zero.

Based on the scenario above? which action do you take to ensure your function cleanup() is executed as specified?

1) use shared_ptr_deleter instead of shared_ptr
2) pass cleanup as the second argument to shared_ptr
3) call addDeleter(cleanup) on the shared_ptr reference
4) override the destruction of the shared_ptr you create to point to cleanup
5) set the deleter property of the shared_ptr