So, I use boost::shared_ptr for all the various reference-counting benefits it provides — reference counting for starters, obviously, but also the ability to copy, assign, and therefore store in STL Containers.
The problem is, if I pass it to just one “malicious” function or object, the object can save the ptr and then I’ll never be able to de-allocate it without the foreign function or object nicely relinquishing its ownership.
Ultimately, I try to keep object ownership explicit. I accomplish this by having the owner keep the only shared_ptr to the object, and “guest” objects only store weak_ptrs to the object.
I really don’t want the “shared” part of shared_ptr, but I’m required to use shared_ptr in order to make weak_ptrs. I want to use scoped_ptr, but it’s extremely limited since you can’t copy it. You can’t store it in a container, you can’t lend out weak_ptrs from it, and you can’t transfer ownership to a new manager.
What’s the solution?
It’s good enough to use weak_ptr for guest objects, as you described in question. Otherwise you will have a problem with dead pointers.
I would consider to do application rearchitect to remove “malicious” functions/objects or at least fix their behavior.