Equality comparing boost::function with functor.members.func_ptr

Question

I'm currently trying to implement an event manager in C++. In principle it keeps a map of event types (uint64_t) to a list of boost::function<void(const IEventDataPtr&)>s.

User can register new listeners by calling EventManager::add(boost::function<void(const IEventDataPtr&)> delegate, EventType event). However, a user might want to deregister their listener later. This would involve finding this particular function object and removing it from the respective list.

I know that boost::function is generally not comparable. When playing around in the debugger I found that by comparing functor.members.func_ptr I could actually do what I was trying to do. It works as expected for lambdas, boost::bind, static member functions and regular functions. Is this safe to do? Are there any gotchas?

My expectation would be for the same object (i.e. the same lambda, function, etc. pp.) to have the same address, that is not shared with others.