1) You're lucky. If not, you'll get a segmentation fault.
2) The memory was not overwritten in any way.
3) You could use slot::track to automatically disconnect when the tracked object gets deleted. Boost.Signals2 could track objects that are managed by boost::shared_ptr.
#include <boost/signals2.hpp>
#include <boost/shared_ptr.hpp>
struct object_with_slot
{
void operator()()
{
std::cout << "Slot called!" << std::endl;
member = 50500;
}
int member;
};
//
int main()
{
typedef boost::signals2::signal<void ()> sig_type;
sig_type sig;
{
boost::shared_ptr<object_with_slot> ptr(new object_with_slot);
sig.connect(sig_type::slot_type(*ptr).track(ptr));
// 'object_with_slot' managed by ptr is destroyed
}
sig(); // 'object_with_slot' not called here.
return 0;
}
UPDATE:
Added code to track objects for std::shared_ptr and std::weak_ptr:
#include <memory>
#include <boost/signals2.hpp>
// added specializations for std::weak_ptr and std::shared_ptr
namespace boost
{
namespace signals2
{
template<typename T> struct weak_ptr_traits<std::weak_ptr<T> >
{
typedef std::shared_ptr<T> shared_type;
};
template<typename T> struct shared_ptr_traits<std::shared_ptr<T> >
{
typedef std::weak_ptr<T> weak_type;
};
}
}
struct object_with_slot
{
void operator()()
{
std::cout << "Slot called!" << std::endl;
member = 50500;
}
int member;
};
//
int main()
{
typedef boost::signals2::signal<void ()> sig_type;
sig_type sig;
std::shared_ptr<object_with_slot> ptr(new object_with_slot);
sig.connect(sig_type::slot_type(*ptr).track_foreign(ptr)); // ptr is tracked
sig();
return 0;
}