Question

I would like to ensure that an object’s destructor does not run. Is there any way to do this other than putting the object on the heap and not calling delete?

Answer 1

Not recommended, but here’s another way:

char buffer[sizeof(T) + alignof(T)];
char* aligned_buffer = buffer + alignof(T) - reinterpret_cast<intptr_t>(buffer) % alignof(T);
T* object = new (aligned_buffer) T;

However, although this means the compiler won’t automatically call the destructor, the programmer still can:

object->~T();

Of course, that’s also true with heap allocation:

delete object;

To prevent that, you’ll have to make the destructor inaccessible:

struct T
{
private:
   ~T() {};
};

Or really inaccessible (related: Why must a base class destructor be accessible only when a custom constructor is declared?):

class indestructible_base
{
    ~indestructible_base();
};

struct T : indestructible_base
{
};