questions regarding shared_from_this

Question

I have a function which takes a shared_ptr. In some member function memfun of MyClass, I need to pass this

Answer 1

1) No, it's not impossible to do this without shared_from_this. You can simply construct a shared_ptr with a no-op deleter:

void do_nothing(MyClass*) {}

void MyClass:memfun()
{
    func(shared_ptr(this, do_nothing));
}

Seeing as you don't actually seem to need shared_from_this after all, I'm going to skip the next two parts of your question.