C ++ 11-如何使用shared_ptr的向量将此对象放入priority_queue？

Question

I have a base class with a priority_queue like this:

class base
{
   //...
   std::priority_queue<std::shared_ptr<Obj>, std::vector<std::shared_ptr<Obj>>, obj_less> obj_queue;
   //...
}

On my Obj class , I have a method that should push this object into the priority_queue :

void Obj::set ()
{
    BaseServer& myObj = BaseFactory::getBase();
    myObj.set(this); //<------ won't compile :(
}

And this set() will call a set() on my base class :

void base::set(const Obj& o)
{
    obj_queue.push(o);
}

I want to use the this , to get the pointer to this same Obj , and push it into my vector , inside my priority_queue ....

But it won't even compile, and I'm a bit lost...

Any ideas what I'm missing here?

Answer 1

You actually shouln't do this, since, it's really bad idea and you will have no problems only and only if you has raw pointer on Obj in place of calling set function. Idea of your code is strange, but, it's actually better to use shared_ptr and enable_shared_from_this .

class Obj : public std::enable_shared_from_this<Obj>
{
public:
   // ...
   void set()
   {
      BaseServer& myObj = BaseFactory::getBase();
      myObj.set(std::shared_from_this()); //<------ won't compile :(
   }
};

And BaseServer should have function set , that receives shared_ptr on Obj . And of course you should use shared_ptr<Obj> in code, that calls set . For example something like this

class Obj : public std::enable_shared_from_this<Obj>
{
private:
   Obj() {}
public:
   static std::shared_ptr<Obj> create()
   {
      return std::make_shared<Obj>();
   }
   // rest code
};

// code, that calls set function
auto object = Obj::create();
object->set();

Answer 2

myObj.set(this);

passes a pointer, but

void base::set(const Obj& o)

expects an object.

Do

void base::set(const Obj *o)
{
    obj_queue.push(*o);
}

Or

 myObj.set(*this);