Is it possible to use reference type alias with pointer operator to declare a reference to pointer?

Question

I have a simple example here: I used type alias using using keyword for a reference type then I want to know whether I can use that type alias with pointer operator(*) to declare a reference to pointer:

int main(){

    using ref_int = int&;

    int x = 10;
    int* p = &x;

    //int*(&rpx) = p;
    //ref_int * rptrx = p; // pointer to reference is not allowed.
    *ref_int(rptrx) = p; // rptrx is undefined

}

• Because as a matter of curiosity when I used the Element-type of std::vector<int>::reference I wanted to combine it with pointer operator * to declare a reference to pointer:

  int* ptr = new int(1000);
  std::vector<int>::*(reference rptr) = ptr; // error: expected expression
  

• But I can to use pointer type alias combined with reference operator "&" to declare it:

  using pInt = int*;
  
  int i = 57;
  int* ptrI = &i;
  pInt(&rpInt) = ptrI;
  
  cout << *rpInt << endl;
  

** I know I cannot have a pointer to a reference because a reference is just an alias name for an already existing object while a pointer is an object thus we can have a pointer or a reference to it.

Answer 1

You can't have a pointer to a reference in C++. In C++, references are just aliases for the thing that they refer to, the standard doesn't even require them to take up any storage. Trying to use a reference alias to make a reference to a pointer will not work because using the alias will only ever give you a pointer to a reference type.

So, if you want a pointer to the thing the reference refers to you just use

auto * ptr = &reference_to_thing;

---

If you want a reference to a pointer that syntax is

int foo = 42;
int* ptr = &foo;
int*& ptr_ref = ptr;