Friendship with method of other class in other File

[Josz]

I have the file configuration below showed; All in independent files.
I would like to give friendship only to "void myClass::print() method" from "myClass" and not to the full "myClass" object.

Please, somebody know how to replace "friend myClass"; for "friend void myClass::print()"

Thanks in advance

//mysubclass.h
#ifndef MYSUBCLASS_H_
#define MYSUBCLASS_H_

class myClass;  //forward declaration is needed

class mySubClass
{
  int i;
  friend myClass;    //<-- I would like to replace it for any like friend void myClass::print()
};

#endif

//myclass.h
#ifndef MYCLASS_H_
#define MYCLASS_H_

class myClass
{
   mySubClass msc;

public
   void print();
};

#endif

//myclass.cpp
#include "mysubclass.h"

void myClass::print() {
  std::cout << msc.i << std::endl;
}

[JKSH]

@Josz I'm not sure if C++ lets you do that exactly. How about https://msdn.microsoft.com/en-us/library/465sdshe.aspx#Class members as friends ?

[jsulm]

@Josz Is mySubClass derived from myClass?

[Josz]

@jsulm No

[karlheinzreichel]

see
https://www.geeksforgeeks.org/friend-class-function-cpp/

regards
karl-heinz

[VRonin]

@karlheinzreichel solution requires mySubClass to know the full definition of myClass. You can't just pre-declare class myClass; //forward declaration is needed

An alternative is

class FriendHelper{
public:
static void actualPrint(myClass& sender);
};

now move the body of void print(); inside the body of actualPrint and change it to void print() {FriendHelper::actualPrint(*this);}

No you can make FriendHelper a friend of both myClass and mySubClass