Why is this’s friend function not accessing private variables???

[Ctylersills]

#include <iostream>
using namespace std;


class StankFist
{
    public:
        StankFist(){stinkyVar=0;}
    private:
          int stinkyVar;
    friend void stinkysFriend(StankFist &sfo);
};


void stinkyFriend(StankFist &sfo)
{
    sfo.stinkyVar=99;
    cout << sfo.stinkyVar<< endl;
}


int main()
{
    StankFist bob;
    stinkysFriend(bob);
    return 0;
}

Why am i getting this error when the function is a friend?

error: ‘stinkyVar” is a private member of ‘StankFist’
sfo.stinkyVar=99;
- —^

note: declared private here
int stinkyVar;
- - ^