c++ - std::bind overload resolution

Question

The following code works fine

#include <functional>

using namespace std;
using namespace std::placeholders;

class A
{
  int operator()( int i, int j ) { return i - j; }
};

A a;
auto aBind = bind( &A::operator(), ref(a), _2, _1 );

This does not

#include <functional>

using namespace std;
using namespace std::placeholders;

class A
{
  int operator()( int i, int j ) { return i - j; }
  int operator()( int i ) { return -i; }
};

A a;
auto aBind = bind( &A::operator(), ref(a), _2, _1 );

I have tried playing around with the syntax to try and explicitly resolve which function I want in the code that does not work without luck so far. How do I write the bind line in order to choose the call that takes the two integer arguments?

Answer 1

You need a cast to disambiguate the overloaded function:

(int(A::*)(int,int))&A::operator()