std::bind overload resolution

Question

The following code works fine

#include 

using namespace std;
using namespace std::placeholders;

class A
{
  int operator()( int i, int j          


        

Answer 1

There are some "lift" macros available that automate passing overload sets as parameters by wrapping them into a lambda that simply forwards all parameters passed to it. One that is provided by Boost can make the code compile via

#include <boost/hof/lift.hpp>

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

There are also proposals for making it easier to pass overload sets, see e.g. P0834, but I don't know whether this will find or found consensus.

Answer 2

You need a cast to disambiguate the overloaded function:

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

Answer 3

If you have C++11 available you should prefer lambdas over std::bind since it usually results in code that is more readable:

auto aBind = [&a](int i, int j){ return a(i, j); };

compared to

auto aBind = std::bind(static_cast<int(A::*)(int,int)>(&A::operator()), std::ref(a), std::placeholders::_2, std::placeholders::_1);