Multiple inputs of the same signature

In some cases, a class may want to receive multiple signals of the same signature. For example, the following class could receive void() signals both through operator() and through AltInput:

class Signal2VoidInputs
    : public signals::consumer<Signal2VoidInputs>
{
public:
    Signal2VoidInputs() : result(0) {};
    void operator()()
    {
        result++;
    }
    void AltInput()
    {
        result+=10;
    }
    int GetResult()
    {
        return result;
    }
private:
    int result;
}; // end class Signal2VoidInputs

The following example shows how to connect signals to all of the above slots. For the class Signal2VoidInputs, this is accomplished using the bind_mem_fn function:

signals::storage<void()> banger;
Signal2VoidInputs inputs;

banger
    | inputs // this will connect to operator()()
    | signals::bind_mem_fn(&Signal2VoidInputs::AltInput, inputs);

banger();
BOOST_CHECK_EQUAL(inputs.GetResult(), 11);