Does a no-op “do nothing” function object exist in C++(0x)?

Question

I realize this is a ludicrous question for something that takes less than 2 seconds to implement. But I vaguely remember reading that one was introduced with the new standar

Answer 1

I use this as a drop-in no-op for cases where I expect a functor that does not return any value.

struct VoidNoOp {
    void operator()() const { }
    template
    void operator()(A a) const { (void)(a); }
    template
    void operator()(A a, B b) const { (void)(a); (void)(b); }
    template
    void operator()(A a, B b, C c) const { (void)(a); (void)(b); (void)(c); }
};

Here is a C++11 variation for arbitrary numbers of parameters:

struct VoidNoOp {
    void operator()() const { };
    template
    void operator()(P1 p1, Params... parameters) {
        (void)(p1);             // we do this just to remove warnings -- requires the recursion
        operator()(parameters...);
    }
};