20 General utilities library [utilities]

20.9 Function objects [function.objects]

20.9.11 Polymorphic function wrappers [func.wrap]

20.9.11.2 Class template function [func.wrap.func]

20.9.11.2.7 specialized algorithms [func.wrap.func.alg]

template<class R, class... ArgTypes> void swap(function<R(ArgTypes...)>& f1, function<R(ArgTypes...)>& f2);

Effects: f1.swap(f2);