19 General utilities library [utilities]

19.14 Function objects [function.objects]

19.14.14 Polymorphic function wrappers [func.wrap]

19.14.14.2 Class template function [func.wrap.func]

19.14.14.2.2 Modifiers [func.wrap.func.mod]

void swap(function& other) noexcept;
Effects: Interchanges the targets of *this and other.