22 General utilities library [utilities]

22.10 Function objects [function.objects]

22.10.17 Polymorphic function wrappers [func.wrap] Copyable wrapper [func.wrap.copy] Utility [func.wrap.copy.util]

void swap(copyable_function& other) noexcept;
Effects: Exchanges the target objects of *this and other.
friend void swap(copyable_function& f1, copyable_function& f2) noexcept;
Effects: Equivalent to f1.swap(f2).
friend bool operator==(const copyable_function& f, nullptr_t) noexcept;
Returns: true if f has no target object, otherwise false.