20 General utilities library [utilities]

20.14 Function objects [function.objects]

20.14.16 Function template mem_­fn [func.memfn]

template<class R, class T> constexpr unspecified mem_fn(R T::* pm) noexcept;
Returns: A simple call wrapper ([func.def]) fn with call pattern invoke(pmd, call_­args...), where pmd is the target object of fn of type R T​::​* direct-non-list-initialized with pm, and call_­args is an argument pack used in a function call expression ([expr.call]) of pm.