deduction guides for
Defined in header
template<class R, class... ArgTypes>
function(R(*)(ArgTypes...)) -> function<R(ArgTypes...)>;
function(F) -> function</*see below*/>;
The type deduced by these deduction guides may change in a later standard revision (in particular, this might happen if noexcept support is added to std::function in a later standard).
 Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
|DR||Applied to||Behavior as published||Correct behavior|
|LWG 3238||C++17||behavior of (2) was unclear||clarified|