[functional.syn] (original) (raw)

22 General utilities library [utilities]

22.10 Function objects [function.objects]

22.10.2 Header synopsis [functional.syn]

namespace std { // [func.invoke], invoke template<class F, class... Args> constexpr invoke_result_t<F, Args...> invoke(F&& f, Args&&... args) // freestanding noexcept(is_nothrow_invocable_v<F, Args...>);template<class R, class F, class... Args> constexpr R invoke_r(F&& f, Args&&... args) // freestanding noexcept(is_nothrow_invocable_r_v<R, F, Args...>);// [refwrap], reference_wrapper template<class T> class reference_wrapper; // freestanding template<class T> constexpr reference_wrapper<T> ref(T&) noexcept; // freestanding template<class T> constexpr reference_wrapper<const T> cref(const T&) noexcept; // freestanding template<class T> void ref(const T&&) = delete; // freestanding template<class T> void cref(const T&&) = delete; // freestanding template<class T> constexpr reference_wrapper<T> ref(reference_wrapper<T>) noexcept; // freestanding template<class T> constexpr reference_wrapper<const T> cref(reference_wrapper<T>) noexcept; // freestanding // [refwrap.common.ref], common_reference related specializations template<class R, class T, template<class> class RQual, template<class> class TQual> requires see below struct basic_common_reference<R, T, RQual, TQual>;template<class T, class R, template<class> class TQual, template<class> class RQual> requires see below struct basic_common_reference<T, R, TQual, RQual>;// [arithmetic.operations], arithmetic operations template<class T = void> struct plus; // freestanding template<class T = void> struct minus; // freestanding template<class T = void> struct multiplies; // freestanding template<class T = void> struct divides; // freestanding template<class T = void> struct modulus; // freestanding template<class T = void> struct negate; // freestanding template<> struct plus<void>; // freestanding template<> struct minus<void>; // freestanding template<> struct multiplies<void>; // freestanding template<> struct divides<void>; // freestanding template<> struct modulus<void>; // freestanding template<> struct negate<void>; // freestanding // [comparisons], comparisons template<class T = void> struct equal_to; // freestanding template<class T = void> struct not_equal_to; // freestanding template<class T = void> struct greater; // freestanding template<class T = void> struct less; // freestanding template<class T = void> struct greater_equal; // freestanding template<class T = void> struct less_equal; // freestanding template<> struct equal_to<void>; // freestanding template<> struct not_equal_to<void>; // freestanding template<> struct greater<void>; // freestanding template<> struct less<void>; // freestanding template<> struct greater_equal<void>; // freestanding template<> struct less_equal<void>; // freestanding // [comparisons.three.way], class compare_three_way struct compare_three_way; // freestanding // [logical.operations], logical operations template<class T = void> struct logical_and; // freestanding template<class T = void> struct logical_or; // freestanding template<class T = void> struct logical_not; // freestanding template<> struct logical_and<void>; // freestanding template<> struct logical_or<void>; // freestanding template<> struct logical_not<void>; // freestanding // [bitwise.operations], bitwise operations template<class T = void> struct bit_and; // freestanding template<class T = void> struct bit_or; // freestanding template<class T = void> struct bit_xor; // freestanding template<class T = void> struct bit_not; // freestanding template<> struct bit_and<void>; // freestanding template<> struct bit_or<void>; // freestanding template<> struct bit_xor<void>; // freestanding template<> struct bit_not<void>; // freestanding // [func.identity], identity struct identity; // freestanding // [func.not.fn], function template not_fn template<class F> constexpr unspecified not_fn(F&& f); // freestanding template<auto f> constexpr unspecified not_fn() noexcept; // freestanding // [func.bind.partial], function templates bind_front and bind_back template<class F, class... Args> constexpr unspecified bind_front(F&&, Args&&...); // freestanding template<auto f, class... Args> constexpr unspecified bind_front(Args&&...); // freestanding template<class F, class... Args> constexpr unspecified bind_back(F&&, Args&&...); // freestanding template<auto f, class... Args> constexpr unspecified bind_back(Args&&...); // freestanding // [func.bind], bind template<class T> struct is_bind_expression; // freestanding template<class T> constexpr bool is_bind_expression_v = // freestanding is_bind_expression<T>::value;template<class T> struct is_placeholder; // freestanding template<class T> constexpr int is_placeholder_v = // freestanding is_placeholder<T>::value;template<class F, class... BoundArgs> constexpr unspecified bind(F&&, BoundArgs&&...); // freestanding template<class R, class F, class... BoundArgs> constexpr unspecified bind(F&&, BoundArgs&&...); // freestanding namespace placeholders { // M is the implementation-defined number of placeholders see below _1; // freestanding see below _2; // freestanding ⋮see below _ M; // freestanding } // [func.memfn], member function adaptors template<class R, class T> constexpr unspecified mem_fn(R T::*) noexcept; // freestanding // [func.wrap], polymorphic function wrappers // [func.wrap.badcall], class bad_function_call class bad_function_call;// [func.wrap.func], class template function template<class> class function; // not defined template<class R, class... ArgTypes> class function<R(ArgTypes...)>;// [func.wrap.func.alg], function specialized algorithms template<class R, class... ArgTypes> void swap(function<R(ArgTypes...)>&, function<R(ArgTypes...)>&) noexcept;// [func.wrap.func.nullptr], function null pointer comparison operator functions template<class R, class... ArgTypes> bool operator==(const function<R(ArgTypes...)>&, nullptr_t) noexcept;// [func.wrap.move], move-only wrapper template<class... S> class move_only_function; // not defined template<class R, class... ArgTypes> class move_only_function<R(ArgTypes...) cv _ref_ noexcept(_noex_)>; // see below // [func.wrap.copy], copyable wrapper template<class... S> class copyable_function; // not defined template<class R, class... ArgTypes> class copyable_function<R(ArgTypes...) cv _ref_ noexcept(_noex_)>; // see below // [func.wrap.ref], non-owning wrapper template<class... S> class function_ref; // freestanding, not defined template<class R, class... ArgTypes> class function_ref<R(ArgTypes...) cv noexcept(_noex_)>; // freestanding, see below // [func.search], searchers template<class ForwardIterator1, class BinaryPredicate = equal_to<>> class default_searcher; // freestanding template<class RandomAccessIterator,class Hash = hash<typename iterator_traits<RandomAccessIterator>::value_type>,class BinaryPredicate = equal_to<>> class boyer_moore_searcher;template<class RandomAccessIterator,class Hash = hash<typename iterator_traits<RandomAccessIterator>::value_type>,class BinaryPredicate = equal_to<>> class boyer_moore_horspool_searcher;// [unord.hash], class template hash template<class T> struct hash; // freestanding namespace ranges { // [range.cmp], concept-constrained comparisons struct equal_to; // freestanding struct not_equal_to; // freestanding struct greater; // freestanding struct less; // freestanding struct greater_equal; // freestanding struct less_equal; // freestanding } template<class Fn, class... Args> concept callable = // exposition only requires (Fn&& fn, Args&&... args) { std::forward<Fn>(fn)(std::forward<Args>(args)...);};template<class Fn, class... Args> concept nothrow-callable = // exposition only callable<Fn, Args...> && requires (Fn&& fn, Args&&... args) { { std::forward<Fn>(fn)(std::forward<Args>(args)...) } noexcept;};template<class Fn, class... Args> using call-result-t = decltype(declval<Fn>()(declval<Args>()...)); // exposition only template<const auto& T> using decayed-typeof = decltype(auto(T)); // exposition only }

[Example 1:

If a C++ program wants to have a by-element addition of two vectors aand b containing double and put the result into a, it can do:transform(a.begin(), a.end(), b.begin(), a.begin(), plus<double>());

— _end example_]

[Example 2:

To negate every element of a:

transform(a.begin(), a.end(), a.begin(), negate<double>()); — _end example_]