[func.bind.partial] (original) (raw)

22 General utilities library [utilities]

22.10 Function objects [function.objects]

22.10.14 Function templates bind_front and bind_back [func.bind.partial]

template<class F, class... Args> constexpr _unspecified_ bind_front(F&& f, Args&&... args);template<class F, class... Args> constexpr _unspecified_ bind_back(F&& f, Args&&... args);

Within this subclause:

• g is a value of the result of a bind_front or bind_back invocation,
• FD is the type decay_t<F>,
• fd is the target object of g ([func.def]) of type FD, direct-non-list-initialized with std​::​forward<F​>(f),
• BoundArgs is a pack that denotes decay_t<Args>...,
• bound_args is a pack of bound argument entities of g ([func.def]) of types BoundArgs..., direct-non-list-initialized with std​::​forward<Args>(args)..., respectively, and
• call_args is an argument pack used in a function call expression ([expr.call]) of g.

Mandates: is_constructible_v<FD, F> &&is_move_constructible_v<FD> && (is_constructible_v<BoundArgs, Args> && ...) && (is_move_constructible_v<BoundArgs> && ...) is true.

Returns: A perfect forwarding call wrapper ([func.require]) gwith call pattern:

• invoke(fd, bound_args..., call_args...)for a bind_front invocation, or
• invoke(fd, call_args..., bound_args...)for a bind_back invocation.

Throws: Any exception thrown by the initialization of the state entities of g ([func.def]).

template<auto f, class... Args> constexpr _unspecified_ bind_front(Args&&... args);template<auto f, class... Args> constexpr _unspecified_ bind_back(Args&&... args);

Within this subclause:

• F is the type of f,
• g is a value of the result of a bind_front or bind_back invocation,
• BoundArgs is a pack that denotes decay_t<Args>...,
• bound_args is a pack of bound argument entities ofg ([func.def]) of types BoundArgs..., direct-non-list-initialized with std​::​forward<Args>(args)..., respectively, and
• call_args is an argument pack used in a function call expression ([expr.call]) of g.

Mandates:

• (is_constructible_v<BoundArgs, Args> && ...) is true, and
• (is_move_constructible_v<BoundArgs> && ...) is true, and
• if is_pointer_v<F> || is_member_pointer_v<F> is true, then f != nullptr is true.

Returns: A perfect forwarding call wrapper ([func.require]) g that does not have a target object, and has the call pattern:

• invoke(f, bound_args..., call_args...)for a bind_front invocation, or
• invoke(f, call_args..., bound_args...)for a bind_back invocation.

Throws: Any exception thrown by the initialization of bound_args.