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:

(1.1)
g is a value of the result of a bind_front or bind_back invocation,
(1.2)
FD is the type decay_t<F>,
(1.3)
fd is the target object of g ([func.def]) of type FD, direct-non-list-initialized with std::forward<F>(f),
(1.4)
BoundArgs is a pack that denotes decay_t<Args>...,
(1.5)
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
(1.6)
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.

Preconditions: FD meets the Cpp17MoveConstructible requirements.

For each

T_{i}

in BoundArgs, if

T_{i}

is an object type,

T_{i}

meets the Cpp17MoveConstructible requirements.

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

(4.1)
invoke(fd, bound_args..., call_args...) for a bind_front invocation, or
(4.2)
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]).