std::move_only_function<R(Args...) cv ref noexcept(noex)>::move_only_function
move_only_function() noexcept; |
(1) | (since C++23) |
move_only_function( std::nullptr_t ) noexcept; |
(2) | (since C++23) |
move_only_function( move_only_function&& other ) noexcept; |
(3) | (since C++23) |
move_only_function( const move_only_function& ) = delete; |
(4) | (since C++23) |
template< class F > move_only_function( F&& f ); |
(5) | (since C++23) |
template< class T, class... CArgs > explicit move_only_function( std::in_place_type_t<T>, CArgs&&... args ); |
(6) | (since C++23) |
template< class T, class U, class... CArgs >
explicit move_only_function( std::in_place_type_t<T>,
std::initializer_list<U> il, CArgs&&... args ); |
(7) | (since C++23) |
Creates a new std::move_only_function.
1-2) Default constructor and the constructor taking
nullptr construct an empty
std::move_only_function.
3) Move constructor constructs a
5) Let
std::move_only_function whose target is that of
other.
other is in a valid but unspecified state after move construction.
VT be
std::decay_t<F>. If
f is a null function pointer, a null pointer to member function, or an empty
std::move_only_function (may be any specialization), then constructs an empty
std::move_only_function. Otherwise, constructs a
std::move_only_function whose target is of type
VT and direct-non-list-initialized with
std::forward<F>(f).
- This overload participates in overload resolution only if
VTis neither same asmove_only_functionnor a specialization ofstd::in_place_type_t, and/*is-callable-from*/<VT>(see below) istrue. - The program is ill-formed if
std::is_constructible_v<VT, F>is nottrue.
VT be
std::decay_t<T>. Constructs a
std::move_only_function whose target is of type
VT and direct-non-list-initialized with
std::forward<CArgs>(args)....
- This overload participates in overload resolution only if both
std::is_constructible_v<VT, CArgs...>and/*is-callable-from*/<VT>(see below) aretrue. - The program is ill-formed if
VTis not the same type asT.
VT be
std::decay_t<T>. Constructs a
std::move_only_function whose target is of type
VT and direct-non-list-initialized with
il, std::forward<CArgs>(args)....
- This overload participates in overload resolution only if both
std::is_constructible_v<VT, std::initializer_list<U>&, CArgs...>and/*is-callable-from*/<VT>(see below) aretrue. - The program is ill-formed if
VTis not the same type asT.
For constructors (5-7), the behavior is undefined if VT does not satisfy the Destructible requirements, or std::is_move_constructible_v<VT> is true but VT does not satisfy the MoveConstructible requirements.
The constant /*is-callable-from*/<VT> is dependent on cv, ref, and noex in the template parameter of std::move_only_function as below:
cv ref noexcept(noex) |
/*is-callable-from*/<VT> |
|---|---|
noexcept(false) |
std::is_invocable_r_v<R, VT, Args...> && |
noexcept(true) |
std::is_nothrow_invocable_r_v<R, VT, Args...> && |
const noexcept(false) |
std::is_invocable_r_v<R, const VT, Args...> && |
const noexcept(true) |
std::is_nothrow_invocable_r_v<R, const VT, Args...> && |
& noexcept(false) |
std::is_invocable_r_v<R, VT&, Args...> |
& noexcept(true) |
std::is_nothrow_invocable_r_v<R, VT&, Args...> |
const & noexcept(false) |
std::is_invocable_r_v<R, const VT&, Args...> |
const & noexcept(true) |
std::is_nothrow_invocable_r_v<R, const VT&, Args...> |
&& noexcept(false) |
std::is_invocable_r_v<R, VT, Args...> |
&& noexcept(true) |
std::is_nothrow_invocable_r_v<R, VT, Args...> |
const && noexcept(false) |
std::is_invocable_r_v<R, const VT, Args...> |
const && noexcept(true) |
std::is_nothrow_invocable_r_v<R, const VT, Args...> |
Parameters
| other | - | another std::move_only_function to move from |
| f | - | a function or a Callable object to wrap |
| args | - | arguments to construct the target object |
| il | - | std::initializer_list to construct the target object |
Exceptions
5-7) May throw
std::bad_alloc on allocation failure or propagate the exception thrown by the initialization of the target. No exception is thrown if
VT is a function pointer type or a specialization of
std::reference_wrapper.
Example
See also
constructs a new std::function instance (public member function of std::function<R(Args...)>) |
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