std::move_only_function::move_only_function

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std::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 std::move_only_function whose target is that of other. other
4) Copy constructor is deleted. std::move_only_function does not satisfy CopyConstructible
5) Let VT be std::decay_t<F>. If f is a null function pointer, a null pointer to member value, or an empty std::move_only_function (may be any other 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 VT is neither same as move_only_function nor a specialization of std::in_place_type_t, and /*is-callable-from*/<VT> (see below) is true
  • The program is ill-formed if std::is_constructible_v<VT, F> is not true
6) Let 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) are true
  • The program is ill-formed if VT is not the same type as T.
7) Let 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) are true
  • The program is ill-formed if VT is not the same type as T.

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

The constant /*is-callable-from*/<VT> is dependent on cv, ref, and noex in the template parameter of std::move_only_function

cv ref noexcept( noex ) /*is-callable-from*/<VT>
noexcept(false) std::is_invocable_r_v <R, VT, Args...> &&

std::is_invocable_r_v<R, VT&, Args...>
noexcept(true) std::is_nothrow_invocable_r_v <R, VT, Args...> &&

std::is_nothrow_invocable_r_v<R, VT&, Args...>
const noexcept(false) std::is_invocable_r_v <R, const VT, Args...> &&

std::is_invocable_r_v <R, const VT&, Args...>

const noexcept(true) std::is_nothrow_invocable_r_v <R, const VT, Args...> &&

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

This section is incomplete
Reason: no example

See also

 constructs a new std::function instance
(public member function of std::function<R(Args...)>)
constructs a new std::copyable_function object
(public member function of std::copyable_function)
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