std::copyable_function::copyable_function
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< cpp | utility | functional | copyable function
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copyable_function() noexcept;
(1)
(since C++26)
copyable_function( std::nullptr_t ) noexcept;
(2)
(since C++26)
copyable_function( const copyable_function& other );
(3)
(since C++26)
copyable_function( copyable_function&& other ) noexcept;
(4)
(since C++26)
template< class F >
copyable_function( F&& f );
(5)
(since C++26)
copyable_function( F&& f );
template< class T, class... CArgs >
explicit copyable_function( std::in_place_type_t <T>, CArgs&&... args );
(6)
(since C++26)
explicit copyable_function( std::in_place_type_t <T>, CArgs&&... args );
template< class T, class U, class... CArgs >
(7)
(since C++26)
explicit copyable_function( std::in_place_type_t <T>,
Creates a new std::copyable_function.
1,2) Default constructor and the constructor taking nullptr construct an empty
std::copyable_function.3) Copy constructor constructs a
std::copyable_function whose target is a copy of the target of other. Otherwise, constructs an empty std::copyable_function if other is empty.4) Move constructor constructs a
std::copyable_function whose target is that of other. other is in a valid but unspecified state after move construction.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::copyable_function (may be any other specialization), then constructs an empty std::copyable_function. Otherwise, constructs a std::copyable_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 ascopyable_functionnor 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> or std::is_copy_constructible_v <VT> is not true.
6) Let
VT be std::decay_t <T>. Constructs a std::copyable_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
VTis not the same type asTor std::is_copy_constructible_v <VT> is not true.
7) Let
VT be std::decay_t <T>. Constructs a std::copyable_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
VTis not the same type asTor std::is_copy_constructible_v <VT> is not true.
For constructors (5-7), the behavior is undefined unless VT satisfies both Destructible and CopyConstructible requirements.
The constant /*is-callable-from*/<VT> is dependent on cv, ref, and noex in the template parameter of std::copyable_function as below:
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...>
Contents
[edit] Parameters
other
-
another
std::copyable_function to copy or 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
[edit] Exceptions
3) May throw std::bad_alloc on allocation failure or propagate the exception thrown by the initialization of the target.
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 .[edit] Example
This section is incomplete
Reason: no example
Reason: no example
[edit] See also
constructs a new
(public member function of
std::function instance (public member function of
std::function<R(Args...)>) [edit]
constructs a new
(public member function of
std::move_only_function object (public member function of
std::move_only_function) [edit]