std::copyable_function:: copyable_function

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std::copyable_function
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)
template < class T, class ... CArgs >
explicit copyable_function ( std:: in_place_type_t < T > , CArgs && ... args ) ;
(6) (since C++26)
template < class T, class U, class ... CArgs >

explicit copyable_function ( std:: in_place_type_t < T > ,

std:: initializer_list < U > il, CArgs && ... args ) ;
(7) (since C++26)

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 ) .
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 ) ... .
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 ) ... .

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... >

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

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 .

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::move_only_function object
(public member function of std::move_only_function )
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