std::copyable_function::copyable_function

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<cpp‎ |utility‎ |functional‎ |copyable function

Compiler support
Freestanding and hosted
Language
Standard library
Standard library headers
Named requirements
Feature test macros(C++20)
Language support library
Concepts library(C++20)
Diagnostics library
Memory management library
Metaprogramming library(C++11)
General utilities library
Containers library
Iterators library
Ranges library(C++20)
Algorithms library
Strings library
Text processing library
Numerics library
Date and time library
Input/output library
Filesystem library(C++17)
Concurrency support library(C++11)
Execution control library(C++26)
Technical specifications
Symbols index
External libraries

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Utilities library

Language support

Type support (basic types, RTTI)

Library feature-test macros(C++20)

Program utilities

Variadic functions

initializer_list

(C++11)

is_constant_evaluated

(C++20)

is_within_lifetime

(C++26)

source_location

(C++20)

Coroutine support(C++20)

Contract support(C++26)

Three-way comparison

three_way_comparablethree_way_comparable_with

(C++20)(C++20)

strong_ordering

(C++20)

weak_ordering

(C++20)

partial_ordering

(C++20)

common_comparison_category

(C++20)

compare_three_way_result

(C++20)

(C++20)

(C++20)

(C++20)

(C++20)

compare_strong_order_fallback

(C++20)

compare_weak_order_fallback

(C++20)

compare_partial_order_fallback

(C++20)

is_eqis_ltis_lteq

(C++20)(C++20)(C++20)

is_neqis_gtis_gteq

(C++20)(C++20)(C++20)

General utilities

Function objects
Bit manipulation(C++20)
C-style bit manipulation(C++26)
bitset
hash (C++11)

Relational operators(deprecated in C++20)

rel_ops::operator!=rel_ops::operator>

rel_ops::operator<=rel_ops::operator>=

Integer comparison functions

cmp_equalcmp_lesscmp_less_than

(C++20)(C++20)(C++20)

cmp_not_equalcmp_greatercmp_greater_than

(C++20)(C++20)(C++20)

in_range

(C++20)

Swap andtype operations

swap
ranges::swap (C++20)
exchange (C++14)
declval (C++11)
to_underlying (C++23)

forward (C++11)
forward_like (C++23)
move (C++11)
move_if_noexcept (C++11)
as_const (C++17)

Common vocabulary types

pair
tuple (C++11)
optional (C++17)
any (C++17)
variant (C++17)

tuple_size (C++11)
tuple_element (C++11)
apply (C++17)
make_from_tuple (C++17)
expected (C++23)

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Function objects

Function wrappers
function (C++11)
move_only_function (C++23)
copyable_function (C++26)
function_ref (C++26)
mem_fn (C++11)
bad_function_call (C++11)

Partial function application
bind_frontbind_back (C++20)(C++23)
bind (C++11)
is_bind_expression (C++11)
is_placeholder (C++11)
_1, _2, _3, ... (C++11)

Function invocation
invokeinvoke_r (C++17)(C++23)
Identity function object
identity (C++20)

Reference wrappers
reference_wrapper (C++11)
refcref (C++11)(C++11)
unwrap_referenceunwrap_ref_decay (C++20)(C++20)

Operator wrappers

plus
minus
negate
multiplies
divides
modulus
bit_and
bit_or
bit_not (C++14)
bit_xor

equal_to
not_equal_to
greater
less
greater_equal
less_equal
logical_and
logical_or
logical_not

Transparent operator wrappers

plus<> (C++14)
minus<> (C++14)
negate<> (C++14)
multiplies<> (C++14)
divides<> (C++14)
modulus<> (C++14)
bit_and<> (C++14)
bit_or<> (C++14)
bit_not<> (C++14)
bit_xor<> (C++14)

equal_to<> (C++14)
not_equal_to<> (C++14)
greater<> (C++14)
less<> (C++14)
greater_equal<> (C++14)
less_equal<> (C++14)
logical_and<> (C++14)
logical_or<> (C++14)
logical_not<> (C++14)

Negators
not_fn (C++17)
Searchers
default_searcher (C++17)
boyer_moore_searcher (C++17)
boyer_moore_horspool_searcher (C++17)

Constrained comparators
ranges::equal_to (C++20)
ranges::not_equal_to (C++20)
ranges::greater (C++20)
ranges::less (C++20)
ranges::greater_equal (C++20)
ranges::less_equal (C++20)
compare_three_way (C++20)

Old binders and adaptors

unary_function (until C++17*)
binary_function (until C++17*)
ptr_fun (until C++17*)
pointer_to_unary_function (until C++17*)
pointer_to_binary_function (until C++17*)
mem_fun (until C++17*)
mem_fun_tmem_fun1_tconst_mem_fun_tconst_mem_fun1_t (until C++17)(until C++17)(until C++17)(until C++17)
not1 (until C++20*)
not2 (until C++20*)

binder1stbinder2nd (until C++17)(until C++17)
bind1stbind2nd (until C++17)(until C++17)

mem_fun_ref (until C++17*)
mem_fun_ref_tmem_fun1_ref_tconst_mem_fun_ref_tconst_mem_fun1_ref_t (until C++17)(until C++17)(until C++17)(until C++17)
unary_negate (until C++20*)
binary_negate (until C++20*)

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std::copyable_function

Member functions
copyable_function::copyable_function
copyable_function::~copyable_function
copyable_function::operator=
copyable_function::swap
copyable_function::operator bool
copyable_function::operator()
Non-member functions
operator==
swap(std::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)
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 newstd::copyable_function.

1,2) Default constructor and the constructor takingnullptr construct an emptystd::copyable_function.

3) Copy constructor constructs astd::copyable_function whose target is a copy of the target ofother. Otherwise, constructs an emptystd::copyable_function ifother is empty.

4) Move constructor constructs astd::copyable_function whose target is that ofother.other is in a valid but unspecified state after move construction.

5) LetVT bestd::decay_t<F>. Iff is a null function pointer, a null pointer to member value, or an emptystd::copyable_function (may be any other specialization), then constructs an emptystd::copyable_function. Otherwise, constructs astd::copyable_function whose target is of typeVT and direct-non-list-initialized withstd::forward<F>(f).

This overload participates in overload resolution only ifVT is neither same ascopyable_function nor a specialization ofstd::in_place_type_t, and/*is-callable-from*/<VT> (see below) istrue.
The program is ill-formed ifstd::is_constructible_v<VT, F> orstd::is_copy_constructible_v<VT> is nottrue.

6) LetVT bestd::decay_t<T>. Constructs astd::copyable_function whose target is of typeVT and direct-non-list-initialized withstd::forward<CArgs>(args)....

This overload participates in overload resolution only if bothstd::is_constructible_v<VT, CArgs...> and/*is-callable-from*/<VT> (see below) aretrue.
The program is ill-formed ifVT is not the same type asT orstd::is_copy_constructible_v<VT> is nottrue.

7) LetVT bestd::decay_t<T>. Constructs astd::copyable_function whose target is of typeVT and direct-non-list-initialized withil,std::forward<CArgs>(args)....

This overload participates in overload resolution only if bothstd::is_constructible_v<VT,std::initializer_list<U>&, CArgs...> and/*is-callable-from*/<VT> (see below) aretrue.
The program is ill-formed ifVT is not the same type asT orstd::is_copy_constructible_v<VT> is nottrue.

For constructors(5-7), the behavior is undefined unlessVT satisfies bothDestructible andCopyConstructible requirements.

The constant/*is-callable-from*/<VT> is dependent oncv,ref, andnoex in the template parameter ofstd::copyable_function as below:

cvrefnoexcept(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...>
constnoexcept(false)	std::is_invocable_r_v<R,const VT, Args...>&& std::is_invocable_r_v<R,const VT&, Args...>
constnoexcept(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...>

[edit]Parameters

other	-	another`std::copyable_function` to copy or move from
f	-	a function or aCallable object to wrap
args	-	arguments to construct the target object
il	-	std::initializer_list to construct the target object

[edit]Exceptions

3) May throwstd::bad_alloc on allocation failure or propagate the exception thrown by the initialization of the target.

5-7) May throwstd::bad_alloc on allocation failure or propagate the exception thrown by the initialization of the target. No exception is thrown ifVT is a function pointer type or a specialization ofstd::reference_wrapper.

[edit]Example

This section is incomplete
Reason: no example

[edit]See also

(constructor)	constructs a new`std::function` instance (public member function of`std::function<R(Args...)>`)[edit]
(constructor)	constructs a new`std::move_only_function` object (public member function of`std::move_only_function`)[edit]