std::function_ref:: function_ref
|
template
<
class
F
>
function_ref ( F * f ) noexcept ; |
(1) | (since C++26) |
|
template
<
class
F
>
function_ref ( F && f ) noexcept ; |
(2) | (since C++26) |
|
template
<
auto
f
>
function_ref ( std:: nontype_t < f > ) noexcept ; |
(3) | (since C++26) |
|
template
<
auto
f,
class
U
>
function_ref ( std:: nontype_t < f > , U && obj ) noexcept ; |
(4) | (since C++26) |
|
template
<
auto
f,
class
T
>
function_ref ( std:: nontype_t < f > , /*cv*/ T * obj ) noexcept ; |
(5) | (since C++26) |
|
function_ref
(
const
function_ref
&
other
)
=
default
;
|
(6) | (since C++26) |
Creates a new
std::function_ref
.
bound-entity
with
f
, and
thunk-ptr
with the address of a function
thunk
. The behavior is undefined if
f
is a null pointer.
- This overload participates in overload resolution only if both std:: is_function_v < F > and /*is-invocable-using*/ < F > are true .
bound-entity
with
std::
addressof
(
f
)
, and
thunk-ptr
with the address of a function
thunk
.
-
Let
T
be
std::
remove_reference_t
<
F
>
. This overload participates in overload resolution only if :
-
std::
remove_cvref_t
<
F
>
is not the same type as
function_ref, - std:: is_member_pointer_v < T > is false , and
- /*is-invocable-using*/ < /*cv*/ T & > is true .
-
std::
remove_cvref_t
<
F
>
is not the same type as
bound-entity
with a pointer to an unspecified object or null pointer value, and
thunk-ptr
with the address of a function
thunk
.
- Let F be decltype ( f ) . This overload participates in overload resolution only if /*is-invocable-using*/ < F > is true .
- The program is ill-formed if f ! = nullptr is false when std:: is_pointer_v < F > || std:: is_member_pointer_v < F > is true .
bound-entity
with
std::
addressof
(
obj
)
, and
thunk-ptr
with the address of a function
thunk
.
-
Let
T
be
std::
remove_reference_t
<
U
>
and
F
be
decltype
(
f
)
. This overload participates in overload resolution only if :
- std:: is_rvalue_reference_v < U && > is false , and
- /*is-invocable-using*/ < F, /*cv*/ T & > is true .
- The program is ill-formed if f ! = nullptr is false when std:: is_pointer_v < F > || std:: is_member_pointer_v < F > is true .
bound-entity
with
obj
, and
thunk-ptr
with the address of a function
thunk
. The behavior is undefined if
obj
is a null pointer when
std::
is_member_pointer_v
<
F
>
is
true
.
- Let F be decltype ( f ) . This overload participates in overload resolution only if /*is-invocable-using*/ < F, /*cv*/ T * > is true .
- The program is ill-formed if f ! = nullptr is false when std:: is_pointer_v < F > || std:: is_member_pointer_v < F > is true .
bound-entity
and
thunk-ptr
of
other
.
The address of a function
thunk
is used to initialize
thunk-ptr
such that a call to
thunk
(
bound-entity
,
call-args
...
)
is
expression-equivalent
to:
| Overloads | Expression-equivalence |
|---|---|
| ( 1,3 ) |
std::
invoke_r
<
R
>
(
f,
call-args
...
)
|
| ( 2 ) |
std::
invoke_r
<
R
>
(
static_cast
<
cv
T
&
>
(
f
)
,
call-args
...
)
|
| ( 4 ) |
std::
invoke_r
<
R
>
(
f,
static_cast
<
cv
T
&
>
(
obj
)
,
call-args
...
)
|
| ( 5 ) |
std::
invoke_r
<
R
>
(
f, obj,
call-args
...
)
|
/*is-invocable-using*/ < T... > is true if and only if:
- std:: is_nothrow_invocable_r_v < R, T..., Args... > is true if noex is true , or
- std:: is_invocable_r_v < R, T..., Args... > is true
Parameters
| other | - |
another
function_ref
to copy from
|
| f | - | a function or a Callable object to wrap |
| obj | - | an object or pointer to bound |
Example
|
This section is incomplete
Reason: no example |
See also
constructs a new
std::move_only_function
object
(public member function of
std::move_only_function
)
|