std::ranges:: iter_move
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Defined in header
<iterator>
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||
|
inline
namespace
/* unspecified */
{
inline
constexpr
/* unspecified */
iter_move
=
/* unspecified */
;
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(since C++20)
(customization point object) |
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Call signature
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||
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template
<
class
T
>
requires
/* see below */
|
(since C++20) | |
Obtains an rvalue reference or a prvalue temporary from a given iterator.
A ranges :: iter_move ( t ) is expression-equivalent to:
-
iter_move
(
t
)
, if
t
has a class or enumeration type and the expression is well-formed when treated as an
unevaluated operand
, where the
overload resolution
of
iter_moveis performed only with the candidates found by argument-dependent lookup . - Otherwise, std :: move ( * t ) if * t is well-formed and is an lvalue.
- Otherwise, * t if * t is well-formed and is an rvalue.
In all other cases, a call to
ranges::iter_move
is ill-formed, which can result in
substitution failure
when
ranges
::
iter_move
(
e
)
appears in the immediate context of a template instantiation.
If ranges :: iter_move ( e ) is not equal to * e , the program is ill-formed, no diagnostic required.
Customization point objects
The name
ranges::iter_move
denotes a
customization point object
, which is a const
function object
of a
literal
semiregular
class type. For exposition purposes, the cv-unqualified version of its type is denoted as
__iter_move_fn
.
All instances of
__iter_move_fn
are equal. The effects of invoking different instances of type
__iter_move_fn
on the same arguments are equivalent, regardless of whether the expression denoting the instance is an lvalue or rvalue, and is const-qualified or not (however, a volatile-qualified instance is not required to be invocable). Thus,
ranges::iter_move
can be copied freely and its copies can be used interchangeably.
Given a set of types
Args...
, if
std::
declval
<
Args
>
(
)
...
meet the requirements for arguments to
ranges::iter_move
above,
__iter_move_fn
models
- std:: invocable < __iter_move_fn, Args... > ,
- std:: invocable < const __iter_move_fn, Args... > ,
- std:: invocable < __iter_move_fn & , Args... > , and
-
std::
invocable
<
const
__iter_move_fn
&
, Args...
>
.
Otherwise, no function call operator of
__iter_move_fn
participates in overload resolution.
Example
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This section is incomplete
Reason: no example |
See also
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(C++20)
|
casts the result of dereferencing the adjusted underlying iterator to its associated rvalue reference type
(function) |
|
(C++20)
|
casts the result of dereferencing the underlying iterator to its associated rvalue reference type
(function) |