std::experimental::ranges:: value_type
|
Defined in header
<experimental/ranges/iterator>
|
||
|
template
<
class
I
>
struct value_type { } ; |
(1) | |
|
template
<
class
T
>
struct value_type < T * > ; |
(2) | |
|
template
<
class
I
>
requires
std::
is_array
<
I
>
::
value
|
(3) | |
|
template
<
class
T
>
struct value_type < const T > : value_type < std:: decay_t < T >> { } ; |
(4) | |
|
template
<
class
T
>
requires requires
{
typename
T
::
value_type
;
}
|
(5) | |
|
template
<
class
T
>
requires requires
{
typename
T
::
element_type
;
}
|
(6) | |
Computes the associated value type of the type
I
, if any. Users may specialize
value_type
for a program-defined type.
T
is an object type, provides a member type
type
equal to
std::
remove_cv_t
<
T
>
. Otherwise, there is no member
type
.
value_type
. If
T::value_type
is an object type, provides a member type
type
equal to
T::value_type
. Otherwise, there is no member
type
.
element_type
(e.g.,
std::shared_ptr
). If
T::element_type
is an object type, provides a member type
type
equal to
std::
remove_cv_t
<
typename
T
::
element_type
>
. Otherwise, there is no member
type
.
Helper alias template
|
template
<
class
T
>
using value_type_t = typename ranges :: value_type < T > :: type ; |
(ranges TS) | |
Notes
If a type contains both a
value_type
member and a
element_type
member, then the specializations
(5)
and
(6)
are ambiguous.
value_type
is intended for use with
Readable
types such as iterators. It is not intended for use with ranges.
Example
|
This section is incomplete
Reason: no example |
See also
specifies that a type is readable by applying operator
*
(concept) |
|
|
compatibility traits class that collects an iterator’s associated types
(alias template) |