std::ranges::view_interface<D>::data
constexpr
auto data(
)
requires std::contiguous_iterator < ranges::iterator_t <D>> ; |
(1) | (since C++20) |
constexpr
auto data(
)
const
requires ranges::range
<
const D>
&&
|
(2) | (since C++20) |
The default implementation of data()
member function obtains the address denoted by the beginning iterator via std::to_address, which is also the lowest address of the contiguous storage (implied by contiguous_iterator
derived
be
static_cast
<D&
>
(
*this)
. Equivalent to
return
std::to_address
(
ranges::begin
(derived)
)
;
derived
is
static_cast
<
const D&
>
(
*this)
Parameters
(none)
Return value
The address denoted by the beginning iterator.
Notes
Following derived types may use the default implementation of data()
:
- std::ranges::common_view
- std::ranges::drop_view
- std::ranges::drop_while_view
- std::ranges::ref_view
- std::ranges::subrange
- std::ranges::take_view
- std::ranges::take_while_view
Following types are derived from std::ranges::view_interface and do not declare their own data()
member function, but they cannot use the default implementation, because their iterator types never satisfy contiguous_iterator
- std::ranges::basic_istream_view
- std::ranges::elements_view
- std::ranges::filter_view
- std::ranges::iota_view
- std::ranges::join_view
- std::ranges::lazy_split_view
- std::ranges::reverse_view
- std::ranges::split_view
- std::ranges::transform_view
Example
#include <array> #include <iostream> #include <ranges> #include <string_view> int main() { constexpr std::string_view str { "Hello, C++20!" }; std::cout << (str | std::views::drop(7)).data() << '\n'; constexpr static std::array a { 1,2,3,4,5 }; constexpr auto v { a | std::views::take(3) }; static_assert( &a[0] == v.data() ); }
Output:
C++20!
See also
(C++17)
|
obtains the pointer to the underlying array (function template) |
(C++20)
|
obtains a pointer to the beginning of a contiguous range (customization point object) |
(C++20)
|
obtains a pointer to the beginning of a read-only contiguous range (customization point object) |
(C++20)
|
obtains a raw pointer from a pointer-like type (function template) |