std::ranges::view_interface<D>:: data

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Ranges library
Range adaptors
constexpr auto data ( )
requires std:: contiguous_iterator < ranges:: iterator_t < D >> ;
(1) (since C++20)
constexpr auto data ( ) const

requires ranges:: range < const D > &&

std:: contiguous_iterator < ranges:: iterator_t < 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 ) referenced by the view of the derived type when the view is not empty.

1) Let derived be static_cast < D & > ( * this ) . Equivalent to return std:: to_address ( ranges:: begin ( derived ) ) ; .
2) Same as (1) , except that 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() :

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 :

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)
obtains a pointer to the beginning of a contiguous range
(customization point object)
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)