std::ranges::view_interface::data - cppreference.com (original) (raw)

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. Same as (1), except that derived is static_cast<const D&>(*this).

[edit] Return value

The address denoted by the beginning iterator.

[edit] 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

[edit] Example

#include #include #include #include   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:

[edit] See also

| | obtains the pointer to the underlying array (function template) [edit] | | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | | obtains a pointer to the beginning of a contiguous range(customization point object)[edit] | | | obtains a pointer to the beginning of a read-only contiguous range(customization point object)[edit] | | | obtains a raw pointer from a pointer-like type (function template) [edit] |