std::ranges::concat_view<Views...>::begin
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std::ranges::concat_view
concat_view::begin
constexpr /*iterator*/<false> begin()
requires (!(/*simple-view*/<Views> && ...));
(1)
(since C++26)
requires (!(/*simple-view*/<Views> && ...));
constexpr /*iterator*/<true> begin() const
(2)
(since C++26)
requires (ranges::range <const Views> && ...) &&
Returns an iterator to the beginning of the concat_view.
1) Equivalent to
it.template
return it;.
iterator <false> it(this, std::in_place_index <0>, ranges::begin (std::get<0>(views_ )));it.template
satisfy <0>();return it;.
2) Equivalent to
it.template
return it;.
iterator <true> it(this, std::in_place_index <0>, ranges::begin (std::get<0>(views_ )));it.template
satisfy <0>();return it;.
[edit] Return value
As specified above.
[edit] Example
The preliminary version can be checked out on Compiler Explorer.
Run this code
#include <ranges> #include <string_view> using namespace std::literals; int main() { static constexpr auto c = {"🐱", "🐶"}; static constexpr auto a = {"🤡"sv}; static constexpr auto t = {"💚"sv}; static constexpr auto cat{std::views::concat (c, a, t)}; static_assert(*cat.begin() == "\U0001F431" and cat.begin()[1] == "🐶" and *(cat.begin() + 2) == "\N{CLOWN FACE}"); }