1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9// UNSUPPORTED: c++03, c++11, c++14, c++17
10
11// take_view() requires default_initializable<V> = default;
12
13#include <cassert>
14#include <ranges>
15#include <type_traits>
16
17int buff[8] = {1, 2, 3, 4, 5, 6, 7, 8};
18
19struct DefaultConstructible : std::ranges::view_base {
20 constexpr DefaultConstructible() : begin_(buff), end_(buff + 8) { }
21 constexpr int const* begin() const { return begin_; }
22 constexpr int const* end() const { return end_; }
23private:
24 int const* begin_;
25 int const* end_;
26};
27
28struct NonDefaultConstructible : std::ranges::view_base {
29 NonDefaultConstructible() = delete;
30 int* begin() const;
31 int* end() const;
32};
33
34constexpr bool test() {
35 {
36 std::ranges::take_view<DefaultConstructible> tv;
37 assert(tv.begin() == buff);
38 assert(tv.size() == 0);
39 }
40
41 // Test SFINAE-friendliness
42 {
43 static_assert( std::is_default_constructible_v<std::ranges::take_view<DefaultConstructible>>);
44 static_assert(!std::is_default_constructible_v<std::ranges::take_view<NonDefaultConstructible>>);
45 }
46
47 return true;
48}
49
50int main(int, char**) {
51 test();
52 static_assert(test());
53
54 return 0;
55}
56

source code of libcxx/test/std/ranges/range.adaptors/range.take/ctor.default.pass.cpp