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: no-localization
10// UNSUPPORTED: c++03, c++11, c++14, c++17
11
12// constexpr explicit basic_istream_view(basic_istream<CharT, Traits>& stream);
13
14#include <cassert>
15#include <ranges>
16#include <sstream>
17
18#include "test_macros.h"
19#include "utils.h"
20
21// test that the constructor is explicit
22static_assert(std::constructible_from<std::ranges::istream_view<int>, std::istream&>);
23static_assert(!std::convertible_to<std::istream&, std::ranges::istream_view<int>>);
24
25#ifndef TEST_HAS_NO_WIDE_CHARACTERS
26static_assert(std::constructible_from<std::ranges::wistream_view<int>, std::wistream&>);
27static_assert(!std::convertible_to<std::wistream&, std::ranges::wistream_view<int>>);
28#endif
29
30template <class CharT>
31void test() {
32 // test constructor init the stream pointer to the passed one
33 {
34 auto iss = make_string_stream<CharT>("123");
35 std::ranges::basic_istream_view<int, CharT> isv{iss};
36 auto it = isv.begin();
37 assert(*it == 123);
38 }
39
40 // LWG 3568. basic_istream_view needs to initialize value_
41 {
42 auto iss = make_string_stream<CharT>("123");
43 std::ranges::basic_istream_view<int, CharT> isv{iss};
44 using Iter = std::ranges::iterator_t<decltype(isv)>;
45 Iter iter{isv};
46 assert(*iter == 0);
47 }
48}
49
50int main(int, char**) {
51 test<char>();
52#ifndef TEST_HAS_NO_WIDE_CHARACTERS
53 test<wchar_t>();
54#endif
55
56 return 0;
57}
58

source code of libcxx/test/std/ranges/range.factories/range.istream.view/ctor.pass.cpp