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// <iterator>
10
11// class istream_iterator
12
13// istream_iterator(); // constexpr since C++11
14// C++17 says: If is_trivially_default_constructible_v<T> is true, then this
15// constructor is a constexpr constructor.
16
17#include <cassert>
18#include <iterator>
19#include <string>
20#include <type_traits>
21
22#include "test_macros.h"
23
24struct S { S(); }; // not constexpr
25
26#if TEST_STD_VER > 14
27template <typename T, bool isTrivial = std::is_trivially_default_constructible_v<T>>
28struct test_trivial {
29void operator ()() const {
30 constexpr std::istream_iterator<T> it;
31 (void)it;
32 }
33};
34
35template <typename T>
36struct test_trivial<T, false> {
37void operator ()() const {}
38};
39#endif
40
41
42int main(int, char**) {
43 {
44 typedef std::istream_iterator<int> T;
45 T it;
46 assert(it == T());
47#if TEST_STD_VER >= 11
48 constexpr T it2;
49 (void)it2;
50#endif
51 }
52
53#if TEST_STD_VER > 14
54 test_trivial<int>()();
55 test_trivial<char>()();
56 test_trivial<double>()();
57 test_trivial<S>()();
58 test_trivial<std::string>()();
59#endif
60
61 return 0;
62}
63

source code of libcxx/test/std/iterators/stream.iterators/istream.iterator/istream.iterator.cons/default.pass.cpp