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// <tuple>
10
11// constexpr unspecified ignore;
12
13// UNSUPPORTED: c++03
14
15#include <cassert>
16#include <tuple>
17#include <type_traits>
18
19#include "test_macros.h"
20
21constexpr bool test_ignore_constexpr()
22{
23#if TEST_STD_VER > 11
24 { // Test that std::ignore provides constexpr converting assignment.
25 auto& res = (std::ignore = 42);
26 assert(&res == &std::ignore);
27 }
28 { // Test that std::ignore provides constexpr copy/move constructors
29 auto copy = std::ignore;
30 auto moved = std::move(copy);
31 ((void)moved);
32 }
33 { // Test that std::ignore provides constexpr copy/move assignment
34 auto copy = std::ignore;
35 copy = std::ignore;
36 auto moved = std::ignore;
37 moved = std::move(copy);
38 }
39#endif
40 return true;
41}
42
43int main(int, char**) {
44 {
45 constexpr auto& ignore_v = std::ignore;
46 ((void)ignore_v);
47 }
48 {
49 static_assert(test_ignore_constexpr(), "");
50 }
51 {
52 LIBCPP_STATIC_ASSERT(std::is_trivial<decltype(std::ignore)>::value, "");
53 }
54
55 return 0;
56}
57

source code of libcxx/test/std/utilities/tuple/tuple.general/ignore.pass.cpp