1// Copyright (c) 2016-2024 Antony Polukhin
2//
3// Distributed under the Boost Software License, Version 1.0. (See accompanying
4// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
5
6#include <boost/pfr/ops.hpp>
7#include <boost/pfr/io.hpp>
8
9#include <iostream>
10#include <typeinfo>
11#include <tuple>
12#include <sstream>
13#include <set>
14#include <string>
15
16#include <boost/config.hpp>
17#include <boost/core/lightweight_test.hpp>
18
19#ifdef __clang__
20# pragma clang diagnostic ignored "-Wmissing-braces"
21#endif
22
23union test_union {
24 int i;
25 float f;
26};
27
28constexpr bool operator< (test_union l, test_union r) noexcept { return l.i < r.i; }
29constexpr bool operator<=(test_union l, test_union r) noexcept { return l.i <= r.i; }
30constexpr bool operator> (test_union l, test_union r) noexcept { return l.i > r.i; }
31constexpr bool operator>=(test_union l, test_union r) noexcept { return l.i >= r.i; }
32constexpr bool operator==(test_union l, test_union r) noexcept { return l.i == r.i; }
33constexpr bool operator!=(test_union l, test_union r) noexcept { return l.i != r.i; }
34
35
36template <class T>
37void test_constexpr_comparable() {
38 using namespace boost::pfr;
39 constexpr T s1 {110, 1, true, 6,17,8,9,10,11};
40 constexpr T s2 = s1;
41 constexpr T s3 {110, 1, true, 6,17,8,9,10,11111};
42 static_assert(eq(s1, s2), "");
43 static_assert(le(s1, s2), "");
44 static_assert(ge(s1, s2), "");
45 static_assert(!ne(s1, s2), "");
46 static_assert(!eq(s1, s3), "");
47 static_assert(ne(s1, s3), "");
48 static_assert(lt(s1, s3), "");
49 static_assert(gt(s3, s2), "");
50 static_assert(le(s1, s3), "");
51 static_assert(ge(s3, s2), "");
52}
53
54namespace foo {
55struct comparable_struct {
56 int i; short s; bool bl; int a,b,c,d,e,f;
57};
58}
59
60int main() {
61 // MSVC fails to use strucutred bindings in constexpr:
62 //
63 // error C2131: expression did not evaluate to a constant
64 // pfr/detail/functional.hpp(21): note: failure was caused by a read of a variable outside its lifetime
65#if !defined(_MSC_VER) || (_MSC_VER >= 1927) || !BOOST_PFR_USE_CPP17
66 test_constexpr_comparable<foo::comparable_struct>();
67
68 struct local_comparable_struct {
69 int i; short s; bool bl; int a,b,c,d,e,f;
70 };
71 test_constexpr_comparable<local_comparable_struct>();
72
73 struct local_comparable_struct_with_union {
74 int i; short s; bool bl; int a,b,c,d,e; test_union u;
75 };
76 test_constexpr_comparable<local_comparable_struct>();
77#endif
78 return boost::report_errors();
79}
80
81
82

source code of boost/libs/pfr/test/core/run/constexpr_ops.cpp