68 lines · cpp
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-exception6//7//===----------------------------------------------------------------------===//8 9// <functional>10 11// reference_wrapper12 13// template <ObjectType T> reference_wrapper<T> ref(reference_wrapper<T> t);14 15#include <functional>16#include <cassert>17 18#include "counting_predicates.h"19 20#include "test_macros.h"21 22bool is5 ( int i ) { return i == 5; }23 24template <typename T>25bool call_pred ( T pred ) { return pred(5); }26 27namespace adl {28 struct A {};29 void ref(A) {}30}31 32TEST_CONSTEXPR_CXX20 bool test()33{34 {35 int i = 0;36 std::reference_wrapper<int> r1 = std::ref(i);37 std::reference_wrapper<int> r2 = std::ref(r1);38 assert(&r2.get() == &i);39 }40 {41 adl::A a;42 std::reference_wrapper<adl::A> a1 = std::ref(a);43 std::reference_wrapper<adl::A> a2 = std::ref(a1);44 assert(&a2.get() == &a);45 }46 return true;47}48 49int main(int, char**)50{51 test();52#if TEST_STD_VER > 1753 static_assert(test());54#endif55 56 {57 unary_counting_predicate<bool(*)(int), int> cp(is5);58 assert(!cp(6));59 assert(cp.count() == 1);60 assert(call_pred(cp));61 assert(cp.count() == 1);62 assert(call_pred(std::ref(cp)));63 assert(cp.count() == 2);64 }65 66 return 0;67}68