| //===----------------------------------------------------------------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| // UNSUPPORTED: c++98, c++03 |
| |
| // <stack> |
| |
| // template <class... Args> decltype(auto) emplace(Args&&... args); |
| // return type is 'decltype(auto)' in C++17; 'void' before |
| // whatever the return type of the underlying container's emplace_back() returns. |
| |
| #include <stack> |
| #include <cassert> |
| #include <vector> |
| |
| #include "test_macros.h" |
| |
| #include "../../../Emplaceable.h" |
| |
| template <typename Stack> |
| void test_return_type() { |
| typedef typename Stack::container_type Container; |
| typedef typename Container::value_type value_type; |
| typedef decltype(std::declval<Stack>().emplace(std::declval<value_type &>())) stack_return_type; |
| |
| #if TEST_STD_VER > 14 |
| typedef decltype(std::declval<Container>().emplace_back(std::declval<value_type>())) container_return_type; |
| static_assert(std::is_same<stack_return_type, container_return_type>::value, ""); |
| #else |
| static_assert(std::is_same<stack_return_type, void>::value, ""); |
| #endif |
| } |
| |
| int main(int, char**) |
| { |
| test_return_type<std::stack<int> > (); |
| test_return_type<std::stack<int, std::vector<int> > > (); |
| |
| std::stack<Emplaceable> q; |
| #if TEST_STD_VER > 14 |
| typedef Emplaceable T; |
| T& r1 = q.emplace(1, 2.5); |
| assert(&r1 == &q.top()); |
| T& r2 = q.emplace(2, 3.5); |
| assert(&r2 == &q.top()); |
| T& r3 = q.emplace(3, 4.5); |
| assert(&r3 == &q.top()); |
| #else |
| q.emplace(1, 2.5); |
| q.emplace(2, 3.5); |
| q.emplace(3, 4.5); |
| #endif |
| assert(q.size() == 3); |
| assert(q.top() == Emplaceable(3, 4.5)); |
| |
| return 0; |
| } |