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 // UNSUPPORTED: libcpp-has-no-threads
10 // UNSUPPORTED: c++98, c++03, c++11, c++14, c++17
11 // REQUIRES: verify-support
12 
13 // <future>
14 
15 // template <class F, class... Args>
16 //     future<typename result_of<F(Args...)>::type>
17 //     async(F&& f, Args&&... args);
18 
19 // template <class F, class... Args>
20 //     future<typename result_of<F(Args...)>::type>
21 //     async(launch policy, F&& f, Args&&... args);
22 
23 
24 #include <future>
25 #include <atomic>
26 #include <memory>
27 #include <cassert>
28 
29 #include "test_macros.h"
30 
31 int foo (int x) { return x; }
32 
33 int main(int, char**)
34 {
35     std::async(                    foo, 3); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
36     std::async(std::launch::async, foo, 3); // expected-warning {{ignoring return value of function declared with 'nodiscard' attribute}}
37 
38     return 0;
39 }
40