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
11 
12 // <semaphore>
13 
14 #include <semaphore>
15 #include <thread>
16 
17 #include "test_macros.h"
18 
19 int main(int, char**)
20 {
21   std::counting_semaphore<> s(0);
22 
23   s.release();
24   s.acquire();
25 
26   std::thread t([&](){
27     s.acquire();
28   });
29   s.release(2);
30   t.join();
31   s.acquire();
32 
33   return 0;
34 }
35