libcxx/test/std/thread/thread.semaphore/try_acquire.pass.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-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // UNSUPPORTED: no-threads
  10 // UNSUPPORTED: c++03, c++11, c++14, c++17
  11
  12 // XFAIL: availability-synchronization_library-missing
  13
  14 // <semaphore>
  15
  16 #include <cassert>
  17 #include <semaphore>
  18 #include <thread>
  19
  20 #include "make_test_thread.h"
  21 #include "test_macros.h"
  22
  23 int main(int, char**)
  24 {
  25   std::counting_semaphore<> s(1);
  26
  27   assert(s.try_acquire());
  28   assert(!s.try_acquire());
  29   s.release();
  30   assert(s.try_acquire());
  31   assert(!s.try_acquire());
  32   s.release(2);
  33   std::thread t = support::make_test_thread([&](){
  34     assert(s.try_acquire());
  35   });
  36   t.join();
  37   assert(s.try_acquire());
  38   assert(!s.try_acquire());
  39
  40   return 0;
  41 }