libcxx/test/std/thread/thread.mutex/thread.mutex.requirements/thread.sharedtimedmutex.requirements/thread.sharedtimedmutex.class/try_lock.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
  11
  12 // ALLOW_RETRIES: 2
  13
  14 // <shared_mutex>
  15
  16 // class shared_timed_mutex;
  17
  18 // bool try_lock();
  19
  20 #include <cassert>
  21 #include <chrono>
  22 #include <cstdlib>
  23 #include <shared_mutex>
  24 #include <thread>
  25
  26 #include "make_test_thread.h"
  27 #include "test_macros.h"
  28
  29 std::shared_timed_mutex m;
  30
  31 typedef std::chrono::system_clock Clock;
  32 typedef Clock::time_point time_point;
  33 typedef Clock::duration duration;
  34 typedef std::chrono::milliseconds ms;
  35 typedef std::chrono::nanoseconds ns;
  36
  37 void f()
  38 {
  39     time_point t0 = Clock::now();
  40     assert(!m.try_lock());
  41     assert(!m.try_lock());
  42     assert(!m.try_lock());
  43     while(!m.try_lock())
  44         ;
  45     time_point t1 = Clock::now();
  46     m.unlock();
  47     ns d = t1 - t0 - ms(250);
  48     assert(d < ms(200));  // within 200ms
  49 }
  50
  51 int main(int, char**)
  52 {
  53     m.lock();
  54     std::thread t = support::make_test_thread(f);
  55     std::this_thread::sleep_for(ms(250));
  56     m.unlock();
  57     t.join();
  58
  59   return 0;
  60 }