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