libstdc++-v3/testsuite/30_threads/condition_variable/members/68519.cc

   1 // Copyright (C) 2017-2021 Free Software Foundation, Inc.
   2 //
   3 // This file is part of the GNU ISO C++ Library.  This library is free
   4 // software; you can redistribute it and/or modify it under the
   5 // terms of the GNU General Public License as published by the
   6 // Free Software Foundation; either version 3, or (at your option)
   7 // any later version.
   8
   9 // This library is distributed in the hope that it will be useful,
  10 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 // GNU General Public License for more details.
  13
  14 // You should have received a copy of the GNU General Public License along
  15 // with this library; see the file COPYING3.  If not see
  16 // <http://www.gnu.org/licenses/>.
  17
  18 // { dg-do run }
  19 // { dg-additional-options "-pthread" { target pthread } }
  20 // { dg-require-effective-target c++11 }
  21 // { dg-require-gthreads "" }
  22
  23 #include <condition_variable>
  24 #include <testsuite_hooks.h>
  25
  26 // PR libstdc++/68519
  27
  28 void
  29 test_wait_for()
  30 {
  31   std::mutex mx;
  32   std::condition_variable cv;
  33
  34   for (int i = 0; i < 3; ++i)
  35   {
  36     std::unique_lock<std::mutex> l(mx);
  37     auto start = std::chrono::system_clock::now();
  38     cv.wait_for(l, std::chrono::duration<float>(1), [] { return false; });
  39     auto t = std::chrono::system_clock::now();
  40     VERIFY( (t - start) >= std::chrono::seconds(1) );
  41   }
  42 }
  43
  44 // In order to ensure that the delta calculated in the arbitrary clock overload
  45 // of condition_variable::wait_until fits accurately in a float, but the result
  46 // of adding it to steady_clock with a float duration does not, this clock
  47 // needs to use a more recent epoch.
  48 struct recent_epoch_float_clock
  49 {
  50   using duration = std::chrono::duration<float>;
  51   using rep = duration::rep;
  52   using period = duration::period;
  53   using time_point
  54     = std::chrono::time_point<recent_epoch_float_clock, duration>;
  55   static constexpr bool is_steady = true;
  56
  57   static const std::chrono::steady_clock::time_point epoch;
  58
  59   static time_point now()
  60   {
  61     const auto steady = std::chrono::steady_clock::now();
  62     return time_point{steady - epoch};
  63   }
  64 };
  65
  66 const std::chrono::steady_clock::time_point recent_epoch_float_clock::epoch =
  67   std::chrono::steady_clock::now();
  68
  69 void
  70 test_wait_until()
  71 {
  72   using clock = recent_epoch_float_clock;
  73
  74   std::mutex mx;
  75   std::condition_variable cv;
  76
  77   for (int i = 0; i < 3; ++i)
  78   {
  79     std::unique_lock<std::mutex> l(mx);
  80     const auto start = clock::now();
  81     const auto wait_time = start + std::chrono::duration<float>{1.0};
  82
  83     // In theory we could get a spurious wakeup, but in practice we won't.
  84     const auto result = cv.wait_until(l, wait_time);
  85
  86     VERIFY( result == std::cv_status::timeout );
  87     const auto elapsed = clock::now() - start;
  88     VERIFY( elapsed >= std::chrono::seconds(1) );
  89   }
  90 }
  91
  92 int
  93 main()
  94 {
  95   test_wait_for();
  96   test_wait_until();
  97 }