libstdc++-v3/testsuite/30_threads/lock/4.cc

   1 // { dg-do run }
   2 // { dg-additional-options "-pthread" { target pthread } }
   3 // { dg-require-effective-target c++11 }
   4 // { dg-require-gthreads "" }
   5
   6 // Copyright (C) 2010-2021 Free Software Foundation, Inc.
   7 //
   8 // This file is part of the GNU ISO C++ Library.  This library is free
   9 // software; you can redistribute it and/or modify it under the
  10 // terms of the GNU General Public License as published by the
  11 // Free Software Foundation; either version 3, or (at your option)
  12 // any later version.
  13
  14 // This library is distributed in the hope that it will be useful,
  15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  17 // GNU General Public License for more details.
  18
  19 // You should have received a copy of the GNU General Public License along
  20 // with this library; see the file COPYING3.  If not see
  21 // <http://www.gnu.org/licenses/>.
  22
  23
  24 #include <mutex>
  25 #include <testsuite_hooks.h>
  26
  27 struct unreliable_lock
  28 {
  29   std::mutex m;
  30   std::unique_lock<std::mutex> l;
  31
  32   static int count;
  33   static int throw_on;
  34   static int lock_on;
  35
  36   unreliable_lock() : l(m, std::defer_lock) { }
  37
  38   ~unreliable_lock()
  39   {
  40     VERIFY( !l.owns_lock() );
  41   }
  42
  43   void lock()
  44   {
  45     if (count == throw_on)
  46       throw throw_on;
  47     ++count;
  48     l.lock();
  49   }
  50   bool try_lock()
  51   {
  52     if (count == throw_on)
  53       throw throw_on;
  54     std::unique_lock<std::mutex> l2(m, std::defer_lock);
  55     if (count == lock_on)
  56       l2.lock();
  57     ++count;
  58     return l.try_lock();
  59   }
  60
  61   void unlock()
  62   {
  63     VERIFY( l.owns_lock() );
  64     l.unlock();
  65   }
  66
  67 };
  68
  69 int unreliable_lock::count = 0;
  70 int unreliable_lock::throw_on = -1;
  71 int unreliable_lock::lock_on = -1;
  72
  73 void test01()
  74 {
  75   unreliable_lock l1, l2, l3;
  76
  77   try
  78     {
  79       unreliable_lock::count = 0;
  80       std::lock(l1, l2, l3);
  81       VERIFY( unreliable_lock::count == 3 );
  82       l1.unlock();
  83       l2.unlock();
  84       l3.unlock();
  85     }
  86   catch (...)
  87     {
  88       VERIFY( false );
  89     }
  90 }
  91
  92 void test02()
  93 {
  94   // test behaviour when a lock is already held
  95   try
  96     {
  97       unreliable_lock::lock_on = 1;
  98       while (unreliable_lock::lock_on < 3)
  99       {
 100         unreliable_lock::count = 0;
 101         unreliable_lock l1, l2, l3;
 102         std::lock(l1, l2, l3);
 103         VERIFY( unreliable_lock::count > 3 );
 104         l1.unlock();
 105         l2.unlock();
 106         l3.unlock();
 107         ++unreliable_lock::lock_on;
 108       }
 109     }
 110   catch (...)
 111     {
 112       VERIFY( false );
 113     }
 114 }
 115
 116 void test03()
 117 {
 118   // test behaviour when an exception is thrown
 119   unreliable_lock::throw_on = 0;
 120   while (unreliable_lock::throw_on < 3)
 121   {
 122     unreliable_lock::count = 0;
 123     unreliable_lock l1, l2, l3;
 124     bool test = false;
 125     try
 126       {
 127         std::lock(l1, l2, l3);
 128       }
 129     catch (...)
 130       {
 131         test = true;
 132       }
 133     VERIFY( test );
 134     ++unreliable_lock::throw_on;
 135   }
 136 }
 137
 138 int main()
 139 {
 140   test01();
 141   test02();
 142   test03();
 143   return 0;
 144 }