libstdc++-v3/testsuite/30_threads/call_once/39909.cc

   1 // { dg-do run }
   2 // { dg-options "-pthread"  }
   3 // { dg-require-effective-target c++11 }
   4 // { dg-require-effective-target pthread }
   5 // { dg-require-gthreads "" }
   6
   7 // Copyright (C) 2009-2019 Free Software Foundation, Inc.
   8 //
   9 // This file is part of the GNU ISO C++ Library.  This library is free
  10 // software; you can redistribute it and/or modify it under the
  11 // terms of the GNU General Public License as published by the
  12 // Free Software Foundation; either version 3, or (at your option)
  13 // any later version.
  14
  15 // This library is distributed in the hope that it will be useful,
  16 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  17 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18 // GNU General Public License for more details.
  19
  20 // You should have received a copy of the GNU General Public License along
  21 // with this library; see the file COPYING3.  If not see
  22 // <http://www.gnu.org/licenses/>.
  23
  24
  25 #include <mutex>
  26 #include <thread>
  27 #include <testsuite_hooks.h>
  28
  29 std::once_flag flag;
  30 int value = 0;
  31
  32 struct Inc { void operator()() const { ++value; } };
  33
  34 struct Func
  35 {
  36    void operator()() const
  37    {
  38        Inc inc;
  39        for (int i = 0; i < 10000;  ++i)
  40            std::call_once(flag, inc);
  41    }
  42 };
  43
  44 int main()
  45 {
  46    Func f;
  47    std::thread t1(f);
  48    std::thread t2(f);
  49    std::thread t3(f);
  50    t1.join();
  51    t2.join();
  52    t3.join();
  53    VERIFY( value == 1 );
  54    return 0;
  55 }