libstdc++-v3/testsuite/30_threads/call_once/call_once1.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) 2008-2020 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 <system_error>
  27 #include <testsuite_hooks.h>
  28
  29 std::once_flag value_flag;
  30 int value = 1;
  31
  32 void add_to_value(int i)
  33 {
  34   value += i;
  35 }
  36
  37 int main()
  38 {
  39   try
  40     {
  41       std::call_once(value_flag, add_to_value, 2);
  42       std::call_once(value_flag, add_to_value, 2);
  43     }
  44   catch (const std::system_error& e)
  45     {
  46       VERIFY( false );
  47     }
  48   catch (...)
  49     {
  50       VERIFY( false );
  51     }
  52
  53   VERIFY( value == 3 );
  54
  55   return 0;
  56 }