libstdc++-v3/testsuite/30_threads/call_once/call_once1.cc

   1 // { dg-do run { target c++11 } }
   2 // { dg-additional-options "-pthread" { target pthread } }
   3
   4 // Copyright (C) 2008-2024 Free Software Foundation, Inc.
   5 //
   6 // This file is part of the GNU ISO C++ Library.  This library is free
   7 // software; you can redistribute it and/or modify it under the
   8 // terms of the GNU General Public License as published by the
   9 // Free Software Foundation; either version 3, or (at your option)
  10 // any later version.
  11
  12 // This library is distributed in the hope that it will be useful,
  13 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15 // GNU General Public License for more details.
  16
  17 // You should have received a copy of the GNU General Public License along
  18 // with this library; see the file COPYING3.  If not see
  19 // <http://www.gnu.org/licenses/>.
  20
  21
  22 #include <mutex>
  23 #include <system_error>
  24 #include <testsuite_hooks.h>
  25
  26 std::once_flag value_flag;
  27 int value = 1;
  28
  29 void add_to_value(int i)
  30 {
  31   value += i;
  32 }
  33
  34 int main()
  35 {
  36   try
  37     {
  38       std::call_once(value_flag, add_to_value, 2);
  39       std::call_once(value_flag, add_to_value, 2);
  40     }
  41   catch (const std::system_error& e)
  42     {
  43       VERIFY( false );
  44     }
  45   catch (...)
  46     {
  47       VERIFY( false );
  48     }
  49
  50   VERIFY( value == 3 );
  51
  52   return 0;
  53 }