// { dg-do run { target *-*-freebsd* *-*-netbsd* *-*-linux* *-*-solaris* *-*-cygwin *-*-darwin* alpha*-*-osf* mips-sgi-irix6* } }// { dg-options " -std=gnu++0x -pthread" { target *-*-freebsd* *-*-netbsd* *-*-linux* alpha*-*-osf* mips-sgi-irix6* } }// { dg-options " -std=gnu++0x -pthreads" { target *-*-solaris* } }// { dg-options " -std=gnu++0x " { target *-*-cygwin *-*-darwin* } }// { dg-require-cstdint "" }// { dg-require-gthreads "" }// Copyright (C) 2009 Free Software Foundation, Inc.//// This file is part of the GNU ISO C++ Library. This library is free// software; you can redistribute it and/or modify it under the// terms of the GNU General Public License as published by the// Free Software Foundation; either version 3, or (at your option)// any later version.// This library is distributed in the hope that it will be useful,// but WITHOUT ANY WARRANTY; without even the implied warranty of// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the// GNU General Public License for more details.// You should have received a copy of the GNU General Public License along// with this library; see the file COPYING3. If not see// <http://www.gnu.org/licenses/>.#include <mutex>#include <thread>#include <testsuite_hooks.h>std::once_flag flag;int value = 0;struct Inc { void operator()() const { ++value; } };struct Func{void operator()() const{Inc inc;for (int i = 0; i < 10000; ++i)std::call_once(flag, inc);}};int main(){Func f;std::thread t1(f);std::thread t2(f);std::thread t3(f);t1.join();t2.join();t3.join();VERIFY( value == 1 );return 0;}