// Copyright (C) 2001-2003
// William E. Kempf
//
//  Distributed under the Boost Software License, Version 1.0. (See accompanying 
//  file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)

#include 
#include 
#include 

boost::mutex mutex;
int counter=0;

void change_count()
{
    boost::mutex::scoped_lock lock(mutex);
    int i = ++counter;
    std::cout