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// Copyright (C) 2001-2003
// William E. Kempf
//
// Permission to use, copy, modify, distribute and sell this software
// and its documentation for any purpose is hereby granted without fee,
// provided that the above copyright notice appear in all copies and
// that both that copyright notice and this permission notice appear
// in supporting documentation. William E. Kempf makes no representations
// about the suitability of this software for any purpose.
// It is provided "as is" without express or implied warranty.
#include <boost/thread/recursive_mutex.hpp>
#include <boost/thread/thread.hpp>
#include <iostream>
class counter
{
public:
counter() : count(0) { }
int add(int val) {
boost::recursive_mutex::scoped_lock scoped_lock(mutex);
count += val;
return count;
}
int increment() {
boost::recursive_mutex::scoped_lock scoped_lock(mutex);
return add(1);
}
private:
boost::recursive_mutex mutex;
int count;
};
counter c;
void change_count()
{
std::cout << "count == " << c.increment() << std::endl;
}
int main(int, char*[])
{
const int num_threads=4;
boost::thread_group threads;
for (int i=0; i < num_threads; ++i)
threads.create_thread(&change_count);
threads.join_all();
return 0;
}
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