48 lines
978 B
C++
48 lines
978 B
C++
// Copyright (C) 2001-2003
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// William E. Kempf
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//
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// Distributed under the Boost Software License, Version 1.0. (See accompanying
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// file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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#include <boost/thread/mutex.hpp>
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#include <boost/thread/thread.hpp>
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#include <iostream>
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boost::mutex io_mutex; // The iostreams are not guaranteed to be thread-safe!
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class counter
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{
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public:
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counter() : count(0) { }
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int increment() {
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boost::unique_lock<boost::mutex> scoped_lock(mutex);
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return ++count;
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}
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private:
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boost::mutex mutex;
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int count;
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};
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counter c;
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void change_count()
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{
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int i = c.increment();
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boost::unique_lock<boost::mutex> scoped_lock(io_mutex);
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std::cout << "count == " << i << std::endl;
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}
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int main(int, char*[])
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{
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const int num_threads = 4;
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boost::thread_group thrds;
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for (int i=0; i < num_threads; ++i)
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thrds.create_thread(&change_count);
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thrds.join_all();
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return 0;
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}
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