实施升压自旋锁。示例所需 [英] Implementing a spinlock in Boost. Example Needed

问题描述

我想知道是否提升有协助执行自旋锁的库。我知道升压支持互斥体，但我无法找到任何显示例子或描述boost.Any自旋锁的例子说明了如何使用boost（preferably）来实现自旋锁将AP preciated。（C ++ 98 ）

I wanted to know if boost has any libraries that assist in implementing spin locks. I know boost supports mutexes but I could not find any examples that show or describe spinlocks in boost.Any examples showing how to implement a spin lock using boost(preferably) would be appreciated.(C++98)

推荐答案

使用的 Boost.Atomic ：

#include <boost/atomic.hpp>

class SpinLock
{
    boost::atomic_flag flag; // it differs from std::atomic_flag a bit -
                             // does not require ATOMIC_FLAG_INIT
public:
    void lock()
    {
        while( flag.test_and_set(boost::memory_order_acquire) )
            ;
    }
    bool try_lock()
    {
        return !flag.test_and_set(boost::memory_order_acquire);
    }
    void unlock()
    {
        flag.clear(boost::memory_order_release);
    }
};

上Coliru 现场演示

#include <boost/range/algorithm.hpp>
#include <boost/atomic.hpp>
#include <boost/thread.hpp>
#include <iostream>
#include <vector>

class SpinLock
{
    boost::atomic_flag flag;
public:
    void lock()
    {
        while( flag.test_and_set(boost::memory_order_acquire) )
            ;
    }
    bool try_lock()
    {
        return !flag.test_and_set(boost::memory_order_acquire);
    }
    void unlock()
    {
        flag.clear(boost::memory_order_release);
    }
};

int main()
{
    using namespace std; using namespace boost;

    SpinLock lock;
    vector<thread> v;
    for(auto i = 0; i!=4; ++i)
        v.emplace_back([&lock, i]
        {
            for(auto j = 0; j!=16; ++j)
            {
                this_thread::yield();
                lock_guard<SpinLock> x(lock);
                cout << "Hello from " << i << flush << "\tj = " << j << endl;
            }
        });
    for(auto &t: v)
        t.join();
}

输出是：

Hello from 0    j = 0
Hello from 1    j = 0
Hello from 3    j = 0
Hello from 2    j = 0
Hello from 3    j = 1
Hello from 1    j = 1
Hello from 3    j = 2
Hello from 2    j = 1
Hello from 1    j = 2
Hello from 2    j = 2
Hello from 1    j = 3
Hello from 2    j = 3
Hello from 1    j = 4
Hello from 3    j = 3
Hello from 2    j = 4
Hello from 1    j = 5
Hello from 2    j = 5
Hello from 1    j = 6
Hello from 2    j = 6
Hello from 1    j = 7
Hello from 2    j = 7
Hello from 1    j = 8
Hello from 2    j = 8
Hello from 3    j = 4
Hello from 2    j = 9
Hello from 3    j = 5
Hello from 1    j = 9
Hello from 2    j = 10
Hello from 1    j = 10
Hello from 2    j = 11
Hello from 3    j = 6
Hello from 1    j = 11
Hello from 2    j = 12
Hello from 3    j = 7
Hello from 1    j = 12
Hello from 2    j = 13
Hello from 3    j = 8
Hello from 2    j = 14
Hello from 3    j = 9
Hello from 1    j = 13
Hello from 2    j = 15
Hello from 1    j = 14
Hello from 3    j = 10
Hello from 1    j = 15
Hello from 3    j = 11
Hello from 3    j = 12
Hello from 3    j = 13
Hello from 3    j = 14
Hello from 3    j = 15
Hello from 0    j = 1
Hello from 0    j = 2
Hello from 0    j = 3
Hello from 0    j = 4
Hello from 0    j = 5
Hello from 0    j = 6
Hello from 0    j = 7
Hello from 0    j = 8
Hello from 0    j = 9
Hello from 0    j = 10
Hello from 0    j = 11
Hello from 0    j = 12
Hello from 0    j = 13
Hello from 0    j = 14
Hello from 0    j = 15

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