我可以拥有一个无锁的lambda队列吗? [英] Can I have a boost lock-free queue of lambdas?

问题描述

我正在尝试实现一个跨多个线程工作的消息传递系统. boost::lockfree::queue似乎是一个不错的选择，但是我在创建std::function或boost::function类型的队列时遇到了麻烦，因为它们显然没有琐碎的分配和析构函数，这是boost::lockfree::queue的要求

I'm trying to implement a messaging system that will work across multiple threads. boost::lockfree::queue seemed like a good direction to go in, unfortunately I'm having trouble creating a queue of either std::function or boost::function types as apparently they don't have trivial assignment and destructor's which is a requirement of boost::lockfree::queue.

我的以下代码:

#include <cassert>
//#include <functional>
#include <iostream>

#include <boost/function.hpp>
#include <boost/lockfree/queue.hpp>

int main()
{
  boost::lockfree::queue<boost::function<void(int)>> queue;
  assert(queue.is_lock_free());

  for(int j = 0; j < 50; ++j) {
    queue.push([] (int i) { std::cout << i << std::endl; });
  }

  int i = 0;
  boost::function<void(int)> functor;
  while (queue.pop(functor)) {
    functor(i++);
  }
}

产生以下输出:

In file included from /usr/include/boost/integer.hpp:23:0,
                 from /usr/include/boost/function/function_base.hpp:21,
                 from /usr/include/boost/function/detail/prologue.hpp:17,
                 from /usr/include/boost/function.hpp:24,
                 from lockfree.cpp:5:
/usr/include/boost/lockfree/queue.hpp: In instantiation of ‘class boost::lockfree::queue<boost::function<void(int)> >’:
lockfree.cpp:10:54:   required from here
/usr/include/boost/lockfree/queue.hpp:81:5: error: static assertion failed (boost::has_trivial_destructor<T>::value)
     BOOST_STATIC_ASSERT((boost::has_trivial_destructor<T>::value));
     ^
/usr/include/boost/lockfree/queue.hpp:85:5: error: static assertion failed (boost::has_trivial_assign<T>::value)
     BOOST_STATIC_ASSERT((boost::has_trivial_assign<T>::value));

有什么办法可以使这项工作成功吗?

Is there any way to make this work?

推荐答案

如果可以的话，您仍然可以将 stateless lambda与原始函数指针一起使用:

You could still use stateless lambdas with raw function pointers, if that's an option:

#include <cassert>
#include <functional>
#include <iostream>

#include <boost/function.hpp>
#include <boost/lockfree/queue.hpp>

int main() {
    //boost::lockfree::queue<boost::function<void(int)>> queue(50);
    boost::lockfree::queue<void (*)(int)> queue(50);
    assert(queue.is_lock_free());

    for (int j = 0; j < 50; ++j) {
        queue.push([](int i) { std::cout << i << std::endl; });
    }

    int i = 0;
    boost::function<void(int)> functor;
    while (queue.pop(functor)) {
        functor(i++);
    }
}

http://coliru.stacked-crooked.com/a/d57770e3be029760

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