boost::thread and std::unique_ptr

Is it somehow possible to pass an std::unique_ptr as a parameter to a boost::thread constructor? If not, what is the best workaround?

A small example:

// errors: g++ uniqueptr_thread.cpp -std=c++0x

#include <iostream>
#include <memory>
#include <boost/thread.hpp>

class TestThread{
public:
  void operator()(std::unique_ptr<int> val){
    std::cout << "parameter: " << val << std::endl;
  }

};

int main(int argc, char* argv[]){

  std::unique_ptr<int> ptr(new int(5));

  boost::thread th( new TestThread(), std::move(ptr))开发者_Go百科;

}

This compiles and runs for me:

#include <iostream>
#include <memory>
#include <thread>

class TestThread{
public:
  void operator()(std::unique_ptr<int> val){
    std::cout << "parameter: " << *val << std::endl;
  }
};

int main()
{

  std::unique_ptr<int> ptr(new int(5));

  std::thread th( TestThread(), std::move(ptr));
  th.join();

}

But it has to be in C++0x mode. I don't know if the boost move emulation is good enough to do this or not.

A std::unique_ptr is, as the name suggests, unique. There can be only one!

Now, if your thread function takes a std::unique_ptr&&, and you use std::move to move the parameter in the thread function, then you can pass the std::unique_ptr. But then your copy will be empty, since you moved it to the other thread.

If std::move does not work, then your compiler or standard library may have bugs in it. I imagine that transferring ownership across threads like this isn't a common occurrence. And C++11 is still fairly new.

Are you sure your problem is with the unique_ptr? Why does your example use new to create your functor? That line should just read:

boost::thread th(TestThread(), std::move(ptr));