c++ - 使用或不使用 boost::bind() 创建一个 boost::thread

Question

有些人似乎使用 boost::bind() 函数启动 boost::threads，例如在以下问题的公认答案中:

Using boost thread and a non-static class function

而其他人根本不使用它，例如在这个问题中获得最多赞成票的答案:

Best way to start a thread as a member of a C++ class?

那么，如果存在差异，那有什么区别呢？

Answer 1

从下面编译并给出预期输出的代码可以看出，boost::bind 对于将 boost::thread 与自由函数、成员函数和静态成员函数一起使用是完全不必要的:

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

void FreeFunction()
{
  std::cout << "hello from free function" << std::endl;
}

struct SomeClass
{
  void MemberFunction()
  {
    std::cout << "hello from member function" << std::endl;
  }

  static void StaticFunction()
  {
    std::cout << "hello from static member function" << std::endl;
  }
};

int main()
{
  SomeClass someClass;

  // this free function will be used internally as is
  boost::thread t1(&FreeFunction);
  t1.join();

  // this static member function will be used internally as is
  boost::thread t2(&SomeClass::StaticFunction);
  t2.join();

  // boost::bind will be called on this member function internally
  boost::thread t3(&SomeClass::MemberFunction, someClass);
  t3.join();
}

输出:

hello from free function
hello from static member function
hello from member function

构造函数中的内部绑定(bind)为您完成所有工作。

刚刚添加了一些关于每种函数类型会发生什么的额外注释。 (希望我已经正确阅读了源代码!)据我所知，在外部使用 boost::bind 不会导致它也加倍并在内部被调用，因为它将按原样传递。