title: Multithread share 2 variable problem with nonlock
body: <p>I have a question about multithread share variable problem.
  the two variable is like:</p>
  <pre><code>{
      void* a;
      uint64_t b;
  }
  </code></pre>
  <p>only one thread can modify the two variable, other thread will frequently read these two variable.
  I want to change a and b at one time, other thread will see the change together(see new value a and new value b).
  Because many thread will frequently read these two variables, so I don't want to add lock, I want to ask if there is a method to combine change a and b operation, make it like a atomic operation? like use memory fence, will it work? Thank you!</p>