title: Boost::this_thread::get_id() without string operation
body: <p>i'm in a situation where i need to get boost::thread::id into a variable, but this variable is NOT a string, neither a string operation is allowed. is that possible?</p>
  
  <p>maybe something like</p>
  
  <p><code>char *tid = (casting something) boost::this_thread::get_id()</code></p>
  
  <p>this is c++ on unix system.
  the reason why avoiding using string operation is because it slows down the whole application speed. thanks before.</p>