title: Get absolute path with boost::filesystem::path
body: <p>My current working directory is located at <code>/home/myuser/program</code>, I created a <code>boost::filesystem::path</code> object pointing to it. I appended <code>/../somedir</code> so it becomes <code>/home/myuser/program/../somedir</code>. But I need to get its resolved absolute path, which would be <code>/home/myuser/somedir</code>.</p>
  
  <p>I have been trying for long time and I do not find any method in <a href="http://www.boost.org/doc/libs/1_51_0/libs/filesystem/doc/reference.html" rel="noreferrer">their reference</a> to do this. There is a method called <code>make_absolute</code>, which seems to be supposed to do what I expect, but I have to give it a “root” path argument. Which should it be? do I really need to do this to get the real absolute path? Is there any other way?</p>