title: how do you check your version of boost?
body: <p>I need to have my boost library in a version of 1.40. How do I check my version of the boost library?</p>
  
  <p>I am trying to compile the PCL library, like described in <a href="http://pointclouds.org/downloads/source.html" rel="noreferrer">http://pointclouds.org/downloads/source.html</a>.</p>