title: What is the difference between var, cvar and ivar in python's sphinx?
body: <p>I was reading through the sphinx documentation pages and ironically found that the documentation on the difference between var, ivar, and cvar very lacking.  I was wondering if someone could explain the difference between each of the different name spaces in inline code.</p>
  
  <p>Example:</p>
  
  <pre><code>class foo(object):
      """
        :var str first:
        :ivar str last:
        :cvar str middle:
      """
  </code></pre>
  
  <p>How are each of these sphinx tags different from each other and how do I know which one is the correct one to use correctly as designed?</p>