title: Check if the Main Thread is still alive from another thread
body: <p><strong>How can I check if the Main Thread is alive from another ( non-daemon, child ) thread?</strong></p>
  
  <p>The child thread is a non-daemon thread and I'd like to check if the Main thread is still running or not, and stop this non-daemon thread based on the result.</p>
  
  <p>( Making the thread daemon is not good for my situation because my thread writes to <em><code>stdout</code></em> which creates problems when the thread is set as a daemon)</p>
  
  <p>Using python 2.7</p>