title: python : how to know max size of a queue
body: <p>Size of a queue can be known by using <code>qsize()</code> </p>
  
  <ul>
  <li>How do we know the max size of a queue? Or in other way, when the condition <code>queue.full()</code> will return <code>True</code>?</li>
  <li><p>Why is the result for <code>q.put(i)</code> always resulting in <code>None</code> whereas <code>q.get(i)</code> is resulting in corresponding value?</p>
  
  <pre><code>from queue import Queue
  q = Queue()
  
  print("------Queue info when putting -----")
  
  for i in range(5):
     print("---Loop---- :",i) 
     print("queue empty : ", q.empty())
     print("put : ",q.put(i))
     print("queue size : ", q.qsize())
     print("queue full : ", q.full())
  
  print("------Queue info when getting -----")        
  
  for i in range(5): 
     print("---Loop---- :",i)
     print("get : ",q.get(i))
     print("task done : ",q.task_done())
     print("queue empty : ", q.empty())
  </code></pre></li>
  </ul>
  
  <hr>
  
  <h2>output is as follows :</h2>
  
  <pre><code>------Queue info when putting -----     
  ---Loop---- : 0    
  queue empty :  True    
  put :  None    
  queue size :  1    
  queue full :  False    
  (loop continues for 5 times)
  
  
  ------Queue info when getting -----
  ---Loop---- : 0    
  get :  0    
  task done :  None    
  queue empty :  False     
  (loop continues for 5 times)
  </code></pre>