title: Python Multiprocessing using Queue to write to same file
body: <p>I know there are many post on Stack Exchange related to writing results from multiprocessing to single file and I have developed my code after reading only those posts. What I am trying to achieve is that run 'RevMapCoord' function in parallel and write its result in one single file using multiprocess.queue. But I am having problem while queuing my job. My Code:</p>
  
  <pre><code>def RevMapCoord(list):
      "Read a file, Find String and Do something"
  
  def feed(queue, parlist):
      for par in parlist:
          print ('Echo from Feeder: %s' % (par))
          queue.put(par)
      print ('**Feeder finished queing**')
  
  def calc(queueIn, queueOut):
       print ('Worker function started')
       while True:
           try:
               par = queueIn.get(block = False)
               res = RevMapCoord(final_res)
               queueOut.put((par,res))
           except:
               break
  
  def write(queue, fname):
      fhandle = open(fname, "w")
      while True:
           try:
              par, res = queue.get(block = False)
              print &gt;&gt;fhandle, par, res
           except:
              break
      fhandle.close()
  
  
  feedProc = Process(target = feed , args = (workerQueue, final_res))
  calcProc = [Process(target = calc , args = (workerQueue, writerQueue)) for i in range(nproc)]
  writProc = Process(target = write, args = (writerQueue, sco_inp_extend_geno))
  
  feedProc.start()
  print ('Feeder is joining')
  feedProc.join ()
  for p in calcProc:
      p.start()
  for p in calcProc:
      p.join()
  writProc.start()
  writProc.join ()
  </code></pre>
  
  <p>When I run this code script stucks at "feedProc.start()" step. The last few output lines from screen shows print statement from the end of "feedProc.start()":</p>
  
  <pre><code>Echo from Feeder: &gt;AK779,AT61680,50948-50968,50959,6,0.406808,Ashley,Dayne
  Echo from Feeder: &gt;AK832,AT30210,1091-1111,1102,7,0.178616,John,Caine
  **Feeder finished queing**
  </code></pre>
  
  <p>But hangs before executing next line "feedProc.join ()". Code gives no error and keep on running but doing nothing(hangs). Please tell me what mistake I am making.</p>