title: Python: How to read stdout of subprocess in a nonblocking way
body: <p>I am trying to make a simple python script that starts a subprocess and monitors its standard output. Here is a snippet from the code:</p>
  
  <pre><code>process = subprocess.Popen([path_to_exe, os.path.join(temp_dir,temp_file)], stdout=subprocess.PIPE)
  while True:   
      output=process.stdout.readline()
      print "test"
  </code></pre>
  
  <p>The problem is that the script hangs on <code>output=process.stdout.readline()</code> and that the line <code>print "test"</code> only executes after the subprocess is terminated.</p>
  
  <p>Is there a way to read standard output and print it without having to wait for the subprocess to terminate?</p>
  
  <p>The subprocess which I am starting is a Windows binary for which I do not have the source code.</p>
  
  <p>I have found several similar questions, but the answers are only applicable on Linux or in case I have the source of the suprocess I am starting.</p>