title: Python subprocess.call and subprocess.Popen giving me different outputs
body: <p>When using subprocess.call, the output is what is expected.</p>
  
  <pre><code>result = subprocess.call([securefx, '/NoPrompt', '/Q', '/RetryCount', retries, 
                '/RetryDelay', '1', '/Log', sfxLogFile, '/List', '/S', session])
  </code></pre>
  
  <p>Printing the result will output something like 
  -533428 or 0 </p>
  
  <p>But when I run </p>
  
  <pre><code>args = [securefx, '/NoPrompt', '/Q', '/RetryCount', retries, '/RetryDelay', '1', 
         '/Log', sfxLogFile, '/List', '/S', session]
  process = subprocess.Popen(args, stdout=subprocess.PIPE)
  result = process.communicate()[0]
  </code></pre>
  
  <p>and print the result, I get blank or otherwise stderr = "None".</p>
  
  <p>Why are they different? The reason I'm trying Popen even though call is working is because of this: <a href="https://stackoverflow.com/questions/6922129/python-subprocess-call-on-sfxcl-exe-not-working-from-windows-2003-task-scheduler">Python subprocess.call on sfxcl.exe not working from Windows 2003 Task Scheduler</a> &lt;- thought I'd give it a go...</p>