parameters: (topic, blocking=False)
return_statement: return None, None, None
docstring: Get the topic type.
  
      :param topic: topic name, ``str``
      :param blocking: (default False) block until topic becomes available, ``bool``
      
      :returns: topic type, real topic name and fn to evaluate the message instance
        if the topic points to a field within a topic, e.g. /rosout/msg. fn is None otherwise. ``(str, str, fn)``
      :raises: :exc:`ROSTopicException` If master cannot be contacted
docstring_summary: Get the topic type.
docstring_tokens: Get the topic type .
function: def get_topic_type(topic, blocking=False):
      """
      Get the topic type.
  
      :param topic: topic name, ``str``
      :param blocking: (default False) block until topic becomes available, ``bool``
      
      :returns: topic type, real topic name and fn to evaluate the message instance
        if the topic points to a field within a topic, e.g. /rosout/msg. fn is None otherwise. ``(str, str, fn)``
      :raises: :exc:`ROSTopicException` If master cannot be contacted
      """
      topic_type, real_topic, msg_eval = _get_topic_type(topic)
      if topic_type:
          return topic_type, real_topic, msg_eval
      elif blocking:
          sys.stderr.write("WARNING: topic [%s] does not appear to be published yet\n"%topic)
          while not rospy.is_shutdown():
              topic_type, real_topic, msg_eval = _get_topic_type(topic)
              if topic_type:
                  return topic_type, real_topic, msg_eval
              else:
                  _sleep(0.1)
      return None, None, None
function_tokens: def get_topic_type ( topic , blocking = False ) : topic_type , real_topic , msg_eval = _get_topic_type ( topic ) if topic_type : return topic_type , real_topic , msg_eval elif blocking : sys . stderr . write ( "WARNING: topic [%s] does not appear to be published yet\n" % topic ) while not rospy . is_shutdown ( ) : topic_type , real_topic , msg_eval = _get_topic_type ( topic ) if topic_type : return topic_type , real_topic , msg_eval else : _sleep ( 0.1 ) return None , None , None