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[roscore] Following the tutorials ... unexpected output?

asked 2012-07-13 12:48:43 -0500

1morelearner gravatar image

updated 2014-04-20 14:09:23 -0500

ngrennan gravatar image

Hi guys,

Following the Tutorial #6.- "Understanding Topics Basics", at the first step (1.1.1.- roscore), quoting:

Let's start by making sure that we have roscore running, in a new terminal:

$ roscore

If you left roscore running from the last tutorial, you may get the error message:

roscore cannot run as another roscore/master is already running. 
Please kill other roscore/master processes before relaunching

However, if I let one "roscore" process running, and launch a new one in a different terminal Window, I get the following error:

ERROR: Unable to start XML-RPC server, port 11311 is already in use
Unhandled exception in thread started by <bound method of <rosgraph.xmlrpc.XmlRpcNode object at 0x8cd3e2c>>

And after the stacktrace:

socket.error: [Errno 98] Address already in use
ERROR: could not contact master [http://pfc-VirtualBox:11311/]
[master] killing on exit

So, my question is: Is this a kind of "bug" in the tutorial or may I worry about that error being threw instead of the suggested output @ tutorial?

Thanks in advance for your answer!

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Hi, bro I met the same problem with you , I want to know if the problem has been solved ? If solved, can you give me some help? Thank you very much!

LittleFishLove gravatar image LittleFishLove  ( 2018-02-02 00:16:55 -0500 )edit

This problem was solved; see the answer below. If that solution doesn't work for you, you should ask a new question. Asking other users to contact you directly is against the community spirit of the forum, so I've removed your email address from your comment.

ahendrix gravatar image ahendrix  ( 2018-02-02 00:36:51 -0500 )edit

1 Answer

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answered 2012-07-13 13:12:46 -0500

Mac gravatar image

Almost certainly a bug in the tutorial. In general, you can't have more than one roscore running; a good rule of thumb is to fire one up, minimize that window, and forget about it.

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Asked: 2012-07-13 12:48:43 -0500

Seen: 1,141 times

Last updated: Jul 13 '12