The issue is that TF output is streamed to each node, and is buffered in the listener -- if you create the listener inside the callback, you have no history of tf data before creation -- which means you often can't find the lookup you desire.

-Mike

On Tue, Apr 5, 2011 at 6:10 PM, Jack O'Quin <jack.oquin@gmail.com> wrote:
On Tue, Apr 5, 2011 at 5:05 PM, Dejan Pangercic
<dejan.pangercic@gmail.com> wrote:
> Hi Sabrina,
>
>> you should instantiate the TransformListener outside the callback:
>>
>> tf::TransformListener *tf_listener;
> this is very interesting. But do you know why would it be necessary to
> have it outside the callback? Is there a documentation about this?

I believe the destructor for the listener will shut down the connection.

Many ROS interfaces use the RAII approach.
--
 joq
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