[ros-users] error: cannot load message class. Are you messages built?

[Ugo Cupcic]

 Is it ok to use  "rosmake --pre-clean ardusim" to make sure everything
that needs to be deleted is deleted?

Cheers,

Ugo

On 12/08/10 17:57, Ken Conley wrote:
> You will need to delete src/ardusim/msg/*.py as well.
>
> I general, there are a lot of problems copying compiled code trees
> from one platform to another. In this case, there is the
> incompatibilities of:
>
>  * Mac->Ubuntu
>  * cturtle -> boxturtle
>
> Both of those are likely to cause problems.
>
> HTH,
> Ken
>
> 2010/8/12 Gonçalo Cabrita <goncabrita at gmail.com>:
>> Thanks for your replies guys!
>>
>> I'm pretty sure ROS_PACKAGE_PATH is set correctly. Ardusim was already in the Eee PC, I just deleted it and copied the new version from my computer. I deleted everything in the build folder and run rosmake ardusim. Everything went as usual. I also checked for the build msg line at the cmake file.
>>
>> I've tried to delete everything and leave only the code inside src and the .msg files inside msg hoping there could be something that came from cturtle that is not allowing it to run in boxturtle, but still after everything compiles fine rostopic echo is not running.
>>
>> I'll try recording some data with rosbag and write a small node to read the published topics. If the problem is just with rostopic echo I should be able to continue my work. On the other hand I must find out what's wrong or I wont be able to sleep tonight! :D
>>
>> Gonçalo Cabrita
>> ISR - University of Coimbra
>> Portugal
>>
>> On Aug 12, 2010, at 5:27 PM, Ken Conley wrote:
>>
>>> This message usually occurs when rostopic cannot load
>>> ardusim/src/ardusim/msg/_TPA.py, which it needs to deserialize the
>>> messages it echos. The rest of the tests with type/show/etc... don't
>>> need the .py file, which is why they don't error.  I would attempt to
>>> rebuild the ardusim package and check for errors. I would also make
>>> sure that ardusim is on your ROS_PACKAGE_PATH.
>>>
>>> - Ken
>>>
>>> 2010/8/12 Gonçalo Cabrita <goncabrita at gmail.com>:
>>>> Hi guys!
>>>>
>>>> I have made an ROS node for reading sensors connected to an arduino. Along with the node I created some ROS msgs for the sensors. I compiled and tested everything on my MacBook running Ubuntu 10.04 with cturtle, however, when I copy the node to the robots (Eee PC also with Ubuntu 10.04 with boxturtle) I run into some problems.
>>>>
>>>> Everything compiles fine, and the node runs just fine, however I cannot rostopic echo my custom msgs! It gives me this error:
>>>>
>>>> error: cannot load message class for [ardusim/TPA]. Are you messages built?
>>>>
>>>> The topics show up on rostopic list. I can run rostopic type and rosmsg show. I've also tried roswtf but everything seems fine.
>>>>
>>>> What am I missing here? Could it have something to do with having cturtle on one computer and boxturtle on the other? The node was created on the MacBook with boxturtle previous to the cturtle update.
>>>>
>>>> Thanks for the help,
>>>>
>>>> Gonçalo Cabrita
>>>> ISR - University of Coimbra
>>>> Portugal
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Ugo Cupcic         |  Shadow Robot Company | ugo at shadowrobot.com
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